IMMUNO-EXOSOMES AND METHODS OF USE THEREOF REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the priority benefit of United States provisional application number 62/641,523, filed March 12, 2018, the entire contents of which is incorporated herein by reference.

BACKGROUND

1. Field

[0002] The present invention relates generally to the fields of biology, medicine, oncology, and immunology. More particularly, it concerns immunomodulatory exosomes and their therapeutic use.

2. Description of Related Art

[0003] Extracellular vesicles (EVs), including exosomes, are nanosized intracellular communication vehicles that participate in several physiological processes and contain DNA, RNA, and proteins. Many surface proteins have been identified on exosomes with varying frequencies but largely they are not immunomodulatory. Dendritic cell-derived exosomes have been identified to have mild immunomodulatory activity but T-cell responses are minimal. Exosomes isolated from epithelial cells and mesenchymal cells are generally not immunomodulatory but bind and enter other cells efficiently. As such, there is a need to develop exosomes-based immunomodulatory drugs with the specific capacity to enable activation of T cells.

SUMMARY

[0004] As such, provided herein are exosomes that have immunomodulatory molecules, e.g., ICOSL and/or OX40L, on their surface. In one embodiment, provided herein are compositions comprising exosomes, wherein the exosomes comprise a payload on their surface, wherein the payload is an immunomodulatory molecule. In some aspects, the immunomodulatory molecule is CD80, CD86, PD-L1, PD-L2, HVEM, GAL9, CTLA-4, PD- 1, PD-1H, CD 160, BTLA, TIM3, KIR, LAG3, A2aR, OX40L, CD27L, CD137L, BAFF, APRIL, CD70, CD40, B7H3, ICOSL, 0X40, CD40L, BMC A, TACI, GITR, BAFFR, CD27, CD137, ICOS, and/or CD28. In some aspects, the exosomes comprise OX40L on their surface. In some aspects, the exosomes comprise ICOSL on their surface. In various aspects, the exosomes further comprise CD47 on their surface. In some aspects, at least 50%, 60%, 70%, 80%, or 90% of the exosomes comprise an immunomodulatory molecule on their surface. In certain aspects, the exosomes are isolated from a cell over expressing the immunomodulatory molecule. In some aspects, the exosomes are isolated from a patient in need of treatment.

[0005] In some aspects, the exosomes further comprise a therapeutic agent as an intravesicular payload. In various aspects, the therapeutic agent is a therapeutic protein, an antibody (e.g., a full-length antibody, a monoclonal antibody, an scFv, a Fab fragment, a F(ab’)2, a diabody, a triabody, or a minibody), an inhibitory RNA, a CRISPR system, or a small molecule drug. In some aspects, the therapeutic protein is a protein whose loss or inactivation is known to relate to a disease to be treated, such as, for example, a tumor suppressor, a kinase, a phosphatase, or a transcription factor. In some aspects, the antibody binds an intracellular antigen. Such an intracellular antigen may be a protein whose activity is required for cell proliferation and/or survival, such as an oncogene. In some cases, the antibody prevents the function of the antigen. In some cases, the antibody disrupts a protein- protein interaction. In some aspects, the inhibitory RNA is a siRNA, shRNA, miRNA, or pre- miRNA. In various aspects, the inhibitory RNA prevents the expression of a protein whose activity is necessary for the maintenance of a certain disease state, such as, for example, an oncogene. In cases where the oncogene is a mutated form of a gene, then the inhibitory RNA may preferentially prevent the expression of the mutant oncogene and not the wild-type protein. In some aspects, the CRISPR system comprises a guide RNA and an endonuclease, such as a Cas endonuclease. In some aspects, the small molecule drug is an imaging agent. In some aspects, the small molecule drug is a chemotherapeutic agent.

[0006] In one embodiment, pharmaceutical compositions are provided comprising exosomes of any one of the present embodiments and an excipient. In some aspects, the composition is formulated for parenteral administration. In some aspects, the composition is formulated for intravenous, intramuscular, sub-cutaneous, or intraperitoneal injection. In some aspects, the compositions further comprise an antimicrobial agent. In some aspects, the antimicrobial agent is benzalkonium chloride, benzethonium chloride, benzyl alcohol, bronopol, centrimide, cetylpyridinium chloride, chlorhexidine, chlorobutanol, chlorocresol, chloroxylenol, cresol, ethyl alcohol, glycerin, exetidine, imidurea, phenol, phenoxyethanol, phenylethyl alcohol, phenlymercuric nitrate, propylene glycol, or thimerosal.

[0007] In one embodiment, methods of treating a disease in a patient in need thereof are provided, the methods comprising administering a composition of any one of the present embodiments to the patient, thereby treating the disease in the patient. In some aspects, administration causes immunomodulation in the patient. In some aspects, the disease is an immune disease, a cancer, an infectious disease, or an autoimmune disease. In some aspects, the disease is a cancer. In some aspects, the administration is systemic administration. In certain aspects, the systemic administration is intravenous administration. In some aspects, the methods further comprise administering at least a second therapy to the patient. In certain aspects, the second therapy comprises a surgical therapy, chemotherapy, radiation therapy, cryotherapy, hormonal therapy, immunotherapy, an immune checkpoint blockade, or cytokine therapy. In some aspects, the second anticancer therapy comprises an adoptive T cell therapy, an anti-PDl antibody, an anti-CTLA-4 antibody, and/or an anti-PD-Ll antibody. In some aspects, the patient is a human. In some aspects, the exosomes are autologous to the patient.

[0008] In one embodiment, methods are provided for treating a disease in a patient in need thereof comprising electroporating liposomes or exosomes with a therapeutic agent (e.g., a protein payload) and provided the electroporated liposomes exosomes to the patient, thereby treating the disease in the patient. In some aspects, the liposomes or exosomes comprise an immunomodulatory molecule on their surface. In some aspects, the disease is an immune disease, a cancer, an infectious disease, or an autoimmune disease. In some aspects, the disease is a cancer. In some aspects, the protein payload is a monoclonal antibody that specifically or selectively binds an intracellular antigen.

[0009] In one embodiment, methods are provided for administering a therapeutic protein to a patient in need thereof comprising transfecting exosomes that comprise an immunomodulatory molecule on their surface with a nucleic acid (e.g., a DNA or an RNA) encoding a therapeutic protein (e.g., a monoclonal antibody or an antigen-binding fragment thereof), incubating the transfected exosomes under conditions to allow for expression of the therapeutic protein within the exosomes, and providing the incubated exosomes to the patient, thereby administering the therapeutic protein to the patient. [0010] In one embodiment, compositions comprising exosomes are provided for use in the treatment of a disease in a patient, wherein the exosomes comprise a payload on their surface, wherein the payload is an immunomodulatory molecule. In some aspects, the immunomodulatory molecule is CD86, PD-L1, PD-L2, HVEM, GAL9, CTLA-4, PD-l, PD- 1H, CD 160, CD80, BTLA, TIM3, KIR, LAG3, A2aR, OX40L, CD27L, CD137L, BAFF, APRIL, CD70, CD40, B7H3, ICOSL, 0X40, CD40L, BMC A, TACI, GITR, BAFFR, CD27, CD137, ICOS, and/or CD28. In some aspects, the exosomes comprise OX40L on their surface. In some aspects, the exosomes comprise ICOSL on their surface. In various aspects, the exosomes further comprise CD47 on their surface. In some aspects, at least 50%, 60%, 70%, 80%, or 90% of the exosomes comprise an immunomodulatory molecule on their surface. In some aspects, the exosomes further comprise an intravesicular protein payload. In some aspects, the disease is an immune disease, a cancer, an infectious disease, or an autoimmune disease. In some aspects, the disease is a cancer. In some aspects, the composition is formulated for parenteral or systemic administration. In some aspects, the composition is formulated for intravenous, intramuscular, sub-cutaneous, or intraperitoneal injection. In some aspects, the compositions further comprise an antimicrobial agent. In certain aspects, the antimicrobial agent is benzalkonium chloride, benzethonium chloride, benzyl alcohol, bronopol, centrimide, cetylpyridinium chloride, chlorhexidine, chlorobutanol, chlorocresol, chloroxylenol, cresol, ethyl alcohol, glycerin, exetidine, imidurea, phenol, phenoxyethanol, phenylethyl alcohol, phenlymercuric nitrate, propylene glycol, or thimerosal. In some aspects, the compositions further comprise at least a second therapy. In certain aspects, the second therapy comprises a surgical therapy, chemotherapy, radiation therapy, cryotherapy, hormonal therapy, or immunotherapy. In some aspects, the patient is a human. In some aspects, the exosomes are autologous to the patient.

[0011] In one embodiment, uses of exosomes in the manufacture of a medicament for the treatment of a disease are provided herein, wherein the exosomes comprise a payload on their surface, wherein the payload is an immunomodulatory molecule. In some aspects, the immunomodulatory molecule is CD86, PD-L1, PD-L2, HVEM, GAL9, CTLA-4, PD-l, PD- 1H, CD 160, CD80, BTLA, TIM3, KIR, LAG3, A2aR, OX40L, CD27L, CD137L, BAFF, APRIL, CD70, CD40, B7H3, ICOSL, 0X40, CD40L, BMC A, TACI, GITR, BAFFR, CD27, CD137, ICOS, and/or CD28. In some aspects, the exosomes comprise OX40L on their surface. In some aspects, the exosomes comprise ICOSL on their surface. In various aspects, the exosomes further comprise CD47 on their surface. In some aspects, at least 50%, 60%, 70%, 80%, or 90% of the exosomes comprise an immunomodulatory molecule on their surface. In some aspects, the exosomes further comprise an intravesicular protein payload. In some aspects, the disease is an immune disease, a cancer, an infectious disease, or an autoimmune disease. In some aspects, the disease is a cancer. In some aspects, the composition is formulated for parenteral or systemic administration. In some aspects, the composition is formulated for intravenous, intramuscular, sub-cutaneous, or intraperitoneal injection. In some aspects, the compositions further comprise an antimicrobial agent. In certain aspects, the antimicrobial agent is benzalkonium chloride, benzethonium chloride, benzyl alcohol, bronopol, centrimide, cetylpyridinium chloride, chlorhexidine, chlorobutanol, chlorocresol, chloroxylenol, cresol, ethyl alcohol, glycerin, exetidine, imidurea, phenol, phenoxyethanol, phenylethyl alcohol, phenlymercuric nitrate, propylene glycol, or thimerosal.

[0012] As used herein,“essentially free,” in terms of a specified component, is used herein to mean that none of the specified component has been purposefully formulated into a composition and/or is present only as a contaminant or in trace amounts. The total amount of the specified component resulting from any unintended contamination of a composition is therefore well below 0.05%, preferably below 0.01%. Most preferred is a composition in which no amount of the specified component can be detected with standard analytical methods.

[0013] As used herein the specification,“a” or“an” may mean one or more. As used herein in the claim(s), when used in conjunction with the word“comprising,” the words“a” or“an” may mean one or more than one.

[0014] The use of the term“or” in the claims is used to mean“and/or” unless explicitly indicated to refer to alternatives only or the alternatives are mutually exclusive, although the disclosure supports a definition that refers to only alternatives and“and/or.” As used herein“another” may mean at least a second or more.

[0015] Throughout this application, the term“about” is used to indicate that a value includes the inherent variation of error for the device, the method being employed to determine the value, or the variation that exists among the study subjects.

[0016] Other objects, features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present invention. The invention may be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments presented herein.

[0018] FIG. 1. Real-time PCR analysis of 293T cells stably transfected with ICOSLG and OX40L expression plasmids.

[0019] FIGS. 2A-B. Western blot analysis of 293T cells stably transfected with ICOSLG and OX40L expression plasmids as well as exosomes isolated therefrom. FIG. 2A shows the expression of ICOSLG. FIG. 2B shows the expression of the control vinculin.

[0020] FIG. 3. Flow cytometric analysis of 293T cells stably transfected with ICOSLG and OX40L expression plasmids as well as exosomes isolated therefrom.

[0021] FIG. 4. Schematic representation of the experiments to determine the activity of ICOSLG ⁺ and OX40L ⁺ exosomes.

[0022] FIG. 5. Flow cytometric analysis of the effects of ICOSLG ⁺ exosomes on T cell proliferation using naive T cells.

[0023] FIG. 6. Flow cytometric analysis of the effects of ICOSLG ⁺ exosomes on T cell proliferation using splenic T cells from a tumor bearing mouse.

[0024] FIGS. 7A-J. Analysis of the effects of various treatment regimens using ICOSLG ⁺ exosomes and OX40L ⁺ exosomes alone and in combination with anti-CTLA-4 on tumor volume in mice. FIG. 7A shows the tumor volumes from mice of each treatment group at days 9, 11, 13, and 15 post implantation. FIG. 7B shows the tumor volumes of mice from treatment groups Gl and G7 over time up to 19 days. FIG. 7C shows the tumor volumes of mice from treatment groups G2 and G7 over time up to 19 days. FIG. 7D shows the tumor volumes of mice from treatment groups G3 and G7 over time up to 19 days. FIG. 7E shows the tumor volumes of mice from treatment groups G4 and G7 over time up to 19 days. FIG. 7F shows the tumor volumes of mice from treatment groups G5 and G7 over time up to 19 days. FIG. 7G shows the tumor volumes of mice from treatment groups G6 and G7 over time up to 19 days. FIG. 7H shows the tumor volumes of mice from treatment groups G3 and G6 over time up to 19 days. FIG. 71 shows the tumor volumes of mice from treatment groups Gl and G5 over time up to 19 days. FIG. 7J shows the tumor volumes of mice from treatment groups G4 and G6 over time up to 19 days.

DETAILED DESCRIPTION

[0025] Provided herein are novel and efficient methods to generate exosomes with the capacity to modulate the adaptive immune system with applications in cancer and other diseases. As a proof of concept, 239T-derived exosomes were generated that express ICOSL or OX40L. The exosomes were used to demonstrate in vitro and in vivo activity that highlights T cell activation properties and anti-tumor immunity. These imExosomes represent next generation immunomodulatory drugs that can function with similar or better properties than agonist and antagonist antibodies that regulate tumor immunity, and also potential small molecules that regulate the immune system. Treatment of naive T cells and splenic T cells from tumor-bearing mice with imExosomes ^ICOSL and imExosomes° ^X40L leads to activation of T cells and production of INF-g and IL-2. Injection of imExosomes ^ICOSL and imExosomes° ^X40L leads to inhibition of B16F10 melanoma tumor both in combination with anti-CTLA4 and by themselves. This imExosomes platform has the capacity to generate exosomes with surface and intraluminal protein payloads to modulate the immune system.

I. Lipid-based Nanoparticles

[0026] In some embodiments, a lipid-based nanoparticle is a liposomes, an exosomes, lipid preparations, or another lipid-based nanoparticle, such as a lipid-based vesicle (e.g. , a DOTAP:cholesterol vesicle). Lipid-based nanoparticles may be positively charged, negatively charged or neutral.

B. Liposomes

[0027] A “liposome” is a generic term encompassing a variety of single and multilamellar lipid vehicles formed by the generation of enclosed lipid bilayers or aggregates. Liposomes may be characterized as having vesicular structures with a bilayer membrane, generally comprising a phospholipid, and an inner medium that generally comprises an aqueous composition. Liposomes provided herein include unilamellar liposomes, multilamellar liposomes, and multivesicular liposomes. Liposomes provided herein may be positively charged, negatively charged, or neutrally charged. In certain embodiments, the liposomes are neutral in charge.

[0028] A multilamellar liposome has multiple lipid layers separated by aqueous medium. Such liposomes form spontaneously when lipids comprising phospholipids are suspended in an excess of aqueous solution. The lipid components undergo self rearrangement before the formation of closed structures and entrap water and dissolved solutes between the lipid bilayers. Lipophilic molecules or molecules with lipophilic regions may also dissolve in or associate with the lipid bilayer.

[0029] In specific aspects, a polypeptide, a nucleic acid, or a small molecule drug may be, for example, encapsulated in the aqueous interior of a liposome, interspersed within the lipid bilayer of a liposome, attached to a liposome via a linking molecule that is associated with both the liposome and the polypeptide/nucleic acid, entrapped in a liposome, complexed with a liposome, or the like.

[0030] A liposome used according to the present embodiments can be made by different methods, as would be known to one of ordinary skill in the art. For example, a phospholipid, such as for example the neutral phospholipid dioleoylphosphatidylcholine (DOPC), is dissolved in tert-butanol. The lipid(s) is then mixed with a polypeptide, nucleic acid, and/or other component(s). Tween 20 is added to the lipid mixture such that Tween 20 is about 5% of the composition's weight. Excess tert-butanol is added to this mixture such that the volume of tert-butanol is at least 95%. The mixture is vortexed, frozen in a dry ice/acetone bath and lyophilized overnight. The lyophilized preparation is stored at -20°C and can be used up to three months. When required the lyophilized liposomes are reconstituted in 0.9% saline.

[0031] Alternatively, a liposome can be prepared by mixing lipids in a solvent in a container, e.g., a glass, pear-shaped flask. The container should have a volume ten-times greater than the volume of the expected suspension of liposomes. Using a rotary evaporator, the solvent is removed at approximately 40°C under negative pressure. The solvent normally is removed within about 5 min to 2 h, depending on the desired volume of the liposomes. The composition can be dried further in a desiccator under vacuum. The dried lipids generally are discarded after about 1 week because of a tendency to deteriorate with time.

[0032] Dried lipids can be hydrated at approximately 25-50 mM phospholipid in sterile, pyrogen-free water by shaking until all the lipid film is resuspended. The aqueous liposomes can be then separated into aliquots, each placed in a vial, lyophilized and sealed under vacuum.

[0033] The dried lipids or lyophilized liposomes prepared as described above may be dehydrated and reconstituted in a solution of a protein or peptide and diluted to an appropriate concentration with a suitable solvent, e.g., DPBS. The mixture is then vigorously shaken in a vortex mixer. Unencapsulated additional materials, such as agents including but not limited to hormones, drugs, nucleic acid constructs and the like, are removed by centrifugation at 29,000 x g and the liposomal pellets washed. The washed liposomes are resuspended at an appropriate total phospholipid concentration, e.g., about 50-200 mM. The amount of additional material or active agent encapsulated can be determined in accordance with standard methods. After determination of the amount of additional material or active agent encapsulated in the liposome preparation, the liposomes may be diluted to appropriate concentrations and stored at 4°C until use. A pharmaceutical composition comprising the liposomes will usually include a sterile, pharmaceutically acceptable carrier or diluent, such as water or saline solution.

[0034] Additional liposomes which may be useful with the present embodiments include cationic liposomes, for example, as described in W002/100435A1, U.S Patent 5,962,016, U.S. Application 2004/0208921, W003/015757A1, WO04029213A2, U.S. Patent 5,030,453, and U.S. Patent 6,680,068, all of which are hereby incorporated by reference in their entirety without disclaimer.

[0035] In preparing such liposomes, any protocol described herein, or as would be known to one of ordinary skill in the art may be used. Additional non-limiting examples of preparing liposomes are described in U.S. Patents 4,728,578, 4,728,575, 4,737,323, 4,533,254, 4,162,282, 4,310,505, and 4,921,706; International Applications

PCT/US85/01161 and PCT/US89/05040, each incorporated herein by reference. [0036] In certain embodiments, the lipid-based nanoparticle is a neutral liposome (e.g., a DOPC liposome).“Neutral liposomes” or“non-charged liposomes”, as used herein, are defined as liposomes having one or more lipid components that yield an essentially- neutral, net charge (substantially non-charged). By“essentially neutral” or“essentially non- charged”, it is meant that few, if any, lipid components within a given population (e.g., a population of liposomes) include a charge that is not canceled by an opposite charge of another component (/. _<? ., fewer than 10% of components include a non-canceled charge, more preferably fewer than 5%, and most preferably fewer than 1%). In certain embodiments, neutral liposomes may include mostly lipids and/or phospholipids that are themselves neutral under physiological conditions (/. _<? ., at about pH 7).

[0037] Liposomes and/or lipid-based nanoparticles of the present embodiments may comprise a phospholipid. In certain embodiments, a single kind of phospholipid may be used in the creation of liposomes (e.g., a neutral phospholipid, such as DOPC, may be used to generate neutral liposomes). In other embodiments, more than one kind of phospholipid may be used to create liposomes. Phospholipids may be from natural or synthetic sources. Phospholipids include, for example, phosphatidylcholines, phosphatidylglycerols, and phosphatidylethanolamines; because phosphatidylethanolamines and phosphatidyl cholines are non-charged under physiological conditions (/. _<? ., at about pH 7), these compounds may be particularly useful for generating neutral liposomes. In certain embodiments, the phospholipid DOPC is used to produce non-charged liposomes. In certain embodiments, a lipid that is not a phospholipid (e.g., a cholesterol) may be used

[0038] Phospholipids include glycerophospholipids and certain sphingolipids. Phospholipids include, but are not limited to, dioleoylphosphatidylycholine (“DOPC”), egg phosphatidylcholine (“EPC”), dilauryloylphosphatidylcholine (“DLPC”), dimyristoylphosphatidylcholine (“DMPC”), dipalmitoylphosphatidylcholine (“DPPC”), distearoylphosphatidylcholine (“DSPC”), l-myristoyl-2-palmitoyl phosphatidylcholine (“MPPC”), l-palmitoyl-2-myristoyl phosphatidylcholine (“PMPC”), l-palmitoyl-2-stearoyl phosphatidylcholine (“PSPC”), l-stearoyl-2-palmitoyl phosphatidylcholine (“SPPC”), dilauryloylphosphatidylglycerol (“DLPG”), dimyristoylphosphatidylglycerol (“DMPG”), dipalmitoylphosphatidylglycerol (“DPPG”), distearoylphosphatidylglycerol (“DSPG”), distearoyl sphingomyelin (“DSSP”), distearoylphophatidylethanolamine (“DSPE”), dioleoylphosphatidylglycerol (“DOPG”), dimyristoyl phosphatidic acid (“DMPA”), dipalmitoyl phosphatidic acid (“DPP A”), dimyristoyl phosphatidylethanolamine (“DMPE”), dipalmitoyl phosphatidylethanolamine (“DPPE”), dimyristoyl phosphatidylserine (“DMPS”), dipalmitoyl phosphatidylserine (“DPPS”), brain phosphatidylserine (“BPS”), brain sphingomyelin (“BSP”), dipalmitoyl sphingomyelin (“DPSP”), dimyristyl phosphatidylcholine (“DMPC”), l,2-distearoyl-sn-glycero-3-phosphocholine (“DAPC”), 1,2- diarachidoyl-sn-glycero-3-phosphocholine (“DBPC”), l,2-dieicosenoyl-sn-glycero-3- phosphocholine (“DEPC”), dioleoylphosphatidylethanolamine (“DOPE”), palmitoyloeoyl phosphatidylcholine (“POPC”), palmitoyloeoyl phosphatidylethanolamine (“POPE”), lysophosphatidylcholine, lysophosphatidylethanolamine, and dilinoleoylphosphatidylcholine.

C. Exosomes

[0039] “Extracellular vesicles” and “EVs” are cell-derived and cell-secreted microvesicles which, as a class, include exosomes, exosome-like vesicles, ectosomes (which result from budding of vesicles directly from the plasma membrane), microparticles, microvesicles, shedding microvesicles (SMVs), nanoparticles and even (large) apoptotic blebs or bodies (resulting from cell death) or membrane particles.

[0040] The terms “microvesicle” and “exosomes,” as used herein, refer to a membranous particle having a diameter (or largest dimension where the particles is not spheroid) of between about 10 nm to about 5000 nm, more typically between 30 nm and 1000 nm, and most typically between about 50 nm and 750 nm, wherein at least part of the membrane of the exosomes is directly obtained from a cell. Most commonly, exosomes will have a size (average diameter) that is up to 5% of the size of the donor cell. Therefore, especially contemplated exosomes include those that are shed from a cell.

[0041] Exosomes may be detected in or isolated from any suitable sample type, such as, for example, body fluids. As used herein, the term“isolated” refers to separation out of its natural environment and is meant to include at least partial purification and may include substantial purification. As used herein, the term“sample” refers to any sample suitable for the methods provided by the present invention. The sample may be any sample that includes exosomes suitable for detection or isolation. Sources of samples include blood, bone marrow, pleural fluid, peritoneal fluid, cerebrospinal fluid, urine, saliva, amniotic fluid, malignant ascites, broncho-alveolar lavage fluid, synovial fluid, breast milk, sweat, tears, joint fluid, and bronchial washes. In one aspect, the sample is a blood sample, including, for example, whole blood or any fraction or component thereof. A blood sample suitable for use with the present invention may be extracted from any source known that includes blood cells or components thereof, such as venous, arterial, peripheral, tissue, cord, and the like. For example, a sample may be obtained and processed using well-known and routine clinical methods (e.g., procedures for drawing and processing whole blood). In one aspect, an exemplary sample may be peripheral blood drawn from a subject with cancer.

[0042] Exosomes may also be isolated from tissue samples, such as surgical samples, biopsy samples, tissues, feces, and cultured cells. When isolating exosomes from tissue sources it may be necessary to homogenize the tissue in order to obtain a single cell suspension followed by lysis of the cells to release the exosomes. When isolating exosomes from tissue samples it is important to select homogenization and lysis procedures that do not result in disruption of the exosomes. Exosomes contemplated herein are preferably isolated from body fluid in a physiologically acceptable solution, for example, buffered saline, growth medium, various aqueous medium, etc.

[0043] Exosomes may be isolated from freshly collected samples or from samples that have been stored frozen or refrigerated. In some embodiments, exosomes may be isolated from cell culture medium. Although not necessary, higher purity exosomes may be obtained if fluid samples are clarified before precipitation with a volume-excluding polymer, to remove any debris from the sample. Methods of clarification include centrifugation, ultracentrifugation, filtration, or ultrafiltration. Most typically, exosomes can be isolated by numerous methods well-known in the art. One preferred method is differential centrifugation from body fluids or cell culture supernatants. Exemplary methods for isolation of exosomes are described in (Losche et al., 2004; Mesri and Altieri, 1998; Morel el al. , 2004). Alternatively, exosomes may also be isolated via flow cytometry as described in (Combes et al , 1997).

[0044] One accepted protocol for isolation of exosomes includes ultracentrifugation, often in combination with sucrose density gradients or sucrose cushions to float the relatively low-density exosomes. Isolation of exosomes by sequential differential centrifugations is complicated by the possibility of overlapping size distributions with other microvesicles or macromolecular complexes. Furthermore, centrifugation may provide insufficient means to separate vesicles based on their sizes. However, sequential centrifugations, when combined with sucrose gradient ultracentrifugation, can provide high enrichment of exosomes. [0045] Isolation of exosomes based on size, using alternatives to the ultracentrifugation routes, is another option. Successful purification of exosomes using ultrafiltration procedures that are less time consuming than ultracentrifugation, and do not require use of special equipment have been reported. Similarly, a commercial kit is available (EXOMIR™, Bioo Scientific) which allows removal of cells, platelets, and cellular debris on one microfilter and capturing of vesicles bigger than 30 nm on a second microfilter using positive pressure to drive the fluid. However, for this process, the exosomes are not recovered, their RNA content is directly extracted from the material caught on the second microfilter, which can then be used for PCR analysis. HPLC-based protocols could potentially allow one to obtain highly pure exosomes, though these processes require dedicated equipment and are difficult to scale up. A significant problem is that both blood and cell culture media contain large numbers of nanoparticles (some non-vesicular) in the same size range as exosomes. For example, some miRNAs may be contained within extracellular protein complexes rather than exosomes; however, treatment with protease (e.g., proteinase K) can be performed to eliminate any possible contamination with “extraexosomal” protein.

[0046] In another embodiment, cancer cell-derived exosomes may be captured by techniques commonly used to enrich a sample for exosomes, such as those involving immunospecific interactions (e.g., immunomagnetic capture). Immunomagnetic capture, also known as immunomagnetic cell separation, typically involves attaching antibodies directed to proteins found on a particular cell type to small paramagnetic beads. When the antibody- coated beads are mixed with a sample, such as blood, they attach to and surround the particular cell. The sample is then placed in a strong magnetic field, causing the beads to pellet to one side. After removing the blood, captured cells are retained with the beads. Many variations of this general method are well-known in the art and suitable for use to isolate exosomes. In one example, the exosomes may be attached to magnetic beads (e.g., aldehyde/sulphate beads) and then an antibody is added to the mixture to recognize an epitope on the surface of the exosomes that are attached to the beads. Exemplary proteins that are known to be found on cancer cell-derived exosomes include ATP-binding cassette sub family A member 6 (ABCA6), tetraspanin-4 (TSPAN4), SLIT and NTRK-like protein 4 (SLITRK4), putative protocadherin beta-l8 (PCDHB18), myeloid cell surface antigen CD33 (CD33), and glypican-l (GPC1). Cancer cell-derived exosomes may be isolated using, for example, antibodies or aptamers to one or more of these proteins. [0047] As used herein, analysis includes any method that allows direct or indirect visualization of exosomes and may be in vivo or ex vivo. For example, analysis may include, but not limited to, ex vivo microscopic or cytometric detection and visualization of exosomes bound to a solid substrate, flow cytometry, fluorescent imaging, and the like. In an exemplary aspect, cancer cell-derived exosomes are detected using antibodies directed to one or more of ATP-binding cassette sub-family A member 6 (ABCA6), tetraspanin-4 (TSPAN4), SLIT and NTRK-like protein 4 (SLITRK4), putative protocadherin beta- 18 (PCDHB18), myeloid cell surface antigen CD33 (CD33), glypican-l (GPC1), Histone H2A type 2-A (HIST1H2AA), Histone H2A type l-A (HIST1H1AA), Histone H3.3 (H3F3A), Histone H3.1 (HIST1H3A), Zinc finger protein 37 homolog (ZFP37), Laminin subunit beta-l (LAMB1), Tubulointerstitial nephritis antigen-like (TINAGL1), Peroxiredeoxin-4 (PRDX4), Collagen alpha-2(IV) chain (COL4A2), Putative protein C3P1 (C3P1), Hemicentin-l (HMCN1), Putative rhophilin-2-like protein (RHPN2P1), Ankyrin repeat domain-containing protein 62 (ANKRD62), Tripartite motif-containing protein 42 (TRIM42), Junction plakoglobin (JUP), Tubulin beta-2B chain (TUBB2B), Endoribonuclease Dicer (DICER1), E3 ubiquitin-protein ligase TRIM71 (TRIM71), Katanin p60 ATPase-containing subunit A-like 2 (KATNAL2), Protein S100-A6 (S100A6), 5’-nucleotidase domain-containing protein 3 (NT5DC3), Valine- tRNA ligase (VARS), Kazrin (KAZN), ELAV-like protein 4 (ELAVL4), RING finger protein 166 (RNF166), FERM and PDZ domain-containing protein 1 (FRMPD1), 78 kDa glucose-regulated protein (HSPA5), Trafficking protein particle complex subunit 6A (TRAPPC6A), Squalene monooxygenase (SQLE), Tumor susceptibility gene 101 protein (TSG101), Vacuolar protein sorting 28 homolog (VPS28), Prostaglandin F2 receptor negative regulator (PTGFRN), Isobutyryl-CoA dehydrogenase, mitochondrial (ACAD8), 26S protease regulatory subunit 6B (PSMC4), Elongation factor l-gamma (EEF1G), Titin (TTN), Tyrosine -protein phosphatase type 13 (PTPN13), Triosephosphate isomerase (TPI1), or Carboxypeptidase E (CPE) and subsequently bound to a solid substrate and/or visualized using microscopic or cytometric detection.

[0048] It should be noted that not all proteins expressing in a cell are found in exosomes secreted by that cell. For example, calnexin, GM130, and LAMP-2 are all proteins expressed in MCF-7 cells but not found in exosomes secreted by MCF-7 cells (Baietti et al, 2012). As another example, one study found that 190/190 pancreatic ductal adenocarcinoma patients had higher levels of GPC1+ exosomes than healthy controls (Melo et al, 2015, which is incorporated herein by reference in its entirety). Notably, only 2.3% of healthy controls, on average, had GPC1+ exosomes.

2. Exemplary Protocol for Collecting Exosomes from Cell Culture

[0049] On Day 1, seed enough cells (e.g., about five million cells) in T225 flasks in media containing 10% FBS so that the next day the cells will be about 70% confluent. On Day 2, aspirate the media on the cells, wash the cells twice with PBS, and then add 25-30 mL base media (/. _<? ., no PenStrep or FBS) to the cells. Incubate the cells for 24-48 hours. A 48 hour incubation is preferred, but some cells lines are more sensitive to serum-free media and so the incubation time should be reduced to 24 hours. Note that FBS contains exosomes that will heavily skew NanoSight results.

[0050] On Day 3/4, collect the media and centrifuge at room temperature for five minutes at 800 x g to pellet dead cells and large debris. Transfer the supernatant to new conical tubes and centrifuge the media again for 10 minutes at 2000 x g to remove other large debris and large vesicles. Pass the media through a 0.2 pm filter and then aliquot into ultracentrifuge tubes (e.g., 25 x 89 mm Beckman Ultra-Clear) using 35 mL per tube. If the volume of media per tube is less than 35 mL, fill the remainder of the tube with PBS to reach 35 mL. Ultracentrifuge the media for 2-4 hours at 28,000 rpm at 4°C using a SW 32 Ti rotor (k-factor 266.7, RCF max 133,907). Carefully aspirate the supernatant until there is roughly l-inch of liquid remaining. Tilt the tube and allow remaining media to slowly enter aspirator pipette. If desired, the exosomes pellet can be resuspended in PBS and the ultracentrifugation at 28,000 rpm repeated for 1-2 hours to further purify the population of exosomes.

[0051] Finally, resuspend the exosomes pellet in 210 pL PBS. If there are multiple ultracentrifuge tubes for each sample, use the same 210 pL PBS to serially resuspend each exosomes pellet. For each sample, take 10 pL and add to 990 pL FLO to use for nanoparticle tracking analysis. Use the remaining 200 pL exosomes-containing suspension for downstream processes or immediately store at -80°C.

3. Exemplary Protocol for Extracting Exosomes from Serum Samples

[0052] First, allow serum samples to thaw on ice. Then, dilute 250 pL of cell-free serum samples in 11 mL PBS; filter through a 0.2 pm pore filter. Ultracentrifuge the diluted sample at 150,000 x g overnight at 4°C. The following day, carefully discard the supernatant and wash the exosomes pellet in 11 mL PBS. Perform a second round of ultracentrifugation at 150,000 x g at 4°C for 2 hours. Finally, carefully discard the supernatant and resuspend the exosomes pellet in 100 pL PBS for analysis.

D. Exemplary Protocol for Electroporation of Exosomes and Liposomes

[0053] Mix 1 x 10 ⁸ exosomes (measured by NanoSight analysis) or 100 nm liposomes (e.g., purchased from Encapsula Nano Sciences) and 1 pg of siRNA (Qiagen) or shRNA in 400 pL of electroporation buffer (1.15 mM potassium phosphate, pH 7.2, 25 mM potassium chloride, 21% Optiprep). Electroporate the exosomes or liposomes using a 4 mm cuvette (see, e.g., Alvarez- Erviti et al., 2011; El-Andaloussi et al, 2012). After electroporation, treat the exosomes or liposomes with protease-free RNAse followed by addition of lOx concentrated RNase inhibitor. Finally, wash the exosomes or liposomes with PBS under ultracentrifugation methods, as described above.

II. Immunomodulatory Molecules

[0054] Provided herein are novel and efficient methods to generate exosomes with the capacity to modulate the adaptive immune system with applications in cancer and other diseases. To this end, exosomes are generated that have immunomodulatory molecules on their surface. As a proof of concept, 239T-derived exosomes were generated that express ICOSL or OX40L. The exosomes were used to demonstrate in vitro and in vivo activity that highlights T cell activation properties and anti-tumor immunity. This imExosomes platform has the capacity to generate exosomes with surface and intraluminal protein payloads to modulate the immune system. Immunomodulatory molecules may either enhance or inhibit an immune response. The following references, which discuss immune checkpoint modulation and various ligand:receptor pairs, are incorporated by reference herein in their entirety for all purposes: Pardoll (2014); Wykes & Lewin (2018); Pico de Coana et al. (2015).

[0055] For example, it may be desirable to increase signaling through inhibitory molecules by using exosomes that comprise ligands for immune inhibitory receptors, to, without being bound by theory, directly stimulate signaling through the inhibitory receptors present on the surface of immune cells. Examples of inhibitory-receptor ligands that can be delivered as exosomes payloads include, without limitation, CD80, CD86, PD-L1, PD-L2, HVEM, and GAL9. Alternatively, the exosomes payload may comprise an antibody that acts as an agonist for an immune inhibitory receptor, as discussed below.

[0056] For example, it may be desirable to decrease signaling through inhibitory molecules by using exosomes that comprise immune inhibitory receptors, to, without being bound by theory, act as a sponge for the receptor’ s ligand and prevent ligand binding to the inhibitory receptors present on the surface of immune cells. Examples of inhibitory receptors that can be delivered as exosomes payloads include, without limitation, CTLA-4, PD-l, PD- 1H, CD160, CD80, BTLA, TIM3, KIR, LAG3, and A2aR. Alternatively, the exosomes payload may comprise an antibody that acts as an antagonist for an immune inhibitory receptor or an antibody that binds the ligand and thereby prevents the ligand from binding its receptor, as discussed below.

[0057] For example, it may be desirable to increase signaling through stimulatory molecules by using exosomes that comprise ligands for immune stimulatory receptors, to, without being bound by theory, directly stimulate signaling through the stimulatory receptors present on the surface of immune cells. Examples of stimulatory-receptor ligands that can be delivered as exosomes payloads include, without limitation, OX40L, CD27L, CD137L, BAFF, APRIL, CD70, CD40, B7H3, ICOSL, CD80, and CD86. Alternatively, the exosomes payload may comprise an antibody that acts as an agonist for an immune stimulatory receptor, as discussed below.

[0058] For example, it may be desirable to decrease signaling through stimulatory molecule by using exosomes that comprise immune stimulatory receptors, to, without being bound by theory, act as a sponge for the receptor’ s ligand and prevent ligand binding to the stimulatory receptors present on the surface of immune cells. Examples of stimulatory receptors that can be delivered as exosomes payloads include, without limitation, 0X40, CD40L, BMCA, TACI, GITR, BAFFR, CD27, CD137, ICOS, and CD28. Alternatively, the exosomes payload may comprise an antibody that acts as an antagonist for an immune stimulatory receptor or an antibody that binds the ligand and thereby prevents the ligand from binding its receptor, as discussed below.

III. Treatment of Diseases

[0059] Certain aspects of the present invention provide for treating a patient in need of immunomodulation with exosomes that comprise immunomodulatory molecules, e.g., OX40L or ICOSL, on their surface. The immunomodulatory molecule may be membrane bound. The exosomes may induce immunomodulation in the patient, i.e., the exosomes may either enhance or inhibit an immune response, as needed. As such, the treatment of any disease where modulation of an immune response is desirable is contemplated. For example, and without limitation, the disease may be an immune disease, cancer, an infectious disease, or an autoimmune disease.

[0060] In addition to the immunomodulatory molecule on the surface of the exosomes, and as exosomes are known to comprise the machinery necessary to complete mRNA transcription and protein translation (see PCT/US2014/068630, which is incorporated herein by reference in its entirety), mRNA or DNA nucleic acids encoding a therapeutic protein may be transfected into exosomes. Alternatively, a therapeutic protein itself may be electroporated into the exosomes or incorporated directly into a liposome.

[0061] The term“subject” as used herein refers to any individual or patient to which the subject methods are performed. Generally the subject is human, although as will be appreciated by those in the art, the subject may be an animal. Thus other animals, including mammals, such as rodents (including mice, rats, hamsters, and guinea pigs), cats, dogs, rabbits, farm animals (including cows, horses, goats, sheep, pigs, etc.), and primates (including monkeys, chimpanzees, orangutans, and gorillas) are included within the definition of subject.

[0062]“Treatment” and “treating” refer to administration or application of a therapeutic agent to a subject or performance of a procedure or modality on a subject for the purpose of obtaining a therapeutic benefit of a disease or health-related condition. For example, a treatment may include administration of exosomes comprising OX40L or ICOSL on its surface, chemotherapy, immunotherapy, or radiotherapy, performance of surgery, or any combination thereof.

[0063] The term“therapeutic benefit” or“therapeutically effective” as used herein refers to anything that promotes or enhances the well-being of the subject with respect to the medical treatment of this condition. This includes, but is not limited to, a reduction in the frequency or severity of the signs or symptoms of a disease. For example, treatment of cancer may involve, for example, a reduction in the invasiveness of a tumor, reduction in the growth rate of the cancer, or prevention of metastasis. Treatment of cancer may also refer to prolonging survival of a subject with cancer. Treatment of an autoimmune disease may involve, for example, inducing tolerance of a self-antigen against which there is an undesired immune response or inhibiting the immune response towards the self- antigen. Treatment of an infectious disease may involve, for example, eliminating the infectious agent, reducing the level of the infectious agent, or maintaining the level of the infectious agent at a certain level.

[0064] The term“cancer,” as used herein, may be used to describe a solid tumor, metastatic cancer, or non-metastatic cancer. In certain embodiments, the cancer may originate in the bladder, blood, bone, bone marrow, brain, breast, colon, esophagus, duodenum, small intestine, large intestine, colon, rectum, anus, gum, head, kidney, liver, lung, nasopharynx, neck, ovary, pancreas, prostate, skin, stomach, testis, tongue, or uterus.

[0065] The cancer may specifically be of the following histological type, though it is not limited to these: neoplasm, malignant; carcinoma; carcinoma, undifferentiated; giant and spindle cell carcinoma; small cell carcinoma; papillary carcinoma; squamous cell carcinoma; lymphoepithelial carcinoma; basal cell carcinoma; pilomatrix carcinoma; transitional cell carcinoma; papillary transitional cell carcinoma; adenocarcinoma; gastrinoma, malignant; cholangiocarcinoma; hepatocellular carcinoma; combined hepatocellular carcinoma and cholangiocarcinoma; trabecular adenocarcinoma; adenoid cystic carcinoma; adenocarcinoma in adenomatous polyp; adenocarcinoma, familial polyposis coli; solid carcinoma; carcinoid tumor, malignant; branchiolo- alveolar adenocarcinoma; papillary adenocarcinoma; chromophobe carcinoma; acidophil carcinoma; oxyphilic adenocarcinoma; basophil carcinoma; clear cell adenocarcinoma; granular cell carcinoma; follicular adenocarcinoma; papillary and follicular adenocarcinoma; nonencapsulating sclerosing carcinoma; adrenal cortical carcinoma; endometroid carcinoma; skin appendage carcinoma; apocrine adenocarcinoma; sebaceous adenocarcinoma; ceruminous adenocarcinoma; mucoepidermoid carcinoma; cystadenocarcinoma; papillary cystadenocarcinoma; papillary serous cystadenocarcinoma; mucinous cystadenocarcinoma; mucinous adenocarcinoma; signet ring cell carcinoma; infiltrating duct carcinoma; medullary carcinoma; lobular carcinoma; inflammatory carcinoma; paget's disease, mammary; acinar cell carcinoma; adenosquamous carcinoma; adenocarcinoma w/squamous metaplasia; thymoma, malignant; ovarian stromal tumor, malignant; thecoma, malignant; granulosa cell tumor, malignant; androblastoma, malignant; sertoli cell carcinoma; leydig cell tumor, malignant; lipid cell tumor, malignant; paraganglioma, malignant; extra-mammary paraganglioma, malignant; pheochromocytoma; glomangiosarcoma; malignant melanoma; amelanotic melanoma; superficial spreading melanoma; malignant melanoma in giant pigmented nevus; epithelioid cell melanoma; blue nevus, malignant; sarcoma; fibrosarcoma; fibrous histiocytoma, malignant; myxosarcoma; liposarcoma; leiomyosarcoma; rhabdomyosarcoma; embryonal rhabdomyosarcoma; alveolar rhabdomyosarcoma; stromal sarcoma; mixed tumor, malignant; mullerian mixed tumor; nephroblastoma; hepatoblastoma; carcinosarcoma; mesenchymoma, malignant; brenner tumor, malignant; phyllodes tumor, malignant; synovial sarcoma; mesothelioma, malignant; dysgerminoma; embryonal carcinoma; teratoma, malignant; struma ovarii, malignant; choriocarcinoma; mesonephroma, malignant; hemangiosarcoma; hemangioendothelioma, malignant; kaposi's sarcoma; hemangiopericytoma, malignant; lymphangiosarcoma; osteosarcoma; juxtacortical osteosarcoma; chondrosarcoma; chondroblastoma, malignant; mesenchymal chondrosarcoma; giant cell tumor of bone; ewing’s sarcoma; odontogenic tumor, malignant; ameloblastic odontosarcoma; ameloblastoma, malignant; ameloblastic fibrosarcoma; pinealoma, malignant; chordoma; glioma, malignant; ependymoma; astrocytoma; protoplasmic astrocytoma; fibrillary astrocytoma; astroblastoma; glioblastoma; oligodendroglioma; oligodendroblastoma; primitive neuroectodermal; cerebellar sarcoma; ganglioneuroblastoma; neuroblastoma; retinoblastoma; olfactory neurogenic tumor; meningioma, malignant; neurofibrosarcoma; neurilemmoma, malignant; granular cell tumor, malignant; malignant lymphoma; hodgkin's disease; hodgkin's; paragranuloma; malignant lymphoma, small lymphocytic; malignant lymphoma, large cell, diffuse; malignant lymphoma, follicular; mycosis fungoides; other specified non-hodgkin’ s lymphomas; malignant histiocytosis; multiple myeloma; mast cell sarcoma; immunoproliferative small intestinal disease; leukemia; lymphoid leukemia; plasma cell leukemia; erythroleukemia; lymphosarcoma cell leukemia; myeloid leukemia; basophilic leukemia; eosinophilic leukemia; monocytic leukemia; mast cell leukemia; megakaryoblastic leukemia; myeloid sarcoma; and hairy cell leukemia. Nonetheless, it is also recognized that the present invention may also be used to treat a non-cancerous disease (e.g., a fungal infection, a bacterial infection, a viral infection, a neurodegenerative disease, an autoimmune disease, and/or a genetic disorder).

[0066] Autoimmune diseases include those in which a subject’s own antibodies react with host tissue or in which immune effector T cells are autoreactive to endogenous self peptides and cause destruction of tissue. Autoimmune diseases for which the present treatment methods are useful include, without limitation, Addison’s disease, Alzheimer’s disease amyotrophic lateral sclerosis, ankylosing spondylitis, atherosclerosis, autoimmune diabetes mellitus (e.g., type 1 diabetes mellitus; insulin-dependent diabetes mellitus), autoimmune encephalomyelitis, autoimmune hemolytic anemia, autoimmune liver disease, autoimmune thrombocytopenic purpura, autoimmune thyroid disease, bullous pemphigoid, celiac disease, Crohn’s disease, glomerulonephritis (e.g., crescentic glomerulonephritis, proliferative glomerulonephritis), Goodpasture’s syndrome, graft vs. host disease, Grave’s disease, host vs. graft disease, idiopathic autoimmune-associated infertility, inflammatory bowel disease, insulin resistance, irritable bowel disease, arthritis (e.g., early arthritis, enteropathic arthritis, psoriatic arthritis, reactive arthritis, viral arthritis), familial Mediterranean fever, Hashimoto’s thyroiditis, mixed connective tissue disease, multiple sclerosis, myasthenia gravis (MG), pemphigus (e.g., pemphigus vulgaris), pernicious anemia, polymyositis, psoriasis, rheumatoid arthritis, juvenile rheumatoid arthritis, scleroderma with anti-collagen antibodies, Sjogren’s syndrome, spondyloarthropathy, systemic lupus erythematosus (SLE), transplant rejection, and ulcerative colitis. The diagnosis and treatment of these diseases are well documented in the literature.

[0067] Infectious diseases for which the present treatment methods are useful include, without limitation, bacterial infections, viral infections, fungal infections, parasitic infections, and sepsis. Exemplary viral infections include hepatitis B virus, hepatitis C virus, human immunodeficiency virus 1, human immunodeficiency virus 2, human papilloma vims, herpes simplex vims 1, herpes simplex vims 2, herpes zoster, varicella zoster, coxsackievirus A 16, cytomegalovirus, ebola vims, enterovims, Epstein-Barr vims, hanta virus, hendra vims, viral meningitis, respiratory syncytial vims, rotavirus, west nile vims, adenovirus, and influenza vims infections. Exemplary bacterial infections include Chlamydia trachomatis, Listeria monocytogenes, Helicobacter pylori, Escherichia coli, Borelia burgdorferi, Legionella pneumophilia, Mycobacteria sps (e.g., M. tuberculosis, M. avium, M. intraceliuiar e, M. kansaii, M. gordonae), Staphylococcus aureus, Neisseria gonorrhoeae, Neisseria meningitides, Streptococcus pyogenes (Group A Streptococcus), Streptococcus agalactiae (Group B Streptococcus), Streptococcus (viridans group), Streptococcus faecalis, Streptococcus bovis, Streptococcus (anaerobic sps.), Streptococcus pneumoniae, pathogenic Campylobacter sp., Enterococcus sp., Haemophilus influenzae, Bacillus anthracis, Corynebacterium diphtheriae, corynebacterium sp., Erysipelothrix rhusiopathiae , Clostridium perfringers, Clostridium tetani, Enterobacter aerogenes, Klebsiella pneumoniae, Pasturella multocida, Bacteroides sp., Fusobacterium nucleatum, Streptobacillus moniliformis, Treponema pallidium, Treponema pertenue, Leptospira, Rickettsia, Actinomyces israelii, Shigella sps (e.g., S.flexneri, S. sonnei, S. dysenteriae), and Salmonella spp infections. Exemplary fungal infections include Candida albicans, Candida glabrata, Aspergillus fumigatus, Aspergillus terreus, Cryptococcus neoformans, Histoplasma capsulatum, Coccidioides immitis, Blastomyces dermatitidis, and Chlamydia irachomatis infections.

[0068] The terms“contacted” and“exposed,” when applied to a cell, are used herein to describe the process by which a therapeutic agent is delivered to a target cell or are placed in direct juxtaposition with the target cell. To achieve cell killing, for example, one or more agents are delivered to a cell in an amount effective to kill the cell or prevent it from dividing.

[0069] An effective response of a patient or a patient’ s“responsiveness” to treatment refers to the clinical or therapeutic benefit imparted to a patient at risk for, or suffering from, a disease or disorder. Such benefit may include cellular or biological responses, a complete response, a partial response, a stable disease (without progression or relapse), or a response with a later relapse. For example, an effective response can be reduced tumor size or progression-free survival in a patient diagnosed with cancer.

[0070] Treatment outcomes can be predicted and monitored and/or patients benefiting from such treatments can be identified or selected via the methods described herein.

[0071] Regarding neoplastic condition treatment, depending on the stage of the neoplastic condition, neoplastic condition treatment involves one or a combination of the following therapies: surgery to remove the neoplastic tissue, radiation therapy, and chemotherapy. Other therapeutic regimens may be combined with the administration of the anticancer agents, e.g., therapeutic compositions and chemotherapeutic agents. For example, the patient to be treated with such anti-cancer agents may also receive radiation therapy and/or may undergo surgery.

[0072] For the treatment of disease, the appropriate dosage of a therapeutic composition will depend on the type of disease to be treated, as defined above, the severity and course of the disease, the patient’s clinical history and response to the agent, and the discretion of the attending physician. The agent is suitably administered to the patient at one time or over a series of treatments. [0073] Therapeutic and prophylactic methods and compositions can be provided in a combined amount effective to achieve the desired effect. A tissue, tumor, or cell can be contacted with one or more compositions or pharmacological formulation(s) comprising one or more of the agents, or by contacting the tissue, tumor, and/or cell with two or more distinct compositions or formulations. Also, it is contemplated that such a combination therapy can be used in conjunction with chemotherapy, radiotherapy, surgical therapy, or immunotherapy.

[0074] Administration in combination can include simultaneous administration of two or more agents in the same dosage form, simultaneous administration in separate dosage forms, and separate administration. That is, the subject therapeutic composition and another therapeutic agent can be formulated together in the same dosage form and administered simultaneously. Alternatively, subject therapeutic composition and another therapeutic agent can be simultaneously administered, wherein both the agents are present in separate formulations. In another alternative, the therapeutic agent can be administered just followed by the other therapeutic agent or vice versa. In the separate administration protocol, the subject therapeutic composition and another therapeutic agent may be administered a few minutes apart, or a few hours apart, or a few days apart.

[0075] A first anti-cancer treatment (e.g. , exosomes that comprise OX40L or ICOSL in their surface) may be administered before, during, after, or in various combinations relative to a second anti-cancer treatment. The administrations may be in intervals ranging from concurrently to minutes to days to weeks. In embodiments where the first treatment is provided to a patient separately from the second treatment, one would generally ensure that a significant period of time did not expire between the time of each delivery, such that the two compounds would still be able to exert an advantageously combined effect on the patient. In such instances, it is contemplated that one may provide a patient with the first therapy and the second therapy within about 12 to 24 or 72 h of each other and, more particularly, within about 6-12 h of each other. In some situations it may be desirable to extend the time period for treatment significantly where several days (2, 3, 4, 5, 6, or 7) to several weeks (1, 2, 3, 4, 5, 6, 7, or 8) lapse between respective administrations·

[0076] In certain embodiments, a course of treatment will last 1-90 days or more (this such range includes intervening days). It is contemplated that one agent may be given on any day of day 1 to day 90 (this such range includes intervening days) or any combination thereof, and another agent is given on any day of day 1 to day 90 (this such range includes intervening days) or any combination thereof. Within a single day (24-hour period), the patient may be given one or multiple administrations of the agent(s). Moreover, after a course of treatment, it is contemplated that there is a period of time at which no anti-cancer treatment is administered. This time period may last 1-7 days, and/or 1-5 weeks, and/or 1-12 months or more (this such range includes intervening days), depending on the condition of the patient, such as their prognosis, strength, health, etc. It is expected that the treatment cycles would be repeated as necessary.

[0077] Various combinations may be employed. For the example below a first anti cancer therapy is“A” and a second anti-cancer therapy is“B”:

A/B/A B/A/B B/B/A A/A/B A/B/B B/A/A A/B/B/B B/A/B/B

B/B/B/A B/B/A/B A/A/B/B A/B/A/B A/B/B/A B/B/A/A

B/A/B/A B/A/A/B A/A/A/B B/A/A/A A/B/A/A A/A/B/A

[0078] Administration of any compound or therapy of the present invention to a patient will follow general protocols for the administration of such compounds, taking into account the toxicity, if any, of the agents. Therefore, in some embodiments there is a step of monitoring toxicity that is attributable to combination therapy.

1. Chemotherapy

[0079] A wide variety of chemotherapeutic agents may be used in accordance with the present invention. The term“chemotherapy” refers to the use of drugs to treat cancer. A “chemotherapeutic agent” is used to connote a compound or composition that is administered in the treatment of cancer. These agents or drugs are categorized by their mode of activity within a cell, for example, whether and at what stage they affect the cell cycle. Alternatively, an agent may be characterized based on its ability to directly cross-link DNA, to intercalate into DNA, or to induce chromosomal and mitotic aberrations by affecting nucleic acid synthesis.

[0080] Examples of chemotherapeutic agents include alkylating agents, such as thiotepa and cyclosphosphamide; alkyl sulfonates, such as busulfan, improsulfan, and piposulfan; aziridines, such as benzodopa, carboquone, meturedopa, and uredopa; ethylenimines and methylamelamines, including altretamine, triethylenemelamine, trietylenephosphoramide, triethiylenethiophosphoramide, and trimethylolomelamine; acetogenins (especially bullatacin and bullatacinone); a camptothecin (including the synthetic analogue topotecan); bryostatin; callystatin; CC-1065 (including its adozelesin, carzelesin and bizelesin synthetic analogues); cryptophycins (particularly cryptophycin 1 and cryptophycin 8); dolastatin; duocarmycin (including the synthetic analogues, KW-2189 and CB1-TM1); eleutherobin; pancratistatin; a sarcodictyin; spongistatin; nitrogen mustards, such as chlorambucil, chlornaphazine, cholophosphamide, estramustine, ifosfamide, mechlorethamine, mechlorethamine oxide hydrochloride, melphalan, novembichin, phenesterine, prednimustine, trofosfamide, and uracil mustard; nitrosureas, such as carmustine, chlorozotocin, fotemustine, lomustine, nimustine, and ranimnustine; antibiotics, such as the enediyne antibiotics (e.g., calicheamicin, especially calicheamicin gammall and calicheamicin omegall); dynemicin, including dynemicin A; bisphosphonates, such as clodronate; an esperamicin; as well as neocarzinostatin chromophore and related chromoprotein enediyne antiobiotic chromophores, aclacinomysins, actinomycin, authramycin, azaserine, bleomycins, cactinomycin, carabicin, carminomycin, carzinophilin, chromomycinis, dactinomycin, daunorubicin, detorubicin, 6-diazo-5-oxo-L-norleucine, doxorubicin (including morpholino-doxorubicin, cyanomorpholino-doxorubicin, 2-pyrrolino- doxorubicin and deoxy doxorubicin), epirubicin, esorubicin, idarubicin, marcellomycin, mitomycins, such as mitomycin C, mycophenolic acid, nogalamycin, olivomycins, peplomycin, potfiromycin, puromycin, quelamycin, rodorubicin, streptonigrin, streptozocin, tubercidin, ubenimex, zinostatin, and zorubicin; anti-metabolites, such as methotrexate and 5- fluorouracil (5-FU); folic acid analogues, such as denopterin, pteropterin, and trimetrexate; purine analogs, such as fludarabine, 6-mercaptopurine, thiamiprine, and thioguanine; pyrimidine analogs, such as ancitabine, azacitidine, 6-azauridine, carmofur, cytarabine, dideoxyuridine, doxifluridine, enocitabine, and floxuridine; androgens, such as calusterone, dromostanolone propionate, epitiostanol, mepitiostane, and testolactone; anti-adrenals, such as mitotane and trilostane; folic acid replenisher, such as frolinic acid; aceglatone; aldophosphamide glycoside; aminolevulinic acid; eniluracil; amsacrine; bestrabucil; bisantrene; edatraxate; defofamine; demecolcine; diaziquone; elformithine; elliptinium acetate; an epothilone; etoglucid; gallium nitrate; hydroxyurea; lentinan; lonidainine; maytansinoids, such as maytansine and ansamitocins; mitoguazone; mitoxantrone; mopidanmol; nitraerine; pentostatin; phenamet; pirarubicin; losoxantrone; podophyllinic acid; 2-ethylhydrazide; procarbazine; PSKpolysaccharide complex; razoxane; rhizoxin; sizofiran; spirogermanium; tenuazonic acid; triaziquone; 2,2',2"-trichlorotriethylamine; trichothecenes (especially T-2 toxin, verracurin A, roridin A and anguidine); urethan; vindesine; dacarbazine; mannomustine; mitobronitol; mitolactol; pipobroman; gacytosine; arabinoside (“Ara-C”); cyclophosphamide; taxoids, e.g., paclitaxel and docetaxel gemcitabine; 6-thioguanine; mercaptopurine; platinum coordination complexes, such as cisplatin, oxaliplatin, and carboplatin; vinblastine; platinum; etoposide (VP- 16); ifosfamide; mitoxantrone; vincristine; vinorelbine; novantrone; teniposide; edatrexate; daunomycin; aminopterin; xeloda; ibandronate; irinotecan (e.g., CPT-l l); topoisomerase inhibitor RFS 2000; difluorometlhylornithine (DMFO); retinoids, such as retinoic acid; capecitabine; carboplatin, procarbazine, plicomycin, gemcitabien, navelbine, famesyl-protein tansferase inhibitors, transplatinum, and pharmaceutically acceptable salts, acids, or derivatives of any of the above.

2. Radiotherapy

[0081] Other factors that cause DNA damage and have been used extensively include what are commonly known as g-rays, X-rays, and/or the directed delivery of radioisotopes to tumor cells. Other forms of DNA damaging factors are also contemplated, such as microwaves, proton beam irradiation (U.S. Patents 5,760,395 and 4,870,287), and UV- irradiation. It is most likely that all of these factors affect a broad range of damage on DNA, on the precursors of DNA, on the replication and repair of DNA, and on the assembly and maintenance of chromosomes. Dosage ranges for X-rays range from daily doses of 50 to 200 roentgens for prolonged periods of time (3 to 4 wk), to single doses of 2000 to 6000 roentgens. Dosage ranges for radioisotopes vary widely, and depend on the half-life of the isotope, the strength and type of radiation emitted, and the uptake by the neoplastic cells.

3. Immunotherapy

[0082] The skilled artisan will understand that additional immunotherapies may be used in combination or in conjunction with methods of the invention. In the context of cancer treatment, immunotherapeutics, generally, rely on the use of immune effector cells and molecules to target and destroy cancer cells. Rituximab (Rituxan®) is such an example. The immune effector may be, for example, an antibody specific for some marker on the surface of a tumor cell. The antibody alone may serve as an effector of therapy or it may recruit other cells to actually affect cell killing. The antibody also may be conjugated to a drug or toxin (chemotherapeutic, radionuclide, ricin A chain, cholera toxin, pertussis toxin, etc.) and serve merely as a targeting agent. Alternatively, the effector may be a lymphocyte carrying a surface molecule that interacts, either directly or indirectly, with a tumor cell target. Various effector cells include cytotoxic T cells and NK cells.

[0083] In one aspect of immunotherapy, the tumor cell must bear some marker that is amenable to targeting, i.e., is not present on the majority of other cells. Many tumor markers exist and any of these may be suitable for targeting in the context of the present invention. Common tumor markers include CD20, carcinoembryonic antigen, tyrosinase (p97), gp68, TAG-72, HMFG, Sialyl Lewis Antigen, MucA, MucB, PLAP, laminin receptor, erb B, and pl55. An alternative aspect of immunotherapy is to combine anticancer effects with immune stimulatory effects. Immune stimulating molecules also exist including: cytokines, such as IL-2, IL-4, IL-12, GM-CSF, gamma-IFN, chemokines, such as MIP-l, MCP-l, IL-8, and growth factors, such as FLT3 ligand.

[0084] Examples of immunotherapies currently under investigation or in use are immune adjuvants, e.g., Mycobacterium bovis, Plasmodium falciparum, dinitrochlorobenzene, and aromatic compounds (U.S. Patents 5,801,005 and 5,739,169; Hui and Hashimoto, 1998; Christodoulides et al, 1998); cytokine therapy, e.g., interferons a, b, and g, IL-l, GM-CSF, and TNF (Bukowski et al, 1998; Davidson et al, 1998; Hellstrand et al, 1998); gene therapy, e.g., TNF, IL-l, IL-2, and p53 (Qin et al, 1998; Austin-Ward and Villaseca, 1998; U.S. Patents 5,830,880 and 5,846,945); and monoclonal antibodies, e.g., anti-CD20, anti-ganglioside GM2, and anti-pl85 (Hollander, 2013; Hanibuchi et al, 1998; U.S. Patent 5,824,311). It is contemplated that one or more anti-cancer therapies may be employed with the antibody therapies described herein.

[0085] In some embodiments, the immunotherapy may be an immune checkpoint inhibitor. Immune checkpoints either turn up a signal (e.g., co-stimulatory molecules) or turn down a signal. Inhibitory immune checkpoints that may be targeted by immune checkpoint blockade include adenosine A2A receptor (A2AR), B7-H3 (also known as CD276), B and T lymphocyte attenuator (BTLA), cytotoxic T-lymphocyte-associated protein 4 (CTLA-4, also known as CD152), indoleamine 2,3-dioxygenase (IDO), killer-cell immunoglobulin (KIR), lymphocyte activation gene-3 (LAG3), programmed death 1 (PD-l), T-cell immunoglobulin domain and mucin domain 3 (TIM-3) and V-domain Ig suppressor of T cell activation (VISTA). In particular, the immune checkpoint inhibitors target the PD-l axis and/or CTLA- 4. [0086] The immune checkpoint inhibitors may be drugs such as small molecules, recombinant forms of ligand or receptors, or, in particular, are antibodies, such as human antibodies (e.g., International Patent Publication W02015016718; Pardoll, Nat Rev Cancer, 12(4): 252-64, 2012; both incorporated herein by reference). Known inhibitors of the immune checkpoint proteins or analogs thereof may be used, in particular chimerized, humanized or human forms of antibodies may be used. As the skilled person will know, alternative and/or equivalent names may be in use for certain antibodies mentioned in the present disclosure. Such alternative and/or equivalent names are interchangeable in the context of the present disclosure. For example, it is known that lambrolizumab is also known under the alternative and equivalent names MK-3475 and pembrolizumab.

[0087] In some embodiments, the PD-l binding antagonist is a molecule that inhibits the binding of PD-l to its ligand binding partners. In a specific aspect, the PD-l ligand binding partners are PDL1 and/or PDL2. In another embodiment, a PDL1 binding antagonist is a molecule that inhibits the binding of PDL1 to its binding partners. In a specific aspect, PDL1 binding partners are PD-l and/or B7-1. In another embodiment, the PDL2 binding antagonist is a molecule that inhibits the binding of PDL2 to its binding partners. In a specific aspect, a PDL2 binding partner is PD-l. The antagonist may be an antibody, an antigen binding fragment thereof, an immunoadhesin, a fusion protein, or oligopeptide. Exemplary antibodies are described in U.S. Patent Nos. 8,735,553, 8,354,509, and 8,008,449, all incorporated herein by reference. Other PD-l axis antagonists for use in the methods provided herein are known in the art such as described in U.S. Patent Publication Nos. 20140294898, 2014022021, and 20110008369, all incorporated herein by reference.

[0088] In some embodiments, the PD-l binding antagonist is an anti-PD-l antibody (e.g., a human antibody, a humanized antibody, or a chimeric antibody). In some embodiments, the anti-PD-l antibody is selected from the group consisting of nivolumab, pembrolizumab, and CT-011. In some embodiments, the PD-l binding antagonist is an immunoadhesin (e.g., an immunoadhesin comprising an extracellular or PD-l binding portion of PDL1 or PDL2 fused to a constant region (e.g., an Fc region of an immunoglobulin sequence). In some embodiments, the PD-l binding antagonist is AMP- 224. Nivolumab, also known as MDX-1106-04, MDX-1106, ONO-4538, BMS-936558, and OPDIVO ^® , is an anti- PD-l antibody described in W02006/121168. Pembrolizumab, also known as MK-3475, Merck 3475, lambrolizumab, KEYTRUDA ^® , and SCH-900475, is an anti-PD-l antibody described in W02009/114335. CT-011, also known as hBAT or hBAT-l, is an anti-PD-l antibody described in W02009/101611. AMP-224, also known as B7-DCIg, is a PDL2-Fc fusion soluble receptor described in W02010/027827 and WO2011/066342.

[0089] Another immune checkpoint that can be targeted in the methods provided herein is the cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), also known as CD152. The complete cDNA sequence of human CTLA-4 has the Genbank accession number L15006. CTLA-4 is found on the surface of T cells and acts as an“off’ switch when bound to CD80 or CD86 on the surface of antigen-presenting cells. CTLA4 is a member of the immunoglobulin superfamily that is expressed on the surface of Helper T cells and transmits an inhibitory signal to T cells. CTLA4 is similar to the T-cell co-stimulatory protein, CD28, and both molecules bind to CD80 and CD86, also called B7-1 and B7-2 respectively, on antigen-presenting cells. CTLA4 transmits an inhibitory signal to T cells, whereas CD28 transmits a stimulatory signal. Intracellular CTLA4 is also found in regulatory T cells and may be important to their function. T cell activation through the T cell receptor and CD28 leads to increased expression of CTLA-4, an inhibitory receptor for B7 molecules.

[0090] In some embodiments, the immune checkpoint inhibitor is an anti-CTLA-4 antibody (e.g., a human antibody, a humanized antibody, or a chimeric antibody), an antigen binding fragment thereof, an immunoadhesin, a fusion protein, or oligopeptide.

[0091] Anti-human-CTLA-4 antibodies (or VH and/or VL domains derived therefrom) suitable for use in the present methods can be generated using methods well known in the art. Alternatively, art recognized anti-CTLA-4 antibodies can be used. For example, the anti-CTLA-4 antibodies disclosed in: US Patent No. 8,119,129, WO 01/14424, WO 98/42752; WO 00/37504 (CP675,206, also known as tremelimumab; formerly ticilimumab), U.S. Patent No. 6,207,156; Hurwitz et al. (1998) Proc Natl Acad Sci USA 95(17): 10067-10071; Camacho et al. (2004) J Clin Oncology 22(145): Abstract No. 2505 (antibody CP-675206); and Mokyr et al. (1998) Cancer Res 58:5301-5304 can be used in the methods disclosed herein. The teachings of each of the aforementioned publications are hereby incorporated by reference. Antibodies that compete with any of these art-recognized antibodies for binding to CTLA-4 also can be used. For example, a humanized CTLA-4 antibody is described in International Patent Application No. WO2001014424, W02000037504, and U.S. Patent No. 8,017,114; all incorporated herein by reference. [0092] An exemplary anti-CTLA-4 antibody is ipilimumab (also known as 10D1, MDX- 010, MDX- 101, and Yervoy®) or antigen binding fragments and variants thereof (see, e.g., WO 01/14424). In other embodiments, the antibody comprises the heavy and light chain CDRs or VRs of ipilimumab. Accordingly, in one embodiment, the antibody comprises the CDR1, CDR2, and CDR3 domains of the VH region of ipilimumab, and the CDR1, CDR2 and CDR3 domains of the VL region of ipilimumab. In another embodiment, the antibody competes for binding with and/or binds to the same epitope on CTLA-4 as the above- mentioned antibodies. In another embodiment, the antibody has at least about 90% variable region amino acid sequence identity with the above-mentioned antibodies (e.g., at least about 90%, 95%, or 99% variable region identity with ipilimumab).

[0093] Other molecules for modulating CTLA-4 include CTLA-4 ligands and receptors such as described in U.S. Patent Nos. 5844905, 5885796 and International Patent Application Nos. WO1995001994 and WO1998042752; all incorporated herein by reference, and immunoadhesins such as described in U.S. Patent No. 8329867, incorporated herein by reference.

[0094] In some embodiment, the immune therapy could be adoptive immunotherapy, which involves the transfer of autologous antigen-specific T cells generated ex vivo. The T cells used for adoptive immunotherapy can be generated either by expansion of antigen- specific T cells or redirection of T cells through genetic engineering (Park, Rosenberg et al. 2011). Isolation and transfer of tumor specific T cells has been shown to be successful in treating melanoma. Novel specificities in T cells have been successfully generated through the genetic transfer of transgenic T cell receptors or chimeric antigen receptors (CARs) (Jena, Doth et al. 2010). CARs are synthetic receptors consisting of a targeting moiety that is associated with one or more signaling domains in a single fusion molecule. In general, the binding moiety of a CAR consists of an antigen-binding domain of a single-chain antibody (scFv), comprising the light and variable fragments of a monoclonal antibody joined by a flexible linker. Binding moieties based on receptor or ligand domains have also been used successfully. The signaling domains for first generation CARs are derived from the cytoplasmic region of the CD3zeta or the Fc receptor gamma chains. CARs have successfully allowed T cells to be redirected against antigens expressed at the surface of tumor cells from various malignancies including lymphomas and solid tumors (Jena, Dotti et al. 2010). [0095] In one embodiment, the present application provides for a combination therapy for the treatment of cancer wherein the combination therapy comprises adoptive T- cell therapy and a checkpoint inhibitor. In one aspect, the adoptive T-cell therapy comprises autologous and/or allogenic T cells. In another aspect, the autologous and/or allogenic T cells are targeted against tumor antigens.

4. Surgery

[0096] Approximately 60% of persons with cancer will undergo surgery of some type, which includes preventative, diagnostic or staging, curative, and palliative surgery. Curative surgery includes resection in which all or part of cancerous tissue is physically removed, excised, and/or destroyed and may be used in conjunction with other therapies, such as the treatment of the present invention, chemotherapy, radiotherapy, hormonal therapy, gene therapy, immunotherapy, and/or alternative therapies. Tumor resection refers to physical removal of at least part of a tumor. In addition to tumor resection, treatment by surgery includes laser surgery, cryosurgery, electrosurgery, and microscopically-controlled surgery (Mohs’ surgery).

[0097] Upon excision of part or all of cancerous cells, tissue, or tumor, a cavity may be formed in the body. Treatment may be accomplished by perfusion, direct injection, or local application of the area with an additional anti-cancer therapy. Such treatment may be repeated, for example, every 1, 2, 3, 4, 5, 6, or 7 days, or every 1, 2, 3, 4, and 5 weeks or every 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 months. These treatments may be of varying dosages as well.

5. Other Agents

[0098] It is contemplated that other agents may be used in combination with certain aspects of the present invention to improve the therapeutic efficacy of treatment. These additional agents include agents that affect the upregulation of cell surface receptors and GAP junctions, cytostatic and differentiation agents, inhibitors of cell adhesion, agents that increase the sensitivity of the hyperproliferative cells to apoptotic inducers, or other biological agents. Increases in intercellular signaling by elevating the number of GAP junctions would increase the anti-hyperproliferative effects on the neighboring hyperproliferative cell population. In other embodiments, cytostatic or differentiation agents can be used in combination with certain aspects of the present invention to improve the anti- hyperproliferative efficacy of the treatments. Inhibitors of cell adhesion are contemplated to improve the efficacy of the present invention. Examples of cell adhesion inhibitors are focal adhesion kinase (FAKs) inhibitors and Lovastatin. It is further contemplated that other agents that increase the sensitivity of a hyperproliferative cell to apoptosis, such as the antibody c225, could be used in combination with certain aspects of the present invention to improve the treatment efficacy.

IV. Pharmaceutical Compositions

[0099] It is contemplated that exosomes comprise OX40L or ICOSL on their surface can be administered systemically or locally to inhibit tumor cell growth and, most preferably, to kill cancer cells in cancer patients with locally advanced or metastatic cancers. They can be administered intravenously, intrathecally, and/or intraperitoneally. They can be administered alone or in combination with anti-proliferative drugs. In one embodiment, they are administered to reduce the cancer load in the patient prior to surgery or other procedures. Alternatively, they can be administered after surgery to ensure that any remaining cancer (e.g., cancer that the surgery failed to eliminate) does not survive.

[00100] It is not intended that the present invention be limited by the particular nature of the therapeutic preparation. For example, such compositions can be provided in formulations together with physiologically tolerable liquid, gel, solid carriers, diluents, or excipients. These therapeutic preparations can be administered to mammals for veterinary use, such as with domestic animals, and clinical use in humans in a manner similar to other therapeutic agents. In general, the dosage required for therapeutic efficacy will vary according to the type of use and mode of administration, as well as the particular requirements of individual subjects.

[00101] Where clinical applications are contemplated, it may be necessary to prepare pharmaceutical compositions comprising recombinant proteins and/or exosomes in a form appropriate for the intended application. Generally, pharmaceutical compositions, which can be parenteral formulations, can comprise an effective amount of one or more recombinant proteins and/or exosomes and/or additional agents dissolved or dispersed in a pharmaceutically acceptable carrier. The phrases “pharmaceutical or pharmacologically acceptable” refers to molecular entities and compositions that do not produce an adverse, allergic, or other untoward reaction when administered to an animal, such as, for example, a human, as appropriate. The preparation of a pharmaceutical composition comprising a recombinant protein and/or exosomes as disclosed herein, or additional active ingredients is as exemplified by Remington’s Pharmaceutical Sciences, l8th Ed., 1990, which is incorporated herein by reference in its entirety for all purposes. Moreover, for animal (e.g., human) administration, it will be understood that preparations should meet sterility, pyrogenicity, general safety, and purity standards as required by the FDA Office of Biological Standards.

[00102] Further in accordance with certain aspects of the present invention, the composition suitable for administration may be provided in a pharmaceutically acceptable carrier with or without an inert diluent. As used herein,“pharmaceutically acceptable carrier” includes any and all aqueous solvents (e.g., water, alcoholic/aqueous solutions, ethanol, saline solutions, parenteral vehicles, such as sodium chloride, Ringer’s dextrose, etc.), non- aqueous solvents (e.g., fats, oils, polyol (for example, glycerol, propylene glycol, and liquid polyethylene glycol, and the like), vegetable oil, and injectable organic esters, such as ethyloleate), lipids, liposomes, dispersion media, coatings (e.g., lecithin), surfactants, antioxidants, preservatives (e.g., antibacterial or antifungal agents, anti-oxidants, chelating agents, inert gases, parabens (e.g., methylparabens, propylparabens), chlorobutanol, phenol, sorbic acid, thimerosal or combinations thereof), isotonic agents (e.g., sugars and sodium chloride), absorption delaying agents (e.g. , aluminum monostearate and gelatin), salts, drugs, drug stabilizers, gels, resins, fillers, binders, excipients, disintegration agents, lubricants, sweetening agents, flavoring agents, dyes, fluid and nutrient replenishers, such like materials and combinations thereof, as would be known to one of ordinary skill in the art. The carrier should be assimilable and includes liquid, semi-solid, i.e., pastes, or solid carriers. In addition, if desired, the compositions may contain minor amounts of auxiliary substances, such as wetting or emulsifying agents, stabilizing agents, or pH buffering agents. The pH and exact concentration of the various components in a pharmaceutical composition are adjusted according to well-known parameters. The proper fluidity can be maintained, for example, by the use of a coating, such as lecithin, by the maintenance of the required particle size in the case of dispersion, and by the use of surfactants.

[00103] A pharmaceutically acceptable carrier is particularly formulated for administration to a human, although in certain embodiments it may be desirable to use a pharmaceutically acceptable carrier that is formulated for administration to a non-human animal but that would not be acceptable (e.g. , due to governmental regulations) for administration to a human. Except insofar as any conventional carrier is incompatible with the active ingredient (e.g., detrimental to the recipient or to the therapeutic effectiveness of a composition contained therein), its use in the therapeutic or pharmaceutical compositions is contemplated. In accordance with certain aspects of the present invention, the composition is combined with the carrier in any convenient and practical manner, i.e., by solution, suspension, emulsification, admixture, encapsulation, absorption, and the like. Such procedures are routine for those skilled in the art.

[00104] Certain embodiments of the present invention may comprise different types of carriers depending on whether it is to be administered in solid, liquid, or aerosol form, and whether it needs to be sterile for the route of administration, such as injection. The compositions can be administered intravenously, intradermally, transdermally, intrathecally, intraarterially, intraperitoneally, intranasally, intravaginally, intrarectally, intramuscularly, subcutaneously, mucosally, orally, topically, locally, by inhalation (e.g. , aerosol inhalation), by injection, by infusion, by continuous infusion, by localized perfusion bathing target cells directly, via a catheter, via a lavage, in lipid compositions (e.g. , liposomes), or by other methods or any combination of the forgoing, which are described, for example, in Remington’s Pharmaceutical Sciences, 18th Ed., 1990, incorporated herein by reference.

[00105] The active compounds can be formulated for parenteral administration, e.g., formulated for injection via the intravenous, intramuscular, sub-cutaneous, or even intraperitoneal routes. As such, the embodiments include parenteral formulations. Typically, such compositions can be prepared as either liquid solutions or suspensions; solid forms suitable for use to prepare solutions or suspensions upon the addition of a liquid prior to injection can also be prepared; and the preparations can also be emulsified.

[00106] According to the subject embodiments, the parenteral formulations can include exosomes as disclosed herein along with one or more solute and/or solvent, one or more buffering agent and/or one or more antimicrobial agents, or any combination thereof. In some aspects, the solvent can include water, water-miscible solvents, e.g., ethyl alcohol, liquid polyethylene glycol, and/or propylene glycol, and/or water-immiscible solvents, such as fixed oils including, for example, com oil, cottonseed oil, peanut oil, and/or sesame oil. In certain versions, the solutes can include one or more antimicrobial agents, buffers, antioxidants, tonicity agents, cryoprotectants and/or lyoprotectants. [00107] Antimicrobial agents according to the subject disclosure can include those provided elsewhere in the subject disclosure as well as benzyl alcohol, phenol, mercurials and/or parabens. Antimicrobial agents can include benzalkonium chloride, benzethonium chloride, benzyl alcohol, bronopol, centrimide, cetylpyridinium chloride, chlorhexidine, chlorobutanol, chlorocresol, chloroxylenol, cresol, ethyl alcohol, glycerin, exetidine, imidurea, phenol, phenoxyethanol, phenylethl alcohol, phenlymercuric nitrate, propylene glycol, and/or thimerosal, or any combination thereof. The antimicrobial agents can, in various aspects, be present in a concentration necessary to ensure sterility as is required for pharmaceutical agents. For example, the agents can be present in bacteriostatic or fungistatic concentrations in preparations, e.g., preparations contained in multiple-dose containers. The agents can, in various embodiments, be preservatives and/or can be present in adequate concentration at the time of use to prevent the multiplication of microorganisms, such as microorganisms inadvertently introduced into the preparation while, for example, withdrawing a portion of the contents with a hypodermic needle and syringe. In various aspects, the agents have maximum volume and/or concentration limits (e.g., phenylmercuric nitrate and thimerosal 0.01 %, benzethonium chloride and benzalkonium chloride 0.01 %, phenol or cresol 0.5%, and chlorobutanol 0.5%). In various instances, agents such as phenylmercuric nitrate, are employed in a concentration of 0.002%. Methyl p- hydroxybenzoate 0.18% and propyl p-hydroxybenzoate 0.02% in combination, and benzyl alcohol 2% also can be applied according to the embodiments. The antimicrobial agents can also include hexylresorcinol 0.5%, phenylmercuric benzoate 0.1 %, and/or therapeutic compounds.

[00108] Antioxidants according to the subject disclosure can include ascorbic acid and/or its salts, and/or the sodium salt of ethylenediaminetetraacetic acid (EDTA). Tonicity agents as described herein can include electrolytes and/or mono- or disaccharides. Cryoprotectants and/or lyoprotectants are additives that protect biopharmaceuticals from detrimental effects due to freezing and/or drying of the product during freezedry processing. Cryoprotectants and/or lyoprotectants can include sugars (non-reducing) such as sucrose or trehalose, amino acids such as glycine or lysine, polymers such as liquid polyethylene glycol or dextran, and polyols such as mannitol or sorbitol all are possible cryo- or lyoprotectants. The subject embodiments can also include antifungal agents such as butyl paraben, methyl paraben, ethyl paraben, propyl paraben, benzoic acid, potassium sorbate, sodium benzoate, sodium propionate, and/or sorbic acid, or any combination thereof. Additional solutes and antimicrobial agents, buffers, antioxidants, tonicity agents, cryoprotectants and/or lyprotectants and characteristics thereof which may be employed according to the subject disclosure, as well as aspects of methods of making the subject parenteral formulations are described, for example, in Remington’s Pharmaceutical Sciences, 2lst Ed., 2005, e.g., Chapter 41, which is incorporated herein by reference in its entirety for all purposes.

[00109] The pharmaceutical forms suitable for injectable use include sterile aqueous solutions or dispersions; formulations including sesame oil, peanut oil, or aqueous propylene glycol; and sterile powders for the extemporaneous preparation of sterile injectable solutions or dispersions. In all cases the form must be sterile and must be fluid to the extent that it may be easily injected. It also should be stable under the conditions of manufacture and storage and must be preserved against the contaminating action of microorganisms, such as bacteria and fungi.

[00110] The therapeutics may be formulated into a composition in a free base, neutral, or salt form. Pharmaceutically acceptable salts include the acid addition salts, e.g., those formed with the free amino groups of a proteinaceous composition, or which are formed with inorganic acids, such as, for example, hydrochloric or phosphoric acids, or such organic acids as acetic, oxalic, tartaric, or mandelic acid and the like. Salts formed with the free carboxyl groups can also be derived from inorganic bases, such as, for example, sodium, potassium, ammonium, calcium, or ferric hydroxides; or such organic bases as isopropylamine, trimethylamine, histidine, or procaine and the like. Upon formulation, solutions will be administered in a manner compatible with the dosage formulation and in such amount as is therapeutically effective. The formulations are easily administered in a variety of dosage forms, such as formulated for parenteral administrations, such as injectable solutions, or aerosols for delivery to the lungs, or formulated for alimentary administrations, such as drug release capsules and the like.

[00111] In a specific embodiment of the present invention, the composition is combined or mixed thoroughly with a semi-solid or solid carrier. The mixing can be carried out in any convenient manner, such as grinding. Stabilizing agents can be also added in the mixing process in order to protect the composition from loss of therapeutic activity, /. _<? . , denaturation in the stomach. Examples of stabilizers for use in a composition include buffers, amino acids, such as glycine and lysine, carbohydrates, such as dextrose, mannose, galactose, fructose, lactose, sucrose, maltose, sorbitol, mannitol, etc. [00112] In further embodiments, the present invention may concern the use of a pharmaceutical lipid vehicle composition comprising one or more lipids and an aqueous solvent. As used herein, the term“lipid” will be defined to include any of a broad range of substances that is characteristically insoluble in water and extractable with an organic solvent. This broad class of compounds is well known to those of skill in the art, and as the term“lipid” is used herein, it is not limited to any particular structure. Examples include compounds that contain long-chain aliphatic hydrocarbons and their derivatives. A lipid may be naturally occurring or synthetic (i.e., designed or produced by man). However, a lipid is usually a biological substance. Biological lipids are well known in the art, and include for example, neutral fats, phospholipids, phosphoglycerides, steroids, terpenes, lysolipids, glycosphingolipids, glycolipids, sulphatides, lipids with ether- and ester-linked fatty acids, polymerizable lipids, and combinations thereof. Of course, compounds other than those specifically described herein that are understood by one of skill in the art as lipids are also encompassed by the compositions and methods.

[00113] One of ordinary skill in the art would be familiar with the range of techniques that can be employed for dispersing a composition in a lipid vehicle. For example, the therapeutic agent may be dispersed in a solution containing a lipid, dissolved with a lipid, emulsified with a lipid, mixed with a lipid, combined with a lipid, covalently bonded to a lipid, contained as a suspension in a lipid, contained or complexed with a micelle or liposome, or otherwise associated with a lipid or lipid structure by any means known to those of ordinary skill in the art. The dispersion may or may not result in the formation of liposomes.

[00114] The term“unit dose” or“dosage” refers to physically discrete units suitable for use in a subject, each unit containing a predetermined quantity of the therapeutic composition calculated to produce the desired responses discussed above in association with its administration, i.e. , the appropriate route and treatment regimen. The quantity to be administered, both according to number of treatments and unit dose, depends on the effect desired. The actual dosage amount of a composition of the present invention administered to a patient or subject can be determined by physical and physiological factors, such as body weight, the age, health, and sex of the subject, the type of disease being treated, the extent of disease penetration, previous or concurrent therapeutic interventions, idiopathy of the patient, the route of administration, and the potency, stability, and toxicity of the particular therapeutic substance. For example, a dose may also comprise from about 1 mg/kg/body weight to about 1000 mg/kg/body weight (this such range includes intervening doses) or more per administration, and any range derivable therein. In non-limiting examples of a derivable range from the numbers listed herein, a range of about 5 pg/kg/body weight to about 100 mg/kg/body weight, about 5 pg/kg/body weight to about 500 mg/kg/body weight, etc. , can be administered. The practitioner responsible for administration will, in any event, determine the concentration of active ingredient(s) in a composition and appropriate dose(s) for the individual subject.

[00115] The actual dosage amount of a composition administered to an animal patient can be determined by physical and physiological factors, such as body weight, severity of condition, the type of disease being treated, previous or concurrent therapeutic interventions, idiopathy of the patient, and on the route of administration. Depending upon the dosage and the route of administration, the number of administrations of a preferred dosage and/or an effective amount may vary according to the response of the subject. The practitioner responsible for administration will, in any event, determine the concentration of active ingredient(s) in a composition and appropriate dose(s) for the individual subject.

[00116] In certain embodiments, pharmaceutical compositions may comprise, for example, at least about 0.1% of an active compound. In other embodiments, an active compound may comprise between about 2% to about 75% of the weight of the unit, or between about 25% to about 60%, for example, and any range derivable therein. Naturally, the amount of active compound(s) in each therapeutically useful composition may be prepared in such a way that a suitable dosage will be obtained in any given unit dose of the compound. Factors, such as solubility, bioavailability, biological half-life, route of administration, product shelf life, as well as other pharmacological considerations, will be contemplated by one skilled in the art of preparing such pharmaceutical formulations, and as such, a variety of dosages and treatment regimens may be desirable.

[00117] In other non-limiting examples, a dose may also comprise from about 1 microgram/kg/body weight, about 5 microgram/kg/body weight, about 10 microgram/kg/body weight, about 50 microgram/kg/body weight, about 100 microgram/kg/body weight, about 200 microgram/kg/body weight, about 350 microgram/kg/body weight, about 500 microgram/kg/body weight, about 1 milligram/kg/body weight, about 5 milligram/kg/body weight, about 10 milligram/kg/body weight, about 50 milligram/kg/body weight, about 100 milligram/kg/body weight, about 200 milligram/kg/body weight, about 350 milligram/kg/body weight, about 500 milligram/kg/body weight, to about 1000 milligram/kg/body weight or more per administration, and any range derivable therein. In non-limiting examples of a derivable range from the numbers listed herein, a range of about 5 milligram/kg/body weight to about 100 milligram/kg/body weight, about 5 microgram/kg/body weight to about 500 milligram/kg/body weight, etc. , can be administered, based on the numbers described above.

V. Nucleic Acids and Vectors

[00118] In certain aspects of the invention, nucleic acid sequences encoding a therapeutic protein or a fusion protein containing a therapeutic protein may be disclosed. Depending on which expression system is used, nucleic acid sequences can be selected based on conventional methods. For example, the respective genes or variants thereof may be codon optimized for expression in a certain system. Various vectors may be also used to express the protein of interest. Exemplary vectors include, but are not limited, plasmid vectors, viral vectors, transposon, or liposome-based vectors.

VI. Recombinant Proteins and Inhibitory RNAs

[00119] Some embodiments concern recombinant proteins and polypeptides. In further aspects, a protein or polypeptide may be modified to increase serum stability. Thus, when the present application refers to the function or activity of “modified protein” or a “modified polypeptide,” one of ordinary skill in the art would understand that this includes, for example, a protein or polypeptide that possesses an additional advantage over the unmodified protein or polypeptide. It is specifically contemplated that embodiments concerning a “modified protein” may be implemented with respect to a “modified polypeptide,” and vice versa.

[00120] Recombinant proteins may possess deletions and/or substitutions of amino acids; thus, a protein with a deletion, a protein with a substitution, and a protein with a deletion and a substitution are modified proteins. In some embodiments, these proteins may further include insertions or added amino acids, such as with fusion proteins or proteins with linkers, for example. A“modified deleted protein” lacks one or more residues of the native protein, but may possess the specificity and/or activity of the native protein. A“modified deleted protein” may also have reduced immunogenicity or antigenicity. An example of a modified deleted protein is one that has an amino acid residue deleted from at least one antigenic region that is, a region of the protein determined to be antigenic in a particular organism, such as the type of organism that may be administered the modified protein.

[00121] Substitution or replacement variants typically contain the exchange of one amino acid for another at one or more sites within the protein and may be designed to modulate one or more properties of the polypeptide, particularly its effector functions and/or bioavailability. Substitutions may or may not be conservative, that is, one amino acid is replaced with one of similar shape and charge. Conservative substitutions are well known in the art and include, for example, the changes of: alanine to serine; arginine to lysine; asparagine to glutamine or histidine; aspartate to glutamate; cysteine to serine; glutamine to asparagine; glutamate to aspartate; glycine to proline; histidine to asparagine or glutamine; isoleucine to leucine or valine; leucine to valine or isoleucine; lysine to arginine; methionine to leucine or isoleucine; phenylalanine to tyrosine, leucine, or methionine; serine to threonine; threonine to serine; tryptophan to tyrosine; tyrosine to tryptophan or phenylalanine; and valine to isoleucine or leucine.

[00122] In addition to a deletion or substitution, a modified protein may possess an insertion of residues, which typically involves the addition of at least one residue in the polypeptide. This may include the insertion of a targeting peptide or polypeptide or simply a single residue. Terminal additions, called fusion proteins, are discussed below.

[00123] The term“biologically functional equivalent” is well understood in the art and is further defined in detail herein. Accordingly, sequences that have between about 70% and about 80%, or between about 81% and about 90%, or even between about 91% and about 99% of amino acids that are identical or functionally equivalent to the amino acids of a control polypeptide are included, provided the biological activity of the protein is maintained. A recombinant protein may be biologically functionally equivalent to its native counterpart in certain aspects.

[00124] It also will be understood that amino acid and nucleic acid sequences may include additional residues, such as additional N- or C-terminal amino acids or 5' or 3' sequences, and yet still be essentially as set forth in one of the sequences disclosed herein, so long as the sequence meets the criteria set forth above, including the maintenance of biological protein activity where protein expression is concerned. The addition of terminal sequences particularly applies to nucleic acid sequences that may, for example, include various non-coding sequences flanking either of the 5' or 3' portions of the coding region or may include various internal sequences, i.e., introns, which are known to occur within genes.

[00125] As used herein, a protein or peptide generally refers, but is not limited to, a protein of greater than about 200 amino acids, up to a full-length sequence translated from a gene; a polypeptide of greater than about 100 amino acids; and/or a peptide of from about 3 to about 100 amino acids. For convenience, the terms“protein,”“polypeptide,” and “peptide are used interchangeably herein.

[00126] As used herein, an “amino acid residue” refers to any naturally occurring amino acid, any amino acid derivative, or any amino acid mimic known in the art. In certain embodiments, the residues of the protein or peptide are sequential, without any non-amino acids interrupting the sequence of amino acid residues. In other embodiments, the sequence may comprise one or more non-amino acid moieties. In particular embodiments, the sequence of residues of the protein or peptide may be interrupted by one or more non-amino acid moieties.

[00127] Accordingly, the term“protein or peptide” encompasses amino acid sequences comprising at least one of the 20 common amino acids found in naturally occurring proteins, or at least one modified or unusual amino acid.

[00128] Certain embodiments of the present invention concern fusion proteins. These molecules may have a therapeutic protein linked at the N- or C-terminus to a heterologous domain. For example, fusions may also employ leader sequences from other species to permit the recombinant expression of a protein in a heterologous host. Another useful fusion includes the addition of a protein affinity tag, such as a serum albumin affinity tag or six histidine residues, or an immunologically active domain, such as an antibody epitope, preferably cleavable, to facilitate purification of the fusion protein. Non-limiting affinity tags include polyhistidine, chitin binding protein (CBP), maltose binding protein (MBP), and glutathione-S-transferase (GST).

[00129] Methods of generating fusion proteins are well known to those of skill in the art. Such proteins can be produced, for example, by de novo synthesis of the complete fusion protein, or by attachment of the DNA sequence encoding the heterologous domain, followed by expression of the intact fusion protein. [00130] Production of fusion proteins that recover the functional activities of the parent proteins may be facilitated by connecting genes with a bridging DNA segment encoding a peptide linker that is spliced between the polypeptides connected in tandem. The linker would be of sufficient length to allow proper folding of the resulting fusion protein.

VII. Kits and Diagnostics

[00131] In various aspects of the invention, a kit is envisioned containing the necessary components to purify exosomes from a body fluid or tissue culture medium. In other aspects, a kit is envisioned containing the necessary components to isolate exosomes comprising OX40L or ICOSL on their surface. The kit may comprise one or more sealed vials containing any of such components. In some embodiments, the kit may also comprise a suitable container means, which is a container that will not react with components of the kit, such as an eppendorf tube, an assay plate, a syringe, a bottle, or a tube. The container may be made from sterilizable materials such as plastic or glass.

[00132] The kit may further include an instruction sheet that outlines the procedural steps of the methods set forth herein, and will follow substantially the same procedures as described herein or are known to those of ordinary skill. The instmction information may be in a computer readable media containing machine -readable instructions that, when executed using a computer, cause the display of a real or virtual procedure of purifying exosomes from a sample.

VIII. Examples

[00133] The following examples are included to demonstrate preferred embodiments of the invention. It should be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered by the inventor to function well in the practice of the invention, and thus can be considered to constitute preferred modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention. Example 1 - Isolation and Purification of ICOSL ⁺ and OX40L ⁺ Exosomes

[00134] HEK293T cells were transfected with OX40L or ICOSLG expression plasmids by treatment with lipofectamine for 72h. Cells were then selected with 1 pg/ml puromycin for 10 days to obtain stably transfected cells. The stable cells were then cultured with 1 pg/ml puromycin containing selection medium.

[00135] Exosomes were collected from non-transfected HEK293T cells, as well as stable HEK293T ICSOLG and HEK293T OX40L cells. Exosomes were purified by differential centrifugation processes, as described previously (Alvarez- Erviti et al, 2011; El- Andaloussi et al, 2012). Supernatant was collected from cells that were cultured in media containing exosomes-depleted FBS for 48 hours, and was subsequently subjected to sequential centrifugation steps for 800g for 5 minutes, and 2000g for 10 minutes. This resulting supernatant was then filtered using 0.2 pm filters in culture bottles, and a pellet was recovered at 28,000g in a SW 32 Ti rotor after 2 hours of ultracentrifugation (Beckman). The supernatant was aspirated and the pellet was resuspended in PBS and subsequently ultracentrifuged for another 2 hours. The purified exosomes were then analyzed and used for experimental procedures.

[00136] In order to determine the level of ICOSL and OX40L transcripts in the stably transfected 293T cells, RNA was retro-transcribed with MultiScribe Reverse Transcriptase (Applied Biosystems) and oligo-d(T) primers following total RNA purification with TRIzol® (Invitrogen), according to the manufacturer’s directions. Real-time PCR analyses were performed on an ABI PRISM® 7300HT Sequence Detection System Instrument using SYBR® Green Master Mix (Applied Biosystems). The transcripts of interest were normalized to 18S transcript levels. Each measurement was performed in triplicate. Threshold cycle, the fractional cycle number at which the amount of amplified target reached a fixed threshold, was determined and expression was measured using the 2 ^~ACt formula. As shown in FIG. 1, wild-type 293T cells showed low basal levels of ICOSLG and OX40L transcripts while the OX40L overexpressing cells had about 10,000 fold higher levels and the ICOSLG overexpressing cells had about 2,500 fold higher levels.

[00137] To assess the protein expression of cells and exosomes, cells and exosomes were harvested in RIPA buffer and protein lysates were normalized using Bradford quantification. 40 pg of lysates were loaded onto acrylamide gels for electrophoretic separation of proteins under denaturing conditions and transferred onto PVDF membranes (ImmobilonP) by wet electrophoretic transfer. The membranes were then blocked for 1 hour at room temperature with 5% non-fat dry milk in PBS/0.05% Tween®-20 and incubated overnight at 4°C with the appropriate primary antibodies. Secondary antibodies were incubated for 1 hour at room temperature. Washes after antibody incubations were done on an orbital shaker, three times at 15 min intervals, with lx PBS 0.05% Tween®-20. Membranes were developed with chemiluminescent reagents from Pierce, according to the manufacturer’s directions and chemiluminescence captured on film. As shown in FIG. 2A, both the stably transfected ICOSLG 293T cells, and the exosomes isolated therefrom, show increased expression of ICOSLG. Expression of vinculin was measured as a control (FIG. 2B). Finally, cells and exosomes expressing either OX40L or ICOSLG were detected using flow cytometry (FIG. 3).

Example 2 - Treatment of T Cells with Exosomes

[00138] Exosomes collected from HEK293T blank cells and HEK293T ICOSLG were used to treat either naive T cells from a C57BI/6 mouse or splenic T cells from a C57BI/6 mouse bearing a 689KPC GEMM tumor. As outlined in FIG. 4, cells were isolated from the spleen of each mouse and negatively selected to enrich for T cells. The isolated cells were labeled with carboxyfluorescein succinimidyl ester (CSFE) and stimulated with CD3/CD28. In addition, the cells were stimulated with either control exosomes, ICOSLG ⁺ exosomes, or OX40L ⁺ exosomes. Following stimulation, proliferation, INF-g production, and IL-2 production were measured. FIG. 5 shows the increase in the number of IL-2 and IFN-g producing naive T cells following stimulation with ICOSLG ⁺ exosomes relative to control exosomes. FIG. 6 shows the increase in the number of IL-2 and IFN-g producing splenic T cells from a tumor-bearing mouse following stimulation with ICOSLG ⁺ exosomes relative to control exosomes.

Example 3 - Treatment of Implanted B16F10 Tumors in vivo

[00139] B16F10 cells were implanted subcutaneously into the back of each mouse. The mice were divided into seven groups. Group 1 was treated with exosomes isolated from wild-type HEK293T cells. Group 2 was treated with exosomes isolated from wild-type HEK293T cells and anti-CTLA-4. Group 3 was treated with exosomes isolated from ICOSL over-expressing HEK293T cells and anti-CTLA-4. Group 4 was treated with exosomes isolated from OX40L over-expressing HEK293T cells and anti-CTLA4. Group 5 was treated with exosomes isolated from ICOSL over-expressing HEK293T cells. Group 6 was treated with anti-CTLA-4 alone. Group 7 was treated with PBS. Mice in each group were injected intravenously (I.V.) every day for two weeks. Tumor volume was measured. As shown in FIGS. 7A-J, the smallest tumor volumes were seen in mice treated with exosomes isolated from ICOSL over-expressing HEK293T cells and anti-CTLA-4.

* * *

[00140] All of the methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the compositions and methods of this invention have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit and scope of the invention. More specifically, it will be apparent that certain agents which are both chemically and physiologically related may be substituted for the agents described herein while the same or similar results would be achieved. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the invention as defined by the appended claims.

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