COMPOSITIONS AND METHODS OF USE THEREOF CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. S.N.

61/739,272 filed December 19, 2012, U.S.S.N. 61/739,287 filed December 19, 2012, and U.S.S.N. 61/739,353 filed December 19, 2012, each of which is incorporated by reference in its entirety.

FIELD OF THE INVENTION

The field of the invention generally relates to B7-H4 specific antibodies and there use in methods of diagnosis and treatment of inflammatory and autoimmune diseases and disorders.

BACKGROUND OF THE INVENTION

Modulating immune responses is important in the treatment of many diseases and disorders. For example, it would be advantageous to enhance an immune response in patients suffering from cancer or infection.

Alternatively, it would be beneficial to inhibit or reduce an immune response in patients suffering from inflammatory conditions.

Chronic and persistent inflammation is a major cause for the pathogenesis and progression of systemic autoimmune diseases such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). RA is a highly inflammatory polyarthritis often leading to joint destruction, deformity and loss of function. Additive, symmetric swelling of peripheral joints is the hallmark of the disease. Extra-articular features and systemic symptoms can commonly occur and may antedate the onset of joint symptoms. Chronic pain, disability and excess mortality are unfortunate sequelae. During progression of RA, the synovial lining layer of the inflamed joints increases its thickness as a result of synovial hyperplasia and infiltration into synovial stroma by CD4+ T cells, B cells, CD8+ T cells, macrophages, dendritic cells and neutrophils (Feldmann, M. et al, Cell, 85:307-10 (1996); Moreland, L.W. et al, N Engl J Med, 337: 141-7 (1997)). In SLE, the production of autoantibodies results in the deposition of immune complex in many tissues and organs including glomeruli, skin, lungs and synovium, thereby generating rheumatic lesions with characteristic chronic inflammation and tissue damage.

Co-signaling molecules, including those with costimulatory and coinhibitory functions, are important for the induction of effective immune response and for the prevention of unwanted autoimmunity. It has been shown that signals through the B7-CD28 family are major regulators of this balance and play a pivotal role in the regulation of autoimmunity. Persistence of inflammatory responses in systemic autoimmune diseases implies either an impaired coinhibitory or enhanced costimulatory functions, leading to the loss of the balance. In this regard, it is particularly interesting that autoantibodies against B7-H1, a primary coinhibitory molecule after binding to its receptor PD- 1 , is found in a significant proportion of RA patients and the presence of the autoantibodies is implicated in the progression of RA symptoms.

B7-H4 is a more recent addition to the B7 family that is a negative regulator of T cell responses. Human and mouse B7-H4 share 87% amino acid identity suggesting an important evolutionarily conserved function. Human and mouse B7-H4 mRNAs are expressed broadly in both lymphoid (spleen and thymus) and nonlymphoid organs (including lung, liver, testis, ovary, placenta, skeletal muscle, pancreas, and small intestine).

Immunohistochemical (IHC) staining using B7-H4 deficient mice as negative controls shows that mouse B7-H4 is expressed by cells of epithelial origin, including pancreatic islet β cells (Wei, et al, J. Exp. Med.,

208(8): 1683-94 (2011)) and the lung epithelial lining (Hofmeyer, et al, J. Immunol, 189(6):3054-63 (2012)). B7-H4 expression has also been observed in tubule epithelial cells of diseased kidneys (Chen, Y., Kidney Int., 70(12):2092-9 (2006) Epub 2006 Oct 18.). B7-H4's expression on hematopoietic cells, however, remains controversial with conflicting reports in the literature. IHC staining shows that B7-H4 is also highly expressed in breast, renal, lung and ovarian tumors, and reverse transcriptase polymerase chain reaction (RT-PCR) analyses indicate that mouse B7-H4 also is highly expressed in a number of tumor cell lines, including prostate, lung, and colon carcinomas. B7-H4 is highly expressed by tumor associated macrophages (TAMs) and is present in tumor vasculature (Kryczek, et al., J. Immunol, 177(l):40-4 (2006), Kryczek, et al., J. Exp. Med., 203(4):871-81 (2006), Kryczek, et al, Cancer Res., 67(18):8900-5 (2007)). Regulatory T cells (Tregs) induce upregulation of B7-H4 on TAMs via IL-6 and IL-10; this is thought to be one of the mechanisms by which Tregs contribute to immune suppression. (Kryczek, J.I., J. Immunol, 177(l):40-44 (2006)).

The receptor for B7-H4 has not been identified. B7-H4 has been shown not to bind to known CD28 family members such as CD28, CTLA-4, ICOS, BTLA and PD-1 (Sica, et al, Immunity, 18:849-861 (2003)), and these are therefore not potential receptors for B7-H4. Functional studies using B7-H4 transfectants and B7-H4-Ig fusion proteins demonstrate that B7-H4 delivers a signal that inhibits TCR-mediated CD4 ⁺ and CD8 ⁺ T cell proliferation, cell-cycle progression and IL-2 production. B7-1

costimulation cannot overcome B7-H4-Ig-induced inhibition. In agreement with the in vitro activity, ectopic expression of B7-H4 promotes tissue tolerance in allograft model (Wang, et al, Cell Transplant, 21(1):99- 111(2012)). The broad and inducible expression of B7-H4, together with functional studies, suggests that B7-H4 serves to downregulate immune responses in peripheral tissues and to maintain peripheral tolerance.

More recent results demonstrate that B7-H4 also acts as a negative regulator of neutrophil response. Neutrophils are a key component of the innate immune system and are a first line of host defense against pathogens. However, neutrophils can also contribute to chronic inflammation and autoimmune disease. B7-H4 knockout mice display increased Thl responses and are more resistant to infection by Listeria monocytogenes due to an augmented immune response that is neutrophil dependent (Suh, et al, Mol Cell Biol, 26(17):6403-11 (2006) and Zhu, G., et al, Blood, 113(8): 1759-67 (2009) Epub 2008 Dec 24.). Mice hydrodynamically transfected with monomeric B7-H4 IgV domain or extracellular domain (ECD) increased neutrophil response to lipopolysaccharide (LPS) and Listeria infection, while dimeric B7-H4-Ig reduces proliferation of bone marrow derived neutrophil precursors (Zhu, G., et al, Blood, 113(8): 1759-67 (2009) Epub 2008 Dec 24). Soluble forms of B7-CD28 family molecules are also implicated in the progression of rheumatoid diseases. Studies shows that soluble PD-1 could be detected in RA patients and the levels of soluble PD-1 are correlated with TNF-alpha concentration in synovial fluid. Soluble B7-H4 (sH4), also referred to herein as cell-free B7-H4, and circulating forms of B7-H4, has been detected in ovarian cancer patients as a potential biomarker, and results from a study of 68 patients with RA and 24 healthy volunteers indicated that soluble B7-H4 was present in blood of 65% of patients with RA, compared with only 13% of healthy people (Simon, et al, Cancer Res., 66(3): 1570-5 (2006), Azuma, et al, PLoS Med., 6(10):el000166 (2009).

Epub 2009 Oct 20). The levels of soluble B7-H4 were significantly higher in RA patients (96.1 ng/ml) compared to healthy people (<5 ng/ml).

In vivo studies in a mouse model indicate that both overexpression of sH4 and deletion of B7-H4 caused inflammation (Azuma, et al., PLoS Med., 6(10):el000166 (2009). Epub 2009 Oct 20). Symptoms in the mice appeared earlier and were more severe than controls, and inflammatory effects of soluble B7-H4 were shown to be dependent on neutrophils. Using a protein that mimics the normal signaling by B7-H4, disease development was prevented in the mice.

Compositions and methods for treating autoimmune and

inflammatory diseases/disorders by using a B7-H4-Ig fusion protein to increase signaling through transmembrane B7-H4 are discussed in, for example, U.S. Published Application Nos. 2012/0177645 and 2012/0276095; and compositions and methods for interfering with the biological activity of soluble B7-H4 are discussed in, for example, U.S. Patent Nos 7,931,896 and 7,989, 173, and U.S. Published Application No. 2009/0142342. However, there remains a need for combination therapies that include an agent that increases signaling through transmembrane B7-H4 and an agent that reduces or blocks cell-free B7-H4-mediated inihibiting signaling through

transmembrane B7-H4.

Therefore, it is an object of the invention to provide compositions and methods for treating immune responses, inflammatory, and autoimmune diseases/disorders. It is a further object of the invention to provide compositions and methods for reducing or inhibiting the biological activity of cell-free B7-H4 while simultaneously increasing transmembrane B7-H4-mediated signaling.

It is a further object of the invention to provide methods of reducing, inhibiting, or blocking production of cell-free B7-H4.

It is another object of the invention to provide compositions and methods for distinguishing soluble proteins that mimic transmembrane B7- H4, such as a B7-H4 Ig fusion protein, from cell-free B7-H4, or from transmembrane B7-H4, or combinations thereof in a sample containing the mimic protein, and cell-free protein, transmembrane protein, or combinations thereof.

It is another object of the invention to provide compositions and methods for distinguishing cell-free B7-H4 from transmembrane B7-H4 in a sample containing both cell-free B7-H4 and transmembrane B7-H4.

It is another object of the invention to provide compositions and methods for assisting in the diagnosis of an autoimmune or inflammatory disease/disorder, or cancer in a subject, or assessing the propensity for a subject to develop an autoimmune or inflammatory disease/disorder, or cancer.

It is a further object of the invention to provide compositions and methods for determining the severity of an autoimmune or inflammatory disease/disorder, or cancer in a subject having or suspected of having an autoimmune or inflammatory disease/disorder, or cancer.

It is another object of the invention to provide compositions and methods for determining the efficacy of a treatment for an autoimmune or inflammatory disease/disorder, or cancer.

It is another object of the invention to provide compositions and methods for selecting a subject for treatment for an autoimmune or inflammatory disease/disorder, or cancer.

It is another object of the invention to provide compositions and methods for measuring pharmacokinetic and pharmacodynamics parameters of B7-H4 therapies, such as soluble proteins that mimic transmembrane B7- H4. SUMMARY OF THE INVENTION

B7-H4 specific antibodies and compositions and methods of use thereof are disclosed. The antibodies can be specific for endogenous forms B7-H4 polypeptides, recombinant B7-H4 proteins and fusions thereof, or combinations thereof. For example, an antibody can recognize most or all species of B7-H4 polypeptides by binding to a conserved domain important for protein function, for example the IgV domain. Alternatively, an antibody can bind to an epitope on a cell-free form of B7-H4 that is masked or absent on transmembrane B7-H4 or a B7-H4-Ig fusion protein. Pharmaceutical compositions including anti-B7-H4 antibodies are also disclosed.

Methods of using B7-H4 specific antibodies to reduce an immune response or to treat an inflammatory or autoimmune disease/dis order are also disclosed. The antibodies can be administered to a subject in need thereof to reduce the levels of cell-free B7-H4 in the subject, or reduce cell-free B7-H4 blockage of B7-H4-mediated signal transduction. Preferably administration of the antibody increases B7-H4-mediated signaling. In some embodiments the antibodies are administered in combination with a B7-H4-Ig fusion protein that mimics transmembrane B7-H4 by inducing B7-H4 signal transduction. Preferably, the antibody binds cell-free B7-H4, without binding to the co-administered B7-H4-Ig fusion protein. In some embodiments, the anti-B7-H4 antibody can bind to transmembrane B7-H4 and reduce, inhibit or prevent proteolytic cleavage of the extracellular domain and thereby reduce or inhibit the formation of cell-free B7-H4 in the subject. Accordingly, in some embodiments, administration of the antibody reduces or prevents production of cell- free B7-H4 in vivo. In a preferred embodiment, the antibody prevents the production of cell-free B7-H4 in vivo, while not interfering with the activity of the transmembrane B7-H4 or soluble proteins that mimic transmembrane B7-H4, their ability to engage the cognative B7-H4 receptor, or their ability to trigger signal transduction through the B7-H4 receptor.

Methods of determining the level of a B7-H4 polypeptide in a biological sample using B7-H4 specific antibodies are also disclosed. For example, in some embodiments, a biological sample such as serum or plasma obtained from a subject is subjected to an immunoassay, wherein the immunoassay includes contacting the biological sample with at least one B7- H4-specific antibody or antigen-binding fragment thereof such as a F(ab')2 fragment, and detecting the antibody or fragment. Preferred immunoassays include, but are not limited to, radioimmunoassays, ELISAs,

immunoprecipitation assays, Western blot, fluorescent immunoassays, and immunohistochemistry. In some embodiments, the level of cell-free B7-H4 in a biological sample is additionally or alternatively measured using mass spectroscopy.

A particularly preferred immunoassay is ELISA. ELISA typically includes the use of two different B7-H4 specific antibodies: a capture antibody and a detection antibody. In some embodiments an antibody or antigen binding fragment thereof that recognizes most or all species of B7- H4, for example an epitope on the IgV domain, is used to capture most or all of the B7-H4 polypeptide species in the sample. A detection antibody that can recognize most or all of the B7-H4 polypeptide species can be used to determine the total level of B7-H4 in the biological sample, or the detection antibody can be specific for a species of B7-H4 polypeptide. In some embodiments, the detection antibody recognizes a different domain or epitope than the capture antibody. For example, if the capture antibody or anitgen binding fragment thereof binds to the IgV domain, then the detection antibody may bind to the IgC domain. In some embodiments, the detection antibody recognizes the second polypeptide of a B7-H4 fusion protein. For example, if the second polypeptide of the fusion protein is the Fc region for human IgGl, the antibody can be an anti-human IgGl Fc antibody. In this way, therapeutic B7-H4 fusion protein can be distinguished from total endogenous B7-H4 protein in a sample. In some embodiments, a fusion protein can be distiniguished from cell-free B7-H4 only, transmembrane B7- H4 only, or a combination thereof.

In some embodiments the detection antibody recognizes an epitope on cell-free B7-H4 that is masked or absent on a B7-H4 fusion protein. For example, in some embodiments the antibody binds to a part of the extracellular domain, such as that last few amino acid of the IgC domain, which are absent from a fusion protein, such as the fusion protein of SEQ ID NO: 10. In this way, the amount of cell-free B7-H4 can be distinguished from other species of B7-H4 polypeptides that may be present in the biological sample, such as therapeutic fusion proteins. In a preferred embodiment, the biological samples is plasma or serum. In other

embodiments, the epitope that is recognized on the cell-free B7-H4 is unable to be recognized on the B7-H4 fusion protein due to conformational changes or complex formations that conceal the epitope.

The disclosed antibodies and methods of detecting B7-H4 can be applied in a number of diagnostic assays. For example, methods for determining the severity of an immune response, inflammatory or autoimmune disease/disorder, or cancer; methods for assisting in the diagnosis of an inflammatory or autoimmune disease/disorder or cancer; or assessing the propensity for developing an inflammatory or autoimmune disease/disorder, or cancer; methods for determining the efficacy of a treatment for an immune response, inflammatory or autoimmune disease/disorder, or cancer; methods for selecting a subject for treatment of an immune response, inflammatory or autoimmune disease/disorder, or cancer; and methods for determining the efficacy of a treatment for an immune response, inflammatory or autoimmune disease/disorder, or cancer in a subject are disclosed. In some embodiments, the methods include additional step(s) of treating the subject for the disease/disorder.

Inflammatory and autoimmune diseases/disorders that can be diagnosed and treated using the disclosed compositions and methods include, but are not limited to, rheumatoid arthritis, systemic lupus erythematosus, Acute Disseminated Encephalomyelitis (AD EM), alopecia areata, anklosing spondylitis, antiphospholipid syndrome, autoimmune Addison's disease, autoimmune hemolytic anemia, autoimmune hepatitis, autoimmune inner ear disease, autoimmune lymphoproliferative syndrome (alps), autoimmune thrombocytopenic purpura (ATP), Behcet's disease, bullous pemphigoid, cardiomyopathy, celiac sprue-dermatitis, chronic fatigue syndrome immune deficiency, syndrome (CFIDS), chronic inflammatory demyelinating polyneuropathy, cicatricial pemphigoid, cold agglutinin disease, Crest syndrome, Crohn's disease, Dego's disease, dermatomyositis,

dermatomyositis - juvenile, discoid lupus, essential mixed cryoglobulinemia, fibromyalgia - fibromyositis, grave's disease, guillain-barre, hashimoto's thyroiditis, idiopathic pulmonary fibrosis, idiopathic thrombocytopenia purpura (ITP), Iga nephropathy, insulin dependent diabetes (Type I), juvenile arthritis, Meniere's disease, mixed connective tissue disease, multiple sclerosis, myasthenia gravis, Optic neuritis (ON), Neuromyelitis Optica (NMO or Devic's disease), pemphigus vulgaris, pernicious anemia, polyarteritis nodosa, polychondritis, polyglancular syndromes, polymyalgia rheumatica, polymyositis and dermatomyositis, primary

agammaglobulinemia, primary biliary cirrhosis, psoriasis, Raynaud's phenomenon, Reiter's syndrome, rheumatic fever, sarcoidosis, scleroderma, Sj5gren's syndrome, stiff-man syndrome, Takayasu arteritis, temporal arteritis/giant cell arteritis, transverse myelitis, ulcerative colitis, uveitis, vasculitis, vitiligo, and Wegener's granulomatosis.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1A-1G are a series of line graphs showing detection

(absorbance 450 nm) of increasing concentrations (ng/mL) of the enzyme- linked anti-B7-H4 antibodies 2H9 (Figure 1A), 2D1 (Figure IB), 6H3 (Figure 1C), hB7-H4.ml (Figure ID), 8E1 1 (Figure IE), HMH4-5G1 (Figure IF) and H74 (Figure 1G) following incubation with ^g/ml of various B7-H4-Ig fusion proteins (SEQ ID NO:29), (SEQ ID NO:31), (SEQ ID NO:33), (SEQ ID NO:35), (SEQ ID NO:37), and (SEQ ID NO:39) immbolized on ELISA plates.

Figure 2 is a diagram mapping the putative recognition sites of antibody binding to the extracellular domains of transmembrane B7-H4. The Figure also illustrates three examplary ELISA schemes that can be used to recoginize three different forms of B7-H4. 2H9/6H3 pair can detect cell-free B7-H4 with complete IgV and IgC domains. 2H9/HMH4-5G1 pair can detect cell-free B7-H4 with complete IgV, and IgC domains, and the juxamembrane domain. 2H9/hB7-H4.ml pair can detect cell-free B7-H4 with IgV domain. Figure 3 is a line graph showing capture (using anti-B7-H4 antibody 2H9) and detection (using anti-B7-H4 6H3-biotin + Europium-labelled streptavidin) as a measure of fluorescence (AU) at increasing concentrations of B7-H4 fusion protein standard (pg/ml). The limit of detection (LOD) of this sandwich ELISA method is 8pg/ml of B7-H4 soluble protein. SEQ ID NO:25 was used as the B7-H4-Ig standard.

Figure 4 is a line graph comparing the capture (using anti-B7-H4 antibody 2H9) and detection (using anti-B7-H4 6H3-biotin + Horseradish peroxidase-labelled streptavidin) as a measure of absorbance (450 nm) at increasing concentrations of mouse or human B7-H4 fusion protein (SEQ ID NO: 1 1) (pg/ml).

Figure 5A and 5B are scatter plots comparing three ELISA methods using the capture/detection pairs: 2H9/6H3, 2H9/HMH4-5G1 or 2H9/hB7- H4.ml, respectively, for detecting cell-free B7-H4. SEQ ID NO:25 was used as the B7-H4-Ig standard.

Figure 6 is a line graph showing capture (using the F(ab')2 fragment of anti-B7-H4 antibody 2H9) and detection (using anti-B7-H4 6H3 or hB7- H4.ml + anti-mouse Ig-biotin+ Europium-labelled streptavidin) as a measure of fluorescence (AU) at increasing concentrations of B7-H4-Ig fusion protein (SEQ ID NO:25).

Figure 7 is a dot plot of cell-free B7-H4 (ng/mL) in serum collected from health donors (HD), subjects with Rheumatoid Arthritis (RA), or subjects with Sj5gren's Syndrome (SS). A solid horizontal line indicates the median value for each subject population. Using 1 ng/ml as a cutoff, the percentage of cell-free B7-H4 high versus low patients in each subject population was shown on the bottom panel. A dotted line indicates the limit of detection (LOD). B7-H4 concentrations were measured by ELISA method using the F(ab')2 fragment of anti-B7-H4 antibody 2H9 for capture and anti- B7-H4 antibody hB7-H4.ml for detection. SEQ ID NO:25 was used as the standard.

Figure 8 is a line graph showing a longitudinal study of serum levels of cell-free B7-H4 (sB7-H4 (ng/ml)) in a series of patients over time during treatment for SLE. B7-H4 concentrations were measured by ELISA method using anti-B7-H4 antibody 2H9 for capture and anti-B7-H4 antibody 6H3 for detection. SEQ ID NO:25 was used as the standard.

Figure 9 is a dot plot of cell-free B7-H4 (ng/niL) in serum collected from healthy donors (HD), ovarian, breast, Non-Small Cell Lung Cancer (NSCLC) and Renal Cell Carcinoma (RCC) patients. A solid horizontal line indicates the median value for each subject population. B7-H4

concentrations were measured by ELISA method using the F(ab')2 fragment of anti-B7-H4 antibody 2H9 for capture and anti-B7-H4 antibody hB7- H4.ml for detection. SEQ ID NO:25 was used as the standard.

Figures 10A-10F are line plots comparing the detection of B7-H4-Ig having IgV and IgC domains (SEQ ID NO: 11), B7-H4-Ig with L form without EPKSC sequence (SEQ ID NO:21) and B7-H4-Ig with L form and HLQLLNSK sequence replacing EPKSC (SEQ ID NO:25) by increasing concentrations of B7-H4 mAbs, including 6H3, 2D 1, 2H9, hB7-H4.ml, HMH4-5G1, and H74, and detected by anti-mouse Ig HRP.

Figures 1 lA-11C are line graphs comparing three ELISA methods 2H9/6H3, 2H9/HMH4-5G1 and 2H9/hB7-H4.ml pairs detecting increasing concentrations of B7-H4-Ig (SEQ ID NO: l 1), B7-H4-Ig with IgV domain only (SEQ ID NO:29), full extracellular domain (ECD) B7-H4-Ig (SEQ ID NO:35) or full ECD (SEQ ID NO:35) and B7-H4-Ig (SEQ ID NO: 11).

2H9/HMH4-5G1 and 2H9/hB7-H4.ml pairs could detect cell-free B7-H4 but not B7-H4-Ig (SEQ ID NO: 1 1).

DETAILED DESCRIPTION OF THE INVENTION

I. Definitions

The term "cell-free B7-H4," also referred to herein as circulating forms of B7-H4, soluble B7-H4 and sH4, includes soluble, monomeric B7- H4 polypeptides that are derived from endogenous transmembrane B7-H4. Cell-free B7-H4 typically includes the extracellular domain of B7-H4 or a biologically active fragment thereof. Human and mouse B7 proteins contain short intracytoplasmic domains, a single transmembrane domain and an extracellular domain. The extracellular domain typically contains two Ig domains; a membrane proximal IgC domain and a membrane distal IgV domain. The term cell-free B7-H4 encompasses any polypeptide fragment of B7-H4 that is shed or cleaved from a transmembrane form of B7-H4 produced by cells in vivo. Cell-free B7-H4 can be approximately 50-kDa by Western blot analysis, a size equal to the entire extracellular domain of a monomeric B7-H4 molecule in denatured condition. Cell-free B7-H4 can circulate systemically within a subject, can be localized to a tissue or microenvironment, or a combination thereof. For example, cell-free B7-H4 can be localized, or increased at a site of inflammation or around a tumor.

The term "transmembrane B7-H4" refers to a B7-H4 protein that contains a transmembrane domain. Transmembrane B7-H4 typically refers to B7-H4 proteins that are anchored in the plasma membrane of a cell.

The term "endogenous" of "endogenous forms" with regard to a nucleic acid or protein refers to nucleic acids or proteins normally present or expressed in the host. The term also encompasses inappropriate or aberrant expression of nucleic acids or protein, but does not encompass expression of recombinant nucleic acids or proteins.

The term "heterologous" refers to elements occurring where they are not normally found. For example, a promoter may be linked to a heterologous nucleic acid sequence, e.g., a sequence that is not normally found operably linked to the promoter. When used herein to describe a promoter element, heterologous means a promoter element that differs from that normally found in the native promoter, either in sequence, species, or number. For example, a heterologous control element in a promoter sequence may be a control/ regulatory element of a different promoter added to enhance promoter control, or an additional control element of the same promoter. The term "heterologous" thus can also encompass "exogenous" and "non-native" elements.

A "mature B7-H4" polypeptide refers to a B7-H4 polypeptide without a leader sequence. The mature B7-H4 polypeptide can also include additional post-translational modifications such as glycosylation that are important for activity of the polypeptide.

The term "antibody" is used in the broadest sense unless clearly indicated otherwise. Therefore, an "antibody" can be naturally occurring or man-made such as monoclonal antibodies produced by conventional hybridoma technology. Anti-B7-H4 antibodies include monoclonal and polyclonal antibodies as well as fragments containing the antigen-binding domain and/or one or more complementarity determining regions of these antibodies. As used herein, the term "antibody" refers to any form of antibody or antigen binding fragment thereof that specifically binds B7-H4 polypeptides, or fragments or fusions thereof and/or exhibits the desired biological activity and specifically covers monoclonal antibodies (including full length monoclonal antibodies), polyclonal antibodies, multispecific antibodies (e.g., bispecific antibodies), and antibody fragments so long as they specifically bind B7-H4 polypeptides, or fragments or fusions thereof and/or exhibit the desired biological activity. Any specific antibody can be used in the methods and compositions provided herein. Thus, in one embodiment the term "antibody" encompasses a molecule comprising at least one variable region from a light chain immunoglobulin molecule and at least one variable region from a heavy chain molecule that in combination form a specific binding site for the target antigen. In one embodiment, the antibody is an IgG antibody. For example, the antibody is a IgGl, IgG2, IgG3, or IgG4 antibody. An "antibody fragment" or "antigen binding fragment" of an antibody is defined as at least a portion of the variable region of the immunoglobulin molecule that binds to its target, i.e., the antigen-binding region. In one embodiment it specifically covers single anti-B7-H4 antibodies and clones thereof (including agonist, antagonist and neutralizing antibodies) and anti-B7-H4 antibody compositions with polyepitopic specificity. The antibody of the present methods and compositions can be monoclonal or polyclonal. An antibody can be in the form of an antigen binding antibody fragment including a Fab fragment, F(ab¾ fragment, a single chain variable region, and the like. Fragments of intact molecules can be generated using methods well known in the art and include enzymatic digestion and recombinant means.

As used herein, any form of the "antigen" can be used to generate an antibody that is specific for B7-H4. Thus, the eliciting B7-H4 antigen may contain a single epitope, multiple epitopes, or can be the entire protein alone or in combination with one or more immunogenicity enhancing agents known in the art. The eliciting antigen may be an isolated full-length protein, a cell surface protein (e.g., immunizing with cells transfected with at least a portion of the antigen), or a soluble protein (e.g., immunizing with only the extracellular domain portion of the protein). The antigen may be produced in a genetically modified cell. The DNA encoding the antigen may genomic or non-genomic (e.g., cDNA) and encodes at least a portion of the extracellular domain. As used herein, the term "portion" refers to the minimal number of amino acids or nucleic acids, as appropriate, to constitute an immunogenic epitope of the antigen of interest. Any genetic vectors suitable for transformation of the cells of interest may be employed, including but not limited to adenoviral vectors, plasmids, and non-viral vectors, such as cationic lipids. In one embodiment, the antibody of the methods and compositions herein specifically bind at least a portion of the extracellular domain of the B7-H4 of interest.

The antibodies or antigen binding fragments thereof provided herein may be conjugated to a "bioactive agent." As used herein, the term

"bioactive agent" refers to any synthetic or naturally occurring compound that binds the antigen and/or enhances or mediates a desired biological effect.

In one embodiment, the binding fragments useful in the present invention are biologically active fragments. As used herein, the term

"biologically active" refers to an antibody or antibody fragment that is capable of binding the desired the antigenic epitope and directly or indirectly exerting a biologic effect.

"Bispecific" antibodies are also useful in the present methods and compositions. As used herein, the term "bispecific antibody" refers to an antibody, typically a monoclonal antibody, having binding specificities for at least two different antigenic epitopes. In one embodiment, the epitopes are from the same antigen. In another embodiment, the epitopes are from two different antigens. Methods for making bispecific antibodies are known in the art. For example, bispecific antibodies can be produced recombinantly using the co-expression of two immunoglobulin heavy chain/light chain pairs. See, e.g., Milstein et al, Nature 305:537-39 (1983). Alternatively, bispecific antibodies can be prepared using chemical linkage. See, e.g., Brennan, et al., Science 229:81 (1985). Bispecific antibodies include bispecific antibody fragments. See, e.g., Hollinger, et al, Proc. Natl. Acad. Sci. U.S.A. 90:6444-48 (1993), Gruber, et al., J. Immunol. 152:5368 (1994).

The monoclonal antibodies herein specifically include "chimeric" antibodies in which a portion of the heavy and/or light chain is identical with or homologous to corresponding sequences in antibodies derived from a particular species or belonging to a particular antibody class or subclass, while the remainder of the chain(s) is identical with or homologous to corresponding sequences in antibodies derived from another species or belonging to another antibody class or subclass, as well as fragments of such antibodies, so long as they specifically bind the target antigen and/or exhibit the desired biological activity (U.S. Pat. No. 4,816,567; and Morrison et al, Proc. Natl. Acad. Sci. USA 81 : 6851-6855 (1984)).

As used herein, the terms "antigenic determinant" and "epitope" are used interchangeably refer to the structure recognized by an antibody.

As used herein, a "conformational epitope" is an epitope that includes discontinuous sections of the antigen's amino acid sequence. Antibodies bind a conformational epitope based on 3-D surface features, shape, or tertiary structure of the antigen.

As used herein, a "linear epitope" is an epitope that formed by a continuous sequence of amino acids from the antigen. Linear epitopes typically include about 5 to about 10 continuous amino acid residues.

Antibodies bind a linear epitope based on the primary sequence of the antigen.

As used herein, the term "immunoassay" refers to an assay that uses an antibody or antibodies to specifically bind an antigen. The immunoassay is characterized by the use of specific binding properties of a particular antibody or antibodies to detect, quantify, and/or target the antigen.

"Specific binding" between a binding agent, e.g., an antibody and a protein, for instance, a biomarker, refers to the ability of a capture- or detection-agent to preferentially bind to a particular agent that is present in a mixture; e.g., a biological sample. Specific binding also means a dissociation constant (¾) that is less than about 10 ^~6 M; preferably, less than about 10 ^~8 M; and, most preferably, less than about 10 ^~9 M.

The phrase "specifically (or selectively) binds" to an antibody or "specifically (or selectively) immunoreactive with" when referring to a protein or peptide, refers to a binding reaction that is determinative of the presence of the protein in a heterogeneous population of proteins and other biologies. Thus, under designated immunoassay conditions, the specified antibodies bind to a particular protein or protein complex at least two times the background and do not substantially bind in a significant amount to other proteins present in the sample.

As used herein, a "label" or a "detectable moiety" is a composition detectable by spectroscopic, photochemical, biochemical, radiographic, immunochemical, chemical, or other physical means. For example, useful labels include ³² P, fluorescent dyes, electron-dense reagents, enzymes (e.g., as commonly used in an ELISA), biotin, digoxigenin, or haptens and proteins or other entities which can be made detectable, e.g., by incorporating a radiolabel into the peptide or used to detect antibodies specifically reactive with the peptide. The labels may be incorporated into nucleic acids, proteins and antibodies at any position. Any method known in the art for conjugating the antibody to the label may be employed, e.g., using methods described in Hermanson, Bioconjugate Techniques 1996, Academic Press, Inc., San Diego.

As used herein, the terms "inhibitors" or "antagonists" refers to compounds or compositions that directly or indirectly partially or totally block activity, decrease, prevent, delay activation, inactivate, desensitize, or down regulate the activity or expression of the targeted biomarker.

Antagonists are, for example, polypeptides, such as antibodies, and soluble receptors, as well as nucleic acids such as siRNA or antisense RNA, as well as naturally occurring and synthetic biomarker antagonists, including small chemical molecules.

As used herein the term "isolated" refers to a compound of interest (e.g., either a polynucleotide or a polypeptide) that is in an environment different from that in which the compound naturally occurs e.g. separated from its natural milieu such as by concentrating a peptide to a concentration at which it is not found in nature. "Isolated" includes compounds that are within samples that are substantially enriched for the compound of interest and/or in which the compound of interest is partially or substantially purified.

An "immune cell" refers to any cell from the hemopoietic origin including but not limited to T cells, B cells, monocytes, dendritic cells, and macrophages.

As used herein, the term "polypeptide" refers to a chain of amino acids of any length, regardless of modification (e.g., phosphorylation or glycosylation).

As used herein, a "costimulatory polypeptide" or "costimulatory molecule" is a polypeptide that, upon interaction with a cell-surface molecule on T cells, modulates T cell responses.

As used herein, a "costimulatory signaling" is the signaling activity resulting from the interaction between costimulatory polypeptides on antigen presenting cells and their receptors on T cells during antigen-specific T cell responses. Antigen-specific T cell response mediated by two signals: 1) engagement of the T cell Receptor (TCR) with antigenic peptide presented in the context of MHC (signal 1), and 2) a second antigen-independent signal delivered by contact between different costimulatory receptor/ligand pairs (signal 2). This "second signal" can be important in determining the type of T cell response (activation vs inhibition) as well as the strength and duration of that response, and is regulated by both positive and negative signals from costimulatory molecules, such as the B7 family of proteins.

As used herein, the term "B7 polypeptide" means a member of the B7 family of proteins that costimulate T cells including, but not limited to B7-1, B7-2, B7-DC (PD-L2), B7-H5, B7-H1 (PD-L1), B7-H2, B7-H3, B7-H4, B7- H6 and biologically active fragments and/or variants thereof. Representative biologically active fragments include the extracellular domain or fragments of the extracellular domain that costimulate T cells.

As used herein, "inflammatory molecules" refers to molecules that results inflammatory responses including, but not limited to, cytokines and metalloproteases such as including, but not limited to, IL-Ι β, TNF-a, TGF- beta, IFN-γ, IL-17, IL-6, IL-23, IL-22, IL-21, and MMPs.

As used herein, a "vector" is a replicon, such as a plasmid, phage, or cosmid, into which another DNA segment may be inserted so as to bring about the replication of the inserted segment. The vectors described herein can be expression vectors.

As used herein, an "expression vector" is a vector that includes one or more expression control sequences

As used herein, an "expression control sequence" is a DNA sequence that controls and regulates the transcription and/or translation of another DNA sequence.

"Operably linked" refers to an arrangement of elements wherein the components so described are configured so as to perform their usual or intended function. Thus, two different polypeptides operably linked together retain their respective biological functions while physically linked together.

As used herein, "valency" refers to the number of binding sites available per molecule.

As used herein, "conservative" amino acid substitutions are substitutions wherein the substituted amino acid has similar structural or chemical properties.

As used herein, the term "host cell" refers to prokaryotic and eukaryotic cells into which a recombinant vector can be introduced.

As used herein, "transformed" and "transfected" encompass the introduction of a nucleic acid (e.g. a vector) into a cell by a number of techniques known in the art.

As used herein, the terms "immunologic", "immunological" or "immune" response is the development of a beneficial humoral (antibody mediated) and/or a cellular (mediated by antigen-specific T cells or their secretion products) response directed against a peptide in a recipient patient. Such a response can be an active response induced by administration of immunogen or a passive response induced by administration of antibody or primed T-cells. A cellular immune response is elicited by the presentation of polypeptide epitopes in association with Class I or Class II MHC molecules to activate antigen-specific CD4 T helper cells and/or CD8 cytotoxic T cells. The response may also involve activation of monocytes, macrophages, NK cells, basophils, dendritic cells, astrocytes, microglia cells, eosinophils, activation or recruitment of neutrophils or other components of innate immunity. The presence of a cell-mediated immunological response can be determined by proliferation assays (CD4 ⁺ T cells) or CTL (cytotoxic T lymphocyte) assays. The relative contributions of humoral and cellular responses to the protective or therapeutic effect of an immunogen can be distinguished by separately isolating antibodies and T-cells from an immunized syngeneic animal and measuring protective or therapeutic effect in a second subject.

An "immunogenic agent" or "immunogen" is capable of inducing an immunological response against itself on administration to a mammal, optionally in conjunction with an adjuvant.

The terms "individual", "host", "subject", and "patient" are used interchangeably herein, and refer to a mammal, including, but not limited to, humans, rodents, such as mice and rats, and other laboratory animals.

The term polypeptide includes proteins and fragments thereof. The polypeptides can be "exogenous," meaning that they are "heterologous," i.e., foreign to the host cell being utilized, such as human polypeptide produced by a bacterial cell. Polypeptides are disclosed herein as amino acid residue sequences. Those sequences are written left to right in the direction from the amino to the carboxy terminus. In accordance with standard nomenclature, amino acid residue sequences are denominated by either a three letter or a single letter code as indicated as follows: Alanine (Ala, A), Arginine (Arg, R), Asparagine (Asn, N), Aspartic Acid (Asp, D), Cysteine (Cys, C), Glutamine (Gin, Q), Glutamic Acid (Glu, E), Glycine (Gly, G), Histidine (His, H), Isoleucine (He, I), Leucine (Leu, L), Lysine (Lys, K), Methionine (Met, M), Phenylalanine (Phe, F), Proline (Pro, P), Serine (Ser, S),

Threonine (Thr, T), Tryptophan (Trp, W), Tyrosine (Tyr, Y), and Valine (Val, V).

"Variant" refers to a polypeptide or polynucleotide that differs from a reference polypeptide or polynucleotide, but retains essential properties. A typical variant of a polypeptide differs in amino acid sequence from another, reference polypeptide. Generally, differences are limited so that the sequences of the reference polypeptide and the variant are closely similar overall and, in many regions, identical. A variant and reference polypeptide may differ in amino acid sequence by one or more modifications (e.g., substitutions, additions, and/or deletions). A substituted or inserted amino acid residue may or may not be one encoded by the genetic code. A variant of a polypeptide may be naturally occurring such as an allelic variant, or it may be a variant that is not known to occur naturally.

Modifications and changes can be made in the structure of the polypeptides of in disclosure and still obtain a molecule having similar characteristics as the polypeptide (e.g., a conservative amino acid substitution). For example, certain amino acids can be substituted for other amino acids in a sequence without appreciable loss of activity. Because it is the interactive capacity and nature of a polypeptide that defines that polypeptide's biological functional activity, certain amino acid sequence substitutions can be made in a polypeptide sequence and nevertheless obtain a polypeptide with like properties.

In making such changes, the hydropathic index of amino acids can be considered. The importance of the hydropathic amino acid index in conferring interactive biologic function on a polypeptide is generally understood in the art. It is known that certain amino acids can be substituted for other amino acids having a similar hydropathic index or score and still result in a polypeptide with similar biological activity. Each amino acid has been assigned a hydropathic index on the basis of its hydrophobicity and charge characteristics. Those indices are: isoleucine (+4.5); valine (+4.2); leucine (+3.8); phenylalanine (+2.8); cysteine/cystine (+2.5); methionine (+1.9); alanine (+1.8); glycine (-0.4); threonine (-0.7); serine (-0.8);

tryptophan (-0.9); tyrosine (-1.3); proline (-1.6); histidine (-3.2); glutamate (- 3.5); glutamine (-3.5); aspartate (-3.5); asparagine (-3.5); lysine (-3.9); and arginine (-4.5).

It is believed that the relative hydropathic character of the amino acid determines the secondary structure of the resultant polypeptide, which in turn defines the interaction of the polypeptide with other molecules, such as enzymes, substrates, receptors, antibodies, antigens, and cofactors. It is known in the art that an amino acid can be substituted by another amino acid having a similar hydropathic index and still obtain a functionally equivalent polypeptide. In such changes, the substitution of amino acids whose hydropathic indices are within ± 2 is preferred, those within ± 1 are particularly preferred, and those within ± 0.5 are even more particularly preferred.

Substitution of like amino acids can also be made on the basis of hydrophilicity, particularly where the biological functional equivalent polypeptide or peptide thereby created is intended for use in immunological embodiments. The following hydrophilicity values have been assigned to amino acid residues: arginine (+3.0); lysine (+3.0); aspartate (+3.0 ± 1); glutamate (+3.0 ± 1); serine (+0.3); asparagine (+0.2); glutamnine (+0.2); glycine (0); proline (-0.5 ± 1); threonine (-0.4); alanine (-0.5); histidine (- 0.5); cysteine (-1.0); methionine (-1.3); valine (-1.5); leucine (-1.8);

isoleucine (-1.8); tyrosine (-2.3); phenylalanine (-2.5); tryptophan (-3.4). It is understood that an amino acid can be substituted for another having a similar hydrophilicity value and still obtain a biologically equivalent, and in particular, an immunologically equivalent polypeptide. In such changes, the substitution of amino acids whose hydrophilicity values are within ± 2 is preferred, those within ± 1 are particularly preferred, and those within ± 0.5 are even more particularly preferred.

As outlined above, amino acid substitutions are generally based on the relative similarity of the amino acid side-chain substituents, for example, their hydrophobicity, hydrophilicity, charge, size, and the like. Exemplary substitutions that take various of the foregoing characteristics into consideration are well known to those of skill in the art and include (original residue: exemplary substitution): (Ala: Gly, Ser), (Arg: Lys), (Asn: Gin, His), (Asp: Glu, Cys, Ser), (Gin: Asn), (Glu: Asp), (Gly: Ala), (His: Asn,

Gin), (He: Leu, Val), (Leu: He, Val), (Lys: Arg), (Met: Leu, Tyr), (Ser: Thr), (Thr: Ser), (Tip: Tyr), (Tyr: Trp, Phe), and (Val: He, Leu). Embodiments of this disclosure thus contemplate functional or biological equivalents of a polypeptide as set forth above. In particular, embodiments of the polypeptides can include variants having about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, or more sequence identity to the polypeptide of interest.

The term "percent (%) sequence identity" is defined as the percentage of nucleotides or amino acids in a candidate sequence that are identical with the nucleotides or amino acids in a reference nucleic acid sequence, after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity. Alignment for purposes of determining percent sequence identity can be achieved in various ways that are within the skill in the art, for instance, using publicly available computer software such as BLAST, BLAST-2, ALIGN, ALIGN-2 or Megalign (DNASTAR) software. Appropriate parameters for measuring alignment, including any algorithms needed to achieve maximal alignment over the full-length of the sequences being compared can be determined by known methods.

For purposes herein, the % sequence identity of a given nucleotides or amino acids sequence C to, with, or against a given nucleic acid sequence D (which can alternatively be phrased as a given sequence C that has or comprises a certain % sequence identity to, with, or against a given sequence D) is calculated as follows:

100 times the fraction W/Z, where W is the number of nucleotides or amino acids scored as identical matches by the sequence alignment program in that program's alignment of C and D, and where Z is the total number of nucleotides or amino acids in D. It will be appreciated that where the length of sequence C is not equal to the length of sequence D, the % sequence identity of C to D will not equal the % sequence identity of D to C.

The term "stringent hybridization conditions" as used herein mean that hybridization will generally occur if there is at least 95% and preferably at least 97% sequence identity between the probe and the target sequence. Examples of stringent hybridization conditions are overnight incubation in a solution comprising 50% formamide, 5X SSC (150 mM aCl, 15 mM trisodium citrate), 50 mM sodium phosphate (pH 7.6), 5X Denhardt's solution, 10% dextran sulfate, and 20 μg/ml denatured, sheared carrier DNA such as salmon sperm DNA, followed by washing the hybridization support in 0.1X SSC at approximately 65°C. Other hybridization and wash conditions are well known and are exemplified in Sambrook et al, Molecular Cloning: A Laboratory Manual, Third Edition, Cold Spring Harbor, N.Y. (2000).

As used herein, the term "pharmaceutically acceptable carrier" encompasses any of the standard pharmaceutical carriers, such as a phosphate buffered saline solution, water and emulsions such as an oil/water or water/oil emulsion, and various types of wetting agents.

II. Compositions

Antibodies binding to one or more B7-H4 polypeptides or B7-H4 fusion proteins, or fragments or variants thereof are disclosed. The antibodies disclosed herein are typically monoclonal antibodies, or antigen binding fragments thereof, that bind to an epitope present on a B7-H4 polypeptide, or fragment or fusion thereof. In some embodiments the antibody binds to a conformational epitope. In some embodiments the antibody binds to a linear epitope. A linear epitope can be 4, 5, 6, 7, 8, 9, 10, 1 1, or more continuous amino acids in length. The epitope can include one or more non-amino acid elements, post-translation modifications, or a combination thereof. Examples of post-translational modifications include, but are not limited to glycosylation, phosphorylation, acetylation, citrullination and ubiquitination. For example, antibodies can bind an epitope that formed at least in part by one or more sugar groups.

The antibody can bind to an epitope that is present on an endogenous

B7-H4 polypeptide and on a recombinant B7-H4 polypeptide, or fragment or fusion thereof. In some embodiments, the antibody binds to an epitope on a B7-H4 polypeptide expressed by a cell that is masked or absent on a recombinant B7-H4 polypeptide or fragment or fusion thereof. In some embodiments, the antibody binds to an epitope on a recombinant B7-H4 polypeptide or fragment or fusion thereof that is masked or absent on an endogenous B7-H4 polypeptide. Endogenous B7-H4 polypeptides can include cell-free forms of B7-H4 and transmembrane B7-H4. Accordingly, in some embodiments, the antibodies can distinguish between recombinant B7-H4 protein, for example a B7-H4-Ig fusion protein, and cell-free B7-H4, or transmembrane B7-H4, or a combination thereof. The antibodies can be used in research, diagnostic and therapeutic applications.

A. B7-H4 Polypeptides and Fusion Proteins

B7-H4 polypeptides, fusions, and pharmaceutical compositions including B7-H4 polypeptides, and fragments and fusion thereof are disclosed in U.S. Published Application Nos. 2012/0177645 and

2012/0276095- which are incorporated herein by reference in their entireties.

1. B7-H4 Proteins

In preferred embodiments an anti-B7-H4 antibody can bind to a B7- H4 polypeptide from a mammalian species. For example, the B7- H4 polypeptide can be of murine, non-human primate (Pan troglodytes, Macaca mulatta or Macaca fascicularis), or human origin. Murine B7-H4 polypeptides can have at least 80, 85, 90, 95 or 100% sequence identity to the B7-H4 polypeptide encoded by the nucleic acid having GenBank Accession Number NM_178594 or AY280973. Useful murine B7-H4 polypeptides have at least about 80, 85, 90, 95 or 100% sequence identity to the B7-H4 polypeptide according to GenBank Accession Number

AAH32925.1 or NP_848709.2. Useful human B7-H4 polypeptides have at least about 80, 85, 90, 95 or 100% sequence identity to the B7-H4 polypeptide encoded by the nucleic acid having GenBank Accession Number AK026071. Useful human B7-H4 polypeptides have at least about 80, 85, 90, 95 or 100% sequence identity to the B7-H4 polypeptide according to GenBank Accession Number NP_078902.2 or BAB 15349.1.

For example, human B7-H4 polypeptides can be encoded by a nucleotide sequence having at least 80%, 85%, 90%, 95%, 99%, or 100% sequence identity to:

atggcttccc tggggcagat cctcttctgg agcataatta gcatcatcat tattctggct 60 ggagcaattg cactcatcat tggctttggt atttcaggga gacactccat cacagtcact 120 actgtcgcct cagctgggaa cattggggag gatggaatcc tgagctgcac ttttgaacct 180 gacatcaaac tttctgatat cgtgatacaa tggctgaagg aaggtgtttt aggcttggtc 240 catgagttca aagaaggcaa agatgagctg tcggagcagg atgaaatgtt cagaggccgg 300 acagcagtgt ttgctgatca agtgatagtt ggcaatgcct ctttgcggct gaaaaacgtg 360 caactcacag atgctggcac ctacaaatgt tatatcatca cttctaaagg caaggggaat 420 gctaaccttg agtataaaac tggagccttc agcatgccgg aagtgaatgt ggactataat 480 gccagctcag agaccttgcg gtgtgaggct ccccgatggt tcccccagcc cacagtggtc 540 tgggcatccc aagttgacca gggagccaac ttctcggaag tctccaatac cagctttgag 600 ctgaactctg agaatgtgac catgaaggtt gtgtctgtgc tctacaatgt tacgatcaac 660 aacacatact cctgtatgat tgaaaatgac attgccaaag caacagggga tatcaaagtg 720 acagaatcgg agatcaaaag gcggagtcac ctacagctgc taaactcaaa ggcttctctg 780 tgtgtctctt ctttctttgc catcagctgg gcacttctgc ctctcagccc ttacctgatg 840 ctaaaataa 849

(SEQ ID NO: l).

In some embodiments, a human B7-H4 polypeptide has at least 80%, 85%, 90%, 95%, 99%, or 100% sequence identity to:

MASLGQILF SIISIIIILA GAIALIIGFG ISGRHSITVT TVASAGNIGE DGILSCTFEP 60

DIKLSDIVIQ LKEGVLGLV HEFKEGKDEL SEQDEMFRGR TAVFADQVIV GNASLRLKNV 120

QLTDAGTYKC YII SKGKGN ANLEYKTGAF SMPEVNVDYN ASSETLRCEA PR FPQPTW 180 ASQVDQGAN FSEVSNTSFE LNSENVTMKV VSVLYNVTIN NTYSCMIEND IAKATGDIKV 240

TESEIKRRSH LQLLNSKASL CVSSFFAIS ALLPLSPYLM LK 282

(SEQ ID NO:2).

The amino acid sequence of the human B7-H4 fusion protein of SEQ ID NO:2 without the signal sequence can be

GFGISGRHSI TVTTVASAGN IGEDGILSCT FEPDIKLSDI VIQ LKEGVL GLVHEFKEGK 60

DELSEQDEMF RGRTAVFADQ VIVGNASLRL KNVQLTDAGT YKCYIITSKG KGNANLEYKT 120

GAFSMPEVNV DYNASSETLR CEAPR FPQP TW ASQVDQ GANFSEVSNT SFELNSENVT 180

MKWSVLYNV TINNTYSCMI ENDIAKATGD IKVTESEIKR RSHLQLLNSK ASLCVSSFFA 240

IS ALLPLSP YLMLK 255

(SEQ ID NO:3),

In some embodiments, a human B7-H4 polypeptide has at least 80%, 85%, 90%, 95%, 99%, or 100% sequence identity to:

MASLGQILFW SIISIIIILA GAIALIIGFG ISGRHSITVT TVASAGNIGE DGIQSCTFEP 60

DIKLSDIVIQ WLKEGVLGLV HEFKEGKDEL SEQDEMFRGR TAVFADQVIV GNASLRLKNV 120

QLTDAGTYKC YIITSKGKGN ANLEYKTGAF SMPEVNVDYN ASSETLRCEA PRWFPQPTW 180

WASQVDQGAN FSEVSNTSFE LNSENVTMKV VSVLYNVTIN NTYSCMIEND IAKATGDIKV 240

TESEIKRRSH LQLLNSKASL CVSSFFAISW ALLPLSPYLM LK 282

(SEQ ID NO:4).

The amino acid sequence of the human B7-H4 fusion protein of SEQ ID NO:4 without the signal sequence can be

GFGISGRHSI TVTTVASAGN IGEDGIQSCT FEPDIKLSDI VIQWLKEGVL GLVHEFKEGK 60

DELSEQDEMF RGRTAVFADQ VIVGNASLRL KNVQLTDAGT YKCYIITSKG KGNANLEYKT 120

GAFSMPEVNV DYNASSETLR CEAPRWFPQP TWWASQVDQ GANFSEVSNT SFELNSENVT 180

MKWSVLYNV TINNTYSCMI ENDIAKATGD IKVTESEIKR RSHLQLLNSK ASLCVSSFFA 240

ISWALLPLSP YLMLK 255

(SEQ ID NO:5). Nucleic acids encoding B7-H4 polypeptides may be optimized for expression in the expression host of choice. Codons may be substituted with alternative codons encoding the same amino acid to account for differences in codon usage between the mammal from which the B7-H4 nucleic acid sequence is derived and the expression host. In this manner, the nucleic acids may be synthesized using expression host-preferred codons.

2. Fragments of B7-H4 Polypeptides

The B7-H4 proteins contain two immunoglobulin domains within the extracellular domain, the IgV domain (or V domain) and the IgC domain (or C domain), which are related to the variable and constant domains of antibodies. The domains can be identified by anyone skilled in the art by searching against family and domain databases. The IgV domain of B7 ligand family members is believed to mediate receptor binding. The IgC domain is believed to stabilize protein structure and contribute to the overall binding affinity of ligand-receptor interaction. Each Ig domain of the extracellular domain includes one disulfide bond formed between intradomain cysteine residues, as is typical for this fold and may be important for structure-function. In SEQ ID NOS: 2 and 4 these cysteines are located at residues 56 and 130 for the IgV domain, and 168 and 225 for the IgC domain.

For example, in some embodiments, the IgV domain includes a polypeptide having an amino acid sequence with 80%, 85%, 90%, 95%, 99%, or 100% sequence identity to the human amino acid sequence:

GFGISGRHSI TVTTVASAGN IGEDGIQSCT FEPDIKLSDI VIQ LKEGVL GLVHEFKEGK 60 DELSEQDEMF RGRTAVFADQ VIVGNASLRL KNVQL DAGT YKCYIITSKG KGNANLEYKT 120 GAFSMPEVN 129

(SEQ ID NO: 6), or

HSITVTTVAS AGNIGEDGIQ SCTFEPDIKL SDIVIQ LKE GVLGLVHEFK EGKDELSEQD 60 EMFRGRTAVF ADQVIVGNAS LRLKNVQLTD AGTYKCYIIT SKGKGNANLE YK 112 (SEQ ID NO:48), or

GFGISGRHSI TVTTVASAGN IGEDGILSCT FEPDIKLSDI VIQWLKEGVL GLVHEFKEGK 60 DELSEQDEMF RGRTAVFADQ VIVGNASLRL KNVQLTDAGT YKCYIITSKG KGNANLEYKT 120 GAFSMPEVN 129

(SEQ ID NO: 7), or HSITVTTVAS AGNIGEDGIL SCTFEPDIKL SDIVIQ LKE GVLGLVHEFK EGKDELSEQD 60 EMFRGRTAVF ADQVIVGNAS LRLKNVQLTD AGTYKCYIIT SKGKGNANLE YK 112

(SEQ ID NO:49).

In some embodiments, the IgC domain includes a polypeptide having an amino acid sequence with 80%, 85%, 90%, 95%, 99%, or 100% sequence identity to the human amino acid sequence:

VDYNASSETL RCEAPR FPQ PTW ASQVD QGANFSEVSN TSFELNSENV TMKWSVLYN 60

VTINNTYSCM IENDIAKATG DIKVT 85

(SEQ ID NO:50),

PEVNVDYNAS SETLRCEAPR FPQPTW A SQVDQGANFS EVSNTSFELN SENVTMKWS 60

VLYNVTINNT YSCMIENDIA KATGDIKVT 89

(SEQ ID NO:51),

FSMPEVNVDY NASSETLRCE APR FPQPTV V ASQVDQGA NFSEVSNTSF ELNSENVTMK 60

WSVLYNVTI NNTYSCMIEN DIAKATGDIK VTESEIKRRS 100 (SEQ ID NO:52),

VNVDYNASSE TLRCEAPR F PQPTW ASQ VDQGANFSEV SNTSFELNSE NVTMKWSVL 60

YNVTINNTYS CMIENDIAKA TGDIKVTESE IKRRS 95

(SEQ ID NO:53), or

YNASSETLRC EAPR FPQPT W ASQVDQG ANFSEVSNTS FELNSENVTM KWSVLYNVT 60 INNTYSCMIE NDIAKATGDI KVTESEIKRR S 91

(SEQ ID NO:54).

In some embodiments, a fragment of B7-H4 includes the IgV and IgC domains, but does not include the entire extracellular domain. For example, in some embodiments, a fragment of full-length B7-H4 includes a polypeptide having an amino acid sequence with 80%, 85%, 90%, 95%,

99%, or 100% sequence identity to the human amino acid sequence:

GFGISGRHSI TVTTVASAGN IGEDGIQSCT FEPDIKLSDI VIQ LKEGVL GLVHEFKEGK 60

DELSEQDEMF RGRTAVFADQ VIVGNASLRL KNVQLTDAGT YKCYIITSKG KGNANLEYKT 120

GAFSMPEVNV DYNASSETLR CEAPR FPQP TW ASQVDQ GANFSEVSNT SFELNSENVT 180 MKWSVLYNV TINNTYSCMI ENDIAKATGD IKVTESEIKR RS 222

(SEQ ID NO: 8), or

GFGISGRHSI TVTTVASAGN IGEDGILSCT FEPDIKLSDI VIQWLKEGVL GLVHEFKEGK 60

DELSEQDEMF RGRTAVFADQ VIVGNASLRL KNVQLTDAGT YKCYIITSKG KGNANLEYKT 120

GAFSMPEVNV DYNASSETLR CEAPRWFPQP TWWASQVDQ GANFSEVSNT SFELNSENVT 180 MKWSVLYNV TINNTYSCMI ENDIAKATGD IKVTESEIKR RS 222

(SEQ ID NO:9).

In addition, there is one predicted N-linked glycosylation site in the IgV domain and six glycosylation sites in the IgC domain, which are conserved between mouse and human B7-H4 sequences. Fragments of B7-H4 polypeptides include cell free fragments. Cell free B7-H4 polypeptide fragments are fragments of B7-H4 polypeptides that may be shed, secreted or otherwise extracted from the producing cells. Cell free fragments of B7-H4 polypeptides can include some or all of the extracellular domain of the polypeptide, and lack some or all of the intracellular and/or transmembrane domains. In one embodiment, B7-H4 polypeptide fragments include the entire extracellular domain of the B7-H4 polypeptide. In other embodiments, the cell free fragments of B7-H4 polypeptides include fragments of the extracellular domain that retain B7-H4 biological activity. The extracellular domain can include 1, 2, 3, 4, or 5 contiguous amino acids from the transmembrane domain, and/or 1, 2, 3, 4, or 5 contiguous amino acids from the signal sequence. Alternatively, the extracellular domain can have 1, 2, 3, 4, 5 or more amino acids removed from the C-terminus, N-terminus, or both. In some embodiments the extracellular domain is only the IgV domain, or the region between the conserved cysteines of the IgV domain located at residues 56 and 130 of the full-length protein.

Generally, the B7-H4 polypeptides or fragments thereof are expressed from nucleic acids that include sequences that encode a signal sequence. The signal sequence is generally cleaved from the immature polypeptide to produce the mature polypeptide lacking the signal sequence. SEQ ID NOs: 3 and 5 each lack a signal peptide. The signal sequence of B7- H4, and optionally, one, two, three, four, five, or more amino acids of the IgV domain can be replaced by the signal sequence of another polypeptide using standard molecule biology techniques to affect the expression levels, secretion, solubility, or other property of the polypeptide. The signal sequence that is used to replace the B7-H4 signal sequence can be any known in the art. SEQ ID NOs: 2 and 4 each contain the endogenous B7-H4 signal peptide, which is from amino acid 1 to about amino acid 24 of SEQ ID NO:2 and 4, see for example UniProtKB/Swiss-Prot: Q7Z7D3.1.

B7-H4 polypeptides, and fragments and fusions thereof, both with and without a signal sequence are provided herein. It is understood that the mature protein, i.e., the protein sequence without the signal sequence, is a putative mature protein. During normal cell expression, a signal sequence can be removed by a cellular peptidase to yield a mature protein. The actual mature protein expressed following in vivo cleavage of the signal sequence many include 1, 2, 3, 4, 5, 6, 7, or 8 more; or 1, 2, 3, 4, 5, 6, 7, or 8 fewer amino acids than the putative mature proteins provided herein. It is also understood that a nucleic acid sequence encoding the putative mature proteins provided herein can be modified to include a nucleic acid sequence encoding an endogenous or heterologous signal sequence at the 5' end, which, when expressed in a cell, yields a mature B7-H4 protein, or fragment, or fusion thereof such as those putative mature proteins provided herein.

3. Variants of B7-H4 Polypeptides

Useful variants include those that increase biological activity, as indicated by any of the assays described herein, or that increase half life or stability of the protein. The B7-H4 polypeptides and B7-H4 fragments, or fusions thereof having B7-H4 activity, can be engineered to increase biological activity. In a preferred embodiment, the B7-H4 polypeptide or fusion protein has been modified with at least one amino acid substitution, deletion, or insertion that increases the binding of the molecule to an immune cell, for example a T cell, and transmits an inhibitory signal into the T cell.

Other preferred variants are those B7-H4 polypeptides that are engineered to selectively bind to one type of T cell versus other immune cells. For example, the B7-H4 polypeptide can be engineered to bind preferentially to Tregs, ThO, Thl, Thl7, or Th22 cells. Preferential binding refers to binding that is at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or greater for one type of cell over another type of cell.

Still other variants of B7-H4 can be engineered to have reduced binding to immune cells relative to wildtype B7-H4. These variants can be used in combination with variants having stronger binding properties to modulate the immune response with a moderate impact.

Finally, variant B7-H4 polypeptides can be engineered to have an increased half-life relative to wildtype. These variants typically are modified to resist enzymatic degradation. Exemplary modifications include modified amino acid residues and modified peptide bonds that resist enzymatic degradation. Various modifications to achieve this are known in the art. For example, the juxtamembrane region of B7-H4 includes a dibasic motif, KRRS, which could potentially be recognized and cleaved, for example by a member of the proprotein convertase family of proteases. This motif (KRRS) can be removed, blocked, or modified to increase half life. The variants can be modified to adjust for effects of affinity for the receptor on the half life of B7-H4 polypeptides, fragments, or fusions thereof at serum and endosomal pH.

4. B7-H4 Fusion Proteins

B7-H4 fusion polypeptides have a first fusion partner comprising all or a part of a B7-H4 protein fused to a second polypeptide directly or via a linker peptide sequence that is fused to the second polypeptide. The fusion proteins optionally contain a domain that functions to dimerize or multimerize two or more fusion proteins. The peptide/polypeptide linker domain can either be a separate domain, or alternatively can be contained within one of the other domains (B7-H4 polypeptide or second polypeptide) of the fusion protein. Similarly, the domain that functions to dimerize or multimerize the fusion proteins can either be a separate domain, or alternatively can be contained within one of the other domains (B7-H4 polypeptide, second polypeptide or peptide/polypeptide linker domain) of the fusion protein. In one embodiment, the dimerization/multimerization domain and the peptide/polypeptide linker domain are the same.

Fusion proteins disclosed herein are of formula I:

wherein "N" represents the N-terminus of the fusion protein, "C" represents the C-terminus of the fusion protein. In the preferred embodiment, "Ri" is a B7-H4 polypeptide, "R ₂ " is an optional peptide/polypeptide linker domain, and "R ₃ " is a second polypeptide. Alternatively, R ₃ may be a B7-H4 polypeptide and Ri may be a second polypeptide.

Dimerization or multimerization can occur between or among two or more fusion proteins through dimerization or multimerization domains. Alternatively, dimerization or multimerization of fusion proteins can occur by chemical crosslinking. The dimers or multimers that are formed can be homodimeric/homomultimeric or heterodimeric/heteromultimeric.

In one embodiment, the first fusion partner is a fragment of B7-H4. As used herein, a fragment of B7-H4 refers to any subset of the polypeptide that is at least one amino acid shorter than full length protein. Useful fragments are those that retain the ability to bind to their natural receptor or receptors. A B7-H4 polypeptide that is a fragment of full-length B7-H4 typically has at least 20 percent, 30 percent, 40 percent, 50 percent, 60 percent, 70 percent, 80 percent, 90 percent, 95 percent, 98 percent, 99 percent, 100 percent, or even more than 100 percent of the ability to bind its natural receptor(s) as compared to full-length B7-H4.

In a preferred embodiment, the fusion protein includes the extracellular domain of B7-H4, or a fragment thereof, and which is without the transmembrane domain, fused to an Ig Fc region. Recombinant B7-H4- Ig fusion proteins can be prepared by fusing the coding region of the extracellular domain of B7-H4 or a fragment thereof to the Fc region of human IgGl or mouse IgG2a, or other suitable Ig domain, as described previously (Chapoval, et al, Methods Mol. Med., 45:247-255 (2000)).

a. Exemplary fusion proteins

In some embodiments, a representative human B7-H4 fusion protein has at least 80%, 85%, 90%, 95%, 99% or 100 i% sequence identity to:

ME S VFLFF LSVTTGVHSG FGISGRHSIT V VASAGNI GEDGIQSCTF EPDIKLSDIV 60

IQ LKEGVLG LVHEFKEGKD ELSEQDEMFR GRTAVFADQV IVGNASLRLK NVQLTDAGTY 120

KCYIITSKGK GNANLEYKTG AFSMPEVNVD YNASSETLRC EAPR FPQPT W ASQVDQG 180

ANFSEVSNTS FELNSENVTM KWSVLYNVT INNTYSCMIE NDIAKATGDI KVTESEIKRR 240

SEPKSCDKTH TCPPCPAPEL LGGPSVFLFP PKPKDTLMIS RTPEVTCVW DVSHEDPEVK 300

FN YVDGVEV HNAKTKPREE QYNSTYRWS VLTVLHQD L NGKEYKCKVS NKALPAPIEK 360 ISKAKGQPR EPQVYTLPPS RDELTKNQVS LTCLVKGFYP SDIAVE ESN GQPENNYKTT 420

PPVLDSDGSF FLYSKLTVDK SR QQGNVFS CSVMHEALHN HYTQKSLSLS PGK 473

(SEQ ID NO: 10).

The amino acid sequence of the human B7-H4 fusion protein of SEQ ID NO: 10 without the signal sequence can be:

GFGISGRHSI TVTTVASAGN IGEDGIQSCT FEPDIKLSDI VIQ LKEGVL GLVHEFKEGK 60

DELSEQDEMF RGRTAVFADQ VIVGNASLRL KNVQLTDAGT YKCYIITSKG KGNANLEYKT 120

GAFSMPEVNV DYNASSETLR CEAPR FPQP TW ASQVDQ GANFSEVSNT SFELNSENVT 180

MKWSVLYNV TINNTYSCMI ENDIAKATGD IKVTESEIKR RSEPKSCDKT HTCPPCPAPE 240

LLGGPSVFLF PPKPKDTLMI SRTPEVTCW VDVSHEDPEV KFN YVDGVE VHNAKTKPRE 300 EQYNSTYRW SVLTVLHQD LNGKEYKCKV SNKALPAPIE KTISKAKGQP REPQVYTLPP 360

SRDELTKNQV SLTCLVKGFY PSDIAVE ES NGQPENNYKT TPPVLDSDGS FFLYSKLTVD 420

KSR QQGNVF SCSVMHEALH NHYTQKSLSL SPGK 454

(SEQ ID NO: 11).

In another embodiment, a representative human B7-H4 fusion protein has at least 80%, 85%, 90%, 95%, 99% or 100% sequence identity to:

ME S VFLFF LSVTTGVHSG FGISGRHSIT V VASAGNI GEDGIQSCTF EPDIKLSDIV 60

IQ LKEGVLG LVHEFKEGKD ELSEQDEMFR GRTAVFADQV IVGNASLRLK NVQLTDAGTY 120

KCYIITSKGK GNANLEYKTG AFSMPEVNVD YNASSETLRC EAPR FPQPT W ASQVDQG 180

ANFSEVSNTS FELNSENVTM KWSVLYNVT INNTYSCMIE NDIAKATGDI KVTESEIKRR 240

SDKTHTCPPC PAPELLGGPS VFLFPPKPKD TLMISRTPEV TCVWDVSHE DPEVKFN YV 300

DGVEVHNAKT KPREEQYNST YRWSVLTVL HQD LNGKEY KCKVSNKALP APIEKTISKA 360

KGQPREPQVY TLPPSRDELT KNQVSLTCLV KGFYPSDIAV E ESNGQPEN NYKTTPPVLD 420

SDGSFFLYSK LTVDKSR QQ GNVFSCSVMH EALHNHYTQK SLSLSPGK 468

(SEQ ID NO: 12).

The amino acid sequence of the human B7-H4 fusion protein of SEQ ID NO: 12 without the signal sequence can be:

GFGISGRHSI TVTTVASAGN IGEDGIQSCT FEPDIKLSDI VIQ LKEGVL GLVHEFKEGK 60

DELSEQDEMF RGRTAVFADQ VIVGNASLRL KNVQLTDAGT YKCYIITSKG KGNANLEYKT 120

GAFSMPEVNV DYNASSETLR CEAPR FPQP TW ASQVDQ GANFSEVSNT SFELNSENVT 180

MKWSVLYNV TINNTYSCMI ENDIAKATGD IKVTESEIKR RSDKTHTCPP CPAPELLGGP 240

SVFLFPPKPK DTLMISRTPE VTCVWDVSH EDPEVKFN Y VDGVEVHNAK TKPREEQYNS 300

TYRWSVLTV LHQD LNGKE YKCKVSNKAL PAPIEKTISK AKGQPREPQV YTLPPSRDEL 360

TKNQVSLTCL VKGFYPSDIA VE ESNGQPE NNYKTTPPVL DSDGSFFLYS KLTVDKSR Q 420

QGNVFSCSVM HEALHNHYTQ KSLSLSPGK 449

(SEQ ID NO: 13).

In another embodiment, a representative human B7-H4 fusion protein has at least 80%, 85%, 90%, 95%, 99% or 100% sequence identity to:

MEWSWVFLFF LSVTTGVHSG FGISGRHSIT VTTVASAGNI GEDGIQSCTF EPDIKLSDIV 60

IQWLKEGVLG LVHEFKEGKD ELSEQDEMFR GRTAVFADQV IVGNASLRLK NVQLTDAGTY 120

KCYIITSKGK GNANLEYKTG AFSMPEVNVD YNASSETLRC EAPRWFPQPT WWASQVDQG 180

ANFSEVSNTS FELNSENVTM KWSVLYNVT INNTYSCMIE NDIAKATGDI KVTESEIDKT 240

HTCPPCPAPE LLGGPSVFLF PPKPKDTLMI SRTPEVTCW VDVSHEDPEV KFNWYVDGVE 300

VHNAKTKPRE EQYNSTYRW SVLTVLHQDW LNGKEYKCKV SNKALPAPIE KTISKAKGQP 360

REPQVYTLPP SRDELTKNQV SLTCLVKGFY PSDIAVEWES NGQPENNYKT TPPVLDSDGS 420

FFLYSKLTVD KSRWQQGNVF SCSVMHEALH NHYTQKSLSL SPGK 464

(SEQ ID NO: 14).

The amino acid sequence of the human B7-H4 fusion protein of SEQ ID NO: 14 without the signal sequence can be:

GFGISGRHSI TVTTVASAGN IGEDGIQSCT FEPDIKLSDI VIQWLKEGVL GLVHEFKEGK 60

DELSEQDEMF RGRTAVFADQ VIVGNASLRL KNVQLTDAGT YKCYIITSKG KGNANLEYKT 120

GAFSMPEVNV DYNASSETLR CEAPRWFPQP TWWASQVDQ GANFSEVSNT SFELNSENVT 180 MKWSVLYNV TINNTYSCMI ENDIAKATGD IKVTESEIDK THTCPPCPAP ELLGGPSVFL 240

FPPKPKDTLM ISRTPEVTCV WDVSHEDPE VKFN YVDGV EVHNAKTKPR EEQYNSTYRV 300

VSVLTVLHQD LNGKEYKCK VSNKALPAPI EKTISKAKGQ PREPQVYTLP PSRDELTKNQ 360

VSLTCLVKGF YPSDIAVE E SNGQPENNYK TTPPVLDSDG SFFLYSKLTV DKSR QQG V 420

FSCSVMHEAL HNHYTQKSLS LSPGK 445

(SEQ ID NO: 15).

In another embodiment, a representative human B7-H4 fusion protein has at least 80%, 85%, 90%, 95%, 99% or 100% sequence identity to:

ME S VFLFF LSVTTGVHSG FGISGRHSIT V VASAGNI GEDGIQSCTF EPDIKLSDIV 60

IQ LKEGVLG LVHEFKEGKD ELSEQDEMFR GRTAVFADQV IVGNASLRLK NVQLTDAGTY 120

KCYIITSKGK GNANLEYKTG AFSMPEVNVD YNASSETLRC EAPR FPQPT W ASQVDQG 180

ANFSEVSNTS FELNSENVTM KWSVLYNVT INNTYSCMIE NDIAKATGDI KVTESEIKRR 240

SHLQLLNSKD KTHTCPPCPA PELLGGPSVF LFPPKPKDTL MISRTPEVTC VWDVSHEDP 300

EVKFN YVDG VEVHNAKTKP REEQYNSTYR WSVLTVLHQ D LNGKEYKC KVSNKALPAP 360

IEKTISKAKG QPREPQVYTL PPSRDELTKN QVSLTCLVKG FYPSDIAVE ESNGQPENNY 420

KTTPPVLDSD GSFFLYSKLT VDKSR QQGN VFSCSVMHEA LHNHYTQKSL SLSPGK 476

(SEQ ID NO: 16).

The amino acid sequence of the human B7-H4 fusion protein of SEQ ID NO: 16 without the signal sequence can be:

GFGISGRHSI TVTTVASAGN IGEDGIQSCT FEPDIKLSDI VIQ LKEGVL GLVHEFKEGK 60

DELSEQDEMF RGRTAVFADQ VIVGNASLRL KNVQLTDAGT YKCYIITSKG KGNANLEYKT 120

GAFSMPEVNV DYNASSETLR CEAPR FPQP TW ASQVDQ GANFSEVSNT SFELNSENVT 180

MKWSVLYNV TINNTYSCMI ENDIAKATGD IKVTESEIKR RSHLQLLNSK DKTHTCPPCP 240

APELLGGPSV FLFPPKPKDT LMISRTPEVT CVWDVSHED PEVKFN YVD GVEVHNAKTK 300

PREEQYNSTY RWSVLTVLH QD LNGKEYK CKVSNKALPA PIEKTISKAK GQPREPQVYT 360

LPPSRDELTK NQVSLTCLVK GFYPSDIAVE ESNGQPENN YKTTPPVLDS DGSFFLYSKL 420

TVDKSR QQG NVFSCSVMHE ALHNHYTQKS LSLSPGK 457

(SEQ ID NO: 17).

In another embodiment, a representative human B7-H4 fusion protein has at least 80%, 85%, 90%, 95%, 99% or 100% sequence identity to:

MEWSWVFLFF LSVTTGVHSG FGISGRHSIT VTTVASAGNI GEDGILSCTF EPDIKLSDIV 60

IQWLKEGVLG LVHEFKEGKD ELSEQDEMFR GRTAVFADQV IVGNASLRLK NVQLTDAGTY 120

KCYIITSKGK GNANLEYKTG AFSMPEVNVD YNASSETLRC EAPRWFPQPT WWASQVDQG 180

ANFSEVSNTS FELNSENVTM KWSVLYNVT INNTYSCMIE NDIAKATGDI KVTESEIKRR 240

SEPKSCDKTH TCPPCPAPEL LGGPSVFLFP PKPKDTLMIS RTPEVTCWV DVSHEDPEVK 300

FNWYVDGVEV HNAKTKPREE QYNSTYRWS VLTVLHQDWL NGKEYKCKVS NKALPAPIEK 360

TISKAKGQPR EPQVYTLPPS RDELTKNQVS LTCLVKGFYP SDIAVEWESN GQPENNYKTT 420

PPVLDSDGSF FLYSKLTVDK SRWQQGNVFS CSVMHEALHN HYTQKSLSLS PGK 473

(SEQ ID NO: 18).

The amino acid sequence of the human B7-H4 fusion protein of SEQ ID NO: 18 without the signal sequence can be:

GFGISGRHSI TVTTVASAGN IGEDGILSCT FEPDIKLSDI VIQWLKEGVL GLVHEFKEGK 60 DELSEQDEMF RGRTAVFADQ VIVGNASLRL KNVQLTDAGT YKCYIITSKG KGNANLEYKT 120

GAFSMPEVNV DYNASSETLR CEAPR FPQP TW ASQVDQ GANFSEVSNT SFELNSENVT 180

MKWSVLYNV TINNTYSCMI ENDIAKATGD IKVTESEIKR RSEPKSCDKT HTCPPCPAPE 240

LLGGPSVFLF PPKPKDTLMI SRTPEVTCW VDVSHEDPEV KFN YVDGVE VHNAKTKPRE 300

EQYNSTYRW SVLTVLHQD LNGKEYKCKV SNKALPAPIE KTISKAKGQP REPQVYTLPP 360

SRDELTKNQV SLTCLVKGFY PSDIAVE ES NGQPENNYKT TPPVLDSDGS FFLYSKLTVD 420

KSR QQGNVF SCSVMHEALH NHYTQKSLSL SPGK 454

(SEQ ID NO: 19).

In another embodiment, a representative human B7-H4 fusion protein has at least 80%, 85%, 90%, 95%, 99% or 100% sequence identity to:

ME S VFLFF LSVTTGVHSG FGISGRHSIT VTTVASAGNI GEDGILSCTF EPDIKLSDIV 60

IQ LKEGVLG LVHEFKEGKD ELSEQDEMFR GRTAVFADQV IVGNASLRLK NVQLTDAGTY 120

KCYIITSKGK GNANLEYKTG AFSMPEVNVD YNASSETLRC EAPR FPQPT W ASQVDQG 180

ANFSEVSNTS FELNSENVTM KWSVLYNVT INNTYSCMIE NDIAKATGDI KVTESEIKRR 240

SDKTHTCPPC PAPELLGGPS VFLFPPKPKD TLMISRTPEV TCVWDVSHE DPEVKFN YV 300

DGVEVHNAKT KPREEQYNST YRWSVLTVL HQD LNGKEY KCKVSNKALP APIEKTISKA 360

KGQPREPQVY TLPPSRDELT KNQVSLTCLV KGFYPSDIAV E ESNGQPEN NYKTTPPVLD 420

SDGSFFLYSK LTVDKSR QQ GNVFSCSVMH EALHNHYTQK SLSLSPGK 468

(SEQ ID NO:20).

The amino acid sequence of the human B7-H4 fusion protein of SEQ ID NO:20 without the signal sequence can be:

GFGISGRHSI TVTTVASAGN IGEDGILSCT FEPDIKLSDI VIQ LKEGVL GLVHEFKEGK 60

DELSEQDEMF RGRTAVFADQ VIVGNASLRL KNVQLTDAGT YKCYIITSKG KGNANLEYKT 120

GAFSMPEVNV DYNASSETLR CEAPRWFPQP TWWASQVDQ GANFSEVSNT SFELNSENVT 180

MKWSVLYNV TINNTYSCMI ENDIAKATGD IKVTESEIKR RSDKTHTCPP CPAPELLGGP 240

SVFLFPPKPK DTLMISRTPE VTCWVDVSH EDPEVKFNWY VDGVEVHNAK TKPREEQYNS 300

TYRWSVLTV LHQDWLNGKE YKCKVSNKAL PAPIEKTISK AKGQPREPQV YTLPPSRDEL 360

TKNQVSLTCL VKGFYPSDIA VEWESNGQPE NNYKTTPPVL DSDGSFFLYS KLTVDKSRWQ 420

QGNVFSCSVM HEALHNHYTQ KSLSLSPGK 449

(SEQ ID NO:21).

In another embodiment, a representative human B7-H4 fusion protein has at least 80%, 85%, 90%, 95%, 99% or 100% sequence identity to:

MEWSWVFLFF LSVTTGVHSG FGISGRHSIT VTTVASAGNI GEDGILSCTF EPDIKLSDIV 60

IQWLKEGVLG LVHEFKEGKD ELSEQDEMFR GRTAVFADQV IVGNASLRLK NVQLTDAGTY 120

KCYIITSKGK GNANLEYKTG AFSMPEVNVD YNASSETLRC EAPRWFPQPT WWASQVDQG 180

ANFSEVSNTS FELNSENVTM KWSVLYNVT INNTYSCMIE NDIAKATGDI KVTESEIDKT 240

HTCPPCPAPE LLGGPSVFLF PPKPKDTLMI SRTPEVTCW VDVSHEDPEV KFNWYVDGVE 300

VHNAKTKPRE EQYNSTYRW SVLTVLHQDW LNGKEYKCKV SNKALPAPIE KTISKAKGQP 360

REPQVYTLPP SRDELTKNQV SLTCLVKGFY PSDIAVEWES NGQPENNYKT TPPVLDSDGS 420

FFLYSKLTVD KSRWQQGNVF SCSVMHEALH NHYTQKSLSL SPGK 464

(SEQ ID NO:22). The amino acid sequence of the human B7-H4 fusion protein of SEQ ID NO:22 without the signal sequence can be:

GFGISGRHSI TVTTVASAGN IGEDGILSCT FEPDIKLSDI VIQ LKEGVL GLVHEFKEGK 60

DELSEQDEMF RGRTAVFADQ VIVGNASLRL KNVQL DAGT YKCYIITSKG KGNANLEYKT 120

GAFSMPEVNV DYNASSETLR CEAPR FPQP TW ASQVDQ GANFSEVSNT SFELNSENVT 180

MKWSVLYNV TINNTYSCMI ENDIAKATGD IKVTESEIDK THTCPPCPAP ELLGGPSVFL 240

FPPKPKDTLM ISRTPEVTCV WDVSHEDPE VKFN YVDGV EVHNAKTKPR EEQYNSTYRV 300

VSVLTVLHQD LNGKEYKCK VSNKALPAPI EKTISKAKGQ PREPQVYTLP PSRDELTKNQ 360

VSLTCLVKGF YPSDIAVE E SNGQPENNYK TTPPVLDSDG SFFLYSKLTV DKSR QQG V 420

FSCSVMHEAL HNHYTQKSLS LSPGK 445

(SEQ ID NO:23).

In another embodiment, a representative human B7-H4 fusion protein has at least 80%, 85%, 90%, 95%, 99% or 100% sequence identity to:

ME S VFLFF LSVTTGVHSG FGISGRHSIT VTTVASAGNI GEDGILSCTF EPDIKLSDIV 60

IQ LKEGVLG LVHEFKEGKD ELSEQDEMFR GRTAVFADQV IVGNASLRLK NVQLTDAGTY 120

KCYIITSKGK GNANLEYKTG AFSMPEVNVD YNASSETLRC EAPR FPQPT W ASQVDQG 180

ANFSEVSNTS FELNSENVTM KWSVLYNVT INNTYSCMIE NDIAKATGDI KVTESEIKRR 240

SHLQLLNSKD KTHTCPPCPA PELLGGPSVF LFPPKPKDTL MISRTPEVTC VWDVSHEDP 300

EVKFN YVDG VEVHNAKTKP REEQYNSTYR WSVLTVLHQ D LNGKEYKC KVSNKALPAP 360

IEKTISKAKG QPREPQVYTL PPSRDELTKN QVSLTCLVKG FYPSDIAVE ESNGQPENNY 420

KTTPPVLDSD GSFFLYSKLT VDKSR QQGN VFSCSVMHEA LHNHYTQKSL SLSPGK 476

(SEQ ID NO:24).

The amino acid sequence of the human B7-H4 fusion protein of SEQ ID NO:24 without the signal sequence can be:

GFGISGRHSI TVTTVASAGN IGEDGILSCT FEPDIKLSDI VIQWLKEGVL GLVHEFKEGK 60

DELSEQDEMF RGRTAVFADQ VIVGNASLRL KNVQLTDAGT YKCYIITSKG KGNANLEYKT 120

GAFSMPEVNV DYNASSETLR CEAPRWFPQP TWWASQVDQ GANFSEVSNT SFELNSENVT 180

MKWSVLYNV TINNTYSCMI ENDIAKATGD IKVTESEIKR RSHLQLLNSK DKTHTCPPCP 240

APELLGGPSV FLFPPKPKDT LMISRTPEVT CWVDVSHED PEVKFNWYVD GVEVHNAKTK 300

PREEQYNSTY RWSVLTVLH QDWLNGKEYK CKVSNKALPA PIEKTISKAK GQPREPQVYT 360

LPPSRDELTK NQVSLTCLVK GFYPSDIAVE WESNGQPENN YKTTPPVLDS DGSFFLYSKL 420

TVDKSRWQQG NVFSCSVMHE ALHNHYTQKS LSLSPGK 457

(SEQ ID NO:25).

In another embodiment, a representative human B7-H4 fusion protein has at least 80%, 85%, 90%, 95%, 99% or 100% sequence identity to:

ME S VFLFF LSVTTGVHSG FGISGRHSIT VTTVASAGNI GEDGILSCTF EPDIKLSDIV 60

IQ LKEGVLG LVHEFKEGKD ELSEQDEMFR GRTAVFADQV IVGNASLRLK NVQLTDAGTY 120

KCYIITSKGK GNANLEYKTG AFSMPEVNVD YNASSETLRC EAPR FPQPT W ASQVDQG 180

ANFSEVSNTS FELNSENVTM KWSVLYNVT INNTYSCMIE NDIAKATGDI KVTESEIKRR 240

SEPKSCDKTH TCPPCPAPEL LGGPSVFLFP PKPKDTLMIS RTPEVTCVW DVSHEDPEVK 300

FN YVDGVEV HNAKTKPREE QYQSTYRWS VLTVLHQD L NGKEYKCKVS NKALPAPIEK 360

TISKAKGQPR EPQVYTLPPS RDELTKNQVS LTCLVKGFYP SDIAVE ESN GQPENNYKTT 420

PPVLDSDGSF FLYSKLTVDK SR QQGNVFS CSVMHEALHN HYTQKSLSLS PGK 473

(SEQ ID NO:26).

The amino acid sequence of the human B7-H4 fusion protein of SEQ ID NO:26 without the signal sequence can be:

GFGISGRHSI TVTTVASAGN IGEDGILSCT FEPDIKLSDI VIQ LKEGVL GLVHEFKEGK 60

DELSEQDEMF RGRTAVFADQ VIVGNASLRL KNVQLTDAGT YKCYIITSKG KGNANLEYKT 120

GAFSMPEVNV DYNASSETLR CEAPR FPQP TW ASQVDQ GANFSEVSNT SFELNSENVT 180

MKWSVLYNV TINNTYSCMI ENDIAKATGD IKVTESEIKR RSEPKSCDKT HTCPPCPAPE 240

LLGGPSVFLF PPKPKDTLMI SRTPEVTCW VDVSHEDPEV KFN YVDGVE VHNAKTKPRE 300

EQYQSTYRW SVLTVLHQD LNGKEYKCKV SNKALPAPIE KTISKAKGQP REPQVYTLPP 360

SRDELTKNQV SLTCLVKGFY PSDIAVE ES NGQPENNYKT TPPVLDSDGS FFLYSKLTVD 420

KSR QQGNVF SCSVMHEALH NHYTQKSLSL SPGK 454

(SEQ ID NO:27).

In another embodiment, a representative human B7-H4 fusion protein has at least 80%, 85%, 90%, 95%, 99% or 100% sequence identity to:

MEWSWVFLFF LSVTTGVHSF GISGRHSITV TTVASAGNIG EDGILSCTFE PDIKLSDIVI 60

QWLKEGVLGL VHEFKEGKDE LSEQDEMFRG RTAVFADQVI VGNASLRLKN VQLTDAGTYK 120

CYIITSKGKG NANLEYKTGA EPKSSDKTHT CPPCPAPELL GGPSVFLFPP KPKDTLMISR 180

TPEVTCVWD VSHEDPEVKF NWYVDGVEVH NAKTKPREEQ YNSTYRWSV LTVLHQDWLN 240

GKEYKCKVSN KALPAPIEKT ISKAKGQPRE PQVYTLPPSR DELTKNQVSL TCLVKGFYPS 300

DIAVEWESNG QPENNYKTTP PVLDSDGSFF LYSKLTVDKS RWQQGNVFSC SVMHEALHNH 360

YTQKSLSLSP G 371

(SEQ ID NO:28).

The amino acid sequence of the human B7-H4 fusion protein of SEQ ID NO:28 without the signal sequence can be:

FGISGRHSIT VTTVASAGNI GEDGILSCTF EPDIKLSDIV IQWLKEGVLG LVHEFKEGKD 60

ELSEQDEMFR GRTAVFADQV IVGNASLRLK NVQLTDAGTY KCYIITSKGK GNANLEYKTG 120

AEPKSSDKTH TCPPCPAPEL LGGPSVFLFP PKPKDTLMIS RTPEVTCVW DVSHEDPEVK 180

FNWYVDGVEV HNAKTKPREE QYNSTYRWS VLTVLHQDWL NGKEYKCKVS NKALPAPIEK 240

TISKAKGQPR EPQVYTLPPS RDELTKNQVS LTCLVKGFYP SDIAVEWESN GQPENNYKTT 300

PPVLDSDGSF FLYSKLTVDK SRWQQGNVFS CSVMHEALHN HYTQKSLSLS PG 352

(SEQ ID NO:29). In another embodiment, a representative human B7-H4 fusion protein has at least 80%, 85%, 90%, 95%, 99% or 100% sequence identity to:

ME S VFLFF LSVTTGVHSF GISGRHSITV TTVASAGNIG EDGILSCTFE PDIKLSDIVI 60

Q LKEGVLGL VHEFKEGKDE LSEQDEMFRG RTAVFADQVI VGNASLRLKN VQLTDAGTYK 120

CYIITSKGKG NANLEYKTGA FSMPEEPKSS DKTHTCPPCP APELLGGPSV FLFPPKPKDT 180

LMISRTPEVT CVWDVSHED PEVKFN YVD GVEVHNAKTK PREEQYNSTY RWSVLTVLH 240

QD LNGKEYK CKVSNKALPA PIEKTISKAK GQPREPQVYT LPPSRDELTK NQVSLTCLVK 300

GFYPSDIAVE ESNGQPENN YKTTPPVLDS DGSFFLYSKL TVDKSR QQG NVFSCSVMHE 360

ALHNHYTQKS LSLSPG 376

(SEQ ID NO:30).

The amino acid sequence of the human B7-H4 fusion protein of SEQ ID NO:30 without the signal sequence can be:

FGISGRHSIT VTTVASAGNI GEDGILSCTF EPDIKLSDIV IQ LKEGVLG LVHEFKEGKD 60

ELSEQDEMFR GRTAVFADQV IVGNASLRLK NVQLTDAGTY KCYIITSKGK GNANLEYKTG 120

AFSMPEEPKS SDKTHTCPPC PAPELLGGPS VFLFPPKPKD TLMISRTPEV TCVWDVSHE 180

DPEVKFN YV DGVEVHNAKT KPREEQYNST YRWSVLTVL HQD LNGKEY KCKVSNKALP 240

APIEKTISKA KGQPREPQVY TLPPSRDELT KNQVSLTCLV KGFYPSDIAV E ESNGQPEN 300

NYKTTPPVLD SDGSFFLYSK LTVDKSR QQ GNVFSCSVMH EALHNHYTQK SLSLSPG 357

(SEQ ID NO:31).

In another embodiment, a representative human B7-H4 fusion protein has at least 80%, 85%, 90%, 95%, 99% or 100% sequence identity to:

MEWSWVFLFF LSVTTGVHSF GISGRHSITV TTVASAGNIG EDGILSCTFE PDIKLSDIVI 60

QWLKEGVLGL VHEFKEGKDE LSEQDEMFRG RTAVFADQVI VGNASLRLKN VQLTDAGTYK 120

CYIITSKGKG NANLEYKTGA FSMPEVNVDE PKSSDKTHTC PPCPAPELLG GPSVFLFPPK 180

PKDTLMISRT PEVTCVWDV SHEDPEVKFN WYVDGVEVHN AKTKPREEQY NSTYRWSVL 240

TVLHQDWLNG KEYKCKVSNK ALPAPIEKTI SKAKGQPREP QVYTLPPSRD ELTKNQVSLT 300

CLVKGFYPSD IAVEWESNGQ PENNYKTTPP VLDSDGSFFL YSKLTVDKSR WQQGNVFSCS 360

VMHEALHNHY TQKSLSLSPG 380

(SEQ ID NO:32).

The amino acid sequence of the human B7-H4 fusion protein of SEQ ID NO:32 without the signal sequence can be:

FGISGRHSIT VTTVASAGNI GEDGILSCTF EPDIKLSDIV IQWLKEGVLG LVHEFKEGKD 60

ELSEQDEMFR GRTAVFADQV IVGNASLRLK NVQLTDAGTY KCYIITSKGK GNANLEYKTG 120

AFSMPEVNVD EPKSSDKTHT CPPCPAPELL GGPSVFLFPP KPKDTLMISR TPEVTCVWD 180

VSHEDPEVKF NWYVDGVEVH NAKTKPREEQ YNSTYRWSV LTVLHQDWLN GKEYKCKVSN 240

KALPAPIEKT ISKAKGQPRE PQVYTLPPSR DELTKNQVSL TCLVKGFYPS DIAVEWESNG 300

QPENNYKTTP PVLDSDGSFF LYSKLTVDKS RWQQGNVFSC SVMHEALHNH YTQKSLSLSP 360

G 361

(SEQ ID NO:33).

In another embodiment, a representative human B7-H4 fusion protein has at least 80%, 85%, 90%, 95%, 99% or 100% sequence identity to: ME S VFLFF LSVTTGVHSF GISGRHSITV TTVASAGNIG EDGILSCTFE PDIKLSDIVI 60

Q LKEGVLGL VHEFKEGKDE LSEQDEMFRG RTAVFADQVI VGNASLRLKN VQLTDAGTYK 120

CYIITSKGKG NANLEYKTGA FSMPEVNVDY NASSETLRCE APR FPQPTV V ASQVDQGA 180

NFSEVSNTSF ELNSENVTMK WSVLYNVTI NNTYSCMIEN DIAKATGDIK VTESEIKRRS 240

HLQLLNSKAS ESKYGPCPPC PAPEFLGGPS VFLFPPKPKD TLMISRTPEV TCVWDVSQE 300

DPEVQFN YV DGVEVHNAKT KPREEQFNST YRWSVLTVL HQD LNGKEY KCKVSNKGLP 360

SSIEKTISKA KGQPREPQVY TLPPSQEEMT KNQVSLTCLV KGFYPSDIAV E ESNGQPEN 420

NYKTTPPVLD SDGSFFLYSR LTVDKSR QE GNVFSCSVMH EALHNHYTQK SLSLSPG 477

(SEQ ID NO:34).

The amino acid sequence of the human B7-H4 fusion protein of SEQ ID NO:34 without the signal sequence can be:

FGISGRHSIT VTTVASAGNI GEDGILSCTF EPDIKLSDIV IQ LKEGVLG LVHEFKEGKD 60

ELSEQDEMFR GRTAVFADQV IVGNASLRLK NVQLTDAGTY KCYIITSKGK GNANLEYKTG 120

AFSMPEVNVD YNASSETLRC EAPR FPQPT W ASQVDQG ANFSEVSNTS FELNSENVTM 180

KWSVLYNVT INNTYSCMIE NDIAKATGDI KVTESEIKRR SHLQLLNSKA SESKYGPCPP 240

CPAPEFLGGP SVFLFPPKPK DTLMISRTPE VTCVWDVSQ EDPEVQFN Y VDGVEVHNAK 300

TKPREEQFNS TYRWSVLTV LHQD LNGKE YKCKVSNKGL PSSIEKTISK AKGQPREPQV 360

YTLPPSQEEM TKNQVSLTCL VKGFYPSDIA VE ESNGQPE NNYKTTPPVL DSDGSFFLYS 420

RLTVDKSR Q EGNVFSCSVM HEALHNHYTQ KSLSLSPG 458

(SEQ ID NO:35).

In another embodiment, a representative human B7-H4 fusion protein has at least 80%, 85%, 90%, 95%, 99% or 100% sequence identity to:

MEWSWVFLFF LSVTTGVHSE VNVDYNASSE TLRCEAPRWF PQPTWWASQ VDQGANFSEV 60

SNTSFELNSE NVTMKWSVL YNVTINNTYS CMIENDIAKA TGDIKVTESE IKQQSHLQLL 120

NSKASEPKSS DKTHTCPPCP APELLGGPSV FLFPPKPKDT LMISRTPEVT CVWDVSHED 180

PEVKFNWYVD GVEVHNAKTK PREEQYNSTY RWSVLTVLH QDWLNGKEYK CKVSNKALPA 240

PIEKTISKAK GQPREPQVYT LPPSRDELTK NQVSLTCLVK GFYPSDIAVE WESNGQPENN 300

YKTTPPVLDS DGSFFLYSKL TVDKSRWQQG NVFSCSVMHE ALHNHYTQKS LSLSPG 356

(SEQ ID NO:36).

The amino acid sequence of the human B7-H4 fusion protein of SEQ ID NO:36 without the signal sequence can be:

EVNVDYNASS ETLRCEAPRW FPQPTWWAS QVDQGANFSE VSNTSFELNS ENVTMKWSV 60

LYNVTINNTY SCMIENDIAK ATGDIKVTES EIKQQSHLQL LNSKASEPKS SDKTHTCPPC 120

PAPELLGGPS VFLFPPKPKD TLMISRTPEV TCVWDVSHE DPEVKFNWYV DGVEVHNAKT 180

KPREEQYNST YRWSVLTVL HQDWLNGKEY KCKVSNKALP APIEKTISKA KGQPREPQVY 240

TLPPSRDELT KNQVSLTCLV KGFYPSDIAV EWESNGQPEN NYKTTPPVLD SDGSFFLYSK 300

LTVDKSRWQQ GNVFSCSVMH EALHNHYTQK SLSLSPG 337

(SEQ ID NO:37).

In another embodiment, a representative human B7-H4 fusion protein has at least 80%, 85%, 90%, 95%, 99% or 100% sequence identity to:

MEWSWVFLFF LSVTTGVHSF GISGRHSITV TTVASAGNIG EDGILSCTFE PDIKLSDIVI 60

QWLKEGVLGL VHEFKEGKDE LSEQDEMFRG RTAVFADQVI VGNASLRLKN VQLTDAGTYK 120 CYIITSKGKG NANLEYKTGA FSMPEVNVDY NASSETLRCE APR FPQPTV V ASQVDQGA 180

NFSEVSNTSF ELNSENVTMK WSVLYNVTI NNTYSCMIEN DIAKATGDIK VTESEIKQQS 240

HLQLLNSKAS EPKSSDKTHT CPPCPAPELL GGPSVFLFPP KPKDTLMISR TPEVTCVWD 300

VSHEDPEVKF N YVDGVEVH NAKTKPREEQ YNSTYRWSV LTVLHQD LN GKEYKCKVSN 360 KALPAPIEKT ISKAKGQPRE PQVYTLPPSR DELTKNQVSL TCLVKGFYPS DIAVE ESNG 420

QPENNYKTTP PVLDSDGSFF LYSKLTVDKS R QQGNVFSC SVMHEALHNH YTQKSLSLSP 480

G 481

(SEQ ID NO:38).

The amino acid sequence of the human B7-H4 fusion protein of SEQ ID NO:38 without the signal sequence can be:

FGISGRHSIT VTTVASAGNI GEDGILSCTF EPDIKLSDIV IQ LKEGVLG LVHEFKEGKD 60

ELSEQDEMFR GRTAVFADQV IVGNASLRLK NVQLTDAGTY KCYIITSKGK GNANLEYKTG 120

AFSMPEVNVD YNASSETLRC EAPR FPQPT W ASQVDQG ANFSEVSNTS FELNSENVTM 180

KWSVLYNVT INNTYSCMIE NDIAKATGDI KVTESEIKQQ SHLQLLNSKA SEPKSSDKTH 240 TCPPCPAPEL LGGPSVFLFP PKPKDTLMIS RTPEVTCVW DVSHEDPEVK FN YVDGVEV 300

HNAKTKPREE QYNSTYRWS VLTVLHQD L NGKEYKCKVS NKALPAPIEK TISKAKGQPR 360

EPQVYTLPPS RDELTKNQVS LTCLVKGFYP SDIAVE ESN GQPENNYKTT PPVLDSDGSF 420

FLYSKLTVDK SR QQGNVFS CSVMHEALHN HYTQKSLSLS PG 462

(SEQ ID NO:39).

The aforementioned exemplary fusion proteins can incorporate any combination of the variants described herein. In another embodiment the terminal lysine of the aforementioned exemplary fusion proteins is deleted.

The disclosed fusion proteins can be isolated using standard molecular biology techniques. For example, an expression vector containing a DNA sequence encoding a B7-H4-Ig fusion protein is transfected into 293 cells by calcium phosphate precipitation and cultured in serum- free DMEM. The supernatant is collected at 72 h and the fusion protein is purified by Protein G, or preferably Protein A SEPHAROSE® columns (Pharmacia, Uppsala, Sweden).

b. Peptide and Polypeptide Modifications

The fusion proteins may be modified by chemical moieties that may be present in polypeptides in a normal cellular environment, for example, phosphorylation, methylation, amidation, sulfation, acylation, glycosylation, sumoylation and ubiquitylation. Fusion proteins may also be modified with a label capable of providing a detectable signal, either directly or indirectly, including, but not limited to, radioisotopes and fluorescent compounds.

The fusion proteins may also be modified by chemical moieties that are not normally added to polypeptides in a cellular environment. For example, the disclosed fusion proteins may also be modified by covalent attachment of polymer chains, including, but not limited to, polyethylene glycol polymer (PEG) chains (i.e. pegylation). Conjugation of

macromolecules to PEG has emerged recently as an effective strategy to alter the pharmacokinetic (PK) profiles of a variety of drugs, and thereby to improve their therapeutic potential. PEG conjugation increases retention of drugs in the circulation by protecting against enzymatic digestion, slowing filtration by the kidneys and reducing the generation of neutralizing antibodies. In addition, PEG conjugates can be used to allow multimerization of the fusion proteins.

Modifications may be introduced into the molecule by reacting targeted amino acid residues of the polypeptide with an organic derivatizing agent that is capable of reacting with selected side chains or terminal residues. Another modification is cyclization of the protein.

Examples of chemical derivatives of the polypeptides include lysinyl and amino terminal residues derivatized with succinic or other carboxylic acid anhydrides. Derivatization with a cyclic carboxylic anhydride has the effect of reversing the charge of the lysinyl residues. Other suitable reagents for derivatizing amino-containing residues include imidoesters such as methyl picolinimidate; pyridoxal phosphate; pyridoxal; chloroborohydride; trinitrobenzenesulfonic acid; 0-methylisourea; 2,4 pentanedione; and transaminase-catalyzed reaction with glyoxylate. Carboxyl side groups, aspartyl or glutamyl, may be selectively modified by reaction with carbodiimides (R— =C=N— R') such as l-cyclohexyl-3-(2-morpholinyl-(4- ethyl)carbodiimide or l-ethyl-3-(4-azonia-4,4-dimethylpentyl) carbodiimide. Furthermore, aspartyl and glutamyl residues can be converted to asparaginyl and glutaminyl residues by reaction with ammonia. Fusion proteins may also include one or more D-amino acids that are substituted for one or more L-amino acids.

c. Modified Binding Properties

Binding properties of the B7-H4 polypeptides, fragments and fusions thereof (collectively referred to as B7-H4 polypeptides) are relevant to the dose and dose regimen to be administered. In one embodiment the disclosed B7-H4 polypeptides have binding properties to at least one receptor on a T cell that demonstrate a higher term, or higher percentage, of occupancy of receptor molecules on immune cells relative to other ligands of the receptor molecules. In other embodiments, the disclosed B7-H4 polypeptides have reduced binding affinity to a receptor on T cells relative to wildtype B7-H4, allowing the protein to dissociate in a period of less than three months, two months, one month, three weeks, two weeks, one week, or a few days after administration.

In some embodiments the B7-H4 polypeptides, or fragments, or fusions thereof have a relatively high affinity for its receptor, and may therefore have a relatively slow off rate. In other embodiments, the B7-H4 polypeptides are administered intermittently over a period of days, weeks or months to dampen immune responses which are allowed to recover prior to the next administration, which may serve to reduce the immune response without completely turning the immune response off and may avoid long term side effects.

5. Isolated Nucleic Acid Molecules

Isolated nucleic acid sequences encoding B7-H4 polypeptides, fragments and fusions thereof are disclosed herein. Useful murine B7-H4 nucleic acids have at least about 80, 85, 90, 95 or 100% sequence identity to the B7-H4 nucleic acid having GenBank Accession Number NM_178594 or AY280973. Useful human B7-H4 nucleic acids have at least about 80, 85, 90, 95 or 100% sequence identity to the B7-H4 nucleic acid having GenBank Accession Number AK026071. As used herein, "isolated nucleic acid" refers to a nucleic acid that is separated from other nucleic acid molecules that are present in a mammalian genome, including nucleic acids that normally flank one or both sides of the nucleic acid in a mammalian genome (e.g., nucleic acids that encode non-B7-H4 proteins). The term "isolated" as used herein with respect to nucleic acids also includes the combination with any non-naturally-occurring nucleic acid sequence, since such non-naturally- occurring sequences are not found in nature and do not have immediately contiguous sequences in a naturally-occurring genome. An isolated nucleic acid can be, for example, a DNA molecule, provided one of the nucleic acid sequences normally found immediately flanking that DNA molecule in a naturally-occurring genome is removed or absent. Thus, an isolated nucleic acid includes, without limitation, a DNA molecule that exists as a separate molecule independent of other sequences (e.g., a chemically synthesized nucleic acid, or a cDNA or genomic DNA fragment produced by PCR or restriction endonuclease treatment), as well as recombinant DNA that is incorporated into a vector, an autonomously replicating plasmid, a virus (e.g., a retrovirus, lentivirus, adenovirus, or herpes virus), or into the genomic DNA of a prokaryote or eukaryote. In addition, an isolated nucleic acid can include an engineered nucleic acid such as a recombinant DNA molecule that is part of a hybrid or fusion nucleic acid. A nucleic acid existing among hundreds to millions of other nucleic acids within, for example, a cDNA library or a genomic library, or a gel slice containing a genomic DNA restriction digest, is not to be considered an isolated nucleic acid.

Nucleic acids encoding polypeptides may be optimized for expression in the expression host of choice. Codons may be substituted with alternative codons encoding the same amino acid to account for differences in codon usage between the mammal from which the B7-H4 nucleic acid sequence is derived and the expression host. In this manner, the nucleic acids may be synthesized using expression host-preferred codons.

Nucleic acids can be in sense or antisense orientation, or can be complementary to a reference sequence encoding a B7-H4 polypeptide. Nucleic acids can be DNA, RNA, or nucleic acid analogs. Nucleic acid analogs can be modified at the base moiety, sugar moiety, or phosphate backbone. Such modification can improve, for example, stability, hybridization, or solubility of the nucleic acid. Modifications at the base moiety can include deoxyuridine for deoxythymidine, and 5-methyl-2'- deoxycytidine or 5-bromo-2'-deoxycytidine for deoxycytidine.

Modifications of the sugar moiety can include modification of the 2' hydroxyl of the ribose sugar to form 2'-0-methyl or 2'-0-allyl sugars. The deoxyribose phosphate backbone can be modified to produce morpholino nucleic acids, in which each base moiety is linked to a six membered, morpholino ring, or peptide nucleic acids, in which the deoxyphosphate backbone is replaced by a pseudopeptide backbone and the four bases are retained. See, for example, Summerton and Weller (1997) Antisense Nucleic Acid Drug Dev. 7: 187-195; and Hyrup et al. (1996) Bioorgan. Med. Chem. 4:5-23. In addition, the deoxyphosphate backbone can be replaced with, for example, a phosphorothioate or phosphorodithioate backbone, a

phosphoroamidite, or an alkyl phosphotriester backbone.

Nucleic acids encoding polypeptides can be administered to subjects in need thereof. Nucleic delivery involves introduction of "foreign" nucleic acids into a cell and ultimately, into a live animal. Compositions and methods for delivering nucleic acids to a subject are known in the art (see Understanding Gene Therapy, Lemoine, N.R., ed., BIOS Scientific

Publishers, Oxford, 2008).

6. Vectors and host cells

Vectors encoding B7-H4 polypeptides, fragments and fusions thereof are also provided. Nucleic acids, such as those described above, can be inserted into vectors for expression in cells. As used herein, a "vector" is a replicon, such as a plasmid, phage, virus or cosmid, into which another DNA segment may be inserted so as to bring about the replication of the inserted segment. Vectors can be expression vectors. An "expression vector" is a vector that includes one or more expression control sequences, and an "expression control sequence" is a DNA sequence that controls and regulates the transcription and/or translation of another DNA sequence.

Nucleic acids in vectors can be operably linked to one or more expression control sequences. As used herein, "operably linked" means incorporated into a genetic construct so that expression control sequences effectively control expression of a coding sequence of interest. Examples of expression control sequences include promoters, enhancers, and transcription terminating regions. A promoter is an expression control sequence composed of a region of a DNA molecule, typically within 100 nucleotides upstream of the point at which transcription starts (generally near the initiation site for RNA polymerase II). To bring a coding sequence under the control of a promoter, it is necessary to position the translation initiation site of the translational reading frame of the polypeptide between one and about fifty nucleotides downstream of the promoter. Enhancers provide expression specificity in terms of time, location, and level. Unlike promoters, enhancers can function when located at various distances from the transcription site. An enhancer also can be located downstream from the transcription initiation site. A coding sequence is "operably linked" and "under the control" of expression control sequences in a cell when RNA polymerase is able to transcribe the coding sequence into mRNA, which then can be translated into the protein encoded by the coding sequence.

Suitable expression vectors include, without limitation, plasmids and viral vectors derived from, for example, bacteriophage, baculoviruses, tobacco mosaic virus, herpes viruses, cytomegalo virus, retroviruses, vaccinia viruses, adenoviruses, and adeno-associated viruses. Numerous vectors and expression systems are commercially available from such corporations as Novagen (Madison, WI), Clontech (Palo Alto, CA), Stratagene (La Jolla, CA), and Invitrogen Life Technologies (Carlsbad, CA).

An expression vector can include a tag sequence. Tag sequences, are typically expressed as a fusion with the encoded polypeptide. Such tags can be inserted anywhere within the polypeptide including at either the carboxyl or amino terminus. Examples of useful tags include, but are not limited to, green fluorescent protein (GFP), glutathione S-transferase (GST), polyhistidine, c-myc, hemagglutinin, Flag™ tag (Kodak, New Haven, CT), maltose E binding protein and protein A. In one embodiment, a nucleic acid molecule encoding a B7-H4 fusion polypeptide is present in a vector containing nucleic acids that encode one or more domains of an Ig heavy chain constant region, preferably having an amino acid sequence corresponding to the hinge, CH2 and CH3 regions of a human

immunoglobulin Cyl chain.

Vectors containing nucleic acids to be expressed can be transferred into host cells. The term "host cell" is intended to include prokaryotic and eukaryotic cells into which a recombinant expression vector can be introduced. As used herein, "transformed" and "transfected" encompass the introduction of a nucleic acid molecule (e.g., a vector) into a cell by one of a number of techniques. Although not limited to a particular technique, a number of these techniques are well established within the art. Prokaryotic cells can be transformed with nucleic acids by, for example, electroporation or calcium chloride mediated transformation. Nucleic acids can be transfected into mammalian cells by techniques including, for example, calcium phosphate co-precipitation, DEAE-dextran-mediated transfection, lipofection, electroporation, or microinjection. Host cells (e.g., a prokaryotic cell or a eukaryotic cell such as a CHO cell) can be used to, for example, produce the B7-H4 polypeptides described herein.

The vectors described can be used to express B7-H4 polypeptides in cells, for example, cells for transplantation such as islet cells. An exemplary vector includes, but is not limited to, an adenoviral vector. One approach includes nucleic acid transfer into primary cells in culture followed by autologous transplantation of the ex vivo transformed cells into the host, either systemically or into a particular organ or tissue. Ex vivo methods can include, for example, the steps of harvesting cells from a subject, culturing the cells, transducing them with an expression vector, and maintaining the cells under conditions suitable for expression of the encoded polypeptides. These methods are known in the art of molecular biology. The transduction step can be accomplished by any standard means used for ex vivo gene therapy, including, for example, calcium phosphate, lipofection, electroporation, viral infection, and biolistic gene transfer. Alternatively, liposomes or polymeric microparticles can be used. Cells that have been successfully transduced then can be selected, for example, for expression of the coding sequence or of a drug resistance gene. The cells then can be lethally irradiated (if desired) and injected or implanted into the subject. In one embodiment, expression vectors containing nucleic acids encoding fusion proteins are transfected into cells that are administered to a subject in need thereof.

In vivo nucleic acid therapy can be accomplished by direct transfer of a functionally active DNA into mammalian somatic tissue or organ in vivo. For example, nucleic acids encoding polypeptides disclosed herein can be administered directly to lymphoid tissues or tumors. Alternatively, lymphoid tissue specific targeting can be achieved using lymphoid tissue-specific transcriptional regulatory elements (TREs) such as a B lymphocyte-, T lymphocyte-, or dendritic cell-specific TRE. Lymphoid tissue specific TREs are known in the art.

Nucleic acids may also be administered in vivo by viral means.

Nucleic acid molecules encoding fusion proteins may be packaged into retrovirus vectors using packaging cell lines that produce replication- defective retroviruses, as is well-known in the art. Other virus vectors may also be used, including recombinant adenoviruses and vaccinia virus, which can be rendered non-replicating. In addition to naked DNA or RNA, or viral vectors, engineered bacteria may be used as vectors.

Nucleic acids may also be delivered by other carriers, including liposomes, polymeric micro- and nanoparticles and polycations such as

asialoglycoprotein/polylysine.

In addition to virus- and carrier-mediated gene transfer in vivo, physical means well-known in the art can be used for direct transfer of DNA, including administration of plasmid DNA and particle-bombardment mediated gene transfer.

7. Methods of Manufacture

a. Methods for Producing Polypeptides

The disclosed B7-H4 polypeptides, fragments and fusions thereof can be manufactured using conventional techniques that are known in the art. Isolated fusion proteins can be obtained by, for example, chemical synthesis or by recombinant production in a host cell. To recombinantly produce a polypeptide, a nucleic acid containing a nucleotide sequence encoding the fusion protein can be used to transform, transduce, or transfect a bacterial or eukaryotic host cell (e.g., an insect, yeast, or mammalian cell). In general, nucleic acid constructs include a regulatory sequence operably linked to a nucleotide sequence encoding the fusion protein. Regulatory sequences (also referred to herein as expression control sequences) typically do not encode a gene product, but instead affect the expression of the nucleic acid sequences to which they are operably linked. Useful prokaryotic and eukaryotic systems for expressing and producing polypeptides are well known in the art include, for example, Escherichia coli strains such as BL-21 , and cultured mammalian cells such as CHO cells.

In eukaryotic host cells, a number of viral-based expression systems can be utilized to express fusion proteins. Viral based expression systems are well known in the art and include, but are not limited to, baculoviral, SV40, retroviral, or vaccinia based viral vectors.

Mammalian cell lines that stably express polypeptides can be produced using expression vectors with appropriate control elements and a selectable marker. For example, the eukaryotic expression vectors pCR3.1 (Invitrogen Life Technologies) and p91023(B) (see Wong et al. (1985) Science 228:810-815) are suitable for expression of variant polypeptides in, for example, Chinese hamster ovary (CHO) cells, COS-1 cells, human embryonic kidney 293 cells, NIH3T3 cells, BHK21 cells, MDCK cells, and human vascular endothelial cells (HUVEC). Additional suitable expression systems include the GS Gene Expression System™ available through Lonza Group Ltd.

Following introduction of an expression vector by electroporation, lipofection, calcium phosphate, or calcium chloride co-precipitation, DEAE dextran, or other suitable transfection method, stable cell lines can be selected (e.g., by metabolic selection, or antibiotic resistance to G418, kanamycin, or hygromycin). The transfected cells can be cultured such that the polypeptide of interest is expressed, and the polypeptide can be recovered from, for example, the cell culture supernatant or from lysed cells.

Alternatively, a fusion protein can be produced by (a) ligating amplified sequences into a mammalian expression vector such as pcDNA3 (Invitrogen Life Technologies), and (b) transcribing and translating in vitro using wheat germ extract or rabbit reticulocyte lysate.

Polypeptides can be isolated using, for example, chromatographic methods such as affinity chromatography, ion exhange chromatography, hydrophobic interaction chromatography, DEAE ion exchange, gel filtration, and hydroxylapatite chromatography. In some embodiments, polypeptides can be engineered to contain an additional domain containing amino acid sequence that allows the polypeptides to be captured onto an affinity matrix. For example, an Fc-fusion polypeptide in a cell culture supernatant or a cytoplasmic extract can be isolated using a protein A column. In addition, a tag such as c-myc, hemagglutinin, polyhistidine, or Flag™ (Kodak) can be used to aid polypeptide purification. Such tags can be inserted anywhere within the polypeptide, including at either the carboxyl or amino terminus. Other fusions that can be useful include enzymes that aid in the detection of the polypeptide, such as alkaline phosphatase. Immunoaffinity

chromatography also can be used to purify polypeptides. Polypeptides can additionally be engineered to contain a secretory signal (if there is not a secretory signal already present) that causes the polypeptide to be secreted by the cells in which it is produced. The secreted polypeptides, for example, fusion proteins can then conveniently be isolated from the cell media.

b. Methods for producing isolated nucleic acid molecules

Isolated nucleic acid molecules can be produced by standard techniques, including, without limitation, common molecular cloning and chemical nucleic acid synthesis techniques. For example, polymerase chain reaction (PCR) techniques can be used to obtain an isolated nucleic acid encoding a polypeptide. PCR is a technique in which target nucleic acids are enzymatically amplified. Typically, sequence information from the ends of the region of interest or beyond can be employed to design oligonucleotide primers that are identical in sequence to opposite strands of the template to be amplified. PCR can be used to amplify specific sequences from DNA as well as RNA, including sequences from total genomic DNA or total cellular RNA. Primers typically are 14 to 40 nucleotides in length, but can range from 10 nucleotides to hundreds of nucleotides in length. General PCR techniques are described, for example in PCR Primer: A Laboratory Manual, ed. by Dieffenbach and Dveksler, Cold Spring Harbor Laboratory Press, 1995. When using RNA as a source of template, reverse transcriptase can be used to synthesize a complementary DNA (cDNA) strand. Ligase chain reaction, strand displacement amplification, self-sustained sequence replication or nucleic acid sequence-based amplification also can be used to obtain isolated nucleic acids. See, for example, Lewis (1992) Genetic Engineering News 12: 1; Guatelli et al. (1990) Proc. Natl. Acad. Set USA 87: 1874-1878; and Weiss (1991) Science 254: 1292-1293.

Isolated nucleic acids can be chemically synthesized, either as a single nucleic acid molecule or as a series of oligonucleotides (e.g., using phosphoramidite technology for automated DNA synthesis in the 3 ' to 5 ' direction). For example, one or more pairs of long oligonucleotides (e.g., >100 nucleotides) can be synthesized that contain the desired sequence, with each pair containing a short segment of complementarity (e.g., about 15 nucleotides) such that a duplex is formed when the oligonucleotide pair is annealed. DNA polymerase can be used to extend the oligonucleotides, resulting in a single, double-stranded nucleic acid molecule per

oligonucleotide pair, which then can be ligated into a vector. Isolated nucleic acids can also obtained by mutagenesis. Polypeptide-encoding nucleic acids can be mutated using standard techniques, including oligonucleotide-directed mutagenesis and/or site-directed mutagenesis through PCR. See, Short Protocols in Molecular Biology. Chapter 8, Green Publishing Associates and John Wiley & Sons, edited by Ausubel et al, 1992. Examples of amino acid positions that can be modified include those described herein.

B. Anti-B7-H4 Antibodies

1. Antibodies that Bind to B7-H4 Polypeptides

Antibodies and antigen binding fragments thereof that bind to an epitope on one or more B7-H4 polypeptides are disclosed. When a recombinant B7-H4 polypeptide, or fragment or fusion thereof contains the epitope recognized by the antibody, the antibody can also bind to the recombinant B7-H4 polypeptide, or fragment or fusion thereof. In some embodiments, the antibody binds to an epitope on a B7-H4 polypeptide expressed by a cell that is masked or absent on a recombinant B7-H4 polypeptide or fragment or fusion thereof. In some embodiments, the antibody binds to an epitope on a recombinant B7-H4 polypeptide or fragment or fusion thereof that is masked or absent on an endogenous B7-H4 polypeptide.

An anti-B7-H4 antibody or anitgen binding fragment thereof can be labeled with a detectable marker or conjugated to a second molecule.

Suitable detectable markers include, but are not limited to, a radioisotope, a fluorescent compound, a bioluminescent compound, biotin,

chemiluminescent compound, a metal chelator or an enzyme. In some embodiments, the second molecule is a drug. Further, bi-specific antibodies specific for two or more B7-H4 epitopes can be generated using methods generally known in the art. Homodimeric antibodies can also be generated by cross-linking techniques known in the art (e.g., Wolff et al., Cancer Res. 53: 2560-2565).

a. Antibodies that Bind to an IgV domain

of B7-H4

Antibodies can bind an epitope within the IgV domain of a B7-H4 polypeptide. Typically, the IgV domain of B7-H4 includes conserved cysteine residues that may be important for formation of disulfide bonds inside the IgV domain. Accordingly, an antibody can bind to a linear epitope that includes 4, 5, 6, 7, 8, 9, 10, 1 1, or more continuous amino acids an IgV domain including between about amino acid 56 and amino acid 130 of SEQ ID NO:2 (i.e., SEQ ID NO:6) or SEQ ID NO:4 (i.e., SEQ ID NO:7) numbered from the N-terminal methionine.

The IgV domain can include about amino acid 37 through about amino acid 154 of SEQ ID NO:2 or SEQ ID NO:4. Accordingly, in some embodiments, the antibody binds to a linear epitope that includes 4, 5, 6, 7, 8, 9, 10, 11, or more continuous amino acids an IgV domain including between about amino acid 37 and amino acid 154 of SEQ ID NO:2 or SEQ ID NO:4 numbered from the N-terminal methionine.

An antibody can bind a conformational epitope that includes a 3-D surface feature, shape, or tertiary structure of the IgV domain of B7-H4.

In some embodiments, the antibody binds a transmembrane B7-H4 expressed by a cell, cell-free B7-H4, and recombinant fragments and fusion thereof that include an IgV domain, but does not bind to recombinant fragments and fusions of B7-H4 where part or all of the IgV has been deleted. For example, in some embodiments, an antibody binds to the polypeptide of SEQ ID NO:2, 4, 10, 18, 28, 30, 32, 34, 38, or a combination thereof but does not bind to SEQ ID NO:36. Therefore, in some

embodiments, the antibody binds to an epitope within or formed by

GFGISGRHSI TVTTVASAGN IGEDGILSCT FEPDIKLSDI VIQ LKEGVL GLVHEFKEGK 60 DELSEQDEMF RGRTAVFADQ VIVGNASLRL KNVQL DAGT YKCYIITSKG KGNANLEYKT 120 GAFSMP 126

(SEQ ID NO:40), or

FGISGRHSIT VTTVASAGNI GEDGILSCTF EPDIKLSDIV IQ LKEGVLG LVHEFKEGKD 60 ELSEQDEMFR GRTAVFADQV IVGNASLRLK NVQLTDAGTY KCYIITSKGK GNANLEYKTG 120 AFSMP 125

(SEQ ID NO:41), or

GFGISGRHSI TVTTVASAGN IGEDGIQSCT FEPDIKLSDI VIQWLKEGVL GLVHEFKEGK 60 DELSEQDEMF RGRTAVFADQ VIVGNASLRL KNVQLTDAGT YKCYIITSKG KGNANLEYKT 120

GAFSMP 126

(SEQ ID NO:42), or

FGISGRHSIT VTTVASAGNI GEDGIQSCTF EPDIKLSDIV IQWLKEGVLG LVHEFKEGKD 60

ELSEQDEMFR GRTAVFADQV IVGNASLRLK NVQLTDAGTY KCYIITSKGK GNANLEYKTG 120 AFSMP 125

(SEQ ID NO:43).

Therefore, the antibody can be used to specifically bind to polypeptides including SEQ ID NO:40, 41, 42, or 43.

Exemplary antibodies that bind to an IgV domain of B7-H4, for example a B7-H4 polypeptide that includes the sequence of SEQ ID NO: 40, 41, 42, or 43, include clone 2H9.

In some embodiments, the antibody binds to "L" variants, but not to "Q" variants of B7-H4. "L" and "Q" variants refer to B7-H4 polypeptides having a leucine ("L") or a glutamine ("Q") at amino acid position number 54 numbering from the initiation methionine of full-length B7-H4. See for example, SEQ ID NO:2 and 3 which are "L" variants and SEQ ID NO:4 and 5 which are "Q" variants. Accordingly, in some embodiments, the antibody binds to an epitope within or formed by the amino acid sequence SEQ ID NO:42 or SEQ ID NO:43, but not an epitope within or formed by the amino acid sequence SEQ ID NO:40 or SEQ ID NO:41. Therefore, the antibody can be used to specifically bind to polypeptides including SEQ ID NO:42 or 43, but not 40, or 41. Exemplary antibodies that bind to an IgV domain of B7-H4 "L" variants, but not bind to an IgV domain of B7-H4 "Q" variants, for example a B7-H4 polypeptide that includes the sequence of SEQ ID NO: 42 or 43 include hB7-H4.ml. Therefore, hB7-H4.ml can bind to the B7-H4- Ig with the amino acid sequence of SEQ ID NO: 10, but not SEQ ID NO: 18.

In alternative embodiments, the antibody binds to an epitope within or formed by the amino acid sequence SEQ ID NO:40 or SEQ ID NO:41, but not an epitope within or formed by the amino acid sequence SEQ ID NO:42 or SEQ ID NO:43. Therefore, the antibody can be used to specifically bind to polypeptides including SEQ ID NO:40 or 41, but not 42, or 43.

b. Antibodies that Bind to the IgC

domain of B7-H4

Antibodies can bind to an epitope within the IgC domain of a B7-H4 polypeptide. Typically, the IgC domain of B7-H4 includes conserved cysteine residues that may be important for formation of disulfide bonds inside the IgC domain. For example, an antibody can bind to a linear epitope that includes 4, 5, 6, 7, 8, 9, 10, 1 1, or more continuous amino acids an IgC domain including between about amino acid 168 and amino acid 225 of SEQ ID NO:2 or SEQ ID NO:4 numbered from the N-terminal methionine.

In some embodiments, the IgC domain can include about amino acid 155 through about amino acid 241 of SEQ ID NO:2 or SEQ ID NO:4.

Accordingly, in some embodiments, the antibody binds to a linear epitope that includes 4, 5, 6, 7, 8, 9, 10, 1 1, or more continuous amino acids an IgC domain including between about amino acid 155 and amino acid 241 of SEQ ID NO:2 or SEQ ID NO:4 numbered from the N-terminal methionine.

An antibody can bind a conformational epitope that includes a 3-D surface feature, shape, or tertiary structure of the IgC domain of B7-H4.

In some embodiments, the antibody binds to transmembrane B7-H4, cell-free B7-H4, and recombinant fragments and fusion thereof that include an IgC domain, but does not bind to recombinant fragments and fusions of B7-H4 where part or all of the IgC has been deleted. For example, in some embodiments, an antibody that binds to the polypeptide of SEQ ID NO:2, 4, 10, 18, 28, 36, 38, or a combination thereof but does not bind to SEQ ID NO:28 or 30. In some embodiments, the antibody binds to an epitope within or formed by

SMPEVNVDYN AS SE TLRCEA PR FPQPTW ASQVDQGAN FSEVSNT S FE LNSENVTMKV 60 VSVLYNVT IN NTYSCMIEND IAKATGD IKV TE SE IKRRS 9 9 (SEQ ID NO:44). Therefore the antibody can be used to specifically bind to polypeptides including SEQ ID NO:44.

Exemplary antibodies that bind to an IgC domain of B7-H4 include clones 2D1, 6H3, 8E11, and H74.

c. Antibodies that Bind Other Regions of B7- H4

Antibodies can bind to an epitope that is not completely within the IgV domain or IgC domain of a B7-H4 polypeptide. For example, the antibody can bind a sequence or conformational epitope that includes a 3-D surface feature, shape, or tertiary structure, or combination thereof that includes part of an IgC domain or IgV domain. In some embodiments, the antibody can bind a sequence or conformational epitope that includes a 3-D surface feature, shape, or tertiary structure, or combination thereof outside of the IgC domain or IgV domain of a B7-H4. For example, the antibody can bind to a linear or conformational epitope that includes part of, or depends on the signal sequence, the transmembrane domain, the cytoplasmic domain, the extracellular domain, or combinations thereof. In a preferred embodiment, the antibody binds to a part of the extracellular domain of B7-H4 that is outside the IgV and IgC domains of B7-H4. For example, in some embodiments the antibody binds to a linear epitope that includes 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or more continuous amino acids that are outside the IgV or IgC domains of B7-H4. The antibody can bind to a linear epitope that includes part of the IgV domain, IgC domain, or a combination thereof, but is not entirely within one of the domains. Accordingly, the antibody can bind to a linear epitope that includes 4, 5, 6, 7, 8, 9, 10, 1 1, or more continuous amino acids where the epitope is not entirely within the IgV or IgC domain of B7-H4. For example, in some embodiments, the entire epitope is not within the amino acid sequence from acid 56 and amino acid 225 of SEQ ID NO:2 or SEQ ID NO:4 numbered from the N-terminal methionine. In a preferred embodiment, the epitope includes a sequence that is a part of the extracellular domain of a B7-H4 polypeptide that is junxatposed to the cellular membrane. The epitope can also include a part of the IgC domain.

In some embodiments, the antibody binds to SEQ ID NO:24 and SEQ

ID NO:34, but does not bind to SEQ ID NO: 10, 20, 28, 30, 32, 36, or 38. In some embodiments the antibody binds to an epitope including or formed by part or all of the amino acid sequence KRRSHLQLLNSK (SEQ ID NO:45), but the antibody does not bind to the sequence KQQSHLQLLNSK (SEQ ID NO:46) or KRRSEPKSC (SEQ ID NO:47). Therefore, the antibody can specifically bind polypeptides including the amino acid sequence of SEQ ID NO:45, but not SEQ ID NO:46, or 47. An exemplary antibody that binds to a polypeptide including the amino acid sequence of SEQ ID NO:45 but does not bind an epitope including the amino acid sequence KQQS is HMH4- 5G1.

2. Antibodies that Bind to B7-H4 Fusion Proteins

Antibodies that bind to recombinant B7-H4 fusion proteins are also disclosed. As discussed above, recombinant B7-H4 fusion proteins typically include a first fusion partner including all or a part of a B7-H4 protein fused to a second polypeptide directly or via a linker peptide sequence that is fused to the second polypeptide. In a preferred embodiment, the fusion protein includes the extracellular domain of B7-H4, or a fragment thereof fused to an Ig Fc region. For example, a recombinant B7-H4-Ig fusion protein includes the extracellular domain of B7-H4 or a fragment thereof fused to the Fc region of human IgGl, human IgG4, or mouse IgG2a. Exemplary B7-H4-Ig fusion proteins include, for example, SEQ ID NO: 10-39.

When a recombinant B7-H4 polypeptide, or fragment or fusion thereof presents an epitope from a B7-H4 polypeptide, such as those discussed above, the antibody can also bind to the recombinant B7-H4 polypeptide, or fragment or fusion thereof. However, in some embodiments, the antibody binds to an epitope on a recombinant B7-H4 fusion protein that is masked or absent on an endogenous B7-H4 polypeptide. For example, the B7-H4 polypeptide of the B7-H4 fusion protein can be a variant B7-H4 polypeptide that includes one or more mutations compared to the corresponding sequence in an endogenous B7-H4 polypeptide. The B7-H4 polypeptide of the B7-H4 fusion protein can include one or more insertions, deletions, substitutions, or combinations thereof relative to the endogenous B7-H4 polypeptide. Therefore, in some embodiments, an antibody that binds to B7-H4 fusion protein containing a variant B7-H4 polypeptide may bind to an epitope that includes a segment of B7-H4 that includes one or more insertions, deletions, substitutions, or combinations thereof relative to the endogenous B7-H4 polypeptide. In some embodiments, the epitope includes a conformational change in the secondary or tertiary structure of the fusion protein that is partially or completely dependent on the insertion, deletion, substitution, or combination thereof. Accordingly, in some embodiments, the antibody binds to the B7- H4 polypeptide of the B7-H4 fusion protein, but not to an endogenous B7- H4 polypeptide.

The epitope can be composed of a sequential amino acids sequence, a secondary or tertiary structure, post-translational modifications, or combinations thereof that is dependent on the second polypeptide or linker sequence of the fusion protein. For example, in some embodiments, the antibody binds to a linear epitope that includes 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1, or more continuous amino acids of the linker region or the second polypeptide of the fusion protein. In some embodiments, the antibody binds to a linear epitope that includes amino acids from the B7-H4 polypeptide and the second polypeptide, the B7-H4 polypeptide and the linker sequence, or the B7-H4 polypeptide, the linker sequence, and the second polypeptide.

The antibody can bind a conformational epitope that includes a 3-D surface feature, shape, or tertiary structure partially, or completely dependent on the linker sequence of the fusion protein, the second polypeptide of the fusion protein, or a combination there. For example, in some embodiments, the antibody can bind to a conformational epitope that includes a 3-D surface feature, shape, or tertiary structure dependent on a combination of the B7-H4 polypeptide and the second polypeptide, the B7-H4 polypeptide and the linker sequence, or the B7-H4 polypeptide, the linker sequence, and the second polypeptide.

In some embodiments, the antibody binds to an epitope on the second polypeptide of the fusion protein. In some methods, B7-H4 fusion proteins can be detected using a detection antibody that is specific for the second polypeptitde of fusion protein. For example, if the second polypeptide is an Fc region of human IgGl, human IgG4, or mouse IgG2a, and antibody can be specific for the the Fc region of human IgGl, human IgG4, or mouse IgG2a respectively.

3. Antibody Composition and Methods of

Manufacture

To prepare an antibody that specifically binds to a B7-H4

polypeptide, fragment or fusion thereof, purified B7-H4 polypeptides, fragments, fusions, or epitopes thereof, or polypeptides expressed from their nucleic acid sequences, can be used. Using the purified B7-H4 polypeptides, fragments, fusions, or epitopes thereof or proteins expressed from their nucleic acid sequences, antibodies can be prepared using any suitable methods known in the art.

The antibodies disclosed herein can be generated in cell culture, in phage, or in various animals, including but not limited to cows, rabbits, goats, mice, rats, hamsters, guinea pigs, sheep, dogs, cats, monkeys, chimpanzees, apes. Therefore, in one embodiment, an antibody is a mammalian antibody. Phage techniques can be used to isolate an initial antibody or to generate variants with altered specificity or avidity characteristics. Such techniques are routine and well known in the art. In one embodiment, the antibody is produced by recombinant means known in the art. For example, a recombinant antibody can be produced by transfecting a host cell with a vector comprising a DNA sequence encoding the antibody. One or more vectors can be used to transfect the DNA sequence expressing at least one VL and one VH region in the host cell. Exemplary descriptions of recombinant means of antibody generation and production include Delves, Antibody Production: Essential Techniques (Wiley, 1997); Shephard, et al, Monoclonal Antibodies (Oxford University Press, 2000); Goding, Monoclonal Antibodies: Principles And Practice (Academic Press, 1993); Current Protocols In Immunology (John Wiley & Sons, most recent edition).

The disclosed antibodies can be modified by recombinant means to increase greater efficacy of the antibody in mediating the desired function. Thus, antibodies can be modified by substitutions using recombinant means. Typically, the substitutions will be conservative substitutions. For example, at least one amino acid in the constant region of the antibody can be replaced with a different residue. See, e.g., U.S. Pat. No. 5,624,821, U.S. Pat. No. 6,194,551, Application No. WO 9958572; and Angal, et al, Mol. Immunol. 30: 105-08 (1993). The modification in amino acids includes deletions, additions, substitutions of amino acids. In some cases, such changes are made to reduce undesired activities, e.g., complement-dependent cytotoxicity. Frequently, the antibodies are labeled by joining, either covalently or non-covalently, a substance which provides for a detectable signal. A wide variety of labels and conjugation techniques are known and are reported extensively in both the scientific and patent literature. These antibodies can be screened for binding to B7-H4 polypeptides, or fragments, or fusions thereof. See e.g., Antibody Engineering: A Practical Approach (Oxford University Press, 1996).

Suitable antibodies with the desired biologic activities can be identified by in vitro assays including but not limited to: proliferation, migration, adhesion, soft agar growth, angiogenesis, cell-cell

communication, apoptosis, transport, signal transduction, and the following in vivo assays such as the inhibition of tumor growth.

The antibodies provided herein can also be useful in diagnostic applications. As capture or non-neutralizing antibodies, they can be screened for the ability to bind to the specific antigen without inhibiting the receptor- binding or biological activity of the antigen. As neutralizing antibodies, the antibodies can be useful in competitive binding assays. They can also be used to quantify the B7-H4 polypeptides or its receptor.

Antibodies that can be used in the disclosed compositions and methods include whole immunoglobulin (i.e., an intact antibody) of any class, fragments thereof, and synthetic proteins containing at least the antigen binding variable domain of an antibody. The variable domains differ in sequence among antibodies and are used in the binding and specificity of each particular antibody for its particular antigen. However, the variability is not usually evenly distributed through the variable domains of antibodies. It is typically concentrated in three segments called complementarity determining regions (CDRs) or hypervariable regions both in the light chain and the heavy chain variable domains. The more highly conserved portions of the variable domains are called the framework (FR). The variable domains of native heavy and light chains each comprise four FR regions, largely adopting a beta-sheet configuration, connected by three CDRs, which form loops connecting, and in some cases forming part of, the beta-sheet structure. The CDRs in each chain are held together in close proximity by the FR regions and, with the CDRs from the other chain, contribute to the formation of the antigen binding site of antibodies.

Also disclosed are fragments of antibodies which have bioactivity.

The fragments, whether attached to other sequences or not, include insertions, deletions, substitutions, or other selected modifications of particular regions or specific amino acids residues, provided the activity of the fragment is not significantly altered or impaired compared to the nonmodified antibody or antibody fragment.

Techniques can also be adapted for the production of single-chain antibodies specific to an antigenic protein of the present disclosure. Methods for the production of single-chain antibodies are well known to those of skill in the art. A single chain antibody can be created by fusing together the variable domains of the heavy and light chains using a short peptide linker, thereby reconstituting an antigen binding site on a single molecule. Single- chain antibody variable fragments (scFvs) in which the C-terminus of one variable domain is tethered to the N-terminus of the other variable domain via a 15 to 25 amino acid peptide or linker have been developed without significantly disrupting antigen binding or specificity of the binding. The linker is chosen to permit the heavy chain and light chain to bind together in their proper conformational orientation. Divalent single-chain variable fragments (di-scFvs) can be engineered by linking two scFvs. This can be done by producing a single peptide chain with two VH and two VL regions, yielding tandem scFvs. ScFvs can also be designed with linker peptides that are too short for the two variable regions to fold together (about five amino acids), forcing scFvs to dimerize. This type is known as diabodies. Diabodies have been shown to have dissociation constants up to 40-fold lower than corresponding scFvs, meaning that they have a much higher affinity to their target. Still shorter linkers (one or two amino acids) lead to the formation of trimers (triabodies or tribodies). Tetrabodies have also been produced. They exhibit an even higher affinity to their targets than diabodies.

A monoclonal antibody is obtained from a substantially

homogeneous population of antibodies, i.e., the individual antibodies within the population are identical except for possible naturally occurring mutations that may be present in a small subset of the antibody molecules. Monoclonal antibodies include "chimeric" antibodies in which a portion of the heavy and/or light chain is identical with or homologous to corresponding sequences in antibodies derived from a particular species or belonging to a particular antibody class or subclass, while the remainder of the chain(s) is identical with or homologous to corresponding sequences in antibodies derived from another species or belonging to another antibody class or subclass, as well as fragments of such antibodies, as long as they exhibit the desired antagonistic activity.

Monoclonal antibodies can be made using any procedure which produces monoclonal antibodies. In a hybridoma method, a mouse or other appropriate host animal is typically immunized with an immunizing agent to elicit lymphocytes that produce or are capable of producing antibodies that will specifically bind to the immunizing agent. Alternatively, the lymphocytes may be immunized in vitro.

Antibodies may also be made by recombinant DNA methods. DNA encoding the disclosed antibodies can be readily isolated and sequenced using conventional procedures (e.g., by using oligonucleotide probes that are capable of binding specifically to genes encoding the heavy and light chains of murine antibodies). Libraries of antibodies or active antibody fragments can also be generated and screened using phage display techniques.

a. Human and Humanized Antibodies

Many non-human antibodies (e.g., those derived from mice, rats, or rabbits) are naturally antigenic in humans, and thus can give rise to undesirable immune responses when administered to humans. Therefore, the use of human or humanized antibodies in the methods serves to lessen the chance that an antibody administered to a human will evoke an undesirable immune response.

Transgenic animals (e.g., mice) that are capable, upon immunization, of producing a full repertoire of human antibodies in the absence of endogenous immunoglobulin production can be employed. For example, it has been described that the homozygous deletion of the antibody heavy chain joining region (J(H)) gene in chimeric and germ-line mutant mice results in complete inhibition of endogenous antibody production. Transfer of the human germ-line immunoglobulin gene array in such germ-line mutant mice will result in the production of human antibodies upon antigen challenge.

Optionally, the antibodies are generated in other species and

"humanized" for administration in humans. Humanized forms of non-human (e.g., murine) antibodies are chimeric immunoglobulins, immunoglobulin chains or fragments thereof (such as Fv, Fab, Fab', F(ab')2, or other antigen- binding subsequences of antibodies) which contain minimal sequence derived from non-human immunoglobulin. Humanized antibodies include human immunoglobulins (recipient antibody) in which residues from a complementarity determining region (CDR) of the recipient antibody are replaced by residues from a CDR of a non-human species (donor antibody) such as mouse, rat or rabbit having the desired specificity, affinity and capacity. In some instances, Fv framework residues of the human immunoglobulin are replaced by corresponding non-human residues.

Humanized antibodies may also contain residues that are found neither in the recipient antibody nor in the imported CDR or framework sequences. In general, the humanized antibody will contain substantially all of at least one, and typically two, variable domains, in which all or substantially all of the CDR regions correspond to those of a non-human immunoglobulin and all or substantially all of the FR regions are those of a human immunoglobulin consensus sequence. The humanized antibody optimally also will contain at least a portion of an immunoglobulin constant region (Fc), typically that of a human immunoglobulin.

Methods for humanizing non-human antibodies are well known in the art. Generally, a humanized antibody has one or more amino acid residues introduced into it from a source that is non-human. These non-human amino acid residues are often referred to as "import" residues, which are typically taken from an "import" variable domain. Antibody humanization techniques generally involve the use of recombinant DNA technology to manipulate the DNA sequence encoding one or more polypeptide chains of an antibody molecule. Humanization can be essentially performed by substituting rodent CDRs or CDR sequences for the corresponding sequences of a human antibody. Accordingly, a humanized form of a non-human antibody (or a fragment thereof) is a chimeric antibody or fragment, wherein substantially less than an intact human variable domain has been substituted by the corresponding sequence from a non-human species. In practice, humanized antibodies are typically human antibodies in which some CDR residues and possibly some FR residues are substituted by residues from analogous sites in rodent antibodies.

The choice of human variable domains, both light and heavy, to be used in making the humanized antibodies is very important in order to reduce antigenicity. According to the "best-fit" method, the sequence of the variable domain of a rodent antibody is screened against the entire library of known human variable domain sequences. The human sequence which is closest to that of the rodent is then accepted as the human framework (FR) for the humanized antibody. Another method uses a particular framework derived from the consensus sequence of all human antibodies of a particular subgroup of light or heavy chains. The same framework may be used for several different humanized antibodies.

It is further important that antibodies be humanized with retention of high affinity for the antigen and other favorable biological properties. To achieve this goal, humanized antibodies are preferably prepared by a process of analysis of the parental sequences and various conceptual humanized products using three dimensional models of the parental and humanized sequences. Three dimensional immunoglobulin models are commonly available and are familiar to those skilled in the art. Computer programs are available which illustrate and display probable three-dimensional conformational structures of selected candidate immunoglobulin sequences. Inspection of these displays permits analysis of the likely role of the residues in the functioning of the candidate immunoglobulin sequence, i.e., the analysis of residues that influence the ability of the candidate

immunoglobulin to bind its antigen. In this way, FR residues can be selected and combined from the consensus and import sequence so that the desired antibody characteristic, such as increased affinity for the target antigen(s), is achieved. In general, the CDR residues are directly and most substantially involved in influencing antigen binding.

b. Single-Chain Antibodies

Methods for the production of single-chain antibodies are well known to those of skill in the art. A single chain antibody is created by fusing together the variable domains of the heavy and light chains using a short peptide linker, thereby reconstituting an antigen binding site on a single molecule. Single-chain antibody variable fragments (scFvs) in which the C- terminus of one variable domain is tethered to the N-terminus of the other variable domain via a 15 to 25 amino acid peptide or linker have been developed without significantly disrupting antigen binding or specificity of the binding. The linker is chosen to permit the heavy chain and light chain to bind together in their proper conformational orientation. These Fvs lack the constant regions (Fc) present in the heavy and light chains of the native antibody.

c. Monovalent Antibodies

In vitro methods are also suitable for preparing monovalent antibodies. Digestion of antibodies to produce fragments thereof, particularly, Fab fragments, can be accomplished using routine techniques known in the art. For instance, digestion can be performed using papain. Papain digestion of antibodies typically produces two identical antigen binding fragments, called Fab fragments, each with a single antigen binding site, and a residual Fc fragment. Pepsin treatment yields a fragment, called the F(ab')2 fragment, that has two antigen combining sites and is still capable of cross-linking antigen.

The Fab fragments produced in the antibody digestion also contain the constant domains of the light chain and the first constant domain of the heavy chain. Fab' fragments differ from Fab fragments by the addition of a few residues at the carboxy terminus of the heavy chain domain including one or more cysteines from the antibody hinge region. The F(ab')2 fragment is a bivalent fragment comprising two Fab' fragments linked by a disulfide bridge at the hinge region. Fab'-SH is the designation herein for Fab' in which the cysteine residue(s) of the constant domains bear a free thiol group. Antibody fragments originally were produced as pairs of Fab' fragments which have hinge cysteines between them. Other chemical couplings of antibody fragments are also known.

d. Hybrid antibodies

The anti-B7-H4 antibody can be a hybrid antibody. In hybrid antibodies, one heavy and light chain pair is homologous to that found in an antibody raised against one epitope, while the other heavy and light chain pair is homologous to a pair found in an antibody raised against another epitope. This results in the property of multi-functional valency, i.e., a bivalent antibody has the ability to bind at least two different epitopes simultaneously. Such hybrids can be formed by fusion of hybridomas producing the respective component antibodies, or by recombinant techniques. Such hybrids may, of course, also be formed using chimeric chains.

e. Conjugates or Fusions of Antibody

Fragments

The targeting function of the antibody can be used therapeutically by coupling the antibody or a fragment thereof with a therapeutic agent. Such coupling of the antibody or fragment (e.g., at least a portion of an immunoglobulin constant region (Fc)) with the therapeutic agent can be achieved by making an immunoconjugate or by making a fusion protein, comprising the antibody or antibody fragment and the therapeutic agent.

Such coupling of the antibody or fragment with the therapeutic agent can be achieved by making an immunoconjugate or by making a fusion protein, or by linking the antibody or fragment to a nucleic acid such as an siRNA, comprising the antibody or antibody fragment and the therapeutic agent.

In some embodiments, the antibody is modified to alter its half-life. In some embodiments, it is desirable to increase the half-life of the antibody so that it is present in the circulation or at the site of treatment for longer periods of time. For example, it may be desirable to maintain titers of the antibody in the circulation or in the location to be treated for extended periods of time. Antibodies can be engineered with Fc variants that extend half-life, e.g., using Xtend™ antibody half-life prolongation technology (Xencor, Monrovia, CA). In other embodiments, the half-life of the anti- DNA antibody is decreased to reduce potential side effects. The conjugates disclosed can be used for modifying a given biological response. The drug moiety is not to be construed as limited to classical chemical therapeutic agents. For example, the drug moiety may be a protein or polypeptide possessing a desired biological activity. Such proteins may include, for example, a toxin such as abrin, ricin A, pseudomonas exotoxin, or diphtheria toxin.

f. Method of Making Antibodies Using

Protein Chemistry

One method of producing proteins comprising the antibodies is to link two or more peptides or polypeptides together by protein chemistry techniques. For example, peptides or polypeptides can be chemically synthesized using currently available laboratory equipment using either Fmoc (9-fluorenylmethyloxycarbonyl) or Boc (tert -butyloxycarbonoyl) chemistry. (Applied Biosystems, Inc., Foster City, CA). One skilled in the art can readily appreciate that a peptide or polypeptide corresponding to the antibody, for example, can be synthesized by standard chemical reactions. For example, a peptide or polypeptide can be synthesized and not cleaved from its synthesis resin whereas the other fragment of an antibody can be synthesized and subsequently cleaved from the resin, thereby exposing a terminal group which is functionally blocked on the other fragment. By peptide condensation reactions, these two fragments can be covalently joined via a peptide bond at their carboxyl and amino termini, respectively, to form an antibody, or fragment thereof. Alternatively, the peptide or polypeptide is independently synthesized in vivo as described above. Once isolated, these independent peptides or polypeptides may be linked to form an antibody or anitgen binding fragment thereof via similar peptide condensation reactions.

For example, enzymatic ligation of cloned or synthetic peptide segments allow relatively short peptide fragments to be joined to produce larger peptide fragments, polypeptides or whole protein domains.

Alternatively, native chemical ligation of synthetic peptides can be utilized to synthetically construct large peptides or polypeptides from shorter peptide fragments. This method consists of a two-step chemical reaction. The first step is the chemos elective reaction of an unprotected synthetic peptide- alpha-thioester with another unprotected peptide segment containing an amino-terminal Cys residue to give a thioester-linked intermediate as the initial covalent product. Without a change in the reaction conditions, this intermediate undergoes spontaneous, rapid intramolecular reaction to form a native peptide bond at the ligation site.

4. Exemplary Anti-B7-H4 Antibodies

Exemplary antibodies that can be used in the compositions and methods described herein are provided. For example, anti-B7-H4 antibodies are disclosed in United States Patents Nos. 7,888,477; 7,737,255; 7,619,068; 6,962,980, and in United States Patent Publication No. 2008/0199461. Anti- B7-H4 antibodies are also disclosed in WO 2013/025779, which is specifically incorporated by reference herein in its entirety.

Other exemplary antibodies include those referred to herein as 2H9, hB7-H4.ml, 2D 1, 6H3, 2E1 1, 8E1 1, H74, HMH4-5G1, as well as fragments, chimerics, variants, particularly humanized variants, thereof. In some embodiments, the antibody is a chimeric antibody that includes, for example, mouse or other non-human anti-B7-H4 light and heavy chain variable regions and a human Fc region (e.g. IgGl, IgG2, IgG3, or IgG4).

Antibody H74 is a commercially available anti-human B7-H4 antibody (eBioscience, San Diego, CA)).

Antibody HMH4-5G1 is a commercially available Armenian

Hamster IgG antibody raised against a mouse B7-H4 human IgGl Fc fusion protein (BioLegend, San Diego, CA).

a. Anti-Human B7-H4 Clone 2H9

The amino acid sequences of the light and heavy chain variable regions of anti-B7-H4 mAbs 2H9 are as follows (CDRs are underlined):

Light Chain Variable Region:

DIVLTQSPAS LAVSLGQRAT ISCRASESID NYGISFMH Y QQKPGQPPKL LIYRASNLES GIPARFSGSG SRTDFTLTIN PVETDDVATY FCQQSDEGRT FGGGTKLEIK (SEQ ID O: 55)

Heavy Chain Variable Region:

EVQLVESGGN LVKPGGSLKL SCAASGFTFS SAMSWVRQT PEKRLE VAT ISDGGRYTYY

PDNVKGRFTI SRDNAKNNLY LQMSHLKSED TALYYCARDR PHWYFDV GT GATVTVSS (SEQ ID

NO:56)

b. Anti-Human B7-H4 Clone 2D1

The amino acid sequences of the light and heavy chain variable regions of anti-B7-H4 mAbs 2D1 are as follows (CDRs are underlined):

Light Chain Variable Region:

DWMTQTPLS LPVSLGDQAS ISCRSSHSLV HSNGNTYLH YLQKPGQSPN LLIYIVSNRF

SGVPDRFSGS GSGTDFTLKI SRVEAEDLGV YFCSQSTHVP P FGAGTKLE LK (SEQ ID

NO:57)

Heavy Chain Variable Region:

EVQLVESGGG LVKPGGSLKL SCAASGFTFN SHGMS VRQT PEKRLD VAT ISDGGTYTYY PV VKGRFTI SRDNAKNNLY LQMSHLKSED TAMYYCARDG GGGAY GQGT LVTVSA (SEQ ID

NO:58)

c. Anti-Human B7-H4 Clone 2E11

The amino acid sequences of the light and heavy chain variable regions of anti-B7-H4 mAbs 2E11 are as follows (CDRs are underlined):

Light Chain Variable Region:

DIVMSQSPSS LAVSVGEKVT VSCKSSQSLL YSTNQRTYLA FQQKPGQSP KLLIYWASTR ESGVPDRF G SGSGTDFTLT ISSVKAEDLA VYYCQQYY Y PLTFGTGTKL ELK (SEQ ID NO:59) Heavy Chain Variable Region:

EVKLVESEGG LVQPGSSMKL SCTASGFKFT DYYMAWVRQV PEKGLEWVAN INYDGSSTYY LDSLKSRFI I SRDNAKNILY LQMNSLKSED TATYYCARKG YFDY GQGTT LTVSS (SEQ ID

NO:60)

d. Anti-Human B7-H4 Clone 6H3

DNA encoding murine anti-human B7-H4 antibody 6H3 was sequenced. The amino acid sequences and encoding polynucleotide sequences of the variable domains of the light and heavy chains are as indicated below. CDR sequences are shown in bold and underlined:

Light Chain Variable Region:

DWMTQTPLS LPVSLGDQAS ISCRSSQSLV HINGNTYLH YLQKPGQSPK VLIYKVSNRF SGVPDRFSGS GSGTDFTLKI SRVEAEDLGV YFCSQSTHVP L FGAGTKLE LK (SEQ ID

NO:61)

Polynucleotide Encoding the Light Chain Variable Region: gatgttgtga tgacccaaac tcctctctcc ctgcctgtca gtcttggaga tcaagcctcc atctcttgca gatctagtca gagccttgta cacattaatg gaaacaccta tttacattgg tacctgcaga agccaggcca gtctccaaag gtcctgatct acaaagtttc caaccgattt tctggggtcc cagacaggtt cagtggcagt ggatcaggga cagatttcac actcaagatc agcagagtgg aggctgagga tctgggagtt tatttctgct ctcaaagtac acatgttccg ctcacgttcg gtgctgggac caagctggag ctgaaac

(SEQ ID NO:62)

Heavy Chain Variable Region:

EVQLQQSGPV LVKPGTSVKM SCKASGYTFT DYYMN VKQS HGKSLE IGV INPYNGDTTY NQKFKGKATL TVDKSSSTAY MEVNSLTFED SAVYYCARYP ESTY GQGTL VTVSA (SEQ ID

NO:63)

Polynucleotide Encoding the Light Chain Variable Region: gaggtccagc tgcaacagtc tggacctgta ctggtgaagc ctgggacttc agtgaagatg tcctgtaagg cttctggata cacattcact gactactata tgaactgggt gaagcagagc catggaaaga gtcttgagtg gattggagtt attaatcctt acaacggtga cactacctac aaccagaagt tcaagggcaa ggccacattg actgttgaca agtcctccag cacagcctac atggaggtca acagcctgac atttgaggac tctgcagtct attactgtgc aagatacccg gagagtactt actggggcca agggactctg gtcactgtct ctgca

(SEQ ID NO:64)

III. Methods of Detection and Diagnosis

A. Methods Detecting B7-H4 in a Biological Sample

In some embodiments, the anti-B7-H4 antibodies are used in a method of detecting B7-H4 in a biological sample. The detection of B7-H4 polypeptides, or fragments or fusion thereof in a biological sample obtained from a subject is made possible by a number of conventional methods. A preferred method includes immunoassays whereby B7-H4 polypeptides, or fragments or fusion are detected by their interaction with a B7-H4 specific antibody. B7-H4 specific antibodies can be used to detect the presence of B7-H4 polypeptides, or fragments or fusion thereof in either a qualitative or quantitative manner. Exemplary immunoassays that can be used for the detection of B7-H4 polypeptides include, but are not limited to,

radioimmunoassays, ELISAs, immunoprecipitation assays, Western blot, fluorescent immunoassays, and immunohistochemistry. Exemplary antibodies that can be used in the methods of detection and diagnosis described below include, but are not limited to, 2H9, hB7-H4.ml, 2D1, 6H3, 8E1 1, H74, HMH4-5G1, and combinations thereof. It will be appreciated that some immunoassays, for example ELISAs, can require two different B7- H4 specific antibodies. Accordingly, the antibodies disclosed herein can be used in any combination suitable to detection of B7-H4 in the biological sample. However, as discussed in more detail below, certain combinations of antibodies are preferred for detection of total B7-H4, or cell-free B7-H4 only, or B7-H4 fusion proteins (e.g. B7-H4-Ig) only.

A biological sample that may contain B7-H4 polypeptides, or fragments or fusions thereof can be obtained from an individual. If the biological sample is of tissue or cellular origin, the sample is solubilized in a lysis buffer optionally containing a chaotropic agent, detergent, reducing agent, buffer, and salts. The sample is preferably a biological fluid sample taken from a subject. Examples of biological samples include urine, barbotage, blood, serum, plasma, tears, saliva, cerebrospinal fluid, tissue, lymph, synovial fluid, or sputum etc. In a preferred embodiment, the biological fluid is whole blood, or more preferably serum or plasma. Serum is the component of whole blood that is neither a blood cell (serum does not contain white or red blood cells) nor a clotting factor. It is the blood plasma with the fibrinogens removed. Accordingly, serum includes all proteins not used in blood clotting (coagulation) and all the electrolytes, antibodies, antigens, hormones, and any exogenous substances (e.g., drugs and microorganisms). The sample can be diluted with a suitable diluent before contacting the sample to the antibody.

Generally, a sample obtained from a subject can be contacted with the antibody that specifically binds B7-H4 polypeptides, or fragments or fusions thereof. Optionally, the antibody can be fixed to a solid support to facilitate washing and subsequent isolation of the complex, prior to contacting the antibody with a sample. Examples of solid supports include glass or plastic in the form of, e.g., a microtiter plate, a stick, a bead, or a microbead. Antibodies can also be attached to a probe substrate or

ProteinChip® array and can be analyzed by gas phase ion spectrometry as described above.

Immuoassays for the detection of B7-H4 polypeptides, or fragments or fusions thereof include the ability to contact a biological sample with an antibody specific to a B7-H4 polypeptide, or fragment or fusion thereof under conditions such that an immunospecific antigen-antibody interaction may occur, followed by the detection or measurement of this interaction. The binding of the antibody to B7-H4 polypeptides, or fragments or fusions thereof may be used to detect the presence and altered production of B7-H4 polypeptides, or fragments or fusions thereof.

An immunoassay can include the steps of detecting and analyzing markers in a sample. For example, a method can include the steps of (a) providing an antibody that specifically binds to a B7-H4 polypeptide, fragment, or fusion thereof; (b) contacting a sample with the antibody; and (c) detecting the presence of a complex of the antibody bound to the B7-H4 polypeptide, fragment, or fusion thereof in the sample. After the antibody is provided, a B7-H4 polypeptide, fragment, or fusion thereof can be detected and/or quantified using any of suitable immunological binding assays known in the art. Useful assays include, for example, an enzyme immune assay (EIA) such as enzyme-linked immunosorbent assay (ELISA), a radioimmune assay (RIA), a Western blot assay, or a slot blot assay. These methods are also described in, e.g., Methods in Cell Biology. Antibodies in Cell Biology, volume 37 (Asai, ed. 1993); Basic and Clinical Immunology (Stites & Terr, eds., 7th ed. 1991); and Harlow & Lane, supra. After incubating the sample with antibodies, the mixture is washed and the antibody-marker complex formed can be detected. This can be accomplished by incubating the washed mixture with a detection reagent. This detection reagent may be, e.g., a second antibody which is labeled with a detectable label. Exemplary detectable labels include magnetic beads (e.g., DY ABEADS™), fluorescent dyes, radiolabels, enzymes (e.g., horse radish peroxide, alkaline phosphatase and others commonly used in an ELISA), and calorimetric labels such as colloidal gold or colored glass or plastic beads. Alternatively, the B7-H4 polypeptide, fragment, or fusion in the sample can be detected using an indirect assay, wherein, for example, a second, labeled antibody is used to detect bound B7-H4-specific antibody, and/or in a competition or inhibition assay wherein, for example, a monoclonal antibody which binds to a distinct epitope of B7-H4 or a fragment or fusion thereof is incubated simultaneously with the mixture.

A common enzyme immunoassay is the "Enzyme-Linked

Immunosorbent Assay (ELISA)." ELISA is a technique for detecting and measuring the concentration of an antigen using a labeled (e.g., enzyme linked) form of the antibody. There are different forms of ELISA, which are well known to those skilled in the art. The standard techniques known in the art for ELISA are described in "Methods in Immunodiagnosis", 2nd Edition, Rose and Bigazzi, eds. John Wiley & Sons, 1980; Campbell et al, "Methods and Immunology", W. A. Benjamin, Inc., 1964; and Oellerich, M., J. Clin. Chem. Clin. Biochem., 22:895-904 (1984).

In a "sandwich ELISA", a first antibody specific for the B7-H4 polypeptide, fragment, or fusion thereof, as referred to herein as the

"capture" antibody is linked to a solid phase (i.e., a microtiter plate) and exposed to a biological sample containing antigen (e.g., biomarker protein). The solid phase is then washed to remove unbound antigen. A second antibody, referred to herein as the "detection" antibody, is then bound to the bound-antigen (if present) forming an antibody-antigen-antibody sandwich. In preferred embodiments the second antibody is labeled (e.g., enzyme linked). In some embodiments, the solid phase is washed to remove unbound antibody, and treated with a third, labeled antibody that binds to and allows detection of the second antibody. Examples of enzymes that can be linked to the antibody are alkaline phosphatase, horseradish peroxidase, luciferase, urease, and B-galactosidase. The enzyme linked antibody reacts with a substrate to generate a colored reaction product that can be measured.

In a "competitive ELISA", antibody is incubated with a sample containing the B7-H4 polypeptide, fragment, or fusion thereof (i.e., antigen). The antigen-antibody mixture is then contacted with a solid phase (e.g., a microtiter plate) that is coated with antigen. The more antigen present in the sample, the less free antibody that will be available to bind to the solid phase. A labeled (e.g., enzyme linked) secondary antibody is then added to the solid phase to determine the amount of primary antibody bound to the solid phase.

Other techniques may be used to detect the biomarkers, according to a practitioner's preference, and based upon the present disclosure. One such technique is Western blotting (Towbin et al, Proc. Nat. Acad. Sci. 76:4350 (1979)), wherein a suitably treated sample is run on an SDS-PAGE gel before being transferred to a solid support, such as a nitrocellulose filter. Detectably labeled antibodies that specifically bind to B7-H4 polypeptide, fragment, or fusion thereof can then be used to assess peptide levels, where the intensity of the signal from the detectable label corresponds to the amount of peptide present. Levels can be quantitated, for example by densitometry.

In some embodiments, the assays incorporate one or more methods or reagents that increase the sensitivity or basal detection level of the assays described herein. For example, MESO-SCALE DISCOVERY® (MSD®) technology can be employed to increase sensitivity of an assay. MSD technology includes a combination of electrochemiluminescence detection and patterned arrays. MSD® microplates have electrodes made of carbon integrated into the bottom of the plate. Biological reagents can be attached to the carbon by passive adsorption and retain a high level of biological activity. MSD® assays use electrochemi-luminescent labels for detection. The labels are non-radioactive, stable, a feature a different coupling chemistries. The electrochemiluminescent labels emit light when electrochemically stimulated, which is detected by electrodes in the bottom of the microplates. Only labels near the electrode are excited and detected, so the assay can be performed without washing steps. Additional coreactants are present in the buffers used for the assay. These coreactants are also stimulated when in proximity to the electrodes in the microplate and enhance the electrochemiluminescence signals.

Assays and kits that include reagents for the detection and qualitative or quantitative measurement of B7-H4 polypeptides, or fragments or fusions thereof in a subject's biological sample are also provided. For example, if detection of the B7-H4 polypeptides, or fragments or fusions thereof is by means of ELISA, components of the assay or kit will include an antibody directed against specific epitopes of the B7-H4 polypeptides, or fragments or fusions thereof, in which the antibody may optionally be linked to an enzyme, fluorescent dye or radioactive label.

B. Exemplary ELISA Assays

A preferred assay to measure the level of B7-H4 in a biological sample is sandwich ELISA. As discussed above, sandwich ELISA requires two antibodies that are specific for the target protein: a capture antibody and a detection antibody. Therefore, two anti-B7-H4 antibodies are needed to measure B7-H4 levels using an ELISA assay or, if specifically trying to detect a B7-H4 fusion protein, one of the two antibodies can bind the B7-H4 fusion partner (e.g. an anti-Fc antibody with detect a B7-H4-Ig fusion protein). Accordingly, a practitioner can select the antibody or antibodies that are appropriate for detection of specific species of B7-H4 in the biological sample. Although the preferred combination of "capture" and "detection" antibodies are provided below, it will appreciated that in some embodiments the "capture" antibodies discussed below are used as

"detection" antibodies and the "detection" antibodies are used as "capture" antibodies.

1. Capture Antibodies

In some embodiments, the capture antibody, or antigen binding fragment thereof binds to a region common to most, or all known species of the B7-H4 polypeptides, as well as many species of the B7-H4-Ig fusion proteins, disclosed above. In a preferred embodiment, the capture antibody can is an F(ab')2 fragment of an antibody against B7-H4. In the most preferred embodiment, the capture antibody is a F(ab')2 fragment of 2H9. Transmembrane B7-H4, cell-free B7-H4, and therapeutic B7-H4 fusion proteins typically include the IgV domain of B7-H4. Therefore, in some embodiments, an antibody that can be used to measure the total amount of B7-H4 polypeptide in a sample can bind to the IgV domain of B7-H4. An exemplary antibody that binds to an IgV domain of B7-H4, for example a B7-H4 polypeptide that includes the sequence of SEQ ID NO:40, 41, 42, or 43, is 2H9 or hB7-H4.ml .

In another example, the capture antibody can bind to the IgC domain of B7-H4, for example an antibody that binds to a polypeptide including SEQ ID NO:44. Exemplary antibodies that bind to an IgC domain of B7-H4 include 2D1, 6H3, 8E11, and H74.

2. Detection Antibodies

In some embodiments, it is desirable to measure all B7-H4 polypeptides in a biological sample. Accordingly, in some embodiments, the detection antibody binds to a region common to most or all known species of endogenous B7-H4 polypeptide, such as the IgV domain or IgC domain. In a preferred embodiment, the capture antibody binds to one domain (e.g. the IgV domain) and the detection antibody binds to another domain (i.e. the IgC domain) or a different region or epitope of the same domain (i.e. IgV domain). Therefore, in some embodiments, the capture and detection antibodies for detecting multiple species of B7-H4 in a single biological sample are two different antibodies selected from the group consisting of 2H9, 2D1, 6H3, 8E11, and H74. For example, in a preferred embodiment for detecting total B7-H4 in a biological sample such as plasma or serum, the capture antibody is 2H9 and the detection antibody is hB7-H4.ml or 6H3. 6H3 is preferred for detecting total B7-H4. In a particular embodiment, the 6H3 is a mouse anti-human B7-H4 antibody, or chimeric antibody thereof including mouse heavy and light chain variable regions and a mouse or human Fc region (e.g., mouse IgGl, mouse IgG2a, human IgGl, human IgG4, etc.). In a preferred embodiment the capture antibody is a F(ab')2 fragment of antibody 2H9 and the detection antibody is hB7-H4.ml or 6H3. In a particular ELISA assay, 2H9 F(ab')2 fragment is used to capture cell-free B7-H4 in a serum sample obtained from a subject. The detection antibody can be biotinylated hB7-H4.ml or 6H3. hB7-H4.ml is preferred for detecting cell free B7-H4. This assay can be used, as discussed in more detail below, to detect, diagnose, or otherwise evaluate a subject for a disease or disorder associated with an elevated level of cell-free B7-H4. Cell-free B7-H4 can be detected using a detection reagent conjugated to avidin or streptavidin. In a preferred embodiment, the ELISA assay is used to detect, diagnose, or determine the disease severity of rheumatoid arthritis, multiple sclerosis, or a cancer.

In some embodiments, it is desirable to distinguish the amount of one or more species of B7-H4 polypeptides from other species of B7-H4 polypeptides in a biological sample. Accordingly, in some embodiments, the detection antibody binds to a region that is specific to the one or more species to be measured. For example, in some embodiments, the antibody binds to an IgV domain of B7-H4 "L" variants, but does not bind to an IgV domain of B7-H4 "Q" variants. An exemplary antibody that binds to an epitpope within or formed by an IgV domain of B7-H4 "L" variants, but does not bind to an IgV domain of B7-H4 "Q" variants, for example an epitope that includes the "Q" in the sequence of SEQ ID NO: 42 or 43 is hB7-H4.ml. In another embodiment, the antibody binds to an epitope within or formed by an IgV domain that includes the "Q" of B7-H4 "Q" variants, but does not bind to an IgV domain that includes the "L" of B7-H4 "L" variants.

In some embodiments, the epitope includes or is formed by part or all of the B7-H4 plasma membrane junxtaposed region of KRRSHLQLLNSK (SEQ ID NO:45). An exemplary antibody that binds an epitope including or formed by SEQ ID NO:45 is HMH4-5G1. Therefore, HMH4-5G1 can be used to specifically bind to a polypeptide including the amino acid sequence of SEQ ID NO: 45. Antibodies that bind to the plasma membrane junxtaposed epitope of SEQ ID NO:45, such as HMH4-5G1, can be used to detect full length B7-H4, as well as species of B7-H4 polypeptides and fusion proteins containing the plasma membrane junxtaposed region including, but not limited to, SEQ ID NO: 16, 17, 24, 25, 34 or 35, but not SEQ ID NO: 10, 11, 12, 13, 14, 15, 18, 19, 20, 21, 22, 23, 26, 27, 28, 29, 30, 31, 32, 33, 36, 37, 38 or 39.

HMH4-5G1 does not bind to the sequence KQQSHLQLLNSK (SEQ ID NO:46) or KRRSEPKSC (SEQ ID NO:47). An antibody that binds to a polypeptide including the amino acid sequence of SEQ ID NO: 45 but does not bind an epitope including the amino acid sequence KQQS, such as HMH4-5G1, can be used as the detection antibody in an ELISA assay format to differentiate transmembrane or cell-free B7-H4 from a B7-H4 fragment or fusion protein to which it does not bind such as SEQ ID NO: 10, 1 1, 12, 13, 14, 15, 18, 19, 20, 21, 22, 23, 26, 27, 28, 29, 30, 31, 32, 33, 36, 37, 38 or 39.

In a preferred embodiment, 2H9 is used as the capture antibody and HMH4-5G1 is used as the detection antibody to detect transmembrane or cell-free B7-H4, but not B7-H4-Ig fusion proteins such as SEQ ID NO: 10, 1 1, 12, 13, 14, 15, 18, 19, 20, 21, 22, 23, 26, 27, 28, 29, 30, 31, 32, 33, 36, 37, 38 or 39. This is particularly useful when the B7-H4 fusion protein is administered therapeutically and determining the level of endogenous transmembrane or cell-free B7-H4 is important, such as for determining if there is a pharmacodynamic effect of therapy on endogenous protein levels, such as a change in the level of endogenous protein in response to therapy. Such an assay is also useful for measuring the efficacy of a therapy that targets cell-free B7-H4 specifcally, but not transmembrane B7-H4, such as an anti-cell-free B7-H4-specific antibody. Such an assay can also be used to specifically measure cell-free B7-H4 in a biological sample such as serum that does not contain cells, or lacks cells expressing transmembrane B7-H4.

In some embodiments, a B7-H4 fusion protein can be detected using a capture antibody that binds to the IgV or IgC domain, in conjunction with a detection antibody that binds to the second fusion portion or the protein. In a preferred embodiment, 2H9 or H74 is used as the capture antibody and an antibody that binds to the second polypeptide is used as the detection antibody to detect B7-H4-Ig such as SEQ ID NO: 10, but not cell-free B7-H4. In some embodiments, the second polypeptide is an IgG such as mouse IgGl, human IgGl, or human IgG4, and the detection antibody is an appropriate anti-IgG antibody such as anti-mouse IgGl, anti-human IgGl, or anti-human IgG4 respectively. This assay format is particularly useful when the B7-H4 fusion protein is administered therapeutically and determining the level of B7-H4 fusion protein without detecting transmembrane or cell-free B7-H4 is required for determining the pharmacokinetics of the therapeutic protein.

In one embodiment, the capture antibody is 2H9 F(ab')2 and the detection antibody is 6H3. This assay is useful for detecting total B7-H4 including soluble B7-H4 and B7-H4-Ig fusion protein.

In another embodiment, the capture antibody is 2H9 F(ab')2 and the detection antibody is hB7-H4.ml. This assay is useful for detecting cell-free B7-H4 alone and does not detect B7-H4-Ig fusion protein.

In still another embodiment, the capture antibody is H74 and the detection antibody is an anti-Fc antibody. This assay is useful for detecting B7-H4-Ig fusion protein.

C. Distinguishing Between Two Species of B7-H4 in a Biological Sample

In some embodiments, a biological sample collected from a subject contains more than one species of B7-H4 polypeptide, fragment, or fusion thereof. As discussed in more detail below, in some embodiments, subjects having an immune response, or with inflammatory or autoimmune diseases/disorders, particularly subjects with elevated levels of cell-free B7- H4, can be administered a therapeutic B7-H4-Ig fusion protein, which can block the function of cell-free B7-H4, increase B7-H4-mediated signal transduction, or a combination thereof. Therefore, in some embodiments, a biological sample such as plasma or serum that is collected from a subject undergoing treatment with a B7-H4-Ig can contain both cell-free B7-H4 as well as a soluble, dimeric B7-H4-Ig fusion protein such as those disclosed above. Accordingly, methods and compositions for distinguishing between total B7-H4 polypeptides, fragments, and fusions thereof, cell-free B7-H4 only, and B7-H4-Ig fusion protein only, thereof are disclosed.

A method for determining the amount of a specific species of B7-H4 polypeptide or a subset of species of B7-H4 polypeptides from the total B7- H4 polypeptides in a biological sample can include performing a first ELISA on the biological sample where the capture and detection antibodies are two different antibodies that detect a region common to most or all known species of B7-H4 polypeptides, such as the IgV domain or IgC domain, for example, 2H9, 2D1, 6H3, 8E11 and H74; performing a second ELISA on the biological sample where the capture antibody detects a region common to most or all known species of B7-H4 polypeptides, such as the IgV domain or IgC domain, for example, 2H9, 2D1, 6H3, 8E11 and H74 and the detection antibody is specific for a species of B7-H4 polypeptide or a subset of specie(s) of B7-H4 polypeptides, but does not bind all of the B7-H4 peptides in the sample.

For example, the level of B7-H4-Ig fusion protein can be measured by a second ELISA method using a B7-H4-specific capture antibody and an hlgGl Fc specific detection antibody. The level of cell free B7-H4 can be measured by a third ELISA method using a capture antibody that detects a region common to most or all known species of B7-H4 polypeptides and a detection antibody that is specific for cell free B7-H4 polypeptide, but not B7-H4-Ig fusion protein peptides in the sample. In some embodiments, the biological sample is a biological fluid such as serum or plasma that is free of cells expressing transmembrane B7-H4.

In some embodiments, the second ELISA is performed with a detection antibody specific for the second polypeptide of a B7-H4 fusion protein. The amount of B7-H4 fusion protein in the sample is determined by the second ELISA, and the total amount of endogenous B7-H4 in the sample is determined by the third ELISA. Such an assay can be used to determine the the pharmacokinetics of a therapeutic B7-H4 fusion protein.

In some embodiments, the second ELISA is performed with a detection antibody specific to cell-free B7-H4. The amount of cell-free B7- H4 in the sample is determined by the second ELISA, and the total amount of B7-H4 fusion protein in the sample is determined by using hlgGl Fc specific detection antibody. Such an assay can be used to determine the the pharmacodynamic effect of treatment on levels cell-free B7-H4. D. Diagnostic Assays

The anti-B7-H4 antibodies, and methods of detecting B7-H4 can be used to detect the presence and altered production of B7-H4 polypeptides, or fragments or fusions thereof.

Cell-free B7-H4 is found in sera of approximately one-third of patients having rheumatoid arthritis (RA) and Sj5gren's Syndrome patients sampled. The concentration of cell-free B7-H4 in an individual correlates closely with the severity, stage and progression of inflammation, particularly in autoimmune diseases. In an experimental mouse model of RA and SLE, the effect of cell-free B7-H4 was recapitulated, and it is believed that cell- free B7-H4 acts as a decoy to block suppressive functions of transmembrane B7-H4, leading to exacerbation of systemic autoimmune diseases (Zhu, G., et al, Blood, 113(8): 1759-67 (2009) Epub 2008 Dec 24). The results demonstrate a role of cell-free B7-H4 in the pathogenesis of systemic autoimmune diseases.

The role of transmembrane forms, and soluble forms of B7-H4 in the development, diagnosis, and prognosis of various cancers are reviewed in He, et al, Clinical and Developmental Immunology, 695834; 8 pages (2011)), which is specifically incorporated by reference in its entirety. For example, B7-H4 has been found to be expressed at the mRNA and protein levels in many types of human cancers and negatively correlate with poor prognosis (See Table 1, below). It is believed that expression of B7-H4 in human tumors is due to aberrant regulation of posttranscription in tumors, since its cell surface protein expression is rare in normal human tissues. Increased B7-H4 expression in tumor cells correlated with decreased cell apoptosis and enhanced outgrowth of tumors in several models, including the severe combined immunodeficiency (SCID)/Beige xenograft outgrowth model, and B7-H4 has been shown to be extensively and variably N- glycosylated, which may serve as a "barrier" mechanism to evade immunosurveillance.

A number of studies are consistent with a role for B7-H4 in antitumor immunity of various cancers, including, but not limited to, cancers of the ovary, esophagus, kidney, stomach, liver, lung, colon, pancreas, breast and prostate, and skin (melanoma), and others described in Table 1, below. Furthermore, cell-free B7-H4 was detected in blood samples from patients of ovarian cancer, RCC, colon cancer, breast cancer, lung cancer, and prostate cancer. These studies indicate that serum B7-H4 may be a useful marker for diagnosis and prognosis of the respective cancer.

Therefore, in some embodiments, the detection of altered levels of cell-free B7-H4 in a biological sample may be indicative of disease, or responsiveness to treatment where determining the level of cell-free B7-H4 is a pharmacodynamic readout. The levels of cell-free B7-H4 can be compared to a control, for example, standards obtained from healthy subjects, such as subjects without an immune response, or autoimmune or inflammatory disease/disorder, or cancer; or to subjects that have been diagnosed with an immune response, or autoimmune or inflammatory disease/disorder or cancer with different disease severity or prognoses. A control can be a single or more preferably pooled or averaged values of like individuals using the same assay.

Compositions and methods for interfering with the biological activity of cell-free B7-H4 are discussed in, for example, U.S. Patent Nos 7,931,896 and 7,989,173, and U.S. Published Application No. 2009/0142342 which are incorporated by reference herein in their entirety.

In one embodiment, the cell-free B7-H4 that can be detected in a sample includes the membrane distal IgV domain and the membrane proximal IgC domain of B7-H4. In another embodiment the cell-free B7-H4 that is detected includes an amino acid sequence that is 80%, 85%, 90%, 95%, or 99% sequence identity to SEQ ID NO:8 or SEQ ID NO:9.

In another embodiment, the cell-free B7-H4 that is detected includes the IgV domain of B7-H4 that includes an amino acid sequence that has at least 80%, 85%, 90%, 95%, or 99% sequence identity to SEQ ID NO:6 or SEQ ID NO:7.

In yet another embodiment, the cell-free B7-H4 that is detected includes a fragment of B7-H4 having an amino acid sequence that has at least 80%, 85%, 90%, 95%, or 99% sequence identity to SEQ ID NO:2 or SEQ ID NO:4. The propensity of the subject for developing or having an

inflammatory or autoimmune disease/disorder, or cancer can be determined based on the levels of cell-free B7-H4 in the subject, preferably serum or plasma levels of cell-free B7-H4 in the subject. If the levels of cell-free B7- H4 in the subject are higher than the average cell-free B7-H4 levels in subjects without an inflammatory or autoimmune disease/disorder, or cancer, the subject is more likely to develop an inflammatory or autoimmune disease/disorder, or cancer; or to have an inflammatory or autoimmune disease/disorder, or cancer.

As illustrated in the Examples below, serum levels of cell-free B7-H4 are elevated in subjects with a number of inflammatory and autoimmune disorders including: rheumatoid arthritis (RA) and Sj5gren's syndrome. The examples also show that cell-free B7-H4 levels at or above 1 ng/ml correlated with disease and severity in humans.

An immune response or condition, an inflammatory or autoimmune disease/disorder, or a cancer in an individual can be diagnosed or detected by quantifying the amount of cell-free B7-H4 in a biological sample of the individual, wherein an elevated amount of cell-free B7-H4 in the individual's biological sample compared to a control is indicative of an immune response or condition, an inflammatory or autoimmune disease/disorder, or a cancer. For example, the method for assisting in the diagnosis of an immune response or condition, an inflammatory or autoimmune disease/disorder, or a cancer or assessing the propensity for developing an immune response or condition, an inflammatory or autoimmune disease/disorder, or a cancer in a subject can included determining the level of cell- free B7-H4 in a biological sample from the subject, wherein an elevated level of cell-free B7-H4 in the biological sample relative to the level of cell-free B7-H4 in a control is indicative of an immune response or condition, an inflammatory or autoimmune disease/disorder, or a cancer or an increased propensity for developing an immune response or condition, an inflammatory or autoimmune disease/disorder, or a cancer.

A method for assisting in the diagnosis or assessing the propensity for developing an immune response or condition, an inflammatory or autoimmune disease/disorder, or a cancer in a subject can also include determining the levels of cell- free B7-H4 in a first biological sample and a second biological sample taken at a time period after the first sample wherein an increase in the level of cell-free B7-H4 in the second sample compared to the first sample is indicative of development or worsening of the immune response or condition, an inflammatory or autoimmune disease/disorder, or a cancer, or a reduction in the level of cell-free B7-H4 is indicative of a pharmcodynamic response to treatment.

A method for determining the severity of an immune response or condition, an inflammatory or autoimmune disease/disorder, or a cancer is also disclosed. The method can include (a) determining the level of cell-free B7-H4 in a biological sample from a subject; and (b) comparing the level of cell-free B7-H4 in the biological sample to reference levels of cell-free B7- H4 that correlate with disease severity of an an immune response or condition, an inflammatory or autoimmune disease/disorder, or a cancer to determine the severity of the immune response or condition, an inflammatory or autoimmune disease/disorder, or a cancer of the subject.

The severity of an immune response or condition, an inflammatory or autoimmune disease/disorder, or a cancer can be detected or assessed by quantifying the level of cell-free B7-H4 in an individual's biological sample and correlating the amount of cell-free B7-H4 in the individual's biological sample with amount(s) of cell-free B7-H4 indicative of different stages of an immune response or condition, an inflammatory or autoimmune

disease/disorder, or a cancer. The amounts of cell-free B7-H4 that correlate with different stages of an immune response or condition, an inflammatory or autoimmune disease/disorder, or a cancer or different levels of severity can be predetermined by quantifying cell-free B7-H4 in patients at different stages of the immune response or condition, an inflammatory or autoimmune disease/disorder, or a cancer, or with different severity of disease.

For example, with RA the following classification for severity is typically employed: Class I: No restriction of ability to perform normal activities; Class II: Moderate restriction, but with an ability to perform most activities of daily living; Class III: Marked restriction, with an inability to perform most activities of daily living and occupation; and Class IV:

Incapacitation with confinement to bed or wheelchair. Levels of cell-free B7- H4 can be determined in patients from each classification to produce a reference level of cell-free B7-H4 that can be correlated with the specific severity level.

A method for selecting a subject for treatment of an immune response or condition, an inflammatory or autoimmune disease/disorder, or a cancer is also disclosed. The method can include (a) determining the level of cell-free B7-H4 in a biological sample obtained from the subject; (b) comparing the level of cell-free B7-H4 in the biological sample to the level of cell- free B7- H4 in a control; and (c) selecting the subject for treatment when the level of cell-free B7-H4 in the biological sample is higher than the level of cell-free B7-H4 in the control. A method for selecting a subject for treatment can also include determining the levels of cell-free B7-H4 in a first biological sample and a second biological sample taken after the first sample, and selecting the subject for treatment when the level of cell-free B7-H4 in the second biological sample is higher than the level of cell-free B7-H4 in the first sample.

As discussed above and in He, et al, Clinical and Developmental Immunology, 695834; 8 pages (2011), some cancers are characterized by increased, aberrant, or inappropriate expression of B7-H4 on or within the cancer cells, but are not necessarily characterized by increase levels of cell- free B7-H4 in a fluid sample. Accordingly, the methods of detecting, diagnosing, evaluating, or selecting subjects with cancer discussed above may alternatively or additionally include steps of measuring the levels of B7- H4 including, but not limited to, transmembrane B7-H4, on or in cancer cells compared to a control such as cells of the same tissue that are non-cancerous.

In some embodiments, the compositions and methods disclosed herein are used to establish, or modify a dosage regime. For example, the subject can be administered a first dose of the composition for a first dosing period; and a second dose of the composition for a second dosing period, optionally followed by one or more additional doses for one or more additional dosing periods. The first dosing period can be less than one week, one week, or more than one week.

In some embodiments the dosage regime is a dose escalating dosage regime. The first dose can be a low dose. Dose escalation can be continued until a satisfactory biochemical or clinical response is reached, for example a reduction in serum or plasma levels of cell-free B7-H4 in the subject. Next, the dosages can be maintained or steadily reduced to a maintenance dose. The methods can used to standardize, optimize, or customize the dose level, dose frequency, or duration of the therapy.

IV. Methods of Diagnosis and Treatment

A. Diseases/disorders to be Diagnosed and Treated

1. Inflammatory and Autoimmune Diseases/disorders Representative inflammatory or autoimmune diseases/disorders that may be detected and treated using the disclosed compositions include, but are not limited to, rheumatoid arthritis, systemic lupus erythematosus, alopecia areata, anklosing spondylitis, antiphospholipid syndrome, autoimmune Addison's disease, autoimmune hemolytic anemia, autoimmune hepatitis, autoimmune inner ear disease, autoimmune lymphoproliferative syndrome (alps), autoimmune thrombocytopenic purpura (ATP), Behcet's disease, bullous pemphigoid, cardiomyopathy, celiac sprue-dermatitis, chronic fatigue syndrome immune deficiency, syndrome (CFIDS), chronic inflammatory demyelinating polyneuropathy, cicatricial pemphigoid, cold agglutinin disease, Crest syndrome, Crohn's disease, Dego's disease, dermatomyositis, dermatomyositis - juvenile, discoid lupus, essential mixed cryoglobulinemia, fibromyalgia - fibromyositis, grave's disease, guillain- barre, hashimoto's thyroiditis, idiopathic pulmonary fibrosis, idiopathic thrombocytopenia purpura (ITP), Iga nephropathy, insulin dependent diabetes (Type I), juvenile arthritis, Meniere's disease, mixed connective tissue disease, multiple sclerosis, myasthenia gravis, pemphigus vulgaris, pernicious anemia, polyarteritis nodosa, polychondritis, polyglancular syndromes, polymyalgia rheumatica, polymyositis and dermatomyositis, primary agammaglobulinemia, primary biliary cirrhosis, psoriasis,

Raynaud's phenomenon, Reiter's syndrome, rheumatic fever, sarcoidosis, scleroderma, Sjogren's syndrome, stiff-man syndrome, Takayasu arteritis, temporal arteritis/giant cell arteritis, ulcerative colitis, uveitis, vasculitis, vitiligo, and Wegener's granulomatosis.

In a preferred embodiment, the inflammatory and autoimmune disease/disorder is rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), Sj5gren's syndrome, lupus nephritis, multiple sclerosis, or type I diabetes.

B7-H4 acts at multiple points in the inflammatory pathway and at a higher level whereby it acts as a master regulator to control to influence the expression and/or activity of effectory cytokines such as TNF-a. Therefore, the B7-H4 compositions described herein are particularly useful for treating patients that do not respond to TNF-a blockers such as ENBREL®

(etanercept), REMICADE® (infliximab), CIMZIA® (certolizumab) and HUMIRA® (adalimumab), or where TNF-a blockers are not safe or effective. In addition, because of its activity as a master regulator in the inflammatory pathway, the B7-H4 compositions disclosed are particularly useful for treating chronic and persistent inflammation. In a preferred embodiment, the B7-H4 compositions described herein are used to treat relapsing and/or remitting multiple sclerosis.

2. Cancers

In some some embodiments, the disclosed compositions and methods are used to diagnose a subject with cancer. Accordingly, in some embodiments, the disclosed compositions and methods are used to diagnose and/or treat a subject with ovary, esophagus, kidney, stomach, liver, lung, colon, pancreas, breast and prostate, and melanoma, or others listed in Table 1, or discussed in He, et al, Clinical and Developmental Immunology, 695834; 8 pages (2011)). In some some embodiments, cell-free B7-H4 serves a biomarker for detection, diagnosis, and/or treatment of ovarian cancer, RCC, colon cancer, breast cancer, lung cancer, and prostate cancer. In preferred embodiments, the cancer is ovarian or breast cancer.

Table 1: Summary of Clinical Studies Investigating Expression of B7-H4 in Cancer Patients (adapted from He, et al, Clinical and

Developmental Immunology, 695834; 8 pages (201 1). Type of No. of Methods Positive Significances Cancer samples Rage (%)

Correlation with

Esophageal gender, distant Squamous cell 112 IHC 98.5% metastasis, TNM Carcinoma stage; reverse

correlation with densities of CD3 ⁺ and CD8 ⁺ T cells, and survival

No correlation with

Renal cell 102 IHC 17.6% age, gender, TNM Carcinoma (early-stage stage,

Tl) lymphovascular invasion or nuclear grade; correlation with recurrence; reverse correlation with survival

Reverse correlation

Melanoma 29 IHC 96.6% with survival; no

(primary), correlation with CD8 ⁺

89.7% T-cell infiltration (metastatic)

Reverse correlation

Gastric cancer 94 RT-PCR 75.5 with survival

%

Reverse correlation

Gastric cancer 156 IHC 44.9% with survival

No correlation with

Ovarian cancer 34 ELISA diagnosis markers

11 types of 289 IHC Overall Correlation with cancer* 52.9% stages

(details refer

to the article)

Higher proportion of

Brenner tumor 34 IHC 100% expression with CA- 125 and CEA

Useful in predicting

Ovarian cancer 98 ELISA short-term (1-year) survival time to progression after chemotherapy Type of No. of Methods Positive Significances

Cancer samples Rage (%)

More powerful than

Pancreatic 36 IHC 91.7% p53, potential ductal diagnostic use adenocarcinoma

Correlation with

Renal cell 101 ELISA 52.5% stage; a potential carcinoma serum marker for diagnosis and prognosis

Correlation with

Breast cancer IHC invasive ductal carcinoma and reduced T- lymphocytes infiltration

Correlation with

Ovarian 103 IHC - Treg cell numbers carcinoma

Correlation with

Uterine 90 IHC, WB 100% high risk of uterine endometrioid endometrioid adenocarcinoma adenocarcinoma;

reverse correlation with T-cell infiltration

48% (stage I) Correlation with

Ovarian cancer 251 ELISA 55% (stage II) poor prognosis

67% (stage III)

A promising

Ovarian cancer 68 ELISA 100% marker for early detection of ovarian cancer

Associated with

Prostate cancer 823 IHC 99% disease spread and poor outcome; an attractive targets for therapeutic manipulation

A potential

Breast and 8 (breast), RT-PCR 100% (breast) therapeutic target colorectal 11 (colorectal) Not consistent

cancers

B7-H4 is a useful

Renal cell 259 IHC 59.1% prognostic marker carcinoma for RRC patients

Correlation with

Non-small-cell 70 IHC 43% lower number of T lung cancer cell infiltration Type of No. of Methods Positive Significances Cancer samples Rage (%)

Higher levels in

Colon, breast, 102.3 ELISA, endometrioid and lung, prostate, (confirmatory IHC serous histotypes and ovarian study:200) than in mucinous cancers histotypes in

ovarian cancer

A potential

Ovarian cancer 125 IHC, WB 99% diagnostic marker

(mucinous), or therapeutic target 100% (other for ovarian cancer histotypes and

metastases)

Among the most

Ovarian serous 19 Microarray highly

papillary overexpressed carcinoma genes, indicating that B7-H4 is a candidate biomarker for early screening

A potential

Breast and 19 (breast), T-PCT, 100% (breast) therapeutic target ovarian cancers 13 (ovarian) WB,IHC 53.8%

(ovarian)

Correlation with

Breast cancer 173 IHC 95.4% negative

(primary), (primary), progesterone

246 97.6% receptor and HER- (metastatic (metastatic 2/neu status, history of chemotherapy; no correlation with grade stage

Ovarian and 22 (ovarian), IHC 85% A potential role in lung cancers 16 (lung) (ovarian),31% the evasion of

(lung) tumor immunity

B. Methods of Treatment

1. Active Agents for Treatment of Inflammatory and

Autoimmune Diseases/Disorders

Methods of using B7-H4 specific antibodies to reduce an immune response, or to treat an inflammatory or autoimmune disease/disorder are also disclosed. The methods can be used to treat diseases/disorders, including, but not limited to those characterized by increased expression of souble B7-H4. The methods typically include administering to a subject in need thereof an immunosuppressive agent.

a. Immunosuppressive Agents - B7-H4 specific In some embodiments, the therapeutic agent effects B7-H4-mediated signal transduction. The therapeutic agent can be an agonist of B7-H4 mediated signal transduction, an antagonist of cell-free B7-H4, or a combination thereof. Suitable therapeutic agents include compounds that inhibit the expression or biological activity of cell-free B7-H4. For example, the agent can be an agonist of transmembrane B7-H4 or its receptor, or an antagonist of cell-free B7-H4, or a combination thereof, in an effective amount to increase B7-H4 mediated signal transduction.

i. Antibodies

The antibodies disclosed herein can be administered to a subject in need thereof to reduce the levels of cell-free B7-H4 in the subject, or reduce cell-free B7-H4 blockage of B7-H4-mediated signal transduction. In one embodiment administration of the antibody has agonistic activity and increases B7-H4 mediated signal transduction. In a preferred embodiment, administration of the antibody reduces sH4 levels in the serum by reducing proteolytic cleavage of transmembrane B7-H4, as described below. In some embodiments the antibodies are administered in combination with an effective amount of a B7-H4-Ig fusion protein that mimics transmembrane B7-H4 to induce B7-H4 mediated signal transduction resulting in inhibitory immune cell responses. In some embodiments, the antibodies are admininstered in combination with another active agent. Preferrably, the antibody binds cell-free B7-H4, without binding to the co-administered B7- H4-Ig fusion protein, without reducing or inhibiting transmembrane B7-H4- mediated signal transduction, or a combination thereof. Accordingly, in some embodiments, administration of the antibody reduces or prevents production of cell-free B7-H4 in vivo.

Exemplary Antibodies

Antibodies or antibody fragments that specifically bind to cell-free B7-H4 can be used to antagonize the biological activity of sH4. An exemplary antibody is mAb hH4.3 (Choi, I.H. et al, J Immunol, 171 :4650-4 (2003)). Other exemplary antibodies include 2H9, hB7-H4.ml, 2D1, 6H3, 8E1 1, HMH4-5G1 and H74.

In preferred embodiments the antibody binds to and inhibits the function of cell-free B7-H4, without binding to, or inhibiting the function of transmembrane B7-H4, or a B7-H4-Ig fusion protein such as those disclosed above.

It is believed that cell-free B7-H4 is generated by enzymatic cleavage of the extracellular portion of B7-H4. 293T cells transfected with full length B7-H4 cDNA release cell-free B7-H4 into culture supernatant, and this secretion can be inhibited by incubation with various proteases inhibitors. In some embodiments, anti-B7-H4 antibody binds to transmembrane B7-H4 and prevents proteolytic cleavage of the extracellular domain, which prevents production of cell- free B7-H4. In preferred embodiments, the antibody prevents cleavage of the extracellular domain of B7-H4 without blocking or inhibiting B7-H4-mediated signal transduction.

It is believed that the KRRS sequence in the membrane juxtaposed region of B7-H4 of the extracellular domain is important for the protease to bind to or to cleave the B7-H4 extracellular domain. Accordingly, in some embodiments the antibody binds to an epitope including the KRRS of the extracellular domain. In some embodiments, the epitope is adjacent to the KRRS of the extracellular domain. For example, in some embodiments the antibody can bind to the amino acid sequence KRRSHLQLLNSK (SEQ ID NO:45), but the antibody does not bind to the sequence KQQSHLQLLNSK (SEQ ID NO:46) or KRRSEPKSC (SEQ ID NO:47). An exemplary antibody that binds to a polypeptide including the amino acid sequence of SEQ ID NO:45 but not bind SEQ ID NO:46 or SEQ ID NO:47 is HMH4- 5G1. Therefore, it is believed that an antibody that binds to the putative protease cleavage epitope, such as antibody HMH4-5G1, could inhibit cleavage of transmembrane B7-H4 and reduce the levels of sH4 in the serum. ii. Protease Inhibitors

As discussed above, it is believed that cell-free B7-H4 is produced by proteolytic cleavage of the extracellular domain of transmembrane B7-H4, thus, in certain embodiments, the therapeutic agent is a protease inhibitor. Exemplary protease inhibitors include, but are not limited to, serine protease inhibitors, cysteine protease inhibitors, aspartic protease inhibitors, and metalloprotease inhibitors. Specific protease inhibitors include leupeptin, PMSF, AEBSF, aprotinin, chymostatin, antithrombin III, 3,4- dichloroisocoumarin, TLCK, TPCK, DIFP, antipain, a2-macroglobulin, N- ethylmaleimide, E-64, chymostatin, pepstatin A, 1, 10-phenanthroline, phosphoramidon, and bestatin.

iii. B7-H4 Polypeptides, Fragments, and Fusions Thereof

The B7-H4 polypeptides, or fragments, or fusions thereof disclosed herein are useful as therapeutic agents. Immune cells, preferably T cells, can be contacted in vivo or ex vivo with B7-H4 fusion polypeptides to decrease or inhibit immune responses including, but not limited to inflammation. The T cells contacted with B7-H4 fusion polypeptides can be any cell which express the T cell receptor, including α/β and γ/δ T cell receptors. T-cells include all cells which express CD3, including T-cell subsets which also express CD4 and CD8. T-cells include both naive and memory cells and effector cells such as CTL. T-cells also include regulatory cells such as Thl, Tel, Th2, Tc2, Th3, Thl 7, Th22, Treg, and Trl cells. T-cells also include NKT-cells and similar unique classes of the T-cell lineage. For example the compositions can be used to modulate Thl, Thl 7, Th22, or other cells that secrete, or cause other cells to secrete, inflammatory molecules, including, but not limited to, IL-Ι β, TNF-a, TGF-beta, IFN-γ, IL-17, IL-6, IL-23, IL- 22, IL-21, and MMPs. The compositions can also be used to increase or promote the activity of Tregs, increase the production of cytokines such as IL-10 from Tregs, increase the differentiation of Tregs, increase the number of Tregs, or increase the survival of Tregs.

Other immune cells that can be treated with the disclosed B7-H4 polypeptides, fragments or fusion thereof include T cell precursors, antigen presenting cells such as dendritic cells and monocytes or their precursors, B cells or combinations thereof. The B7-H4 compositions can be used to modulate the production of antibodies by B cells by contacting the B cells with an effective amount of the B7-H4 composition to inhibit or reduce antibody production by the B cell relative to a control. The B7-H4 compositions can also modulate the production of cytokines by the B cells.

iv. Gene Delivery of B7-H4

Polypeptides, Fragments, and Fusions Thereof

Nucleic acids encoding B7-H4 polypeptides, and fragments and fusion thereof or B7-H4 antibodies can be administered to an individual in need thereof in an amount effective to treat an inflammatory response, inflammatory disease/disorder, or autoimmune disease/dis order. DNA delivery typically involves introduction of a "foreign" DNA into a cell and ultimately, into a live animal. Gene delivery can be achieved using viral vectors or non-viral vectors. Compositions and methods for delivering genes to a subject are known in the art (see Understanding Gene Therapy, Lemoine, N.R., ed., BIOS Scientific Publishers, Oxford, 2008) One approach includes nucleic acid transfer into primary cells in culture followed by autologous transplantation of the ex vivo transformed cells into the individual, either systemically or into a particular organ or tissue.

Nucleic acid therapy can be accomplished by direct transfer of a functionally active DNA into mammalian somatic tissue or organ in vivo. DNA transfer can be achieved using a number of approaches described below. These systems can be tested for successful expression in vitro by use of a selectable marker (e.g., G418 resistance) to select transfected clones expressing the DNA, followed by detection of the presence of the B7-H4 expression product (after treatment with the inducer in the case of an inducible system) using an antibody to the product in an appropriate immunoassay. Efficiency of the procedure, including DNA uptake, plasmid integration and stability of integrated plasmids, can be improved by linearizing the plasmid DNA using known methods, and co-transfection using high molecular weight mammalian DNA as a "carrier". Retroviral-mediated human therapy utilizes amphotrophic, replication-deficient retrovirus systems (Weiss and Taylor, Cell, 82:531-533 (1995)). Such vectors have been used to introduce functional DNA into human cells or tissues, for example, the adenosine deaminase gene into lymphocytes, the NPT-II gene and the gene for tumor necrosis factor into tumor infiltrating lymphocytes. Retro virus-mediated gene delivery generally requires target cell proliferation for gene transfer (Bordignon et al. Science 270:470-475 (1995)). This condition is met by certain of the preferred target cells into which the present DNA molecules are to be introduced, i.e., actively growing tumor cells. Gene therapy of cystic fibrosis using transfection by plasmids using any of a number of methods and by retroviral vectors has been described by Collins et al, U.S. Patent No. 5,240,846.

The DNA molecules encoding the B7-H4 polypeptides or fusion proteins may be packaged into retrovirus vectors using packaging cell lines that produce replication-defective retroviruses, as is well-known in the art. Additional viruses for gene delivery are described in Reynolds et al, Molecular Medicine Today, 5:25-31 (1999)).

Other virus vectors may also be used, including recombinant adenoviruses, herpes simplex virus (HSV) for neuron-specific delivery and persistence. Advantages of adenovirus vectors for human gene therapy include the fact that recombination is rare, no human malignancies are known to be associated with such viruses, the adenovirus genome is double stranded DNA which can be manipulated to accept foreign genes of up to 7.5 kb in size, and live adenovirus is a safe human vaccine organisms. Adeno- associated virus is also useful for human therapy.

Another vector that can express the disclosed DNA molecule and is useful in the present therapeutic setting, particularly in humans, is vaccinia virus, which can be rendered non-replicating.

In addition to naked DNA or RNA, or viral vectors, engineered bacteria may be used as vectors. A number of bacterial strains including

Salmonella, BCG and Listeria monocytogenes (LM) have been used. These organisms display two promising characteristics for use as vaccine vectors: (1) enteric routes of infection, providing the possibility of oral vaccine delivery; and (2) infection of monocytes/macrophages thereby targeting antigens to professional APCs.

In addition to virus -mediated gene transfer in vivo, physical means well-known in the art can be used for direct transfer of DNA, including administration of plasmid DNA and particle-bombardment mediated gene transfer. Furthermore, electroporation, a well-known means to transfer genes into cell in vitro, can be used to transfer DNA molecules to tissues in vivo.

"Carrier mediated gene transfer" has also been described. Preferred carriers are targeted liposomes (Liu et al. Curr Med Chem, 10: 1307-1315 (2003)) such as immunoliposomes, which can incorporate acylated mAbs into the lipid bilayer. Polycations such as asialoglycoprotein/polylysine may be used, where the conjugate includes a molecule which recognizes the target tissue (e.g., asialoorosomucoid for liver) and a DNA binding compound to bind to the DNA to be transfected. Polylysine is an example of a DNA binding molecule which binds DNA without damaging it. This conjugate is then complexed with plasmid DNA for transfer.

Plasmid DNA used for transfection or microinjection may be prepared using methods well-known in the art, for example using the Qiagen procedure (Qiagen), followed by DNA purification using known methods, such as the methods exemplified herein.

b. Immunosuppressive Agents - Non-B7-H4 specific

In some embodiments, the immune response, or

inflammatory/autoimmune disease/dis order is treated by administering to the subject an immunosuppressive agent that is not specific to the B7-H4 signal transduction pathway. The immunosuppressive agent that is not specific for the B7-H4 signal transduction pathway can be administered alone, or in combination with an immunosuppressive agent that is specific for the B7-H4 signal transduction pathway, such as the antibodies described above. Such immunosuppressive agents that are not specific to the B7-H4 signal transduction pathway include, but are not limited to (e.g., antibodies against other lymphocyte surface markers (e.g., CD40, alpha-4 integrin) or against cytokines), other fusion proteins (e.g., CTLA-4-Ig (Orencia®), TNFR-Ig (Enbrel®)), TNF-α blockers such as Enbrel, Remicade, Cimzia and Humira, cyclophosphamide (CTX) (i.e. Endoxan®, Cytoxan®, Neosar®, Procytox®, Revimmune™), methotrexate (MTX) (i.e. Rheumatrex®, Trexall®), belimumab (i.e. Benlysta®), or other immunosuppressive drugs (e.g., cyclosporin A, FK506-like compounds, rapamycin compounds, or steroids), anti-proliferatives, cytotoxic agents, or other compounds that may assist in immunosuppression.

In some embodiments, the agent functions to inhibit or reduce T cell activation through a pathway that is separate from the B7-H4 signal transduction pathway. In one such embodiment, the therapeutic agent is a CTLA-4 fusion protein, such as CTLA-4-Ig (abatacept). CTLA-4-Ig fusion proteins compete with the co-stimulatory receptor, CD28, on T cells for binding to CD80/CD86 (B7-1/B7-2) on antigen presenting cells, and thus function to inhibit T cell activation. In another embodiment, the therapeutic agent is a CTLA-4-Ig fusion protein known as belatacept. Belatacept contains two amino acid substuitutions (L104E and A29Y) that markedly increase its avidity to CD86 in vivo. In another embodiment, the therapeutic agent is Maxy-4.

In another embodiment, the therapeutic agent is cyclophosphamide (CTX). Cyclophosphamide (the generic name for ENDOXAN®,

CYTOXAN®, NEOSAR®, PROCYTOX®, REVIMMUNE™), also known as cytophosphane, is a nitrogen mustard alkylating agent from the oxazophorines group. It is used to treat various types of cancer and some autoimmune disorders. Cyclophosphamide (CTX) is the primary drug used for diffuse proliferative glomerulonephritis in patients with renal lupus.

In some embodiments the therapeutic agent is administered in an effective amount to reduce the blood or serum levels of anti-double stranded DNA (anti-ds DNA) auto antibodies and/or to reduce proteinuria in a patient in need thereof.

In another embodiment, the therapeutic agent increases the amount of adenosine in the serum, see, for example, WO 08/147482. For example, the second therapeutic agent can be CD73-Ig, recombinant CD73, or another agent (e.g. a cytokine or monoclonal antibody or small moelcule) that increases the expression of CD73, see for example WO 04/084933. In another embodiment the therapeutic agent is Interferon-beta.

In another embodiment, the therapeutic agent is Tysabri or another therapeutic for MS. In another embodiment, the second therapeutic agent preferentially treats chronic inflammation, whereby the treatment regimen targets both acute and chronic inflammation. In a preferred embodiment the second therapeutic is a TNF-a blocker.

In another embodiment, the therapeutic agent is a small molecule that inhibits or reduces differentiation, proliferation, activity, and/or cytokine production and/or secretion by Thl, Thl7, Th22, and/or other cells that secrete, or cause other cells to secrete, inflammatory molecules, including, but not limited to, IL-Ι β, TNF-a, TGF-beta, IFN-γ, IL-17, IL-6, IL-23, IL- 22, IL-21, and MMPs. In another embodiment, the therapeutic agent is a small molecule that interacts with Tregs, enhances Treg activity, promotes or enhances IL-10 secretion by Tregs, increases the number of Tregs, increases the suppressive capacity of Tregs, or combinations thereof.

Typically useful small molecules are organic molecules, preferably small organic compounds having a molecular weight of more than 100 and less than about 2,500 daltons, more preferably between 100 and 2000, more preferably between about 100 and about 1250, more preferably between about 100 and about 1000, more preferably between about 100 and about 750, more preferably between about 200 and about 500 daltons. Small molecules comprise functional groups necessary for structural interaction with proteins, particularly hydrogen bonding, and typically include at least an amine, carbonyl, hydroxyl or carboxyl group, preferably at least two of the functional chemical groups. The small molecules often comprise cyclical carbon or heterocyclic structures and/or aromatic or polyaromatic structures substituted with one or more of the above functional groups. Small molecules also include biomolecules including peptides, saccharides, fatty acids, steroids, purines, pyrimidines, derivatives, structural analogs or combinations thereof. In one embodiment, the small molecule is retinoic acid or a derivative thereof. For example, retinoic acid has been shown to inhibit or reduce differentiation and/or activity of Thl7 cells. In some embodiments, the composition increases Treg activity or production. Exemplary Treg enhancing agents include but are not limited to glucocorticoid fluticasone, salmeteroal, antibodies to IL-12, IFN-γ, and IL-4; vitamin D3, and dexamethasone, and combinations thereof.

In some embodiments, the therapeutic agent is an antibody, for example, a functions blocking antibody against a proinflammatory molecule such as IL-6, IL-23, IL-22 or IL-21.

As used herein the term "rapamycin compound" includes the neutral tricyclic compound rapamycin, rapamycin derivatives, rapamycin analogs, and other macrolide compounds which are thought to have the same mechanism of action as rapamycin (e.g., inhibition of cytokine function). The language "rapamycin compounds" includes compounds with structural similarity to rapamycin, e.g., compounds with a similar macrocyclic structure, which have been modified to enhance their therapeutic

effectiveness. Exemplary Rapamycin compounds are known in the art (See, e.g. W095122972, WO 951 16691, WO 95104738, U.S. Patent No.

6,015,809; 5,989,591; U.S. Patent No. 5,567,709; 5,559, 112; 5,530,006; 5,484,790; 5,385,908; 5,202,332; 5, 162,333; 5,780,462; 5, 120,727).

The language "FK506-like compounds" includes FK506, and FK506 derivatives and analogs, e.g., compounds with structural similarity to FK506, e.g., compounds with a similar macrocyclic structure which have been modified to enhance their therapeutic effectiveness. Examples of FK506-like compounds include, for example, those described in WO 00101385.

Preferably, the language "rapamycin compound" as used herein does not include FK506-like compounds.

c. Anti-inflammatories

Other suitable therapeutic agents include, but are not limited to, antiinflammatory agents. The anti-inflammatory agent can be non-steroidal, steroidal, or a combination thereof. One embodiment provides oral compositions containing about 1% (w/w) to about 5% (w/w), typically about 2.5 % (w/w) or an anti-inflammatory agent. Representative examples of non-steroidal anti-inflammatory agents include, without limitation, oxicams, such as piroxicam, isoxicam, tenoxicam, sudoxicam; salicylates, such as aspirin, disalcid, benorylate, trilisate, safapryn, solprin, diflunisal, and fendosal; acetic acid derivatives, such as diclofenac, fenclofenac, indomethacin, sulindac, tolmetin, isoxepac, furofenac, tiopinac, zidometacin, acematacin, fentiazac, zomepirac, clindanac, oxepinac, felbinac, and ketorolac; fenamates, such as mefenamic, meclofenamic, flufenamic, niflumic, and tolfenamic acids; propionic acid derivatives, such as ibuprofen, naproxen, benoxaprofen, flurbiprofen, ketoprofen, fenoprofen, fenbufen, indopropfen, pirprofen, carprofen, oxaprozin, pranoprofen, miroprofen, tioxaprofen, suprofen, alminoprofen, and tiaprofenic; pyrazoles, such as phenylbutazone, oxyphenbutazone, feprazone, azapropazone, and trimethazone. Mixtures of these non-steroidal anti-inflammatory agents may also be employed.

Representative examples of steroidal anti-inflammatory drugs include, without limitation, corticosteroids such as hydrocortisone, hydroxyl- triamcinolone, alpha-methyl dexamethasone, dexamethasone-phosphate, beclomethasone dipropionates, clobetasol valerate, desonide,

desoxymethasone, desoxycorticosterone acetate, dexamethasone, dichlorisone, diflorasone diacetate, diflucortolone valerate, fluadrenolone, fluclorolone acetonide, fludrocortisone, flumethasone pivalate, fluosinolone acetonide, fluocinonide, flucortine butylesters, fluocortolone, fluprednidene (fluprednylidene) acetate, flurandrenolone, halcinonide, hydrocortisone acetate, hydrocortisone butyrate, methylprednisolone, triamcinolone acetonide, cortisone, cortodoxone, flucetonide, fludrocortisone, difluorosone diacetate, fluradrenolone, fludrocortisone, diflurosone diacetate,

fluradrenolone acetonide, medrysone, amcinafel, amcinafide, betamethasone and the balance of its esters, chloroprednisone, chlorprednisone acetate, clocortelone, clescinolone, dichlorisone, diflurprednate, flucloronide, flunisolide, fluoromethalone, fluperolone, fluprednisolone, hydrocortisone valerate, hydrocortisone cyclopentylpropionate, hydrocortamate, meprednisone, paramethasone, prednisolone, prednisone, beclomethasone dipropionate, triamcinolone, and mixtures thereof. 2. Combination Therapy

The therapeutic agents disclosed herein can be administered alone or in combination with each other, or other therapeutic agents. In some embodiments, two therapeutic agents are administered separately, but simultaneously. The two therapeutic agents can also be administered as part of the same composition. In other embodiments, two therapeutic agents are administered separately and at different times, but as part of the same treatment regime.

The subject can be administered a first therapeutic agent 1, 2, 3, 4, 5,

6, or more hours, or 1, 2, 3, 4, 5, 6, 7, or more days before administration of a second therapeutic agent. In some embodiments, the subject can be administered one or more doses of the first agent every 1, 2, 3, 4, 5, 6 7, 14, 21, 28, 35, or 48 days prior to a first administration of second agent.

The therapeutic agents can be administered as part of a therapeutic regimen for the treatment of an inflammatory disease/dis order or an autoimmune disease/disorder. For example, if a first therapeutic agent is administered to a subject every fourth day, the second therapeutic agent can be administered on the first, second, third, or fourth day, or combinations thereof. The first therapeutic agent may be repeatedly administered throughout the entire treatment regiment.

In preferred embodiments one or more B7-H4 specific antibodies are administered in combination with a B7-H4-Ig fusion protein that mimics transmembrane B7-H4, such as SEQ ID NO: 10. Preferably, the antibody binds specifically to cell-free B7-H4 or prevents the cleavage of the extracellular domain of transmembrane B7-H4, without binding to the coadministered B7-H4-Ig fusion protein.

In one example of a co-therapy, B7-H4-Ig and CTX are coadministered in effective amount to prevent or treat a chronic autoimmune disease/disorder such as Systemic lupus erythematosus (SLE). In another embodiment, B7-H4-Ig is cycled with Tysabri or used during a drug holiday in order to allow less frequent dosing with the second therapeutic and reduce the risk of side effects such as PML and to prevent resistance to the second therapeutic.

3. Pharmaceutical compositions

Pharmaceutical compositions including B7-H4 polypeptides, fragments, fusion polypeptides, nucleic acids, and vectors disclosed herein are provided. Pharmaceutical compositions containing peptides or polypeptides may be for administration by parenteral (intramuscular, intraperitoneal, intravenous (IV) or subcutaneous injection), transdermal (either passively or using iontophoresis or electroporation), or transmucosal (nasal, vaginal, rectal, or sublingual) routes of administration or using bioerodible inserts and can be formulated in dosage forms appropriate for each route of administration.

In some in vivo approaches, the compositions disclosed herein are administered to a subject in a therapeutically effective amount. As used herein the term "effective amount" or "therapeutically effective amount" means a dosage sufficient to treat, inhibit, or alleviate one or more symptoms of the disorder being treated or to otherwise provide a desired pharmacologic and/or physiologic effect. The precise dosage will vary according to a variety of factors such as subject-dependent variables (e.g., age, immune system health, etc.), the disease, and the treatment being effected.

For the polypeptide compositions disclosed herein and nucleic acids encoding the same, as further studies are conducted, information will emerge regarding appropriate dosage levels for treatment of various conditions in various patients, and the ordinary skilled worker, considering the therapeutic context, age, and general health of the recipient, will be able to ascertain proper dosing. The selected dosage depends upon the desired therapeutic effect, on the route of administration, and on the duration of the treatment desired. For polypeptide compositions, generally dosage levels of 0.001 to 20 mg/kg of body weight daily are administered to mammals. Generally, for intravenous injection or infusion, dosage may be lower.

In certain embodiments, the polypeptide compositions are administered locally, for example by injection directly into a site to be treated. Typcially, the injection causes an increased localized concentration of the polypeptide compositions which is greater than that which can be achieved by systemic administration. For example, in the case of a neurological disorder like Multiple Sclerosis, the protein may be

administered locally to a site near the CNS. The polypeptide compositions can be combined with a matrix as described above to assist in creating a increased localized concentration of the polypeptide compositions by reducing the passive diffusion of the polypeptides out of the site to be treated.

a. Formulations for parenteral administration

In a preferred embodiment, compositions disclosed herein, including those containing peptides and polypeptides, are administered in an aqueous solution, by parenteral injection. The formulation may also be in the form of a suspension or emulsion. In general, pharmaceutical compositions are provided including effective amounts of a peptide or polypeptide, and optionally include pharmaceutically acceptable diluents, preservatives, solubilizers, emulsifiers, adjuvants and/or carriers. Such compositions optionally include one or more for the following: diluents, sterile water, buffered saline of various buffer content (e.g., Tris-HCl, acetate, phosphate), pH and ionic strength; and additives such as detergents and solubilizing agents (e.g., TWEEN 20 (polysorbate-20), TWEEN 80 (polysorbate-80)), anti-oxidants (e.g., ascorbic acid, sodium metabisulfite), and preservatives (e.g., Thimersol, benzyl alcohol) and bulking substances (e.g., lactose, mannitol). Examples of non-aqueous solvents or vehicles are propylene glycol, polyethylene glycol, vegetable oils, such as olive oil and corn oil, gelatin, and injectable organic esters such as ethyl oleate. The formulations may be lyophilized and redissolved/resuspended immediately before use. The formulation may be sterilized by, for example, filtration through a bacteria retaining filter, by incorporating sterilizing agents into the compositions, by irradiating the compositions, or by heating the

compositions.

b. Formulations for topical administration

Fusion proteins disclosed herein can be applied topically. Topical administration does not work well for most peptide formulations, although it can be effective especially if applied to the lungs, nasal, oral (sublingual, buccal), vaginal, or rectal mucosa.

Compositions can be delivered to the lungs while inhaling and traverse across the lung epithelial lining to the blood stream when delivered either as an aerosol or spray dried particles having an aerodynamic diameter of less than about 5 microns.

A wide range of mechanical devices designed for pulmonary delivery of therapeutic products can be used, including but not limited to nebulizers, metered dose inhalers, and powder inhalers, all of which are familiar to those skilled in the art. Some specific examples of commercially available devices are the Ultravent nebulizer (Mallinckrodt Inc., St. Louis, Mo.); the Acorn II nebulizer (Marquest Medical Products, Englewood, Colo.); the Ventolin metered dose inhaler (Glaxo Inc., Research Triangle Park, N.C.); and the Spinhaler powder inhaler (Fisons Corp., Bedford, Mass.). Nektar, Alkermes and Mannkind all have inhalable insulin powder preparations approved or in clinical trials where the technology could be applied to the formulations described herein.

Formulations for administration to the mucosa will typically be spray dried drug particles, which may be incorporated into a tablet, gel, capsule, suspension or emulsion. Standard pharmaceutical excipients are available from any formulator. Oral formulations may be in the form of chewing gum, gel strips, tablets or lozenges.

Transdermal formulations may also be prepared. These will typically be ointments, lotions, sprays, or patches, all of which can be prepared using standard technology. Transdermal formulations will require the inclusion of penetration enhancers.

c. Controlled delivery polymeric matrices

Fusion proteins disclosed herein may also be administered in controlled release formulations. Controlled release polymeric devices can be made for long term release systemically following implantation of a polymeric device (rod, cylinder, film, disk) or injection (microparticles). The matrix can be in the form of microparticles such as microspheres, where peptides are dispersed within a solid polymeric matrix or microcapsules, where the core is of a different material than the polymeric shell, and the peptide is dispersed or suspended in the core, which may be liquid or solid in nature. Unless specifically defined herein, microparticles, microspheres, and microcapsules are used interchangeably. Alternatively, the polymer may be cast as a thin slab or film, ranging from nanometers to four centimeters, a powder produced by grinding or other standard techniques, or even a gel such as a hydrogel.

Either non-biodegradable or biodegradable matrices can be used for delivery of fusion polypeptides or nucleic acids encoding the fusion polypeptides, although biodegradable matrices are preferred. These may be natural or synthetic polymers, although synthetic polymers are preferred due to the better characterization of degradation and release profiles. The polymer is selected based on the period over which release is desired. In some cases linear release may be most useful, although in others a pulse release or "bulk release" may provide more effective results. The polymer may be in the form of a hydrogel (typically in absorbing up to about 90% by weight of water), and can optionally be crosslinked with multivalent ions or polymers.

The matrices can be formed by solvent evaporation, spray drying, solvent extraction and other methods known to those skilled in the art. Bioerodible microspheres can be prepared using any of the methods developed for making microspheres for drug delivery, for example, as described by Mathiowitz and Langer, J. Controlled Release, 5: 13-22 (1987); Mathiowitz, et al, Reactive Polymers, 6:275-283 (1987); and Mathiowitz, et al, J. Appl. Polymer Set, 35:755-774 (1988).

The devices can be formulated for local release to treat the area of implantation or injection - which will typically deliver a dosage that is much less than the dosage for treatment of an entire body - or systemic delivery. These can be implanted or injected subcutaneously, into the muscle, fat, or swallowed.

C. Methods of Selecting a Subject for Treatment

In some embodiments, the methods of detecting transmembrane B7- H4, cell-free B7-H4, methods of differentiating cell-free from B7-H4 fusion proteins, or methods of diagnosis disclosed above are coupled to a method of treating the disease/disorder that is detected or diagnosed. Accordingly, in some embodiments, the disclosed methods include one or more additional steps of treating the subject. For example, in some embodiments, the methods include administering to the subject an effective amount of a therapeutic agent to reduce one or more symptoms of the disease/disorder that is detected or diagnosed.

Also disclosed are methods of selecting a subject for treatment. For example, in some embodiments, a subject is selected from treatment based on the detection of increased expression of cell-free B7-H4 in a biological sample, or expression or increased expression of transmembrane or cell-free B7-H4 on or from cancer cells compared to a control. The methods of selecting a subject for treatment can include one or more of the methods of detection or diagnosis discussed above, coupled with selecting the subject for treatment, and optionally administering the treatment to the subject.

V. Methods of Determining Therapeutic Efficacy

The detection of cell-free B7-H4 protein levels in biological samples can be useful in monitoring the efficacy of drugs or compounds or procedures used in the treatment of patients with immune-mediated or inflammatory or autoimmune diseases/disorders or cancer. For example, the therapeutic efficacy of a treatment for an immune response or condition, an inflammatory or autoimmune disease/disorder, or a cancer can be assessed by quantifying the level of cell-free B7-H4 in an individual's biological sample over the course of treatment. Levels of cell-free B7-H4 present in a biological sample from the individual can be determined prior to treatment and subsequently at various time intervals during treatment. The levels of cell-free B7-H4 present in the biological sample of the individual undergoing treatment can be compared to the levels of cell-free B7-H4 present in biological samples from the same individual prior to treatment, or at different times during the course of treatment, to determine the efficacy of the treatment in reducing or inhibiting an immune response or condition, an inflammatory or autoimmune disease/disorder, or treating one or more symptoms of cancer. The levels of cell- free B7-H4 in biological samples of the individual undergoing treatment can additionally or alternatively be compared to amounts of cell-free B7-H4 indicative of different stages of an immune response or condition, an inflammatory or autoimmune

disease/disorder, or a cancer.

For example, a method for determining the efficacy of a treatment for an immune response or condition, an inflammatory or autoimmune disease/disorder, or a cancer in a subject can include determining the level of cell-free B7-H4 from one or more biological samples obtained from the subject before or during the course of the treatment, wherein a decrease in the level of cell-free B7-H4 in samples obtained from the subject over time is indicative that the treatment is efficacious.

A method for determining the efficacy of a treatment for an immune response or condition, an inflammatory or autoimmune disease/disorder, or a cancer in a subject can also include determining the levels of cell-free B7-H4 in a first biological sample and a second biological sample taken after the first sample wherein the samples are obtained from the subject over the course of the treatment, and wherein a decrease in the level of cell-free B7- H4 in the second sample compared to the first sample is indicative that the treatment is efficacious.

Examples

Example 1: A Series of Anti-B7-H4 Antibodies Exhibit Varied Binding Properties

Materials and Methods

A series of anti-B7-H4 monoclonal antibodies were prepared (2H9, hB7-H4.ml, 2D 1, 6H3, 8E1 1) or purchased (H74, HMH4-5G1).

A series of B7-H4-Ig fusion proteins were prepared with the sequences: variant 1 (SEQ ID NO:29), variant 2 (SEQ ID NO:31), variant 3 (SEQ ID NO:33), variant 4 (SEQ ID NO:35), variant 5 (SEQ ID NO:37), and variant 6 (SEQ ID NO:39).

The isolated B7-H4-Ig fusion proteins were coated onto microtiter plates and used as a substrate for ELISA assays using increasing

concerntrations of biotinylated anti-B7-H4 antibody, followed by incubation with streptavidin-HRP secondary antibody, and enzyme detection at absorbance 450 nm.

Results

ELISA and Western blot assays were carried out to characterize the binding properties of a series of anti-B7-H4 monoclonal antibodies to various B7-H4-Ig fusion proteins.

Representative results are shown in Figures 1A-1G and presented in Table 2 below. A "+" indicates the antibody bound to the fusion protein, while a "-" indicates that the antibody exhibited little or no binding to the fusion protein.

Figure 2 illustrates the putative locations of the epitopes for the series of antibodies.

Table 2

Example 2: 2H9 and 6H3 or hB7-H4.ml are Effective for Capture and Detection of Mouse and Human Cell-free B7-H4

Materials and Methods

B7-H4 - cell-free B7-H4 mouse or human fusion protein

Antibodies 2H9 or the F(ab')2 fragment of 2H9 (capture); 6H3 or hB7-H4.ml or HMH4-5G1 (detection)

Results

A series of ELISA assays were used to characterize the ability of 2H9 and 6H3 or hB7-H4.ml to capture and detect cell-free B7-H4. The results are illustrated in Figures 3, 4, 5 and 6.

Figure 3 shows a concentration dependent increase in

capture/detection of cell-free B7-H4 by 2H9/6H3.

Figure 4 shows that antibody combination is effective for use in capture/detection of mouse and human cell-free B7-H4.

Figure 5 shows that three ELISA methods with three antibody capture/detection combinations: 2H9/6H3, 2H9/hB7-H4.ml, and

2H9/HMH4-5G1 used to detect cell free B7-H4 have linear correlations.

Figure 6 shows a concentration dependent increase in

capture/detection of cell-free B7-H4 by the F(ab)'2 fragment of 2H9 (capture) and 6H3 or hB7-H4.ml(detection).

Example 3: Measuring Serum Levels Cell-free B7-H4 is a Diagnostic Indicator of Inflammatory/Autoimmune Disorders

Materials and Methods

Serum samples were obtained from healthy individuals (HD) and individuals diagnosed with Rheumatoid Arthritis (RA), Systemic lupus erythematosus (SLE), Sj5gren's Syndrome and Kidney/Ovarian/Breast/Lung Cancer were subjected to a ELISA capture/detection assay using 2H9 F(ab')2/hB7-H4.ml (Figure 7, 8 and 9). Results

Results are presented in Figures 7-9 and Table 3 below.

Table 3 - Cell-free B7-H4 Levels of Figure 7

<lng/ml >lng/ml

RA 32/46(70%) 14/46(30%)

HD 26/26(100%) 0/26(0%)

SS 19/25(79%) 6/25(24%)

Table 3 shows that ratio of total individuals for each disease population (or control) that measured <1 ng/mL and >1 ng/mL.

The results from Figure 7 and Table 3 indicate that there are significantly elevated cell free B7-H4 in RA and Sj5gren's Syndrome patients compared with healthy donors. Cell-free levels of B7-H4 above 1 ng/ml correlate with disease and severity in humans and is the pathogenic threshold for exacerbation of disease in mouse models of RA and SLE; cell- free B7-H4 can be used to diagnosis disease, select patients for treatment, and monitor treatment progress.

The results from Figure 8 show a longitudinal study of serum levels of cell-free B7-H4 in a series of patients being treated for SLE over time. Cell free B7-H4 concentrations changed upon treatment and can be utilized to indicate changes in disease severity and monitor treatment progress.

The results shown in Figure 9 indicate 5-25% cancer patients (Ovarian/Breast/Renal/Lung cancers) have elevated cell free B7-H4. Tumor associated B7-H4 is associated with poor prognosis and implicated in suppression of anti-tumor immune responses. Cell-free B7-H4 in cancer patient serum can be used to diagnosis disease, select patients for treatment, and monitor treatment progress.

Example 4: Use of Differential ELISA Assays to Monitor Cell-free B7- H4 Upon Treatment of Therapeutic B7-H4-Ig Fusion Protein.

Materials and Methods

The ability of different antibody clones to bind to cell-free B7-H4 and B7-H4-Ig was evaluated by direct binding ELISA (see Figure 10). The ability of different sandwich ELISA methods to detect cell-free B7-H4 and B7-H4-Ig fusion protein were evaluated, including the capture/detection combinations: 2H9/6H3, 2H9/HMH4-5G1 and 2H9/hB7-H4.ml (see Figure 1 1).

Results

The results presented Figure 10 and Figure 1 1 indicate 2H9/HMH4- 5G1 and 2H9/hB7-H4.ml pairs could detect cell-free B7-H4 but not B7-H4- Ig. Therefore, 2H9/HMH4-5G1 and 2H9/hB7-H4.ml pairs can be utilized to monitor cell free B7-H4 levels during B7-H4-Ig treatment in autoimmune disease patients.

Example 5: Serum Levels of Cell-Free B7-H4 (sH4) Correlate with Rheumatoid Arthritis Disease Severity

Materials and Methods

Serum samples were obtained from healthy individuals (HD) and individuals diagnosed with Rheumatoid Arthritis (RA), and Sj5gren's Syndrome. Serum samples were subjected to a ELISA capture/detection assay using 2H9 F(ab')2/hB7-H4.ml (Figure 7).

Results

DAS-28 is a combined index that measures the disease activity in patients with Rheumatoid Arthritis (RA) based (1) how many joints in the hands, wrists, elbows, shoulders, and knees are swollen and/or tender; (2) the erythrocyte sedimentation rate (ESR) or C reactive protein (CRP) in the blood to measure the degree of inflammation; (3) the patient's Visual Analogue Score (a simple scale) to assess how they are feeling on that day from 0 (very good) to 10 (very bad). The results are combined to produce the DAS28 score, which correlates with the extent of disease activity:

· <2.6: Disease remission

• 2.6 - 3.2: Low disease activity

• 3.2 - 5.1 : Moderate disease activity

• >5.1 : High disease activity

(Fransen, et al, Clin Exp Rheumatol,23 (Suppl.39): S93-S99 (2005)).

Fourty-eight (48) clinical serum samples from patients with rheumatoid athritis were obtained and subjected to same-day clinical evaluation and DAS-28 scores. The results are presented in Table 4, below. The three highest cell-free B7-H4 (sH4) samples also have the three highest DAS-28 scores. Five moderate samples were borderline positive.

Table 4: Serum Levels of Cell-Free B7-H4 (sH4) in 48 Clinical Samples

Current (DAS 281 sH4>lng/ml

< 3.2 Inactive 0 out of 12

> 3.2 but < 6.0 Moderate 5 out of 29

> 6.0 Very active 3 out of 7

Example 6: Cell-free B7-H4 Serum Levels Correlate with Disease Detection of Multiple Sclerosis (MS)

Materials and Methods

Serum samples obtained from healthy individuals diagnosed with Multiple Sclerosis (MS) were subjected to a ELISA capture/detection assay using 2H9 F(ab')2/hB7-H4.ml (see Tables 5 and 6).

Results

Serum samples obtained from 58 patients undergoing clinical evaluation for multiple sclerosis were acquired from UT-Southwestern. The level of cell-free B7-H4 (sH4) in the serum samples was determined by ELISA assay using 2H9 F(ab)'2 as the capture antibody and 6H3 as the detection antibody. The correlation between cell-free B7-H4 and disease detection and severity are presented in Tables 5 and 6 below.

Table 5: Correlation of Disease Detection and Level of Cell-Free B7-H4 (sH4) in 58 Clinical Samples

Table 6: Level of Cell-Free B7-H4 (sH4) in 8 Clinical Samples