KLRG1 SIGNALING THERAPY

FIELD OF THE INVENTION

[0001] The present invention generally relates to KLRG1 signaling therapy and, in various embodiments, more specifically to KLRGl-based cancer therapy.

BACKGROUND

[0002] Expression of immune checkpoint signaling molecules on immune cells is important to immune system regulation. Co-expression of checkpoint molecules can occur on T cells as well as cancer cells. Prolonged exposure of T cells to cancer cells and to dendritic cells that have processed cancer antigens can lead to complete or partial loss of their immune effector function, resulting in immune exhaustion. Accordingly, inhibition of checkpoint molecules, such as CTLA-4 and PD-1, can re-activate the immune system and lead to effective tumor treatment. Numerous checkpoint signaling molecules expressed on T cells as well as other immune cells have been identified. However, therapeutic developments based upon these signaling molecules are limited and there remains a need for new therapeutics utilizing immune checkpoint signaling pathways for medical therapy.

SUMMARY OF THE INVENTION

[0003] The invention is based, at least in part, on the discovery that killer cell lectin-like receptor Gl (KLRG1) can function as a co-inhibitory receptor like a number of other T cell co-inhibitory receptors such as CTLA-4, PD-1, LAG-3, and TIM-3. Unlike in mice and the teachings of many preceding studies, in humans KLRG1 is a favorable target for

immunotherapy such as cancer immunotherapy. For example, administering to a subject in need thereof an effective amount of killer cell lectin-like receptor Gl (KLRGl)/ligand binding agent can disrupt KLRG1 signaling and activate CD8 ⁺ cytotoxic T and/or NK cells. Thus, the invention has numerous therapeutic uses. For example, the invention can be used for treating cancer through the administration of an effective amount of a killer cell lectin-like receptor Gl (KLRGl)/ligand binding agent.

[0004] Advantages of the invention include the ability to preferentially target CD8 ⁺ cytotoxic T and/or NK cells. Advantages of the invention include greater efficacy and reduced side effects. For example, the population of KLRG1 expressing immune cells more abundantly expresses cytotoxic molecules than the population of CTLA-4 or PD-1 expressing immune cells, hence the potential for greater efficacy; and KLRG1 is a marker that increases with antigen expression, predicting more specific antigen directed immune responses and, hence the potential for reduced side effects.

[0005] In various aspects and embodiments, the invention provides methods of treatment comprising administering to a subject in need thereof an effective amount of a killer cell lectin-like receptor Gl (KLRGl )/ligand binding agent, thereby disrupting KLRGl signaling and activating CD8 ⁺ cytotoxic T and/or NK cells.

[0006] In various aspects and embodiments, the invention provides a method of treating cancer comprising administering to a subject in need thereof an effective amount of a killer cell lectin-like receptor Gl (KLRGl )/ligand binding agent.

[0007] In various aspects and embodiments, the invention provides a killer cell lectin-like receptor Gl (KLRGl) antagonist comprising (i) a killer cell lectin-like receptor Gl

(KLRGl )/ligand binding agent or (ii) an RNAi agent that suppresses KLRGl expression.

[0008] In various aspects and embodiments, the invention provides an mRNA or cDNA encoding the KLRGl antagonist according to the invention.

[0009] In various aspects and embodiments, the invention provides a killer cell lectin-like receptor Gl (KLRGl )/ligand binding agent that neutralizes KLRGl/cadherin (e.g., E- cadherin) binding and disrupts KLRGl signaling, thereby activating CD8 ⁺ cytotoxic T and/or NK cells. The binding agent can cross compete with at least one of clone 13F12F2,

14C2A07, SA231A2, 2F1, 13A2, or REA261. The binding agent can be a human or humanized monoclonal antibody, or a binding fragment thereof, or antibody mimetic.

[0010] In various aspects and embodiments, the invention provides a method of treating a subject comprising administering to a subject in need thereof an effective amount of KLRGl antagonist, thereby disrupting KLRGl signaling and activating CD8 ⁺ cytotoxic T and/or NK cells.

[0011] In various aspects and embodiments, the invention provides a method of treating cancer comprising administering to a subject in need thereof an effective amount of KLRGl antagonist.

[0012] The invention provides a method of treating a melanoma comprising

administering to a subject in need thereof an effective amount of a killer cell lectin-like receptor Gl (KLRGl)/ligand binding agent, wherein the binding agent is an antibody or antigen binding fragment thereof, or antibody mimetic that binds the extracellular domain of human KLRG1 and/or human E-cadherin, N-cadherin, or R-cadherin, thereby disrupting KLRG1 signaling and activating CD8 ⁺ cytotoxic T and/or NK cells.

[0013] The invention provides a method of treating a lung cancer comprising

administering to a subject in need thereof an effective amount of a killer cell lectin-like receptor Gl (KLRGl)/ligand binding agent, wherein the binding agent is an antibody or antigen binding fragment thereof, or antibody mimetic that binds the extracellular domain of human KLRG1 and/or human E-cadherin, N-cadherin, or R-cadherin, thereby disrupting KLRG1 signaling and activating CD8 ⁺ cytotoxic T and/or NK cells.

[0014] The invention provides a method of treating a pancreatic cancer comprising administering to a subject in need thereof an effective amount of a killer cell lectin-like receptor Gl (KLRGl)/ligand binding agent, wherein the binding agent is an antibody or antigen binding fragment thereof, or antibody mimetic that binds the extracellular domain of human KLRG1 and/or human E-cadherin, N-cadherin, or R-cadherin, thereby disrupting KLRG1 signaling and activating CD8 ⁺ cytotoxic T and/or NK cells.

[0015] The invention provides a method of treating a glioma comprising administering to a subject in need thereof an effective amount of a killer cell lectin-like receptor Gl

(KLRGl)/ligand binding agent, wherein the binding agent is an antibody or antigen binding fragment thereof, or antibody mimetic that binds the extracellular domain of human KLRG1 and/or human E-cadherin, N-cadherin, or R-cadherin, thereby disrupting KLRG1 signaling and activating CD8 ⁺ cytotoxic T and/or NK cells.

[0016] The invention provides a method of treating a breast cancer comprising administering to a subject in need thereof an effective amount of a killer cell lectin-like receptor Gl (KLRGl)/ligand binding agent, wherein the binding agent is an antibody or antigen binding fragment thereof, or antibody mimetic that binds the extracellular domain of human KLRG1 and/or human E-cadherin, N-cadherin, or R-cadherin, thereby disrupting KLRG1 signaling and activating CD8 ⁺ cytotoxic T and/or NK cells.

[0017] The invention provides a method of treating an ovarian cancer comprising administering to a subject in need thereof an effective amount of a killer cell lectin-like receptor Gl (KLRGl)/ligand binding agent, wherein the binding agent is an antibody or antigen binding fragment thereof, or antibody mimetic that binds the extracellular domain of human KLRGl and/or human E-cadherin, N-cadherin, or R-cadherin, thereby disrupting KLRGl signaling and activating CD8 ⁺ cytotoxic T and/or NK cells.

[0018] In various embodiments, the subject is a mammal, such as a human.

[0019] In various embodiments, methods according to the invention are carried out in vivo (e.g., as opposed to ex vivo).

[0020] In various embodiments, the binding agent is an antibody or antigen binding fragment thereof, or antibody mimetic.

[0021] In various embodiments, the antibody or antigen binding fragment thereof, or antibody mimetic comprises a human or humanized antibody.

[0022] In various embodiments, the antibody or antigen binding fragment thereof, or antibody mimetic comprises: a. a full length antibody Fab portion that binds KLRGl;

b. a full length antibody Fab portion that binds E-cadherin;

c. a full length antibody Fab portion that binds N-cadherin;

d. a full length antibody Fab portion that binds R-cadherin;

e. a fusion protein E-cadherin/Fc;

f. a fusion protein R-cadherin/Fc;

g. a fusion protein N-cadherin/Fc;

h. a chimeric antigen receptor; or

i. a multispecific antibody.

[0023] In various embodiments, the binding agent is a chimeric antigen receptor and the chimeric antigen receptor comprises a specificity portion of a KLRGl antibody grafted onto a T cell.

[0024] In various embodiments, the binding agent is a multispecific antibody. The multispecific antibody can comprise a bispecific or trispecific antibody.

[0025] In various embodiments, the binding agent binds KLRGl. [0026] In various embodiments, the KLRG1 is the extracellular domain of human KLRG1.

[0027] In various embodiments, the binding agent binds a KLRG1 ligand.

[0028] In various embodiments, the KLRG1 ligand is human E-cadherin, N-cadherin, or R-cadherin.

[0029] In various embodiments, the binding agent binds KLRG1 and/or cadherin at a KLRGl/cadherin binding site.

[0030] In various embodiments, the subject has an epithelial cancer. [0031] In various embodiments, the subject has a carcinoma.

[0032] In various embodiments, the subject has a uveal melanoma, uterine carcinoma, uterine carcinosarcoma, thyroid carcinoma, thymoma, testicular germ cell tumor, melanoma, sarcoma, rectal adenocarcinoma, prostate cancer, pheochromocytoma, pancreatic

adenocarcinoma, ovarian cystadenocarcinoma, mesothelioma, lung squamous cell carcinoma, lung adenocarcinoma, liver hepatocellular carcinoma, kidney papillary cell carcinoma, kidney clear cell carcinoma, kidney chromophobe carcinoma, head and neck squamous cell carcinoma, glioblastoma multiforme, diffuse large B-cell lymphoma, colon adenocarcinoma, cholangiocarcinoma, cervical and/or endocervical cancer, breast invasive carcinoma, brain low grade glioma, bladder cancer, or acute myeloid leukemia.

[0033] In various embodiments, the subject has a melanoma.

[0034] In various embodiments, the subject has a lung cancer.

[0035] In various embodiments, the subject has a pancreatic cancer.

[0036] In various embodiments, the subject has a glioma.

[0037] In various embodiments, the subject has a breast cancer.

[0038] In various embodiments, the subject has an ovarian cancer.

[0039] In various embodiments, the methods further comprise administering to the subject an effective amount of a checkpoint modulator therapy. [0040] In various embodiments, the KLRGl/ligand binding agent and checkpoint modulator therapy are synergistic.

[0041] In various embodiments, the method further comprises administering to the subject an effective amount of a cancer vaccine therapy.

[0042] In various embodiments, the KLRGl/ligand binding agent and cancer vaccine therapy are synergistic.

[0043] In various embodiments, the invention can use a combination of the

KLRGl/ligand binding agent and one or more additional Active Pharmaceutical Ingredient (API). In some embodiments, the API may be a polynucleotide (including an oligonucleotide) a protein or a small molecule. An API can include, for example, an anticancer agent, an antibiotic agent, an antiviral agent, an anti-fungal agent, or an analgesic.

[0044] In various embodiments, the method further comprises administering to the subject an effective amount of a cancer chemotherapy.

[0045] In various embodiments, the checkpoint modulator therapy comprises an anti-PD- 1, anti-PD-Ll, or anti-CTLA-4 therapy.

[0046] In various embodiments, the subject has failed or has not responded to a prior cancer therapy.

[0047] In various embodiments, the subject has elevated KLRG1 expression. The elevated KLRG1 expression can comprise elevated KLRG1 expression on CD8+ cytotoxic T and/or NK cells. In various embodiments, the method can further comprise testing the subject for elevated KLRG1 expression (e.g., before beginning and/or during the therapy).

[0048] In various embodiments, the subject has elevated cadherin expression (e.g., E- cadherin). The elevated cadherin expression can comprise elevated cadherin expression on cancer cells. In various embodiments, the method can further comprise testing the subject for elevated cadherin expression (e.g., before beginning and/or during the therapy).

[0049] In various embodiments, the treatment can prolong the subject's survival. In various embodiments, the treatment can prevent or reduce the progression or the cancer and/or metastasis. [0050] In various embodiments, the binding agent is administered by providing an mRNA encoding the binding agent to the subject.

[0051] In various embodiments, the antagonist disrupts KLRGl signaling, thereby activating CD8 ⁺ cytotoxic T and/or NK cells.

[0052] In various embodiments, the antagonist binds the extracellular domain of human KLRGl or binds a KLRGl ligand.

[0053] In various embodiments, the KLRGl antagonist comprises an antibody or antigen binding fragment.

[0054] In various embodiments, the KLRGl antagonist comprises an Fc-cadherin fusion protein.

[0055] In various embodiments, the antibody is monoclonal.

[0056] In various embodiments, the antibody is human or humanized.

[0057] In various embodiments, the KLRGl antagonist comprises a binding agent that blocks or competes with KLRGl -ligand binding.

[0058] In various embodiments, the KLRGl antagonist comprises a binding agent that cross reacts with the extracellular domains of human and cynomolgus KLRGl, or the human and cynomolgus KLRGl ligand.

[0059] In various embodiments, the KLRGl antagonist comprises a binding agent that binds to an epitope of (i) the extracellular domain of KLRGl or (ii) the KLRGl ligand, wherein the epitope is at least 90% identical in human and cynomolgus. In one embodiment, the KLRGl antagonist comprises a binding agent that binds to the same epitope as any one of clone 13F12F2, 14C2A07, SA231A2, 2F1, 13A2, or REA261.

[0060] In various embodiments, the KLRGl antagonist comprises a binding agent that binds to KLRGl and that is not clone 13F12F2, 14C2A07, SA231A2, 2F1, 13A2, or REA261 (or another previously described anti-KLRGl antibody).

[0061] In various embodiments, the KLRGl antagonist comprises a binding agent that binds to KLRGl and that is not a mouse antibody. [0062] In various embodiments, the antagonist or binding agent cross competes with at least one of clone 13F12F2, 14C2A07, SA231A2, 2F1, 13A2, or REA261.

[0063] In various embodiments, the antagonist, e.g., binding agent, neutralizes

KLRGl/E-cadherin binding.

[0064] In various embodiments, the binding agent is a human or humanized monoclonal antibody, or binding fragment thereof, or antibody mimetic.

[0065] In various embodiments, the KLRGl antagonist comprises an RNAi agent. The RNAi agent can be, inter alia, an siRNA or an mRNA.

[0066] These and other advantages of the present technology will be apparent when reference is made to the accompanying drawings and the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0067] FIG. 1 shows human KLRGl is expressed on greater proportions of cytotoxic T and NK cells than helper T cells.

[0068] FIGS. 2A and 2B show a progression of increasing expression of KLRGl on T cells with increased differentiation.

[0069] FIG. 3 shows a summary of published drug development programs for co- inhibitory receptor modulation by various pharmaceutical companies.

[0070] FIGS. 4A and 4B show CTLA-4 and PD-1 are more highly or similarly expressed on T helper cells (CD4 ⁺ ) than cytotoxic T cells (CD8 ⁺ ) or NK cells, while KRLGl expression is higher on CD8 ⁺ T and NK cells than CD4 ⁺ T helper cells.

[0071] FIG. 5 shows the widespread infiltration of many tumor types by KLRGl expressing T cells and expression of the KLRGl ligand E-cadherin in these tumor samples.

[0072] FIG. 6A and 6B show sera responses of immunized mice to KLRGl.

[0073] FIG. 7 shows binding of antibodies derived from hybridoma clones to human KLRGl extracellular domain. [0074] FIG. 8 shows an analysis of gene expression datasets that demonstrates higher expression of KLRGl in CD8 ⁺ cells compared to CD4 ⁺ T helper cells.

[0075] FIGS. 9A and 9B shows that the cytotoxic potential of CD8 ⁺ T cells, as reflected by gene expression of cytotoxic molecules granzymes and cytokines, is highly correlated with expression of KLRGl but not other checkpoint inhibitor target co-inhibitory receptors.

[0076] FIG. 10 shows E-cadherin is overexpressed in various cancer cell lines.

[0077] FIG. 11 shows the fold-change of E-cadherin and PD-L1 in melanoma TCGA RNAseq data in comparison to normal skin tissue.

[0078] FIG. 12 shows the fold-change of E-cadherin and PD-L1 in lung cancer TCGA RNAseq data in comparison to normal lung tissue.

[0079] FIG. 13 shows the fold-change of E-cadherin and PD-L1 in pancreatic cancer TCGA RNAseq data in comparison to normal pancreatic tissue.

[0080] FIG. 14 shows the fold-change of E-cadherin and PD-L1 in glioma TCGA RNAseq data in comparison to normal brain tissue.

[0081] FIG. 15 shows the fold-change of E-cadherin and PD-L1 in breast cancer TCGA RNAseq data in comparison to normal breast tissue.

[0082] FIG. 16 shows the fold-change of E-cadherin and PD-L1 in TCGA ovarian cancer RNAseq data in comparison to normal ovarian tissue.

[0083] FIGS. 17A-D show that KLRGl is expressed by a large proportion of melanoma infiltrating T cells, including PD-1 negative T cells. FIG. 17A shows a comparison of proportions of infiltrating CD8 ⁺ T cells that express either KLRGl or PD-1. FIG. 17B shows the proportion of PD-1 negative CD8 ⁺ T cells that express KLRGl. FIG. 17C shows the proportion of PD-1 negative CD8 ⁺ T cells that express KLRGl, organized by each of 17 melanoma patient samples (e.g., P53 is patient 53 from dataset GSE72056 within GEO database). FIG. 17D shows individual CD8 ⁺ T cell expression levels of KLRGl (log 2 transcripts per million) organized by each patient sample.

[0084] FIGS. 18A-D show KLRGl ligands E-cadherin and N-cadherin are much more highly expressed by malignant melanoma cells than PD-1 ligands PD-L1 and PD-L2. FIG. 18A shows single cell RNA-seq analysis of expression of KLRG1 and PD-1 ligands in 1184 patient biopsy melanoma cells shows markedly greater E-cadherin and N-cadherin expression than PD-L1 and PD-L2. Mean and SEM shown. FIG. 18B shows fourteen melanoma patient samples show a mean of 76% of melanoma cells expressing E-cadherin or N-cadherin compared to 11% expressing PD-L1 or PD-L2. FIG. 18C and 18D show individual melanoma cell (1184 cells) expression levels (log 2 transcripts per million, "TPM") of E- cadherin (FIG. 18C) organized by each patient sample greatly exceed those of PD-L1 (FIG. 18D).

[0085] FIG. 19 shows a summary of relative expression in cancer tissues versus normal matching tissue for E-cadherin and for PD-L1.

[0086] FIG. 20 shows KLRG1 ⁺ cells infiltrating melanoma tumors in example patients.

[0087] FIG. 21 shows KLRG1 ⁺ cells infiltrating renal cell carcinoma tumors in example patients.

[0088] FIG. 22 shows KLRG1 ⁺ cells infiltrating non-small cell lung cancer tumors in example patients.

[0089] FIG. 23 presents the results of soluble hE-cadherin binding to plate-coated hKLRGl.

[0090] FIG. 24 presents the results of the three chimeric antibodies tested for neutralizing hE-cadherin/hKLRGl binding, with only one chimeric antibody demonstrating neutralizing activity.

[0091] FIG. 25 presents the results of the three chimeric antibodies binding to plate coated KLRG1 in a dose dependent manner.

[0092] While the invention comprises embodiments in many different forms, there are shown in the drawings and will herein be described in detail several specific embodiments with the understanding that the present disclosure is to be considered as an exemplification of the principles of the technology and is not intended to limit the invention to the embodiments illustrated. BRIEF DESCRIPTION OF THE SEQUENCES

[0093] SEQ ID NO: 1 is the sequence of human KLRGl ECD isotype 1.

[0094] SEQ ID NO:2 is the sequence of human KLRGl ECD isotype 2.

[0095] SEQ ID NO:3 is the sequence of cynomolgus KLRGl ECD.

[0096] SEQ ID NO:4 is the sequence of human E-cadherin.

[0097] SEQ ID NO:5 is the sequence of human N-cadherin.

[0098] SEQ ID NO:6 is the sequence of human R-cadherin.

[0099] SEQ ID NO:7 is the sequence of human KLRGl mRNA.

DETAILED DESCRIPTION

[00100] The invention is based, at least in part, on the discovery that KLRGl can function as a co-inhibitory receptor like a number of other T cell co-inhibitory receptors such as CTLA-4, PD-1, LAG-3, and TIM-3. Unlike in mice and the teachings of many preceding studies, in humans KLRGl is a favorable target for immunotherapy (e.g., cancer

immunotherapy). For example, administering to a subject in need thereof an effective amount of a killer cell lectin-like receptor Gl (KLRGl )/ligand binding agent can disrupt KLRGl signaling and activate CD8 ⁺ cytotoxic T and/or NK cells. Thus, the invention has numerous therapeutic uses. For example, the invention can be used for treating cancer through the administration of an effective amount of a killer cell lectin-like receptor Gl (KLRGl )/ligand binding agent.

[00101] Advantages of the invention include the ability to preferentially target CD8 ⁺ cytotoxic T and/or NK cells. Advantages of the invention include greater efficacy and reduced side effects. For example, the population of KLRGl expressing immune cells more abundantly express cytotoxic molecules than the population of CTLA-4 or PD-1 expressing immune cells, hence potential for greater efficacy; and KLRGl is a marker that increases with antigen experience, predicting more specific antigen directed immune responses and, hence potential for reduced side effects.

[00102] Accordingly, in various aspects and embodiments, the invention provides methods of treating a subject comprising administering to a subject in need thereof an effective amount of a killer cell lectin-like receptor Gl (KLRGl )/ligand binding agent, thereby disrupting KLRGl signaling and activating CD8 ⁺ cytotoxic T and/or NK cells. The invention also provides methods of treating cancer comprising administering to a subject in need thereof an effective amount of a killer cell lectin-like receptor Gl (KLRGl )/ligand binding agent.

[00103] In various aspects and embodiments, the invention provides a killer cell lectin-like receptor Gl (KLRGl) antagonist comprising (i) a killer cell lectin-like receptor Gl

(KLRGl )/ligand binding agent or (ii) an RNAi agent that suppresses KLRGl expression. The invention also provides an mRNA or cDNA encoding the KLRGl antagonist according to the invention. The invention also provides a method of treating a subject comprising

administering to a subject in need thereof an effective amount of KLRGl antagonist, thereby disrupting KLRGl signaling and activating CD8 ⁺ cytotoxic T and/or NK cells. The invention also provides a method of treating cancer comprising administering to a subject in need thereof an effective amount of KLRGl antagonist.

[00104] The various features of the invention such as KLRGl and its ligands, binding agents, combination therapies, treatment and administration, cancers, and illustrative examples are discussed, in turn, below.

[00105] Killer Cell Lectin-Like Receptor Gl (KLRGl) and Its Ligands

[00106] Killer cell lectin-like receptor Gl (KLRGl) is type II transmembrane protein surface co-inhibitory receptor modulating the activity of T and NK cells. Its extracellular portion contains a C-type lectin domain whose known ligands are cadherins and its intracellular portion contains an immunoreceptor tyrosine-based inhibitory motif (ΠΊΜ) domain responsible for co-inhibition of T cell receptor (TCR) mediated signaling (Tessmer et al., 2007). In various embodiments, the ligand can be E-cadherin, N-cadherin, R-cadherin, or a combination thereof.

[00107] KLRGl distribution and function differ in the rodent compared to the human. Originally identified on a rodent mast cell line (Guthmann et al., 1995), KLRGl is not expressed on human mast cells, basophils, monocytes, or neutrophils (Voehringer et al., 2002). Human KLRGl is a more potent co-inhibitory receptor than mouse KLRGl. KLRG1- mediated inhibition under physiological conditions is only observed with human lymphocytes because KLRGl dimers have greater potency than monomers, and human KLRGl forms exclusively dimers while mouse KLRG1 exists as monomers and dimers (Hofmann et al., 2012).

[00108] KLRG1 expression in humans is limited to T and NK cells. It is expressed on greater proportions of cytotoxic T and NK cells than helper T cells (FIG. 1, KLRG1 expression of lymphocyte subsets, human blood flow cytometry). Specifically, FIG. 1 shows the greater expression of KLRG1 on cytotoxic CD8 ⁺ T cells and NK cells than on CD4 ⁺ helper T cells. Within the CD8 ⁺ cytotoxic T cell population, increased KLRG1 expression correlates with increased antigen specific potency (FIG. 2A and B). Specifically, FIG. 2 shows increasing expression of KLRG1 on T cells with increased differentiation. FIG. 2A (cytotoxicity and cytokines of CD8 ⁺ T cell subsets, human blood gene expression) shows cytotoxic potential of T cells increases from TN TCM TEM TEMRA. FIG. 2B (% KLRG1 ⁺ CD6 ⁺ T cells of human blood CD8 ⁺ subpopulation by flow cytometry) shows KLRG1 expression increases from TN TCM TEM TEMRA. As CD8 ⁺ cytotoxic T cells differentiate in response to antigen, from naive T cells to central memory, effector memory, and effector memory RA cells, they express increased amounts of KLRG1. Thus, KLRG1 marks cells with high capacity for cytotoxic killing. This cytotoxicity may be undesired (in the case of autoimmune disease and transplant rejection) or desired (in the case of cancer or chronic infectious disease).

[00109] As KLRG1 function in humans is substantially different than KLRG1 function in mice, mouse data is of limited applicability to the treatment of human disease. However, there is a near complete absence of published KLRG1 translational data in human diseases. There are no published studies of KLRG1 expression by immunohistochemistry in any human diseased or healthy tissue sample. There are 4 published studies that contain minor data on KLRG1 expression by flow cytometry in human diseased tissue samples, other than peripheral blood mononuclear cells (PBMCs): tumor-infiltrating lymphocytes in

hepatocellular carcinoma (Brunner et al., 2015) and renal cell carcinoma (Attig et al., 2009); tumor infiltrated lymph node in melanoma (Legat et al., 2013); and synovial T cells in rheumatoid arthritis and spondyloarthropathies (Melis et al., 2014). Approximately 5 published studies contain minor data on KLRG1 expression in diseased PBMCs.

[00110] KLRG1 is a co-inhibitory receptor like a number of other T cell co-inhibitory receptors and, as such, can be compared to CTLA-4, PD-1, LAG-3, and TIM-3. Whereas these later co-inhibitory receptors have been recognized as markers of T cell exhaustion (Blackburn et al., 2009) and 2 of them (CTLA-4 and PD-1) successfully targeted via immunotherapies for the treatment of cancer (Mahoney et al., 2015), KLRGl has not been recognized as an exhaustion marker, but rather as a marker of immunosenescence (Akbar and Henson, 2011, Apetoh et al., 2015). As a marker of immunosenescence, KLRGl has been viewed as an unfavorable target for immunotherapy (Akbar and Henson, 2011).

[00111] Much of the science and attention to CTLA-4 and PD-1 as favorable targets for immunotherapy has developed as a consequence of studies of mouse biology. The

demonstration that CTLA-4 knockout mice had lethal spontaneous systemic autoimmunity propelled attention to targeting this pathway to generate cancer autoimmunity (Tivol et al., 1995). The demonstration that PD-1 knockout mice had spontaneous autoimmunity similarly focused activity on PD-1 targeting for human therapeutic potential (Nishimura et al., 1999).

[00112] In contrast, KLRGl expression in mice has been identified as negatively correlated with that of PD-1 (Blackburn et al., 2009). Unlike CTLA-4 and PD-1 knockout mice, KLRGl knockout mice do not demonstrate spontaneous autoimmunity (Grundemann et al., 2010). Whereas multiple pharmaceutical industry-led clinical development programs exist for most other co-inhibitory T cell receptors (FIG. 3, drug development programs for co- inhibitory receptor modulation by pharmaceutical companies. Gray boxes indicate public domain program exists), no drug development program for KLRGl is currently known in the public domain.

[00113] Furthermore, despite their characterization as senescent and being viewed as unfavorable for targeting for cancer immunotherapy, KLRGl ^"1" T cells can proliferate after modulation of the KLRGl receptor with its ligands (Henson et al., 2009, Henson et al., 2012, Shi et al., 2014). Despite absence of a spontaneous autoimmune phenotype of KLRGl knockout mice, these mice do show increased survival after mycobacterium tuberculosis infection, suggesting heightened immunity in the absence of KLRGl (Cyktor et al., 2013).

[00114] A goal of immune-oncology therapies is the activation of inhibited CD8 ⁺ cytotoxic T and NK cells. Current FDA-approved drugs target CTLA-4 and PD-1. These molecules are more highly or similarly expressed on T helper cells (CD4 ⁺ ) than cytotoxic T cells (CD8 ⁺ ) or NK cells, while KRLG1 expression is higher on CD8 ⁺ T and NK cells than CD4 ⁺ T helper cells (FIG. 4A and B). FIG. 4A (checkpoint expression of lymphocyte subset, human blood flow cytometry) shows proportionately greater expression of KLRGl on lymphocyte subsets than CTLA-4 and PD-1. FIG. 4B (% cells of human blood CD8 ⁺ subpopulation by flow cytometry) shows KLRGl is expressed on a larger proportion of lymphocytes than CTLA-4 or PD-1 and increases from TN TCM TEM TEMRA, while PD-1 and CTLA-4 expression decreases from TEM - TEMRA. Accordingly, one advantage of the present invention is the preferential targeting of CD8 ⁺ cytotoxic T and/or NK cells. Another advantage is the targeting of the most potent (i.e., with greatest cytotoxic potential) subpopulations of CD8 ⁺ cytotoxic T cells and of NK cells.

[00115] With these new insights, further analysis of previously unanalyzed data demonstrates the widespread infiltration of many tumor types by KLRGl expressing T cells and expression of the KLRGl ligand E-cadherin in these tumor samples (FIG. 5, see also Examples 3 and 4 below). E-cadherin expression is substantially greater than that of the PD-1 ligand PD-L1 in a wide array of tumors.

[00116] In various aspects and embodiments, KLRGl is human or cynomolgus KLRGl, preferably human KLRGl, including any functional part thereof. For example, KLRGl can be Human-KLRGl-ECD-Isotype 1 (SEQ ID NO: l), including any functional part thereof.

[00117] In various aspects and embodiments, KLRGl is Human-KLRGl-ECD-Isotype2 (SEQ ID NO:2), including any functional part thereof.

[00118] In various aspects and embodiments, KLRGl is Cynomolgus-KLRGl (SEQ ID NO:3), including any functional part thereof.

[00119] In various aspects and embodiments, KLRGl ligand is a cadherin, preferably a human cadherin, including any functional parts thereof.

[00120] In various aspects and embodiments, KLRGl ligand is human E-cadherin (SEQ ID NO:4), including any functional part thereof.

[00121] In various aspects and embodiments, KLRGl ligand is human N-cadherin (SEQ ID NO:5), including any functional part thereof.

[00122] In various aspects and embodiments, KLRGl ligand is human R-cadherin (SEQ ID NO:6), including any functional part thereof. [00123] In some embodiments, the binding agent targets amino acids in KLRG1 sequence involved in binding cadherin. For example, in one embodiment, the binding agent binds (157)NSFVQ(162) and/or (172)OASSCEV(178) of SEQ ID NO: l and SEQ ID NO:2, respectively.

[00124] Antagonists, Binding Agents

[00125] In various aspects and embodiments, a killer cell lectin-like receptor Gl (KLRG1) antagonist comprises (i) a killer cell lectin-like receptor Gl (KLRGl)/ligand binding agent or (ii) an RNAi agent that suppresses KLRG1 expression. In various aspects and embodiments, the binding agent is an antibody or antigen binding fragment thereof, or antibody mimetic. In general, the antagonist disrupts KLRG1 signaling, thereby achieving a therapeutic effect (e.g., by activating CD8 ⁺ cytotoxic T and/or NK cells). In various embodiments, the antagonist binds the extracellular domain of human KLRG1 or binds a KLRG1 ligand (e.g., thus disrupting KLRG1 signaling).

[00126] The term "antibody" is used in the broadest sense and specifically covers, for example, single anti-KLRGl or anti-KLRGl ligand monoclonal antibodies. The term

"monoclonal antibody" as used herein refers to an antibody obtained from a population of substantially homogeneous antibodies, e.g., the individual antibodies comprising the population are identical except for possible naturally-occurring mutations that may be present in minor amounts. An antibody can be monoclonal. An antibody can be a human or humanized antibody.

[00127] "Antibody fragments" can include a portion of an intact antibody, preferably the antigen binding or variable region of the intact antibody. Examples of antibody fragments include Fab, Fab', F(ab')2, and Fv fragments, diabodies, linear antibodies, single-chain antibody molecules, and multispecific antibodies formed from antibody fragments.

[00128] "Fv" includes the minimum antibody fragment which contains a complete antigen- recognition and binding site. This region consists of a dimer of one heavy- and one light- chain variable domain in tight, non-covalent association. It is in this configuration that the three CDRs of each variable domain interact to define an antigen-binding site on the surface of the VH-VL dimer. Collectively, the six CDRs confer antigen-binding specificity to the antibody. However, even a single variable domain (or half of an Fv comprising only three CDRs specific for an antigen) has the ability to recognize and bind antigen, although at a lower affinity than the entire binding site. The Fab fragment also contains the constant domain of the light chain and the first constant domain (CHI) 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 CHI domain including one or more cysteines from the antibody 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. F(ab')2 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.

[00129] Depending on the amino acid sequence of the constant domain of their heavy chains, immunoglobulins can be assigned to different classes. There are five major classes of immunoglobulins: IgA, IgD, IgE, IgG, and IgM, and several of these may be further divided into subclasses (isotypes), e.g., IgGl, IgG2, IgG3, IgG4, IgA, and IgA2. "Single-chain Fv" or "sFv" antibody fragments comprise the VH and VL domains of antibody, wherein these domains are present in a single polypeptide chain. Preferably, the Fv polypeptide further comprises a polypeptide linker between the VH and VL domains which enables the sFv to form the desired structure for antigen binding.

[00130] In various embodiments, the antibody or antigen binding fragment thereof, or antibody mimetic comprises a human or humanized antibody. 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 complementary determining region (CDR) of the recipient 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 comprise residues which are found neither in the recipient antibody nor in the imported CDR or framework sequences. In general, the humanized antibody can comprise 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. Methods for humanizing non-human antibodies are well known in the art.

[00131] The binding agents may also be affinity matured, for example using selection and/or mutagenesis methods known in the art. In general, an "affinity matured" antibody is one with one or more alterations in one or more hyper variable regions thereof which result in an improvement in the affinity of the antibody for antigen, compared to a parent antibody which does not possess those alteration(s). In one embodiment, an affinity matured antibody has nanomolar or even picomolar affinities for the target antigen. Preferred affinity matured antibodies have an affinity which is five times, more preferably 10 times, even more preferably 20 or 30 times greater than the starting antibody (generally murine, humanized or human) from which the matured antibody is prepared.

[00132] An antibody that "binds to," "specifically binds to," or is "specific for" a particular polypeptide or an epitope on a particular polypeptide is one that binds to that particular polypeptide or epitope on a particular polypeptide without substantially binding to any other polypeptide or polypeptide epitope. As such, a KLRGl/ligand binding agent includes functional equivalents to an anti- KLRGl/ligand antibody according to the invention. A KLRGl/ligand binding agent can be a binding agent that binds to or specifically binds to KLRGl (e.g., human KLRGl). In some cases, the KLRGl/ligand binding agent may be cross reactive with various similar KLRGl proteins (e.g., with highest affinity for one, such as human HLRG1, and lower affinity for others, such as mouse KLRGl). A

KLRGl/ligand binding agent can be a binding agent that binds to or specifically binds to a KLRGl ligand. Again, the KLRGl/ligand binding agent can be a binding agent that binds to or specifically binds to one, or in some cases cross reacts with more than one, KLRGl ligand (e.g., one or more human cadherins).

[00133] In various embodiments, the binding agent is a blocking or antagonist binding agent. "Blocking" or "antagonist" means the agent (e.g., antibody or binding fragment/mimic thereof) is one which inhibits or reduces biological activity of the antigen it binds. Certain blocking agents or antagonist agents substantially or completely inhibit the biological activity of the antigen. For example, a KLRGl/ligand binding agent can block KLRGl signaling (e.g., thereby disrupting KLRGl signaling and activating CD8 ⁺ cytotoxic T and/or NK cells). Example 21 presents one example methodology for identifying and/or characterizing antibodies with neutralizing activity. [00134] In various embodiments, the antibody or antigen binding fragment thereof, or antibody mimetic comprises: a. a full length antibody Fab portion that binds KLRGl;

b. a full length antibody Fab portion that binds E-cadherin;

c. a full length antibody Fab portion that binds N-cadherin;

d. a full length antibody Fab portion that binds R-cadherin;

e. a fusion protein E-cadherin/Fc;

f. a fusion protein R-cadherin/Fc;

a fusion protein N-cadherin/Fc;

h. a chimeric antigen receptor; or

1. a multispecific antibody.

[00135] In various embodiments, the binding agent is a chimeric antigen receptor and the chimeric antigen receptor comprises a specificity portion of a KLRGl antibody grafted onto a

T cell.

[00136] In various embodiments, the binding agent is a multispecific antibody. The multispecific antibody can comprise a bispecific or trispecific antibody.

[00137] In various embodiments, the binding agent binds KLRGl.

[00138] In various embodiments, the KLRGl is the extracellular domain of human KLRGl.

[00139] In various embodiments, the binding agent binds a KLRGl ligand.

[00140] In various embodiments, the KLRGl ligand is human E-cadherin, N-cadherin, or R-cadherin.

[00141] In various embodiments, the binding agent binds KLRGl and/or cadherin at a KLRGl /cadherin binding site.

[00142] In various embodiments, the binding agent is not a prior art antibody. Known anti- KLRG1 antibodies include clone 13F12F2 (eBioscience), which is a mouse anti-human KLRGl antibody that binds to the extracellular domain and has demonstrated reactivity against human cells in flow cytometry, clones 14C2A07 (Biolegend) and SA231A2

(Biolegend), which are reported to be anti-human KLRGl antibodies, and clone 2F1, which is a hamster anti-mouse KLRGl antibody that some vendors (e.g., Biolegend) report to be reactive against human while others (e.g., Abeam) report reactivity to only mouse. Tests of these antibodies failed to demonstrate reactivity to human KLRGl. Clone 13A2

(EBioscience) is said to bind a similar epitope to clone 13F12F2. Clone REA261 (Miltenyi Biotec) also reportedly binds human KLRGl. (Binding not verified.) Known anti-E-cadherin antibodies are described by vendors and include the following examples: clone 67 A4, clone MB2, and clone HECD1 (all sold by Abeam); DECMA1 sold by eBioscience; and clone 36/E-cadherin sold by BD Biosciences. In various embodiments, the KLRGl antagonist comprises a binding agent that binds to KLRGl and that is not clone 13F12F2, 14C2A07, SA231A2, 2F1, 13A2, or REA261 (or another previously described anti-KLRGl antibody)..

[00143] In various embodiments, the KLRGl/ligand binding agent can be administered by providing an mRNA encoding the binding agent to the subject. Such mRNA approaches are being developed by Moderna Therapeutics and the like.

[00144] In various embodiments, the KLRGl antagonist comprises a binding agent that blocks or competes with KLRGl -ligand binding.

[00145] In various embodiments, the KLRGl antagonist comprises a binding agent that cross reacts with the extracellular domains of human and cynomolgus KLRGl, or the human and cynomolgus KLRGl ligand.

[00146] In various embodiments, the KLRGl antagonist comprises a binding agent that binds to an epitope of (i) the extracellular domain of KLRGl or (ii) the KLRGl ligand, wherein the epitope is at least 90% identical in human and cynomolgus. In one embodiment, the KLRGl antagonist comprises a binding agent that binds to the same epitope as any one of clone 13F12F2, 14C2A07, SA231A2, 2F1, 13A2, or REA261.

[00147] In various embodiments, the KLRGl antagonist comprises a binding agent that binds to KLRGl and that is not a mouse antibody.

[00148] In various embodiments, the antagonist neutralizes KLRGl/E-cadherin binding.

[00149] In various embodiments, the invention provides a killer cell lectin-like receptor Gl (KLRGl yiigand binding agent that neutralizes KLRGl /cadherin (e.g., E-cadherin) binding and disrupts KLRGl signaling, thereby activating CD8 ⁺ cytotoxic T and/or NK cells. [00150] In various embodiments, the antagonist or binding agent cross competes with at least one of clone 13F12F2, 14C2A07, SA231A2, 2F1, 13A2, or REA261.

[00151] In various embodiments, the binding agent is a human or humanized monoclonal antibody, or binding fragment thereof.

[00152] In various embodiments, the KLRG1 antagonist comprises an RNAi agent. The RNAi agent can be, inter alia, an siRNA or an mRNA.

[00153] Like antibodies (and their equivalents), RNAi agents that can be applied in the present invention are known in the art. Briefly, RNA interference (RNAi) is a biological process in which RNA molecules inhibit gene expression, typically by causing the destruction of specific mRNA molecules. RNAi is now known as precise, efficient, stable and better than antisense technology for gene suppression. Two types of small ribonucleic acid (RNA) molecules - microRNA (miRNA) and small interfering RNA (siRNA) - are central to RNA interference. RNAs are the direct products of genes, and these small RNAs can bind to other specific messenger RNA (mRNA) molecules and either increase or decrease their activity, for example by preventing an mRNA from producing a protein. However, the present invention is not necessarily limited to siRNA and mRNA.

[00154] Checkpoint Modulator Therapy

[00155] In various embodiments, the methods further comprise administering to the subject an effective amount of a checkpoint modulator therapy. As used herein, the term "checkpoint modulator therapy" includes agents that have a therapeutic effect through modulation of immune system function (e.g., for treating cancer). Immune checkpoints can be stimulatory or inhibitory. Checkpoint therapy can block inhibitory checkpoints (e.g., when used by cancer to evade the immune system), restoring immune system function. Examples of approved and commercially available checkpoint modulator therapies include

Pembrolizumab (Keytruda®), Nivolumab (Opdivo®), and Ipilimumab (Yervoy®). Numerous other checkpoint modulator therapies are under development and in clinical trials (see, e.g., FIG. 3).

[00156] The checkpoint modulator therapy and the KLRGl/ligand binding agent can be administered to the subject essentially simultaneously (e.g., concurrently, during the same day, during the same course of treatment) or within a time period where the checkpoint modulator therapy and the KLRGl/ligand binding agent combine favorably to achieve a desired effect (e.g., effective treatment, synergy). Some checkpoint modulators may induce KLRG1 expression that counteracts the modulators' effectiveness; combining with KLRG1 would restore their effectiveness. In various embodiments, the KLRGl/ligand binding agent and checkpoint modulator therapy are synergistic. Synergy can be defined as the combination having greater than an additive (or otherwise expected) effect, which can be measured by various methods known in the art.

[00157] In various embodiments, the checkpoint modulator therapy is Pembrolizumab (Keytruda®; anti-PD-1). Without limitation, in such embodiments, the cancer can be lung cancer (e.g., non-small cell lung cancer) or melanoma (e.g., metastatic melanoma).

[00158] In various embodiments, the checkpoint modulator therapy is Nivolumab

(Opdivo®). Without limitation, in such embodiments, the cancer can be lung cancer (e.g., non-small cell lung cancer) or melanoma (e.g., metastatic melanoma) or kidney cancer (e.g., renal cell carcinoma).

[00159] In various embodiments, the checkpoint modulator therapy is Ipilimumab (Yervoy®). Without limitation, in such embodiments, the cancer can be melanoma (e.g., metastatic melanoma or stage III melanoma).

[00160] In various embodiments, the checkpoint modulator therapy is PF-05082566 (Pfizer; anti-4-lBB agonist). Without limitation, in such embodiments, the cancer can be a solid tumor or a melanoma (e.g., metastatic melanoma).

[00161] In various embodiments, the checkpoint modulator therapy is Urelumab (BMS; anti-4-lBB agonist). Without limitation, in such embodiments, the cancer can be a solid tumor, head and neck cancer, or melanoma (e.g., metastatic melanoma).

[00162] In various embodiments, the checkpoint modulator therapy is Atezolizumab (Roche; anti-PD-Ll). Without limitation, in such embodiments, the cancer can be a solid tumor, locally advanced or metastatic urothelial carcinoma or lung cancer (e.g., non-small cell lung cancer) or bladder cancer.

[00163] In various embodiments, the checkpoint modulator therapy is Durvalumab (Medlmmune; anti-PD-Ll). Without limitation, in such embodiments, the cancer can be a solid tumor, lung cancer (e.g., non-small cell lung cancer), or melanoma (e.g., metastatic melanoma).

[00164] In various embodiments, the checkpoint modulator therapy is Tremilimumab (Astra-Zeneca; anti-CTLA-4). Without limitation, in such embodiments, the cancer can be a solid tumor, non-small cell lung cancer (e.g., NSCLC), squamous cell carcinoma (e.g., of the head and neck), melanoma (e.g., metastatic melanoma), bladder cancer, pancreatic cancer, gastric cancer, or liver cancer (e.g., HCC).

[00165] In various embodiments, the checkpoint modulator therapy is BMS986016 (BMS; anti-LAG-3). Without limitation, in such embodiments, the cancer can be a solid tumor or melanoma (e.g., metastatic melanoma).

[00166] In various embodiments, the checkpoint modulator therapy is MGB453 (Novartis; anti-TIM-3). Without limitation, in such embodiments, the cancer can be a solid tumor or melanoma (e.g., metastatic melanoma).

[00167] Notwithstanding the foregoing illustrative examples, one skilled in the art will appreciate that the KLRGl/ligand binding agent can be combined with other checkpoint modulator therapies and/or used for different indications.

[00168] Cancer Vaccine Therapy

[00169] In various embodiments, the method further comprises administering to the subject an effective amount of a cancer vaccine therapy. As used herein, the term "cancer vaccine therapy" includes agents that stimulate an immune system response for treating cancer. The term "cancer vaccine therapy" does not include vaccines against pathogens that may later cause cancer (e.g., a hepatitis vaccine that prevents hepatitis, but not a subsequent liver cancer where a hepatitis infection was a causative factor). Examples of approved and commercially available cancer vaccine therapies include Sipuleucel-T (Provenge®) for prostate cancer. Other cancer vaccine therapies are under development and in clinical trials.

[00170] The cancer vaccine therapy and the KLRGl/ligand binding agent can be administered to the subject essentially simultaneously (e.g., concurrently, during the same day, during the same course of treatment) or within a time period where the cancer vaccine therapy and the KLRGl/ligand binding agent combine favorably to achieve a desired effect (e.g., effective treatment, synergy). In some embodiments, the anti-KLRGl therapy allows for a more effective T cell response to the vaccine. In various embodiments, the

KLRGl/ligand binding agent and cancer vaccine therapy are synergistic. Synergy can be defined as the combination having greater than an additive (or otherwise expected) effect, which can be measured by various methods known in the art.

[00171] In various embodiments, the cancer vaccine therapy is Sipuleucel-T (Provenge®). Without limitation, in such embodiments, the cancer can be prostate cancer.

[00172] In various embodiments, the cancer vaccine therapy is INO-3112 (Inovio).

Without limitation, in such embodiments, the cancer can be a human papilloma virus (HPV) driven cancer (e.g., head and neck cancer).

[00173] In various embodiments, the cancer vaccine therapy is INO-5150 (Inovio).

Without limitation, in such embodiments, the cancer can be prostate cancer.

[00174] In various embodiments, the cancer vaccine therapy is TPIV 200 (Taplmmune). Without limitation, in such embodiments, the cancer can be ovarian cancer.

[00175] Notwithstanding the foregoing illustrative examples, one skilled in the art will appreciate that the KLRGl/ligand binding agent can be combined with other cancer vaccine therapies and/or used for different indications.

[00176] Other Active Pharmaceutical Ingredients

[00177] In various embodiments, the invention can use a combination of the

KLRGl/ligand binding agent and one or more additional Active Pharmaceutical Ingredient (API). Accordingly, the invention can increase the efficacy of, and/or decrease undesired side effects from, the KLRGl/ligand binding agent.

[00178] In various embodiments, the method further comprises administering to the subject an effective amount of a cancer chemotherapy.

[00179] In various embodiments, the checkpoint modulator therapy comprises an anti-PD- 1, anti-PD-Ll, or anti-CTLA-4 therapy.

[00180] In various embodiments, the subject has failed or has not responded to a prior cancer therapy. [00181] In various embodiments, the subject has elevated KLRGl expression. The elevated KLRGl expression can comprise elevated KLRGl expression on CD8+ cytotoxic T and/or NK cells. In various embodiments, the method can further comprise testing the subject for elevated KLRGl expression (e.g., before beginning and/or during the therapy).

[00182] In various embodiments, the subject has elevated cadherin expression (e.g., E- cadherin). The elevated cadherin expression can comprise elevated cadherin expression on cancer cells. In various embodiments, the method can further comprise testing the subject for elevated cadherin expression (e.g., before beginning and/or during the therapy).

[00183] In some embodiments, the API may be a polynucleotide (including an

oligonucleotide) a protein or a small molecule.

[00184] In one embodiment the API is a polynucleotide. The polynucleotide may be a genomic DNA fragment, cDNA, mRNA, ssRNA, dsRNA, microRNA, siRNA, shRNA, sdRNA, DsiRNA, LNA, and antisense DNA or RNA.

[00185] Alternatively, the API may be a small molecule drug. Preferably, the molecule has a molecular weight from about 1500 g/mol to about 50 g/mol.

[00186] An API can include, for example, two or more of the following: an anticancer agent, an antibiotic agent, an antiviral agent, an anti-fungal agent, or an analgesic.

[00187] Exemplary anticancer agents may include but are not limited acivicin, aclarubicin, acodazole, ametantrone, aminoglutethimide, anthramycin, asparaginase, azacitidine, azetepa, bisantrene, bleomycin, busulfan, cactinomycin, calusterone, caracemide, carboplatin, carfilzomib, carmustine, carubicin, chlorambucil, cisplatin, cyclophosphamide, cytarabine, dacarbazine, dactinomycin, daunorubicin, dezaguanine, diaziquone, docetaxel, doxorubicin, epipropidine, erlotinib, etoposide, etoprine, floxuridine, fludarabine, fluorouracil,

fluorocitabine, hydroxyurea, iproplatin, leuprolide acetate, lomustine, mechlorethamine, megestrol acetate, melengestrol acetate, mercaptopurine, methotrexate, metoprine, mitocromin, mitogillin, mitomycin, mitosper, mitoxantrone, mycophenolic acid, nocodazole, nogalamycin, oxisuran, paclitaxel, peliomycin, pentamustine, porfiromycin, prednimustine, procarbazine hydrochloride, puromycin, pyrazofurin, riboprine, semustine, sparsomycin, spirogermanium, spiromustine, spiroplatin, streptozocin, talisomycin, tegafur, teniposide, teroxirone, thiamiprine, thioguanine, tiazofurin, triciribine phosphate, triethylenemelamine, trimetrexate, uracil mustard, uredepa, vinblastine, vincristine, vindesine, vinepidine, vinrosidine, vinzolidine, zinostatin and zorubicin.

[00188] Exemplary antibiotic agents may include but are not limited to aminoglycoside; amikacin; gentamicin; kanamycin; neomycin; netilmicin; steptomycin; tobramycin;

ansamycins; geldanamycin; herbimycin; carbacephem; loracarbef; carbacepenem; ertapenem; doripenem; imipenem/cilastatin; meropenem; cephalosporin; cefadroxil; cefazolin; cefalotin or cefalothin; cefalexin; cefaclor; cefamandole; cefoxitin; cefprozil; cefuroxime; cefixime; cefdinir; cefditoren; cefoperazone; cefotaxime; cefpodoxime; ceftazidime; ceftibuten;

ceftizoxime; ceftriaxone; cefepime; ceftobiprole; glycopeptide; teicoplanin; vancomycin; macrolides; azithromycin; clarithromycin; dirithromycin; erythromicin; roxithromycin;

troleandomycin; telithromycin; spectinomycin; monobactam; aztreonam; penicillins;

amoxicillin; ampicillin; azlocillin; carbenicillin; cloxacillin; dicloxacillin; flucloxacillin; mezlocillin; meticillin; nafcillin; oxacillin; penicillin, piperacillin, ticarcillin; bacitracin; colistin; polymyxin B; quinolone; ciprofloxacin; enoxacin; gatifloxacin; levofloxacin;

lomefloxacin; moxifloxacin; norfloxacin; ofloxacin; trovafloxacin; sulfonamide; mafenide; prontosil (archaic); sulfacetamide; sulfamethizole; sufanilimide (archaic); sulfasalazine; sulfisoxazole; trimethoprim; trimethoprim-sulfamethoxazole (co-trimoxazole) (TMP-SMX); tetracycline; demeclocycline; doxycycline; minocycline; oxytetracycline; tetracycline;

arsphenamine; chloramphenicol; clindamycin; lincomycin; ethambutol; fosfomycin; fusidic acid; furazolidone; isoniazid; linezolid; metronidazole; mupirocin; nitrofuantoin;

platensimycin; polymyxin, purazinamide; quinupristin/dalfopristin; rifampin or rifampicin; and timidazole.

[00189] In specific embodiments, the anti-cancer agent is chosen from daunorubicin, doxorubicin, paclitaxel, docetaxel, cisplatin, carboplatin, cytarabine, floxuridine, fludarabine, fluorouracil, iproplatin, leuprolide acetate, carfilzomib, and methotrexate.

[00190] Exemplary antiviral agents may include, but are not limited to thiosemicarbazone; metisazone; nucleoside and/or nucleotide; acyclovir; idoxuridine; vidarabine; ribavirin;

ganciclovir; famciclovir; valaciclovir; cidofovir; penciclovir; valganciclovir; brivudine;

ribavirin, cyclic amines; rimantadine; tromantadine; phosphonic acid derivative; foscamet; fosfonet; protease inhibitor; saquinavir; indinavir; ritonavir; nelfinavir; amprenavir; lopinavir; fosamprenavir; atazanavir; tipranavir; nucleoside and nucleotide reverse transcriptase inhibitor; zidovudine; didanosine; zalcitabine; stavudine; lamivudine; abacavir; tenofovir disoproxil; adefovir dipivoxil; emtricitabine; entecavir; non-nucleoside reverse transcriptase inhibitor; nevirapine; delavirdine; efavirenz; neuraminidase inhibitor; zanamivir; oseltamivir; moroxydine; inosine pranobex; pleconaril; and enfuvirtide.

[00191] Exemplary anti-fungal agents may include but are not limited to allylamine;

terbinafine; antimetabolite; flucytosine; azole; fluconazole; itraconazole; ketoconazole;

ravuconazole; posaconazole; voriconazole; glucan synthesis inhibitor; caspofungin;

micafungin; anidulafungin; polyenes; amphotericin B; amphotericin B Colloidal Dispersion (ABCD); and griseofulvin.

[00192] Exemplary analgesics may include, but are not limited to opiate derivative, codeine, meperidine, methadone, and morphine.

[00193] Pharmaceutical Compositions

[00194] In various embodiments, the KLRGl/ligand binding agent is prepared as a pharmaceutical composition, for example as a pharmaceutical composition for use as a medicament. In various embodiments, the pharmaceutical composition is for use as a cancer therapeutic. In various embodiments, the pharmaceutical composition can include one or more antibiotic, antivirus, anti-diabetes, anti-hypertension, anti-fungal, or analgesic.

[00195] One skilled in the art can formulate the KLRGl/ligand binding agent as a pharmaceutical composition according to known methods.

[00196] Pharmaceutical compositions can include a carrier. "Carriers" as used herein can include pharmaceutically acceptable carriers, excipients, or stabilizers which are nontoxic (or relatively non-toxic) to the cell or subject being exposed thereto at the dosages and concentrations employed. Often the physiologically acceptable carrier is an aqueous pH buffered solution. Examples of physiologically acceptable carriers include buffers such as phosphate, citrate, and other organic acids; antioxidants including ascorbic acid; low molecular weight (less than about 10 residues) polypeptide; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, arginine or lysine; monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrins; chelating agents such as EDTA; sugar alcohols such as mannitol or sorbitol; salt- forming counterions such as sodium; and/or nonionic surfactants such as TWEEN™, polyethylene glycol (PEG), and PLURONICS™.

[00197] In various embodiments, the KLRGl/ligand binding agent is comprised in an injectable formulation, for example, a subcutaneous, intravenous, intramuscular, intrathecal or intraperitoneal injection formulation. Injectable formulations can be aqueous solutions, for example in physiologically compatible buffers such as Hanks' solution, Ringer's solution, or physiological saline buffer. The injectable formulation can contain formulatory agents such as suspending, stabilizing and/or dispersing agents. Alternatively, the KLRGl/ligand binding agent can be in a dried or powder form for constitution with a suitable vehicle, e.g., sterile pyrogen-free water, before use.

[00198] Treatment and Administration, Cancers

[00199] The invention provides methods comprising administering the KLRGl/ligand binding agent according to any of the aspects or embodiments disclosed herein, or the pharmaceutical composition according to any of the aspects or embodiments disclosed herein, to a subject in need thereof. In various embodiments, the subject is a human. In various embodiments, methods according to the invention are carried out in vivo (e.g., as opposed to ex vivo). As used herein, "treatment" can refer to both therapeutic treatment and prophylactic or preventative measures, wherein the object is to prevent or slow down (lessen) the targeted pathologic condition or disorder. Those in need of treatment can include those already with the disorder, those prone to have the disorder, or those in whom the disorder is to be prevented.

[00200] In various aspects and embodiments, the invention provides a method of treating a subject comprising administering to a subject in need thereof an effective amount of a killer cell lectin-like receptor Gl (KLRGl)/ligand binding agent, thereby disrupting KLRG1 signaling and activating CD8 ⁺ cytotoxic T and/or NK cells.

[00201] The invention provides a method of treating cancer comprising administering to a subject in need thereof an effective amount of a killer cell lectin-like receptor Gl

(KLRGl)/ligand binding agent.

[00202] "Administration" and "treatment," as it applies to an animal, human, experimental subject, cell, tissue, organ, or biological fluid, can include contacting an exogenous pharmaceutical, therapeutic agent, diagnostic agent, or composition to the animal, human, subject, cell, tissue, organ, or biological fluid. "Administration" and "treatment" include in vivo, as well as in some embodiments in vitro or ex vivo treatments.

[00203] "Treat" or "treating" means to administer a therapeutic agent, such as a composition containing any of the binding agents of the present invention, internally or externally to a subject or patient having one or more disease symptoms, or being suspected of having a disease, for which the agent has therapeutic activity. Typically, the agent is administered in an amount effective to alleviate one or more disease symptoms in the treated subject or population, whether by inducing the regression of or inhibiting the progression of such symptom(s) by any clinically measurable degree. The amount of a therapeutic agent that is effective to alleviate any particular disease symptom may vary according to factors such as the disease state, age, and weight of the patient, and the ability of the drug to elicit a desired response in the subject. Whether a disease symptom has been alleviated can be assessed by any clinical measurement typically used by physicians or other skilled healthcare providers to assess the severity or progression status of that symptom.

[00204] As such, in various embodiments, the term "effective amount" is a concentration or amount of the KLRGl/ligand binding agent which results in achieving a particular stated purpose. An "effective amount" of a KLRGl/ligand binding agent can be determined empirically. Furthermore, a "therapeutically effective amount" is a concentration or amount of a KLRGl/ligand binding agent which is effective for achieving a stated therapeutic effect. This amount can also be determined empirically.

[00205] The invention provides a method of treating a melanoma comprising

administering to a subject in need thereof an effective amount of a killer cell lectin-like receptor Gl (KLRGl)/ligand binding agent, wherein the binding agent is an antibody or antigen binding fragment thereof, or antibody mimetic that binds the extracellular domain of human KLRG1 and/or human E-cadherin, N-cadherin, or R-cadherin, thereby disrupting KLRG1 signaling and activating CD8 ⁺ cytotoxic T and/or NK cells.

[00206] The invention provides a method of treating a lung cancer comprising

administering to a subject in need thereof an effective amount of a killer cell lectin-like receptor Gl (KLRGl)/ligand binding agent, wherein the binding agent is an antibody or antigen binding fragment thereof, or antibody mimetic that binds the extracellular domain of human KLRG1 and/or human E-cadherin, N-cadherin, or R-cadherin, thereby disrupting KLRG1 signaling and activating CD8 ⁺ cytotoxic T and/or NK cells.

[00207] The invention provides a method of treating a pancreatic cancer comprising administering to a subject in need thereof an effective amount of a killer cell lectin-like receptor Gl (KLRGl)/ligand binding agent, wherein the binding agent is an antibody or antigen binding fragment thereof, or antibody mimetic that binds the extracellular domain of human KLRG1 and/or human E-cadherin, N-cadherin, or R-cadherin, thereby disrupting KLRG1 signaling and activating CD8 ⁺ cytotoxic T and/or NK cells.

[00208] The invention provides a method of treating a glioma comprising administering to a subject in need thereof an effective amount of a killer cell lectin-like receptor Gl

(KLRGl)/ligand binding agent, wherein the binding agent is an antibody or antigen binding fragment thereof, or antibody mimetic that binds the extracellular domain of human KLRG1 and/or human E-cadherin, N-cadherin, or R-cadherin, thereby disrupting KLRG1 signaling and activating CD8 ⁺ cytotoxic T and/or NK cells.

[00209] The invention provides a method of treating a breast cancer comprising administering to a subject in need thereof an effective amount of a killer cell lectin-like receptor Gl (KLRGl)/ligand binding agent, wherein the binding agent is an antibody or antigen binding fragment thereof, or antibody mimetic that binds the extracellular domain of human KLRG1 and/or human E-cadherin, N-cadherin, or R-cadherin, thereby disrupting KLRG1 signaling and activating CD8 ⁺ cytotoxic T and/or NK cells.

[00210] The invention provides a method of treating an ovarian cancer comprising administering to a subject in need thereof an effective amount of a killer cell lectin-like receptor Gl (KLRGl)/ligand binding agent, wherein the binding agent is an antibody or antigen binding fragment thereof, or antibody mimetic that binds the extracellular domain of human KLRG1 and/or human E-cadherin, N-cadherin, or R-cadherin, thereby disrupting KLRG1 signaling and activating CD8 ⁺ cytotoxic T and/or NK cells.

[00211] More generally, the invention provides methods for treating cancer cells and/or tissue, including cancer cells and/or tissue in a subject. Cancer can be caused by malignant tumors formed by an abnormal growth of cells and tissue leading to organ failure.

[00212] In various embodiments, the subject has an epithelial cancer. [00213] In various embodiments, the subject has a carcinoma.

[00214] Solid tumors can be neoplasms (new growth of cells) or lesions (damage of anatomic structures or disturbance of physiological functions) formed by an abnormal growth of body tissue cells other than blood, bone marrow or lymphatic cells. A solid tumor consists of an abnormal mass of cells which may stem from different tissue types such as melanoma, lung, pancreatic, glioma, breast, or ovarian, and which initially grows in the organ of its cellular origin. However, such cancers may spread to other organs through metastatic tumor growth in advanced stages of the disease.

[00215] The subject being treated may have been diagnosed with cancer. The subject may have locally advanced, unresectable, or metastatic cancer and/or may have failed a prior first- line therapy.

[00216] In various embodiments, the subject has a uveal melanoma, uterine carcinoma, uterine carcinosarcoma, thyroid carcinoma, thymoma, testicular germ cell tumor, melanoma, sarcoma, rectal adenocarcinoma, prostate cancer, pheochromocytoma, pancreatic

adenocarcinoma, ovarian cystadenocarcinoma, mesothelioma, lung squamous cell carcinoma, lung adenocarcinoma, liver hepatocellular carcinoma, kidney papillary cell carcinoma, kidney clear cell carcinoma, kidney chromophobe carcinoma, head and neck squamous cell carcinoma, glioblastoma multiforme, diffuse large B-cell lymphoma, colon adenocarcinoma, cholangiocarcinoma, cervical and/or endocervical cancer, breast invasive carcinoma, brain low grade glioma, bladder cancer, or acute myeloid leukemia.

[00217] In various embodiments, the subject has a melanoma.

[00218] In various embodiments, the subject has a lung cancer.

[00219] In various embodiments, the subject has a pancreatic cancer.

[00220] In various embodiments, the subject has a glioma.

[00221] In various embodiments, the subject has a breast cancer.

[00222] In various embodiments, the subject has an ovarian cancer.

[00223] In various embodiments, the KLRGl/ligand binding agent can be administered by providing an mRNA encoding the binding agent to the subject. [00224] In various embodiments, the treatment can prolong the subject's survival. In various embodiments, the treatment can prevent or reduce the progression or the cancer and/or metastasis.

[00225] The following examples are illustrative and not restrictive. Many variations of the technology will become apparent to those of skill in the art upon review of this disclosure. The scope of the technology should, therefore, be determined not with reference to the examples, but instead should be determined with reference to the appended claims along with their full scope of equivalents.

EXAMPLES

[00226] Example 1: Antibodies to KLRGl

[00227] Antibodies binding KLRGl were generated by immunization of mice with purified recombinant protein antigens: Human-KLRGl-ECD-Isotype 1 (SEQ ID NO: l), Human-KLRG 1 -ECD-Isotype2 (SEQ ID NO:2), and Cynomolgus-KLRGl (SEQ ID NO:3). Mice were immunized every 2 weeks and sera collected for testing after the second and fourth immunization.

[00228] FIG. 6A show a specific serum response to the cynomolgus KLRGl in the immunized mice. FIG. 6B show a specific serum response to the human KLRGl in the immunized mice. Anti-KLRGl antibody activity was measured by ELISA. The response was shown to be mediated by production of antibodies in the mouse recognizing human and cynomolgus KLRGl.

[00229] FIG. 7 shows a dose-dependent binding curve of 9 hybridoma clones isolated from immunized mice. ELISA was performed by first immobilizing human KLRGl (SEQ ID NO 2) on immunosorbent 96-well plates, followed by exposure to a dose-dependent titration of antibodies. Bound antibodies were visualized by anti-mouse-HRP conjugated detection. Thus, FIG. 7 shows that splenocytes isolated from the spleens of immunized mice are able to produce antibodies that recognize KLRGl.

[00230] Example 2: Gene expression of KLRGl is higher among CD8 ⁺ and NK cells than CD4 ⁺ T cells, correlates with CD8 ⁺ T cell cytotoxic potential, and is higher than that of checkpoint co-inhibitory receptors CTLA-4 and PD-1 [00231] Analysis of gene expression datasets demonstrates the higher expression of KLRG1 in CD8 ⁺ (relative-fold 4.0) cells compared to CD4 ⁺ T helper cells (relative-fold 1.0) (FIG. 8, KLRG1 gene expression in human blood CD8 ⁺ T cells). In response to antigen exposure, CD8 ⁺ cytotoxic T cells differentiate from naive cells to increasingly potent effector cells, characterized by central memory (TCM), effector memory (TEM), and effector (TEMRA) cells. The cytotoxic potential of CD8 ⁺ T cells within these differentiation subsets, as reflected by gene expression of cytotoxic molecules granzymes and cytokines, is highly correlated with expression of KLRG1 but not other checkpoint inhibitor target co-inhibitory receptors PD-1 and CTLA-4 (see FIG. 9A, cytotoxicity and cytokines of CD8 ⁺ T cell subsets, human blood gene expression and FIG. 9B, checkpoint expression of CD8 ⁺ T cell subsets, human blood gene expression).

[00232] Example 3: Increased expression of KLRG1 in human cancer

[00233] Microarray data from the Gene Expression Omnibus (GEO) and European Bioinformatics Institute (EBI) were compiled, normalized, and analyzed for fold-differences and significance levels. Datasets used were: E-TABM-40, GSE49954, GSE26495,

GSE14926, GSE72642, GSE58173, GSE65010, GSE11507; TCGA data

(http://cancergenome.nih.gov/), and GTEX data (http://www.gtexportal.org/).

[00234] KLRG1 is expressed by tumor infiltrating lymphocytes in a wide variety of cancer, as detected by RNAseq expression. FIG. 5 shows expression of KLRG1 and its ligand E-cadherin, compared with expression of PD-1 and its ligand PD-L1 in tumor samples in many cancer types (9,755 samples and 32 cancer types). Cancer types listed from left to right are: uveal melanoma, uterine carcinoma, uterine carcinosarcoma, thyroid carcinoma, thymoma, testicular germ cell tumor, melanoma, sarcoma, rectal adenocarcinoma, prostate cancer, pheochromocytoma, pancreatic adenocarcinoma, ovarian cysadenocarcinoma, mesothelioma, lung squamous cell carcinoma, lung adenocarcinoma, liver hepatocellular carcinoma, kidney papillary cell carcinoma, kidney clear cell carcinoma, kidney

chromophobe, head and neck squamous cell carcinoma, glioblastoma multiforme, diffuse large B-cell lymphoma, colon adenocarcinoma, cholangiocarcinoma, cervical and

endocervical cancer, breast invasive carcinoma, brain low grade glioma, bladder cancer, and acute myeloid leukemia. Without wishing to be bound by any particular theory, these cancers are particularly promising targets for use with the present invention because they are known to be immunogenic (e.g., melanoma, lung cancer, colon cancer, head and neck cancer). Their high expression of E-cadherin indicates their potential active invasion of immune attack by KLRG1 ⁺ T and NK cells. Accordingly, such cancers are particularly attractive targets for therapies according to the present invention.

[00235] Example 4: Increased expression of E-cadherin in human cancer

[00236] Analysis of the National Cancer Institute's NCI-60 U133A microarray dataset, available through the Biogps portal, demonstrates E-cadherin overexpression in multiple cancer cell lines (microarray data analysis shown in FIG. 10). In analysis of The Cancer Genome Atlas (TCGA) RNAseq data, E-cadherin' s expression in tumor biopsy samples is consistently higher than that of the PD-1 ligand PD-L1 (FIG. 5). Accordingly, lung, breast, colon, prostate, melanoma, and ovarian cancers are particularly attractive targets for therapies according to the present invention.

[00237] Example 5: Production of antibodies that bind human KLRG1

[00238] Antibodies that bind to the extracellular portion of KLRG1 and neutralize or compete with its ligands E-cadherin/N-cadherin/P-cadherin can be produced by several techniques including but not limited to: mouse hybridoma technology, phage display, yeast display, retrocyte display, humanized mouse technology, ribosome display. Other and additional methods are known in the art and can be developed in connection with the application of the present invention.

[00239] For example, mouse hybridoma technology can be used to generate antibodies that bind to KLRG1 and neutralize binding of E-cadherin (or deplete KLRG1 expressing cells). Mouse strains commonly used for antibody generation can be used, for example: Balb/c or SJL strains. Multiple mice can be injected repeatedly at 2 weeks intervals with antigen to produce an immune response. Several forms of the antigen can be injected either alone or in combination and with the addition of adjuvants such as KLH (keyhole limpet hemocyanin) known to enhance the immune response of the host to foreign antigens. Antigens can be in the form of purified recombinant KLRG1, cDNA coding for KLRG1, cells expressing KLRG1 on their surface or peptides derived from the sequence of KLRG1.

[00240] After every administration of antigens to the mice, the immune response against KLRG1 can be monitored by ELISA titer. The ELISA can be carried out by first

immobilizing recombinant KLRG1 on suitable ELISA microtiter plates. After 12 hour incubation, the plates can be washed with phosphate saline and blocked with 1% solution of BSA in phosphate buffered saline. Sera derived from immunized mice can be serially diluted in phosphate buffered saline and allowed to interact with the surface bound antigen in the microtiter plates. Excess sera can be washed away and the amount of binding can be visualized using standard techniques such as addition of anti-mouse antibody conjugated to HRP. Mice can be boosted with antigen until a sufficiently high level of signal can be detected in their serum at which point the spleen can be removed from the mice. Splenocytes derived from immunized mice can be fused with myeloma derived (SP2/0) using standard protocols in use in the field. The resulting hybridoma cells can express and secrete antibodies that can be tested for binding to recombinant KLRG1 using ELISA and to cell expressed KLRG1 using FACS. Hybridoma cell lines that produce antibodies with desired binding characteristics can be sub-cloned and the variable regions of the antibody sequenced.

Recombinant antibodies using these variable mouse regions and human constant regions can produced by standard techniques, and can be evaluated in functional assays (e.g., for binding, neutralization activity).

[00241] Example 6: An assay for the identification of antibodies that neutralize human KLRG1 binding to E-cadherin

[00242] KLRG1 binds to E-cadherin with a relatively low affinity (KD measured to be on the order of 200 μΜ). Due to this low binding affinity, a kinetic binding assay, for example as described in Example 21, can be used to measure the ability of an antibody that binds to KLRG1 to compete with E-cadherin interaction. The assays can use a kinetic binding parameter as measured by OCTET (ForteBio, Inc.) to establish whether antibodies that interact with KLRG1 prevent binding of E-cadherin. The assay can immobilize recombinant KLRG1 extracellular domain to an octet biosensor, either by direct absorption or by using an affinity tag such as anti-His or anti-FLAG. The loaded sensor can then be exposed to a solution of containing the antibody of interest and, if a binding even is measured by the instrument, the antibody under examination can be considered a "binder" and retained for further research and development. Otherwise the antibody can be considered a "non-binder" and discarded.

[00243] Example 7: Anti-KLRGl neutralizing antibodies can result in increased ex vivo human CD8 ⁺ and NK cell proliferation [00244] CD8 ⁺ T cells and NK cells isolated from human PBMCs can be labeled with Carboxyfluorescein succinimidyl ester (CFSE) and stimulated with plate coated anti-CD3 (OKT3 clone) and irradiated APCs. Proliferation in response to presence of anti-KLRGl antibodies can be measured at day 3 and day 6 by FACS by monitoring the proportion of T cells and NK cells with dilution of CSFE staining. In various embodiments, anti-KLRGl treated cells can proliferate at a faster rate compared to control IgG treated cells.

[00245] Example 8: Anti-KLRGl neutralizing antibodies can result in ex vivo human CD8 ⁺ and NK cell proliferation in synergy with other check point inhibitors such as anti-PD-1 or anti-PD-Ll

[00246] CD8 ⁺ T cells and NK cells isolated from human PBMCs can be labeled with Carboxyfluorescein succinimidyl ester (CFSE) and stimulated with plate coated anti-CD3 (OKT3 clone) and irradiated APCs. Proliferation in response to presence of anti-PDl antibodies or anti-PDLl can be measured at day 3 and day 6 by FACS by monitoring the proliferation of T cells and NK cells by dilution of CSFE staining. A second treatment with anti-KLRGl antibodies can then be performed to measure further expansion of T-cells. Proliferation in response to anti-KLRGl antibodies or control can be measured at day 3 and day 6 by FACS by monitoring the proliferation of T cells and NK cells by dilution of CSFE staining. In various embodiments, anti-KLRGl treatment after PD-1/PD-L1 blockade can result in further enhancement of proliferation when compared to anti-PD-1 or anti-PD-Ll treatment alone.

[00247] Example 9: Anti-KLRGl neutralizing antibodies can synergize with other check point inhibitors, such as anti-PD-1 and anti-PD-Ll antibodies, resulting in increased ex vivo human CD8 ⁺ and NK cell cytokine secretion

[00248] CD8 ⁺ T cells and NK cells can be isolated from human PBMCs, stimulated with plate coated anti-CD3 (OKT3 clone), irradiated antigen presenting cells (APCs), and treated with anti-KLRGl antibodies, in the presence of other check point inhibitors such as anti-PDl or anti-PD-Ll or IgG control antibody. Secretion of pro-inflammatory cytokines such as IL2 and IFN-gamma, can be measured in the media 3 and 6 days post stimulation by ELISA or similar technique. In various embodiments, treatment with the combination of anti-KLRGl and either anti-PD-1 or anti-PD-Ll can result in increased secretion of pro -inflammatory cytokines compared to cells treated with either of the antibodies alone. [00249] Example 10: Melanoma

[00250] FIG. 11 shows the fold-change of E-cadherin and PD-Ll in melanoma TCGA RNAseq data in comparison to normal skin tissue from GTEX data (Genotype-Tissue Expression, http://www.gtexportal.org/). Expression of E-cadherin is high in melanoma (fold- change 0.77), and is higher than that of PD-Ll (fold-change 0.45). Accordingly, melanoma is a particularly attractive target for therapies according to the present invention.

[00251] Example 11: Lung Cancer

[00252] FIG. 12 shows the fold-change of E-cadherin and PD-Ll in lung cancer TCGA RNAseq data in comparison to normal lung tissue from GTEX data. Expression of E- cadherin is high in lung cancer (fold-change 0.31), and is higher than that of PD-Ll (fold- change -0.57). Accordingly, lung cancer is a particularly attractive target for therapies according to the present invention.

[00253] Example 12: Pancreatic Cancer

[00254] FIG. 13 shows the fold-change of E-cadherin and PD-Ll in pancreatic cancer TCGA RNAseq data in comparison to normal pancreatic tissue from GTEX data. Expression of E-cadherin is high in pancreatic cancer (fold-change 1.10), and is higher than that of PD- Ll (fold-change 0.01). Accordingly, prostate cancer is a particularly attractive target for therapies according to the present invention.

[00255] Example 13: Glioma

[00256] FIG. 14 shows the fold-change of E-cadherin and PD-Ll in glioma TCGA

RNAseq data in comparison to normal brain tissue from GTEX data. Expression of E- cadherin is high in glioma (fold-change 0.80), and is higher than that of PD-Ll (fold-change - 0.19). Accordingly, brain cancer (e.g., glioma) is a particularly attractive target for therapies according to the present invention.

[00257] Example 14: Breast Cancer

[00258] FIG. 15 shows the fold-change of E-cadherin and PD-Ll in breast cancer TCGA RNAseq data in comparison to normal breast tissue from GTEX data. Expression of E- cadherin is high in breast cancer (fold-change 0.84), and is higher than that of PD-Ll (fold- change 0.01). Accordingly, breast cancer is a particularly attractive target for therapies according to the present invention.

[00259] Example 15: Ovarian Cancer

[00260] FIG. 16 shows the fold-change of E-cadherin and PD-Ll in TCGA ovarian cancer RNAseq data in comparison to normal ovarian tissue from GTEX data. Expression of E- cadherin is high in ovarian cancer (fold-change 1.41), and is higher than that of PD-Ll (fold- change 0.08). Accordingly, ovarian cancer is a particularly attractive target for therapies according to the present invention.

[00261] Example 16: Melanoma

[00262] KLRGl is expressed by a substantial proportion of CD8 ⁺ T cells within melanoma patient biopsies (RNA-seq data GEO database, accession number GSE72056). Specifically, the mean percentage of CD8 ⁺ T cells that express KLRGl (across 17 patient melanoma biopsy samples) is 44% and that express PD-1 is 47% (FIG. 17A, KLRGl and PD-1 CD8 ⁺ expression by melanoma patient sample), similar and not significantly different proportions. Substantial number of PD-1 -negative CD8 ⁺ T cells are KLRGl ^"1" , so that targeting KLRGl can affect a population of cells unaffected by targeting PD-1 with existing drugs such as nivolumab or pembrolizumab. Specifically, across 17 patient melanoma biopsy samples, a mean of 46% (range 20% to 78%) of PD-1 negative CD8 ⁺ T cells express KLRGl (FIG. 17B, KLRGl expression in PD-l-negative CD8 ⁺ T cells and FIG. 17C, KLRGl ⁺ PD-l-negative CD8 ⁺ cells by melanoma patient sample). Expression levels of KLRGl are high (up to 6-8 transcripts per million bases) in many of these KLRGl ^"1" PD-l-negative CD8 ⁺ cells (FIG. 17D, KLRGl expression in PD-l-negative CD8 ⁺ T cells from 17 patient melanoma biopsy samples). Additionally, analysis of this single cell dataset for expression of relevant ligands by malignant melanoma cells demonstrates that KLRGl 's ligand, E-cadherin, is expressed in a substantial proportion of melanoma malignant cells (a mean of 76% across 14 patients) and a far greater proportion than the PD-1 ligand PD-Ll (a mean of 11%) (FIG. 18A-D).

Accordingly, melanoma is a particularly attractive target for therapies according to the present invention.

[00263] Example 17: Summary of relative expression in cancer tissues versus normal matching tissue for E-cadherin and for PD-Ll [00264] FIG. 19 shows a summary of relative expression in cancer tissues versus normal matching tissue for E-cadherin and for PD-L1. These data reflect the data in FIGS. 11-16, which are presented here in a single figure for comparison.

[00265] Example 18: Downregulation of KLRGl gene expression by RNAi

[00266] Human peripheral blood mononuclear cells ("PBMC") can be isolated and treated with RNAi designed to specifically downregulate the expression of KLRGl gene by targeting the coding mRNA. RNAi constructs can be designed applying well know techniques (e.g., as described in Brown et al. (2002) RNA interference in mammalian cell culture: design, execution, and analysis of the siRNA effect. Ambion TechNotes 9(1): 3-5.). Starting from the mRNA for the target of interest (e.g., KLRGl mRNA SEQ ID NO:7) a sequence

corresponding to 20 base pairs is selected and constitutes the "sense" region of the construct. The RNAi construct generally includes a 5 prime "sense" sequence followed by a "loop" region and by an "anti-sense" sequence complementary to the sense sequence. The construct can be synthetized and cloned into a delivery retroviral vector. PBMCs isolated from healthy volunteers can be infected with viral particles carrying the RNAi coding vector and their proliferative capacity can be tested by stimulation with anti-CD3 antibody (OKT3). PBMCs treated with such RNAi can display a higher level of proliferation compared with untreated PBMCs.

[00267] Example 18: Melanoma

[00268] Immunohistochemistry of human melanoma biopsies from 3 patients demonstrates abundant KLRGl ^"1" cells infiltrating tumor (A-C) but absence of KLRGl ^"1" cells in normal skin (D) (FIG. 20). The presence of KLRGl ^"1" cells in tumor tissue render melanoma a particularly attractive target for therapies according to the present invention.

[00269] Example 19: Renal cell carcinoma

[00270] Immunohistochemistry of human renal cell carcinoma biopsies from 4 patients demonstrates abundant KLRGl ^"1" cells infiltrating tumor (FIG. 21). The presence of KLRGl ^"1" cells in tumor tissue render renal cell carcinoma a particularly attractive target for therapies according to the present invention. [00271] Example 20: Non-small cell lung cancer

[00272] Immunohistochemistry of human non-small cell lung cancer biopsies from 4 patients demonstrates abundant KLRGl ^"1" cells infiltrating tumor (FIG. 22). The presence of KLRGl ^"1" cells in tumor tissue render non-small cell lung cancer a particularly attractive target for therapies according to the present invention.

[00273] Example 21: Binding of recombinant human E-cadherin to human KLRGl, and detection of antibodies with neutralizing activity.

[00274] An ELISA based KLRGl/E-cadherin competition assay was developed to measure KLRGl/E-cadherin binding as well as neutralization of KLRGl/E-cadherin binding.

[00275] E-cadherin/KLRGl binding

[00276] Further to Example 6, binding of h (human) KLRGl to h (human) E-cadherin can be detected by ELISA. The ELISA detects the binding of E-cadherin to plate-coated KLRGl, and defines a neutralizing antibody as having the effect of reducing the E-cadherin binding to KLRGl in a dose dependent manner.

[00277] FIG. 23 presents the results of soluble hE-cadherin binding to plate-coated hKLRGl. From this curve, EC50 and EC80 were calculated to be 25 and 100 nM, respectively. Optimal KLRGl/E-cadherin interaction was observed in buffer with the following composition: 1 X PBS, 1% BSA, 2% Dry Milk, 0.05% Tween.

[00278] Anti-KLRGl chimeric antibodies

[00279] Three murine anti-KLRGl antibodies, one of which is commercially available, were used to produce mouse-human chimeric antibodies (labeled HYB01, HYB02, and HYB03). The three chimeric antibodies were compared with respect to neutralizing activity and hKLRGl binding.

[00280] Neutralization of hE-cadherin/hKLRG 1 binding

[00281] FIG. 24 presents the results of the three mouse-human chimeric antibodies neutralizing hE-cadherin/hKLRG 1 binding. The concentration of soluble E-cadherin was fixed at the EC80 value of 100 nM, while the concentration of chimeric antibodies was varied. Chimeric antibody HYB03 shows a dose dependent neutralization (IC50 of 1.1 nM). Chimeric antibodies HYBOl and HYB02 show effectively no dose dependent neutralization (IC50 NA).

[00282] Chimeric antibody/hKLRGl binding

[00283] FIG. 25 presents the results of the three mouse-human chimeric antibodies binding to plate coated KLRGl in a dose dependent manner, as determined by ELISA. HYBOl has an EC50 of 0.6nM, HYB02 has an EC50 of 0.18 nM, and HYB03 has an EC50 of 0.28 nM.

[00284] Summary

[00285] Although all three tested mouse-human chimeric antibodies (HYBOl, HYB02, and HYB03) bind hKLRGl in a dose dependent manner, only one (HYB03) also exhibits dose dependent neutralization. The neutralization assay is thus capable of distinguishing neutralizing antibodies from those that are merely KLRGl binding.

REFERENCES

[00286] Akbar AN, Henson SM. Are senescence and exhaustion intertwined or unrelated processes that compromise immunity? Nat Rev Immunol. 2011;l l(4):289-95.

[00287] Apetoh L, Smyth MJ, Drake CG, Abastado JP, Apte RN, Ayyoub M, et al.

Consensus nomenclature for CD8 ⁺ T cell phenotypes in cancer. Oncoimmunology.

2015;4(4):e998538.

[00288] Attig S, Hennenlotter J, Pawelec G, Klein G, Koch SD, Pircher H, et al.

Simultaneous infiltration of polyfunctional effector and suppressor T cells into renal cell carcinomas. Cancer Res. 2009;69(21):8412-9.

[00289] Blackburn SD, Shin H, Haining WN, Zou T, Workman CJ, Polley A, et al.

Coregulation of CD8 ⁺ T cell exhaustion by multiple inhibitory receptors during chronic viral infection. Nat Immunol. 2009;10(l):29-37.

[00290] Brunner SM, Rubner C, Kesselring R, Martin M, Griesshammer E, Ruemmele P, et al. Tumor-infiltrating, interleukin-33 -producing effector-memory CD8 ⁺ T cells in resected hepatocellular carcinoma prolong patient survival. Hepatology. 2015;61(6): 1957-67. [00291] Cyktor JC, Carruthers B, Stromberg P, Flano E, Pircher H, Turner J. Killer cell lectin-like receptor Gl deficiency significantly enhances survival after Mycobacterium tuberculosis infection. Infect Immun. 2013;81(4): 1090-9.

[00292] Grundemann C, Schwartzkopff S, Koschella M, Schweier O, Peters C, Voehringer D, et al. The NK receptor KLRGl is dispensable for virus-induced NK and CD8 ⁺ T-cell differentiation and function in vivo. Eur J Immunol. 2010;40(5): 1303-14.

[00293] Guthmann MD, Tal M, Pecht I. A new member of the C-type lectin family is a modulator of the mast cell secretory response. Int Arch Allergy Immunol. 1995; 107(l-3):82- 6.

[00294] Henson SM, Franzese O, Macaulay R, Libri V, Azevedo RI, Kiani-Alikhan S, et al. KLRGl signaling induces defective Akt (ser473) phosphorylation and proliferative dysfunction of highly differentiated CD8 ⁺ T cells. Blood. 2009;113(26):6619-28.

[00295] Henson SM, Macaulay R, Franzese O, Akbar AN. Reversal of functional defects in highly differentiated young and old CD8 ⁺ T cells by PDL blockade. Immunology.

2012;135(4):355-63.

[00296] Hofmann M, Schweier O, Pircher H. Different inhibitory capacities of human and mouse KLRGl are linked to distinct disulfide-mediated oligomerizations. Eur J Immunol. 2012;42(9):2484-90.

[00297] Legat A, Speiser DE, Pircher H, Zehn D, Fuertes Marraco SA. Inhibitory

Receptor Expression Depends More Dominantly on Differentiation and Activation than "Exhaustion" of Human CD8 ⁺ T Cells. Front Immunol. 2013;4:455.

[00298] Mahoney KM, Rennert PD, Freeman GJ. Combination cancer immunotherapy and new immunomodulatory targets. Nature reviews Drug discovery. 2015;14(8):561-84.

[00299] Melis L, Van Praet L, Pircher H, Venken K, Elewaut D. Senescence marker killer cell lectin-like receptor Gl (KLRGl) contributes to TNF- alpha production by interaction with its soluble E-cadherin ligand in chronically inflamed joints. Ann Rheum Dis.

2014;73(6): 1223-31. [00300] Nishimura H, Nose M, Hiai H, Minato N, Honjo T. Development of lupus-like autoimmune diseases by disruption of the PD- 1 gene encoding an ITIM motif-carrying immunoreceptor. Immunity. 1999;11(2): 141-51.

[00301] Shi L, Wang JM, Ren JP, Cheng YQ, Ying RS, Wu XY, et al. KLRGl impairs CD4 ⁺ T cell responses via pl6ink4a and p27kipl pathways: role in hepatitis B vaccine failure in individuals with hepatitis C virus infection. J Immunol. 2014;192(2):649-57.

[00302] Dimitri D, Benveniste O, Dubourg O, Maisonobe T, Eymard B, Amoura Z, et al. Shared blood and muscle CD8 ⁺ T-cell expansions in inclusion body myositis. Brain : a journal of neurology 2006; 129(Pt 4): 986-95.

[00303] Marcolino I, Przybylski GK, Koschella M, Schmidt CA, Voehringer D, Schlesier M, et al. Frequent expression of the natural killer cell receptor KLRGl in human cord blood T cells: correlation with replicative history. Eur J Immunol 2004; 34(10): 2672-80.

[00304] Muntzing K, Lindberg C, Moslemi AR, Oldfors A. Inclusion body myositis: clonal expansions of muscle-infiltrating T cells persist over time. Scandinavian journal of immunology 2003; 58(2): 195-200.

[00305] Voehringer D, Koschella M, Pircher H. Lack of proliferative capacity of human effector and memory T cells expressing killer cell lectinlike receptor Gl (KLRGl). Blood 2002; 100(10): 3698-702.