Bioengineered immunomodulatory fusion protein compositions

Abstract

Provided herein are, inter alia, materials and methods for bioengineered immunomodulatory fusion proteins and uses thereof for modulating immune responses, as well as improving a response of a subject in need therefore, such as to a vaccine, or treating a disease or disorder, such as cancer or a pathogen infection.

Description

BIOENGINEERED IMMUNOMODULATORY FUSION PROTEIN COMPOSITIONSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to U.S. Provisional Patent Application No. 63 / 579,643, filed August 30, 2024, which is incorporated by reference herein in its entirety.REFERENCE TO A SEQUENCE LISTING SUBMITTED AS AN XML FILE

[0002] The present application hereby incorporates by reference the entire contents of the Sequence Listing File named “JBI6814WOPCTl_SL.xml” in XML format, having a creation date of August 19, 2024, and a file size of 64,897 bytes.1. FIELD

[0003] Provided herein, inter alia, are materials, methods and systems for bioengineered immunomodulatory fusion proteins and uses thereof, for example detecting, modulating immune responses and / or immune related conditions, as well as materials and methods for screening, diagnosing, influencing, improving a response of a subject in need thereof, such as to a pathogen or vaccine, or treating a disease or disorder, such as neoplasia, hyperplasia, cancers or a pathogen infection(s).1. BACKGROUND

[0004] Immunity is a multifaceted host response involving various molecules. Manzoor Ahmad Mir, Chapter 1 - Introduction to Costimulation and Costimulatory Molecules, Editor(s): Manzoor Ahmad Mir, Developing Costimulatory Molecules for Immunotherapy of Diseases, Academic Press, 2015, Pages 1-43, ISBN 9780128025857. One such molecule involved in an immune response is CD40 ligand (CD40L) (CD154), a Tumor Necrosis Factor (TNF) super family member that is present in various cell and tissue types, and is highly expressed on CD4+T cells and interacts with the CD40 receptor polypeptide to enhance costimulatory signaling. The CD40 receptor polypeptide is expressed on a variety of innate and adaptive cells including dendritic and B cells. Adv Drug Deliv Rev. 2019, 15 ; 141 :92- 103; Immunol Rev. 2009 May; 229(1). CD40 agonism may enhance antigen presentation and is a suitable target for monoclonal antibody applications, such as diagnostic, prognostic and therapy. Cancers (Basel). 2021 Mar 15; 13(6): 1302.2. SUMMARY

[0005] The inventors of the present invention, with the understanding that inter alia CD40 agonist monoclonal antibodies perform poorly in the absence of Fc crosslinking and have shown little clinical benefit, and furthermore, systemic administration of CD40 agonist antibodies has been linked to adverse events and to hepatic toxicity, identified and addressed unmet needs in the art for new, improved constructs of engineered CD40 agonists for modulating immune responses, as well as improving a response of a subject to a vaccine, or treating a disease or disorder, such as cancer or a pathogen infection (e.g., a viral infection), for example. In some embodiments, the vaccine composition does not comprise an oncolytic virus. Accordingly, in one aspect, provided herein is a polypeptide comprising a single chain trimeric CD40 ligand (CD40L) fusion protein, wherein the single chain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by peptide linkers (CD40L trimer). In some embodiments, the single chain trimeric CD40L fusion protein is not in, attached to, or associated with an oncolytic virus. In some embodiments, the CD40L subunits comprise a portion of the CD40L extracellular domain.

[0006] In some embodiments of the polypeptide, the CD40L subunits comprise any one of the sequences selected from SEQ ID NOs:22 or 45, or a fragment thereof. In some embodiments of the polypeptide, at least one of the peptide linkers comprises (G3S J3 (SEQ ID NO:25). In some embodiments, at least two of the peptide linkers have the same sequence. In some embodiments, the single chain trimeric CD40L fusion protein is fused with a peptide or polypeptide not derived from CD40L. In some embodiments, the single chain trimeric CD40L fusion protein is fused to a peptide tether. In some embodiments, the peptide tether is selected from the group consisting of (G4S)3 (SEQ ID NO:24) and (G4S)2 (SEQ ID NO:26). In some embodiments, the peptide tether is fused to the N-terminus of the single chain trimeric CD40L fusion protein or the C-terminus of the single chain trimeric CD40L fusion protein.

[0007] In some embodiments of the polypeptide, the single chain trimeric CD40L fusion protein is fused to a trimerization motif. In some embodiments, the trimerization motif comprises T4 fibritin trimerization motif. In some embodiments, the trimerization motif comprises SEQ ID NO: 41.

[0008] In some embodiments of the polypeptide, the polypeptide further comprises a signal peptide. In some embodiments, the signal peptide comprises the amino acid sequence of SEQ ID NO: 42.

[0009] In another embodiment, a single chain trimeric CD40L Fc fusion protein comprising (a) three CD40 ligand CD40L subunits covalently linked to one another by peptide linkers (CD40L trimer); and (b) an Fc monomer peptide, is provided. In some embodiments, the single chain trimeric CD40L Fc fusion protein is not in, attached to, or associated with an oncolytic virus.

[0010] In some embodiments, the Fc monomer peptide is covalently linked to the CD40L trimer by a peptide tether. In some embodiments, the peptide tether comprises between 0 and 20 amino acids.

[0011] In some embodiments, the CD40 ligand subunits comprise a portion of the CD40L extracellular domain.

[0012] In some embodiments, the CD40 ligand subunits comprise any one of the sequences selected from SEQ ID NOs: 22 and 45, or a fragment thereof. In some embodiments, the CD40 ligand subunits comprise SEQ ID NO:22, or a fragment thereof. In some embodiments, the CD40 ligand subunits comprise SEQ ID NO:45, or a fragment thereof.

[0013] In some embodiments, the Fc monomer peptide comprises a human Fc sequence. In some embodiments, the human Fc sequence comprises a sequence selected from immunoglobulins IgG, IgA, IgM, IgD, and IgE. In some embodiments, the human Fc sequence comprises an IgG sequence. In some embodiments, the IgG sequence is selected from IgGl, IgG2, IgG3, and IgG4. In some embodiments, the IgG sequence comprises an IgGl sequence. In some embodiments, the IgGl sequence comprises SEQ ID NOs:30 or 31, or a fragment thereof. In some embodiments, the IgG sequence comprises an IgG2 sequence. In some embodiments, the IgG2 sequence comprises SEQ ID NO:29 or a fragment thereof.

[0014] In some embodiments, the peptide linker comprises (GiSji (SEQ ID NO:25).

[0015] In some embodiments, the peptide tether comprises (G4S)3 (SEQ ID NO:24) or(G4S)2(SEQ ID NO:26).

[0016] In some embodiments, the single chain trimeric CD40L Fc fusion protein enhances activation of a CD40 polypeptide compared to wild-type CD40L. In some embodiments, the activation of the CD40 polypeptide enhances the immune-stimulatory functions of dendritic cells, B cells, monocytes and macrophages. In some embodiments, the activation of the CD40 polypeptide comprises enhanced T cell activation compared to wildtype CD40L. In some embodiments, the activation of the CD40 polypeptide comprises enhanced dendritic cell activation compared to wild-type CD40L. In some embodiments, thesingle chain trimeric CD40L Fc fusion protein enhances anti-tumor activity compared to wild-type CD40L.

[0017] In yet another aspect, provided herein is a polynucleotide encoding a single chain trimeric CD40L Fc fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide. In some embodiments, the polynucleotide is not in, attached to, or associated with an oncolytic virus.

[0018] In another aspect, provided herein is a polynucleotide encoding a single chain trimeric CD40L fusion protein comprising three CD40L subunits covalently linked to one another by peptide linkers. In some embodiments, the peptide linkers comprise a sequence set forth in SEQ ID NO: 25. In some embodiments, the single chain trimeric CD40L fusion protein further comprises a trimerization motif operably linked to the trimeric CD40L fusion protein. In some embodiments, the trimerization motif is a T4 fibritin trimerization motif. In some embodiments, the T4 fibritin trimerization motif comprises the amino acid sequence set forth in SEQ ID NO:41. In some embodiments, the peptide tether connecting the trimerization motif to the single chain trimeric CD40L Fc fusion protein comprises an amino acid sequence comprising glycine and / or serine residues. In some embodiments, the peptide tether comprises the amino acid sequence of SEQ ID NO:24. In some embodiments, the peptide tether comprises the amino acid sequence of SEQ ID NO:26. In some embodiments, the single chain trimeric CD40L fusion protein further comprises a signal peptide sequence.

[0019] In yet another aspect, provided herein is a vector comprising a polynucleotide encoding a single chain trimeric CD40L fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide. In some embodiments, the vector is not in, attached to, or associated with an oncolytic virus.

[0020] In yet another aspect, provided herein is a vector comprising a polynucleotide encoding a single chain trimeric CD40L fusion protein comprising three CD40L subunits covalently linked to one another by peptide linkers. In some embodiments, the single chain trimeric CD40L fusion protein further comprises a trimerization motif operably linked to the trimeric CD40L fusion protein by a peptide tether. In some embodiments, the trimerization motif is a T4 fibritin trimerization motif. In some embodiments, the T4 fibritin trimerization motif comprises the amino acid sequence set forth in SEQ ID NO:41. In some embodiments, the peptide tether connecting the trimerization motif to the single chain trimeric CD40L fusion protein comprises an amino acid sequence comprising glycine and / or serine residues. In some embodiments, the peptide tether comprises the amino acid sequence of SEQ ID NO:24. In some embodiments, the peptide tether comprises the amino acid sequence of SEQID NO:26. In some embodiments, the single chain trimeric CD40L fusion protein further comprises a signal peptide sequence.

[0021] In yet another aspect, provided herein is a host cell comprising a vector comprising a polynucleotide encoding a single chain trimeric CD40L fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide. In some embodiments, the vector is not in, attached to, or associated with an oncolytic virus.

[0022] In yet another aspect, provided herein is a host cell comprising a vector comprising a polynucleotide encoding a single chain trimeric CD40L fusion protein comprising three CD40L subunits covalently linked to one another by peptide linkers. In some embodiments, the single chain trimeric CD40L fusion protein further comprises a trimerization motif operably linked to the trimeric CD40L fusion protein by a peptide tether. In some embodiments, the single chain trimeric CD40L trimerization fusion protein is not in, attached to, or associated with an oncolytic virus. In some embodiments, the trimerization motif is a T4 fibritin trimerization motif. In some embodiments, the T4 fibritin trimerization motif comprises the amino acid sequence set forth in SEQ ID NO:41. In some embodiments, the peptide tether connecting the trimerization motif to the single chain trimeric CD40L Fc fusion protein comprises an amino acid sequence comprising glycine and / or serine residues. In some embodiments, the peptide tether comprises the amino acid sequence of SEQ ID NO:24. In some embodiments, the peptide tether comprises the amino acid sequence of SEQ ID NO:26. In some embodiments, the single chain trimeric CD40L fusion protein further comprises a signal peptide sequence.

[0023] In yet another aspect, provided herein is a host cell comprising a polynucleotide encoding a single chain trimeric CD40L fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide. In some embodiments, the polynucleotide is not in, attached to, or associated with an oncolytic virus.

[0024] In yet another aspect, provided herein is a host cell comprising a polynucleotide encoding a single chain trimeric CD40L fusion protein comprising three CD40L subunits covalently linked to one another by peptide linkers. In some embodiments, the single chain trimeric CD40L fusion protein further comprises a trimerization motif operably linked to the trimeric CD40L fusion protein by a peptide tether. In some embodiments, the trimerization motif is a T4 fibritin trimerization motif. In some embodiments, the T4 fibritin trimerization motif comprises the amino acid sequence set forth in SEQ ID NO:41. In some embodiments, the peptide tether connecting the trimerization motif to the single chain trimeric CD40L Fcfusion protein comprises an amino acid sequence comprising glycine and / or serine residues. In some embodiments, the peptide tether comprises the amino acid sequence of SEQ ID NO:24. In some embodiments, the peptide tether comprises the amino acid sequence of SEQ ID NO:26. In some embodiments, the single chain trimeric CD40L fusion protein further comprises a signal peptide.

[0025] In yet another aspect, provided herein is a pharmaceutical composition comprising a pharmaceutically acceptable carrier and a single chain trimeric CD40L fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide. In some embodiments, pharmaceutical composition does not comprise an oncolytic virus.

[0026] In yet another aspect, provided herein is a pharmaceutical composition comprising a pharmaceutically acceptable carrier and a single chain trimeric CD40L fusion protein comprising three CD40L subunits covalently linked to one another by peptide linkers. In some embodiments, the single chain trimeric CD40L fusion protein further comprises a trimerization motif operably linked to the trimeric CD40L fusion protein by a peptide tether. In some embodiments, the trimerization motif is a T4 fibritin trimerization motif. In some embodiments, the T4 fibritin trimerization motif comprises the amino acid sequence set forth in SEQ ID NO:41. In some embodiments, the peptide tether connecting the trimerization motif to the single chain trimeric CD40L Fc fusion protein comprises an amino acid sequence comprising glycine and / or serine residues. In some embodiments, the peptide tether comprises the amino acid sequence of SEQ ID NO:24. In some embodiments, the peptide tether comprises the amino acid sequence of SEQ ID NO:26. In some embodiments, the single chain trimeric CD40L fusion protein further comprises a signal peptide.

[0027] In yet another aspect, provided herein is a kit comprising a single chain trimeric CD40L fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide. In some embodiments, the kit does not comprise an oncolytic virus.

[0028] In yet another aspect, provided herein is a kit comprising a single chain trimeric CD40L fusion protein comprising three CD40L subunits covalently linked to one another by peptide linkers. In some embodiments, the single chain trimeric CD40L fusion protein further comprises a trimerization motif operably linked to the trimeric CD40L fusion protein by a peptide tether. In some embodiments, the trimerization motif is a T4 fibritin trimerization motif. In some embodiments, the T4 fibritin trimerization motif comprises the amino acid sequence set forth in SEQ ID NO:41. In some embodiments, the peptide tether connecting thetrimerization motif to the single chain trimeric CD40L Fc fusion protein comprises an amino acid sequence comprising glycine and / or serine residues. In some embodiments, the peptide tether comprises the amino acid sequence of SEQ ID NO:24. In some embodiments, the peptide tether comprises the amino acid sequence of SEQ ID NO:26. In some embodiments, the single chain trimeric CD40L fusion protein further comprises a signal peptide sequence operably linked to each of the three single-chain trimeric CD40 ligand ectodomains.

[0029] In one aspect, provided herein is a system comprising a means for providing a single chain trimeric CD40L fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide. In some embodiments, the single chain trimeric CD40L fusion protein is not in, attached to, or associated with an oncolytic virus. In another aspect, provided herein is a system comprising a means for providing a dimer comprising two single chain trimeric CD40L Fc fusion proteins, each comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide.

[0030] In one aspect, provided herein is a system comprising a means for providing a single chain trimeric CD40L fusion protein comprising three CD40L subunits covalently linked to one another by peptide linkers. In some embodiments, the single chain trimeric CD40L fusion protein further comprises a trimerization motif operably linked to the trimeric CD40L fusion protein by a peptide tether. In some embodiments, the trimerization motif is a T4 fibritin trimerization motif. In some embodiments, the T4 fibritin trimerization motif comprises the amino acid sequence set forth in SEQ ID NO:41. In some embodiments, the peptide tether connecting the trimerization motif to the single chain trimeric CD40L Fc fusion protein comprises an amino acid sequence comprising glycine and / or serine residues. In some embodiments, the peptide tether comprises the amino acid sequence of SEQ ID NO:24. In some embodiments, the peptide tether comprises the amino acid sequence of SEQ ID NO:26. In some embodiments, the single chain trimeric CD40L fusion protein further comprises a signal peptide sequence operably linked to each of the three single-chain trimeric CD40 ligand ectodomains.

[0031] In one aspect, provided herein is a method of activating a CD40 polypeptide comprising contacting the CD40 polypeptide with the single chain trimeric CD40L Fc fusion protein disclosed herein, wherein said single chain trimeric CD40L Fc fusion protein activates the CD40 polypeptide upon binding. In some embodiments, the single chain trimeric CD40L Fc fusion protein is not in, attached to, or associated with an oncolytic virus. In another aspect, provided herein is a method of activating a CD40 polypeptide comprisingcontacting the CD40 polypeptide with a dimer comprising two single chain trimeric CD40L Fc fusion proteins disclosed herein, wherein said single chain trimeric CD40L Fc fusion protein dimer activates the CD40 polypeptide upon binding. In another aspect, provided herein is a method of activating a CD40 polypeptide comprising contacting the CD40 polypeptide with a trimer comprising three single chain trimeric CD40L fusion proteins disclosed herein, wherein said single chain trimeric CD40L fusion protein trimer activates the CD40 polypeptide upon binding. In yet another aspect, provided herein is a method of activating a T-cell comprising contacting the T-cell with an antigen presenting cell in the presence of the single chain trimeric CD40L Fc fusion protein disclosed herein, wherein the antigen presenting cell expresses a CD40 polypeptide, and wherein said single chain trimeric CD40L Fc fusion protein activates the T-cell upon binding the CD40 polypeptide. In yet another aspect, provided herein is a method of activating a T cell comprising contacting the T-cell with an antigen presenting cell in the presence of a dimer comprising two single chain trimeric CD40L Fc fusion proteins disclosed herein, wherein the antigen presenting cell expresses a CD40 polypeptide, and wherein said single chain trimeric CD40L Fc fusion protein dimer activates the T-cell upon binding the CD40 polypeptide. In yet another aspect, provided herein is a method of activating a T cell comprising contacting the T-cell with an antigen presenting cell in the presence of a trimer comprising three single chain trimeric CD40L fusion proteins disclosed herein, wherein the antigen presenting cell expresses a CD40 polypeptide, and wherein said single chain trimeric CD40L fusion protein dimer activates the T-cell upon binding the CD40 polypeptide. In some embodiments, said antigen presenting cell presents an antigen to the T cell. In yet another aspect, provided herein is a method of activating a dendritic cell comprising contacting the CD40 polypeptide with the single chain trimeric CD40L Fc fusion protein disclosed herein, wherein said single chain trimeric CD40L Fc fusion protein activates the dendritic cell upon binding the CD40 polypeptide. In yet another aspect, provided herein is a method of activating a dendritic cell comprising contacting the CD40 polypeptide with a dimer comprising two single chain trimeric CD40L Fc fusion proteins disclosed herein, wherein said single chain trimeric CD40L Fc fusion protein dimer activates the dendritic cell upon binding the CD40 polypeptide. In yet another aspect, provided herein is a method of activating a dendritic cell comprising contacting the CD40 polypeptide with a trimer comprising three single chain trimeric CD40L fusion proteins disclosed herein, wherein said single chain trimeric CD40L fusion protein dimer activates the dendritic cell upon binding the CD40 polypeptide.

[0032] In some embodiments, the method is performed in vitro. In some embodiments, the method is performed in vivo. In some embodiments, the contacting further comprises administering a pharmaceutical composition comprising a pharmaceutically acceptable carrier and the single chain trimeric CD40L Fc fusion proteins. In some embodiments, the contacting enhances an innate anti-neoplastic immune response.

[0033] In one aspect, provided herein is a method of treating cancer in a subject comprising administering to the subject a therapeutically effective amount of the single chain trimeric CD40L Fc fusion protein disclosed herein. In some embodiments, the single chain trimeric CD40L Fc fusion protein is not in, attached to, or associated with an oncolytic virus. In another aspect, provided herein is a method of treating cancer in a subject comprising administering to the subject a therapeutically effective amount of a dimer comprising two single chain trimeric CD40L Fc fusion proteins disclosed herein. In another aspect, provided herein is a method of treating cancer in a subject comprising administering to the subject a therapeutically effective amount of a trimer comprising three single chain trimeric CD40L fusion proteins disclosed herein.

[0034] In some embodiments, the method further comprises administering a pharmaceutical composition comprising a pharmaceutically acceptable carrier and the single chain trimeric CD40L Fc fusion proteins. In some embodiments, the treatment enhances an innate anti-neoplastic immune response. In some embodiments, the method further comprises co-administration of a second therapy. In some embodiments, said cancer is selected from the group consisting of melanoma, mesothelioma, advanced solid tumor, and lymphoma.

[0035] In one aspect, provided herein is a method for producing a single chain trimeric CD40L Fc fusion protein or fragment thereof comprising (a) introducing into a host cell a polynucleotide encoding the single chain trimeric CD40L Fc fusion protein disclosed herein; (b) culturing the host cell under conditions to produce the single chain trimeric CD40L Fc fusion protein or fragment thereof, and (c) recovering the single chain trimeric CD40L Fc fusion protein or fragment thereof from the cell or culture. In another aspect, provided herein is a method of producing a dimer comprising two single chain trimeric CD40L Fc fusion proteins, each comprising (a) introducing into a host cell a polynucleotide encoding of the single chain trimeric CD40L Fc fusion protein disclosed herein; (b) culturing the host cell under conditions to produce the single chain trimeric CD40L Fc fusion protein or fragment thereof; (c) recovering the single chain trimeric CD40L Fc fusion protein or fragment thereof from the cell or culture, and (d) combining single chain trimeric CD40L Fc fusion proteins or fragments thereof under conditions that favor dimerization. In another aspect, provided hereinis a method of producing a trimer comprising three single chain trimeric CD40L fusion proteins, each comprising (a) introducing into a host cell a polynucleotide encoding of the single chain trimeric CD40L fusion protein disclosed herein; (b) culturing the host cell under conditions to produce the single chain trimeric CD40L fusion protein or fragment thereof; (c) recovering the single chain trimeric CD40L fusion protein or fragment thereof from the cell or culture, and (d) combining single chain trimeric CD40L fusion proteins or fragments thereof under conditions that favor trimerization. In yet another aspect, provided herein is a method of producing a pharmaceutical composition of a single chain trimeric CD40L Fc fusion protein or fragment thereof comprising combining the single chain trimeric CD40L Fc fusion protein disclosed herein or fragment thereof with a pharmaceutically acceptable carrier to obtain the pharmaceutical composition.

[0036] In one aspect, provided herein is a polypeptide comprising a single chain trimeric CD40L fusion protein, wherein the single chain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by peptide linkers. In some embodiments, the CD40L subunits comprise a portion of the CD40L extracellular domain. In some embodiments, the CD40L subunits comprise any one of the sequences selected from SEQ ID NOs:20 to 22, or a fragment thereof. In some embodiments, the CD40L subunits comprises SEQ ID NO:22 or a fragment thereof. In some embodiments, the CD40L subunits comprises SEQ ID NO:45 or a fragment thereof.

[0037] In some embodiments, at least one of the peptide linkers comprise (G iSj i (SEQ ID NO:25). In some embodiments, at least two of the peptide linkers comprise (G iSj i (SEQ ID NO:25). In some embodiments, at least two of the peptide linkers have the same sequence.

[0038] In some embodiments, the single chain trimeric CD40L fusion protein comprises any one sequence selected from SEQ ID NOs:43, 44, 46 or 47 or a fragment thereof.

[0039] In another aspect, the single chain trimeric CD40L fusion protein is fused to a peptide tether. In some embodiments, the peptide tether is selected from the group consisting of (G4S)3 (SEQ ID NO:24) and (G4S)2 (SEQ ID NO:26). In some embodiments, the peptide tether is fused to the N-terminus of the single chain trimeric CD40L fusion protein. In some embodiments, the peptide tether is fused to the C-terminus of the single chain trimeric CD40L fusion protein.

[0040] In another aspect, the single chain trimeric CD40L fusion protein is fused to an Fc monomer peptide. In some embodiments, the single chain trimeric CD40L Fc fusion protein is not in, attached to, or associated with an oncolytic virus. In some embodiments, the Fc monomer peptide comprises a human Fc sequence. In some embodiments, the human Fcsequence comprises a sequence selected from immunoglobulins IgG, IgA, IgM, IgD, and IgE. In some embodiments, the human Fc sequence comprises an IgG sequence. In some embodiments, the IgG sequence is selected from IgGl, IgG2, IgG3, and IgG4. In some embodiments, the IgG sequence comprises an IgGl sequence. In some embodiments, the IgGl sequence comprises SEQ ID NOs:30 or 31, or a fragment thereof. In some embodiments, the IgG sequence comprises an IgG2 sequence. In some embodiments, the IgG2 sequence comprises SEQ ID NO:29 or a fragment thereof.

[0041] In some embodiments, the single chain trimeric CD40L fusion protein is fused to trimerization motif via a peptide tether. In some embodiments, the single chain trimeric CD40L trimerization fusion protein is not in, attached to, or associated with an oncolytic virus. In some embodiments, the trimerization motif is a T4 fibritin trimerization motif. In some embodiments, the T4 fibritin trimerization motif comprises the amino acid sequence set forth in SEQ ID NO:41. In some embodiments, the peptide tether connecting the trimerization motif to the single chain trimeric CD40L fusion protein comprises an amino acid sequence comprising glycine and / or serine residues. In some embodiments, the peptide tether comprises the amino acid sequence of SEQ ID NO:24. In some embodiments, the peptide tether comprises the amino acid sequence of SEQ ID NO:26.

[0042] In some embodiments, the CD40L trimer is connected to the N-terminus of the Fc monomer peptide. In some embodiments, the single chain trimeric CD40L Fc fusion protein comprises any one sequence selected from SEQ ID NOs:l-12, or a fragment thereof. In some embodiments, the CD40L trimer is connected to the C-terminus of the Fc monomer peptide. In some embodiments, the single chain trimeric CD40L Fc fusion protein comprises any one sequence selected from SEQ ID NOs: 13-19, or a fragment thereof.

[0043] In another aspect, the single chain trimeric CD40L fusion protein enhances activation of a CD40 polypeptide compared to wild-type CD40L. In some embodiments, the activation of the CD40 polypeptide enhances the immune-stimulatory functions of T cells and / or B cells. In some embodiments, the activation of the CD40 polypeptide comprises enhanced activation of B cells, CD4+ T cells, CD8+ T cells, dendritic cells, macrophages, natural killer cells, monocytes, granulocytes, eosinophils, and / or neutrophils compared to wild-type CD40L.

[0044] In some embodiments, the activation of the CD40 polypeptide comprises increasing expression of the CD40 polypeptide. In some embodiments, the single chain trimeric CD40L fusion protein enhances anti-tumor activity compared to wild-type CD40L. In some embodiments, the single chain trimeric CD40L fusion protein enhances pro-inflammatory activity compared to wild-type CD40L. In some embodiments, the single chain trimeric CD40L fusion protein enhances clearance of an infectious pathogen compared to wild-type CD40L.

[0045] In another aspect, the single chain trimeric CD40L fusion protein increases antibody production by a population of B cells by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, about 100%, about 125%, about 150%, about 175%, about 200%, about 250%, about 300%, about 400%, about 500%, about 600%, about 700%, about 800%, about 900%, or about 1000%.

[0046] In another aspect, the single chain trimeric CD40L fusion protein increases secretion of a pro-inflammatory cytokine by a population of T cells. In some embodiments, the pro-inflammatory cytokine is IL-1, IL-2, IL-6, IL 12, IL-17, IL-22, IL-23, GM-CSF, TNF-a, IFN-y, or any combination thereof. In some embodiments, the cytokine production is increased by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, about 100%, about 125%, about 150%, about 175%, about 200%, about 250%, about 300%, about 400%, about 500%, about 600%, about 700%, about 800%, about 900%, or about 1000%.

[0047] In another aspect, the single chain trimeric CD40L fusion protein increases a minimal percentage of phagocytotic macrophages in a population of macrophages to about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 99%.

[0048] In some embodiments, the single chain trimeric CD40L fusion protein increases a minimal percentage of antigen-presenting dendritic cells in a population of dendritic cells to about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 99%.

[0049] In another aspect, the polypeptide is conjugated to an agent. In some embodiments, the polypeptide conjugated to an agent is not in, attached to, or associated with an oncolytic virus. In some embodiments, the agent is selected from the group consisting of a radioisotope, a metal chelator, an enzyme, a fluorescent compound, a bioluminescent compound, and a chemiluminescent compound.

[0050] In another aspect, provided herein is a polynucleotide encoding a single chain trimeric CD40L fusion protein, wherein the single chain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by peptide linkers.

[0051] In another aspect, provided herein is a vector comprising a polynucleotide encoding a single chain trimeric CD40L fusion protein, wherein the single chain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by peptide linkers. In some embodiments, the vector does not comprise an oncolytic virus.

[0052] In another aspect, provided herein is a host cell comprising a vector comprising a polynucleotide encoding a single chain trimeric CD40L fusion protein, wherein the single chain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by peptide linkers.

[0053] In another aspect, provided herein is a host cell comprising a polynucleotide encoding a single chain trimeric CD40L fusion protein, wherein the single chain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by peptide linkers.

[0054] In another aspect, provided herein is a pharmaceutical composition comprising a pharmaceutically acceptable carrier and a polypeptide comprising a single chain trimeric CD40L fusion protein, wherein the single chain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by peptide linkers.

[0055] In another aspect, provided herein is a kit comprising a polypeptide comprising a single chain trimeric CD40L fusion protein, wherein the single chain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by peptide linkers. In some embodiments, the kit does not comprise an oncolytic virus.

[0056] In another aspect, provided herein is a system comprising a means for providing a polypeptide comprising a single chain trimeric CD40L fusion protein, wherein the single chain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by peptide linkers.

[0057] In another aspect, provided herein is a method for activating a target cell expressing a CD40 polypeptide comprising contacting the target cell with an effective amount of a polypeptide comprising a single chain trimeric CD40L fusion protein, wherein the single chain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by peptide linkers or a polynucleotide encoding said polypeptide, wherein said single chain trimeric CD40L fusion protein activates the target cell uponbinding the CD40 polypeptide. In some embodiments, the single chain trimeric CD40L fusion protein is not in, attached to, or associated with an oncolytic virus.

[0058] In some embodiments, activation of the target cell is measured as increased proliferation or maturation of the target cell. In some embodiments, proliferation or maturation of the target cell is increased by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, about 100%, about 125%, about 150%, about 175%, about 200%, about 250%, about 300%, about 400%, about 500%, about 600%, about 700%, about 800%, about 900%, or about 1000%.

[0059] In some embodiments, activation of the target cell is measured as prolonged survival time of the target cell. In some embodiments, survival time of the target cell is increased by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, about 100%, about 125%, about 150%, about 175%, about 200%, about 250%, about 300%, about 400%, about 500%, about 600%, about 700%, about 800%, about 900%, or about 1000%.

[0060] In some embodiments, the target cell is antigen presenting cells. In some embodiments, the target cell is natural killer cells, B cells, dendritic cells, macrophages, monocytes, granulocytes, eosinophils, neutrophils, or a combination thereof.

[0061] In another aspect, provided herein is a method for promoting antibody production by a population of B cells, comprising contacting the B cells with an effective amount of a polypeptide comprising a single chain trimeric CD40L fusion protein, wherein the single chain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by peptide linkers or a polynucleotide encoding said polypeptide. In some embodiments, the single chain trimeric CD40L fusion protein or polynucleotide encoding said polypeptide is not in, attached to, or associated with an oncolytic virus.

[0062] In some embodiments, antibody production by the population of B cells is increased by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, about 100%, about 125%, about 150%, about 175%, about 200%, about 250%, about 300%, about 400%, about 500%, about 600%, about 700%, about 800%, about 900%, or about 1000%.

[0063] In another aspect, the B cells are contacted with a polypeptide comprising a single chain trimeric CD40L fusion protein, wherein the single chain trimeric CD40L fusion proteincomprises three CD40L subunits covalently linked to one another by peptide linkers or a polynucleotide encoding said polypeptide in the presence of an antigen or a polynucleotide encoding the antigen, and wherein the antibody produced by the B cells specifically binds to the antigen. In some embodiments, the method further promotes formation of memory B cells capable of producing the antibody in response to the antigen.

[0064] In some embodiments the polypeptide or the polynucleotide is in a vaccine composition or adjuvant composition. In some embodiments, the antigen or polynucleotide encoding the antigen is in a vaccine composition. In some embodiments, the antigen is originated or derived from an infectious pathogen. In some embodiments, the infectious pathogen is a virus, a bacteria, a fungus, a parasite, or a combination thereof. In some embodiments, the vaccine composition does not comprise an oncolytic virus. In some embodiments, the antigen is originated or derived from a diseased cell. In some embodiments, the diseased cell is a cancer cell. In some embodiments, the diseased cell is a cell infected by an infectious pathogen. In some embodiments, the infectious pathogen is a virus, a bacteria, a fungus, a parasite, or a combination thereof.

[0065] In some embodiments, the antigen is presented by an antigen presenting cell. In some embodiments, the antigen presenting cell is a dendritic cell. In some embodiments, the antigen is associated with an MHC class I or MHC class II complex.

[0066] In another aspect, provided herein is a method of increasing secretion of pro- inflammatory cytokines by a population of T cells, comprising contacting the population of T cells with a population of antigen presenting cells in the presence an effective amount of a polypeptide comprising a single chain trimeric CD40L fusion protein, wherein the single chain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by peptide linkers or a polynucleotide encoding said polypeptide. In some embodiments, the single chain trimeric CD40L fusion protein is not in, attached to, or associated with an oncolytic virus. In some embodiments, the cytokine is IL-1, IL-2, IL-6, IL- 12, IL-17, IL-22, IL-23, GM-CSF, TNF-a, IFN-y, or any combination thereof. In some embodiments, the cytokine production is increased by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, about 100%, about 125%, about 150%, about 175%, about 200%, about 250%, about 300%, about 400%, about 500%, about 600%, about 700%, about 800%, about 900%, or about 1000%.

[0067] In another aspect, provided herein is a method of increasing phagocytosis of diseased cells by a population of macrophages, comprising contacting the diseased cells, the macrophages, or both the diseased cells and the macrophage with an effective amount of a polypeptide comprising a single chain trimeric CD40L fusion protein, wherein the single chain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by peptide linkers or a polynucleotide encoding said polypeptide. In some embodiments, the single chain trimeric CD40L fusion protein or polynucleotide encoding said polypeptide is not in, attached to, or associated with an oncolytic virus.

[0068] In some embodiments, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 99%. In some embodiments, the phagocytosis by macrophages is measured by co-culturing macrophages labeled with a first fluorescent dye and diseased cells labeled with a second fluorescent dye, wherein the first fluorescent dye and the second fluorescent dye are different. In some embodiments, the percentage of phagocytotic macrophages is measured by determining the percentage of macrophages comprising the diseased cells. In some embodiments, the diseased cells are cancer cells or cell infected by an infectious pathogen. In some embodiments, the infectious pathogen is a virus, a bacteria, a fungus, a parasite, or a combination thereof.

[0069] In another aspect, provided herein is a method of increasing antigen presentation by a population of dendritic cells, comprising contacting the dendritic cells with an effective amount of a polypeptide comprising a single chain trimeric CD40L fusion protein, wherein the single chain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by peptide linkers or a polynucleotide encoding said polypeptide in the presence of the antigen. In some embodiments, the single chain trimeric CD40L fusion protein or polynucleotide encoding said polypeptide is not in, attached to, or associated with an oncolytic virus.

[0070] In some embodiments, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 99%. In some embodiments, the antigen presentation by the dendritic cells is measured by co-culturing dendritic cells labeled with a first fluorescent dye and the antigen labeled with a second fluorescent dye, wherein the first fluorescent dye and the second fluorescent dye are different. In someembodiments, percentage of dendritic cells presenting the antigen is measured by determining the percentage of dendritic cells co-localizing with the antigen in the population of dendritic cells.

[0071] In some embodiments, the antigen is originated or derived from an infectious pathogen. In some embodiments, the infectious pathogen is a virus, a bacteria, a fungus, a parasite, or a combination thereof. In some embodiments, the antigen is originated or derived from a diseased cell. In some embodiments, the diseased cell is a cancer cell. In some embodiments, the diseased cell is a cell infected by an infectious pathogen. In some embodiments, the infectious pathogen is a virus, a bacteria, a fungus, a parasite, or a combination thereof.

[0072] In some embodiments, the polypeptide or the polynucleotide is in a vaccine composition or an adjuvant composition. In some embodiments, the antigen or a polynucleotide encoding the antigen is in a vaccine composition. In some embodiments, the vaccine composition does not comprise an oncolytic virus.

[0073] In another aspect, provided herein is a method of increasing expression of a CD40 polypeptide by a target cell, comprising contacting the target cell with an effective amount of a polypeptide comprising a single chain trimeric CD40L fusion protein, wherein the single chain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by peptide linkers or a polynucleotide encoding said polypeptide. In some embodiments, the single chain trimeric CD40L fusion protein or polynucleotide encoding said polypeptide is not in, attached to, or associated with an oncolytic virus.

[0074] In some embodiments, the target cell is a diseased cell. In some embodiments, the diseased cell is a cancer cell. In some embodiments, the diseased cell is a cell infected by an infectious pathogen. In some embodiments, the infectious pathogen is a virus, a bacteria, a fungus, a parasite, or a combination thereof.

[0075] In some embodiments, the target cell is an immune cell. In some embodiments, the target cell is an antigen presenting cell. In some embodiments, the target cell is natural killer cells, B cells, dendritic cells, macrophages, monocytes, granulocytes, eosinophils, neutrophils, or a combination thereof.

[0076] In some embodiments, the population of the diseased cells is reduced by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 99%.

[0077] In another aspect, provided herein is a method of forming a pro-inflammatory milieu in a tissue surrounding a population of diseased cells, comprising contacting the tissue with an effective amount of a polypeptide comprising a single chain trimeric CD40L fusion protein, wherein the single chain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by peptide linkers or a polynucleotide encoding said polypeptide. In some embodiments, the single chain trimeric CD40L fusion protein or polynucleotide encoding said polypeptide is not in, attached to, or associated with an oncolytic virus.

[0078] In some embodiments, infiltration of activated B cells, CD4+ T cells, CD8+ T cells, dendritic cells, macrophages, natural killer cells, monocytes, granulocytes, eosinophils, and / or neutrophils in the tissue is increased.

[0079] In some embodiments, concentration of a pro-inflammatory cytokine is increased in the tissue. In some embodiments, the pro-inflammatory cytokine is IL-1, IL-2, IL-6, IL 12, IL-17, IL-22, IL-23, GM-CSF, TNF-a, IFN-y, or any combination thereof.

[0080] In some embodiments, presentation of antigens originated or derived from the diseased cells by antigen presentation cells is increased in the tissue.

[0081] In some embodiments, phagocytosis of the diseased cells is increased in the tissue.

[0082] In some embodiments, apoptosis of the diseased cells induced by cell-mediated cytotoxicity is increased in the tissue. In some embodiments, apoptosis of the diseased cells induced by antibody-dependent cellular cytotoxicity is increased in the tissue.

[0083] In some embodiments, the population of the diseased cells is reduced in the tissue. In some embodiments, the population of the diseased cells is reduced by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 99% in the tissue.

[0084] In some embodiments, the method is performed in vitro or in vivo.

[0085] In another aspect, provided herein is a method of eliminating a diseased cell in a subject, comprising administering an effective amount of a polypeptide comprising a single chain trimeric CD40L fusion protein, wherein the single chain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by peptide linkers or a polynucleotide encoding said polypeptide. In some embodiments, the single chain trimeric CD40L fusion protein or polynucleotide encoding said polypeptide is not in, attached to, or associated with an oncolytic virus.

[0086] In some embodiments, the diseased cell does not express a CD40 polypeptide. In some embodiments, the diseased cell expresses a CD40 polypeptide. In some embodiments, the diseased cell is a cancer cell. In some embodiments, the diseased cell is a cell infected by an infectious pathogen. In some embodiments, the infectious pathogen is a virus, a bacteria, a fungus, a parasite, or a combination thereof.

[0087] In another aspect, provided herein is a method of treating cancer in a subject in need thereof, comprising administering an effective amount of a polypeptide comprising a single chain trimeric CD40L fusion protein, wherein the single chain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by peptide linkers or a polynucleotide encoding said polypeptide. In some embodiments, the single chain trimeric CD40L fusion protein or polynucleotide encoding said polypeptide is not in, attached to, or associated with an oncolytic virus. In some embodiments, the treatment enhances an innate, humoral or cell-mediated anti-neoplastic immune response. In some embodiments, the method further comprises co-administration of a second therapy. In some embodiments, the cancer is selected from the group consisting of melanoma, mesothelioma, advanced solid tumor, and lymphoma.

[0088] In another aspect, provided herein is a method of treating an infection in a subject in need thereof, comprising administering an effective amount of a polypeptide comprising a single chain trimeric CD40L fusion protein, wherein the single chain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by peptide linkers or a polynucleotide encoding said polypeptide. In some embodiments, the single chain trimeric CD40L fusion protein or polynucleotide encoding said polypeptide is not in, attached to, or associated with an oncolytic virus. In some embodiments, the treatment enhances an innate, humoral, or cell-mediated anti-infective immune response.

[0089] In some embodiments, the polypeptide or the polynucleotide is co-administered with a vaccine composition for preventing the infection in the subject. In some embodiments, the polypeptide or the polynucleotide is co-administered with the vaccine composition simultaneously or sequentially. In some embodiments, the vaccine composition does not comprise an oncolytic virus.3. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] The foregoing summary, as well as the following detailed description of specific embodiments of the present application, will be better understood when read in conjunctionwith the appended drawings. It should be understood, however, that the application is not limited to the precise embodiments shown in the drawings.

[0091] FIGS. 1A-1B show schematic illustrations of examples of trimeric CD40L Fc fusion proteins. FIG.1A shows an illustration of CD40L trimer design optimization where molecules were designed to address tether length, linker length, and orientation of fusion. FIG. IB shows an illustration of a “Mono Fc” molecule which is a single chain fusion protein containing a CD40L trimer (circled) fused to a Fc monomer peptide, where the Fc contains mutations in its CH3 domain that abrogate dimer formation of this molecule. For Figure 1A, A = Linker length; B = Tether length.

[0092] FIGS. 2A-2B show monodispersity of the CD40L Trimer on Fc after protein A purification. FIG. 2A shows SDS-PAGE gel (left panel) and a SEC chromatogram (right panel) of TPP000161222, while FIG. 2B shows SDS-PAGE gel and a SEC chromatogram of TPP000182983.

[0093] FIG. 3 shows monodispersity of TPP000182983 after size exclusion chromatography measured by analytical ultra-centrifugation (AUC). All samples were analyzed in duplicate (n=2). The protein runs primarily at ~7 s with the main species population being 98%. There are also <1% lower molecular weight species (LMWS), <2% dimer, and <1% high molecular weight species (HMWS) present.

[0094] FIGS. 4A-4C show binding of CD40 agonists to CD40. FIG. 4A shows binding of CD40L trimer to CD40R measured using Meso Scale Discovery (MSD) bioluminescence assay. FIG. 4B shows binding of TPP000182983 to CD40R measured using surface plasmon resonance (SPR). FIG. 4C shows binding of TPP000161222 to CD40R measured using surface plasmon resonance (SPR).

[0095] FIGS. 5A-5C show evaluation of functional activity of the CD40L trimer tested using HEK-Blue reporter assay in FIG. 5A, evaluation of functional activity of CD40L trimer Fc with monocyte derived dendritic cell activation assay using CD86 activation marker in FIG. 5B. and mature dendritic cell activation assay without cross linking antibody treatment in FIG. 5C.

[0096] FIGS. 6A-6D show evaluation of functional activity of CD40L Trimer Fc with CD40 activation marker (FIG. 6A); CD 83 activation marker (FIG. 6B); HLA-DR activation marker (FIG. 6C); and PDL1 activation marker (FIG. 6D), .

[0097] FIGS. 7A-7B show T cell responses generated from moDCs in the presence of CD40 agonists and CEF peptides for CD8+ T cells (FIG. 7A) and CD4+ T cells (FIG. 7B).

[0098] FIGS 8A-8B show mouse surrogate CD40L trimerized peptides. FIG. 8A is a diagram of the mouse surrogate CD40 agonist payload, which is a trimerized, C-terminal fusion protein consisting of trimeric bundles of mouse CD40L ectodomains (SEQ ID NO:48). A: T4 fibritin trimerization motif ; B: (G4S)2 glycine serine tether; C: (GiSji glycine serine linkers: D: Mouse CD40L ectodomain. The molecule features the 27-amino-acid trimerization motif from the fibritin protein of T4 phage fused with a glycine / serine tether to the N-terminus CD40L ectodomain bundles. The CD40L ectodomain trimer bundles consist of individual CD40L protomers fused together by glycine / serine linkers from the C-terminus of one protomer to the N-terminus of the subsequent protomer to form single polypeptide trimeric bundles. A 6-mer polyhistidine (6x-His Tag (SEQ ID NO: 50)) sequence was added to the C-terminus of the final CD40L protomer to aid in purification of recombinant protein by Ni-NTA resin. FIG. 8B is directed to the design of the fusion protein (SEQ ID NO: 48).

[0099] FIGS. 9A-9B show human CD40L trimerized peptides. FIG. 9 A shows the design of a selected CD40 agonist payload (SEQ ID NO: 44). The CD40 agonist is a trimerized, C- terminal fusion protein containing trimeric bundles of human CD40L ectodomains that bind to the CD40 receptor protein. The CD40 agonist has the 27 amino acid trimerization motif from the fibritin protein of T4 phage fused with a glycine / serine tether to the N-terminal CD40L ectodomain trimer bundles. The CD40L ectodomain trimer bundles consist of individual CD40L peptide fused together by glycine / serine linkers from the C-terminus of one peptide to the N-terminus of the subsequent peptide to form single polypeptide trimeric bundles. As shown in Figure 9 A: A: T4 fibritin trimerization motif ; B: (G4S)nglycine serine tether (thick black lines); C: (GiSji glycine serine linkers (shown as thin loops): D: human CD40L ectodomains. A his tag may be added at the C-terminus but is not shown in Figure 9A. FIG. 9B is directed to the design of the fusion protein.

[0100] FIG. 10 shows that the mouse surrogate CD40 agonist payload (shown in Fig. 8) had comparable bioactivity to the human CD40 agonist payload (shown in Fig 9). The bioactivities of purified hCD40ag (human) and mCD40ag (mouse) were assessed using a HEK-Blue reporter assay. CD40 agonist activity results in the production of a colorimetric readout, assessed by optical density at 655 nm (OD655). Recombinant WT mouse CD40L (rmCD40L) and recombinant WT human CD40L (rhCD40L) were included as controls.

[0101] FIG. 11 depicts flow cytometric immunophenotypic analysis of B220 expression and CD138 by mouse splenic cells stimulated with engineered CD40L (mouse). At day 5, cells were analyzed by flow cytometry.

[0102] FIGS. 12A-12B demonstrate the expansion of cells with engineered CD40 agonist (mouse).

[0103] FIGS. 13A-13B show that an Fc-less CD40 agonist termed hCD40ag is bioactive in vitro. FIG. 13A shows the effect of CD40 agonists on CD40 pathway activity using a reporter cell line that emits signal following activation of the CD40 pathway. The CD40 agonists tested were hCD40ag (an Fc-less trimer of CD40L trimer bundles), and hCD40ag2 (includes bivalent CD40L trimer bundles connected to an Fc). Two positive controls (Positive Controls 1 & 2) were tested, as well as a media-only negative control. Activation of the CD40 pathway is represented as optical density (OD) at 650 nm (y-axis) using the CD40 agonists at the concentrations indicated on the x-axis (ng / mL). FIG. 13B shows the effects of the indicated CD40 agonists on dendritic cell (DC) activation, assessed by CD86 expression using flow cytometry. The CD40 agonists tested included hCD40ag, as well as several controls: Positive Controls 1 & 2, wild type CD40 agonist (soluble monomer), and an IgGl isotype control antibody. Each CD40 agonist or control was used at the concentration indicated on the x-axis. gMFI, geometric mean fluorescence intensity.

[0104] FIGS. 14A-14B show the anti-tumor efficacy of several CD40 agonists in vivo using MC38-5AG tumors in human CD40 knock-in mice. The CD40 agonists indicated in FIG. 14A were injected IT on Days 1, 4, and 7 and tumor volume (mm3) was measured on the indicated days after treatment. The tested agonists were hCD40ag (i.e., an Fc-less trimer of CD40L trimer bundles), hCD40ag2 (i.e., bivalent CD40L trimer bundles connected to an Fc), and WT CD40 agonist (CD40L) monomer. An isotype control antibody (IgGl mAh) was also tested. The confidence interval (CI) values are the lower and upper limits of the 95% CI of the tumor growth inhibition (TGI) value, and the p-value compared to isotype control were calculated for each construct tested by InVivoLDA Version 4.8. FIG. 14B provides a comparison of average tumor volumes as measured in mice treated with hCD40ag or isotype control antibody (IgGl mAh). The arrows in FIG. 14B indicate the days on which the mice were treated with hCD40ag or isotype control antibody.4. DETAILED DESCRIPTION

[0105] The present disclosure is based, in part, on the surprising discovery of single CD40L Fc fusion proteins with favorable biophysical properties and enhanced CD40 activation resulting in enhanced T cell and dendritic cell activation. The compositions and methods of the invention thus provide an avenue for novel and improved therapeutic strategies that target the CD40-CD40L pathway.

[0106] Various publications, articles and patents are cited or described in the background and throughout the specification; each of these references is herein incorporated by reference in its entirety. Discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is for the purpose of providing context for the invention. Such discussion is not an admission that any or all of these matters form part of the prior art with respect to any inventions disclosed or claimed.

[0107] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention pertains. Otherwise, certain terms used herein have the meanings as set forth in the specification.

[0108] It must be noted that as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural reference unless the context clearly dictates otherwise.

[0109] Unless otherwise stated, any numerical values, such as a concentration or a concentration range described herein, are to be understood as being modified in all instances by the term “about.” Thus, a numerical value typically includes ± 10 % of the recited value. For example, a concentration of 1 mg / mL includes 0.9 mg / mL to 1.1 mg / mL. Likewise, a concentration range of 1 % to 10 % (w / v) includes 0.9 % (w / v) to 11 % (w / v). As used herein, the use of a numerical range expressly includes all possible subranges, all individual numerical values within that range, including integers within such ranges and fractions of the values unless the context clearly indicates otherwise.

[0110] Unless otherwise indicated, the term “at least” preceding a series of elements is to be understood to refer to every element in the series.

[0111] Those skilled in the art will recognize or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the invention.

[0112] As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having,” “contains” or “containing,” or any other variation thereof, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers and are intended to be non-exclusive or open-ended. For example, a composition, a mixture, a process, a method, an article, or an apparatus that comprises a list of elements is not necessarily limited to only those elements but can include other elements not expressly listed or inherent to such composition, mixture, process, method, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by anyone of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

[0113] As used herein, the conjunctive term “and / or” between multiple recited elements is understood as encompassing both individual and combined options. For instance, where two elements are conjoined by “and / or,” a first option refers to the applicability of the first element without the second. A second option refers to the applicability of the second element without the first. A third option refers to the applicability of the first and second elements together. Any one of these options is understood to fall within the meaning, and therefore satisfy the requirement of the term “and / or” as used herein. Concurrent applicability of more than one of the options is also understood to fall within the meaning, and therefore satisfy the requirement of the term “and / or.”

[0114] As used herein, the term “consists of,” or variations such as “consist of’ or “consisting of,” as used throughout the specification and claims, indicate the inclusion of any recited integer or group of integers, but that no additional integer or group of integers can be added to the specified method, structure, or composition.

[0115] As used herein, the term “consists essentially of,” or variations such as “consist essentially of’ or “consisting essentially of,” as used throughout the specification and claims, indicate the inclusion of any recited integer or group of integers, and the optional inclusion of any recited integer or group of integers that do not materially change the basic or novel properties of the specified method, structure or composition. See M.P.E.P. § 2111.03.

[0116] As used herein, “subject” means any animal, preferably a mammal, most preferably a human. The term “mammal” as used herein, encompasses any mammal. Examples of mammals include, but are not limited to, cows, horses, sheep, pigs, cats, dogs, mice, rats, rabbits, guinea pigs, monkeys, humans, etc. In specific embodiments, the subject is a human. In certain embodiments, the subject is a subject in need thereof.

[0117] As used herein, the term “treat,” “treatment,” or “treating” refers to any method used to partially or completely alleviate, ameliorate, relieve, inhibit, prevent, delay onset of, reduce severity of and / or reduce incidence of one or more symptoms or features of a particular disease, disorder, and / or condition. Treatment may be administered to a subject who does not exhibit signs of a disease and / or exhibits only early signs of the disease for the purpose of decreasing the risk of developing pathology associated with the disease.

[0118] It should also be understood that the terms “about,” “approximately,” “generally,” “substantially,” and like terms, used herein when referring to a dimension or characteristic of a component of the preferred invention, indicate that the described dimension / characteristic isnot a strict boundary or parameter and does not exclude minor variations therefrom that are functionally the same or similar, as would be understood by one having ordinary skill in the art. At a minimum, such references that include a numerical parameter would include variations that, using mathematical and industrial principles accepted in the art (e.g., rounding, measurement or other systematic errors, manufacturing tolerances, etc.), would not vary the least significant digit.

[0119] The terms “identical” or percent “identity,” in the context of two or more nucleic acids or polypeptide sequences, refer to two or more sequences or subsequences that are the same or have a specified percentage of amino acid residues or nucleotides that are the same, when compared and aligned for maximum correspondence, as measured using one of the following sequence comparison algorithms or by visual inspection.

[0120] For sequence comparison, typically one sequence acts as a reference sequence, to which test sequences are compared. When using a sequence comparison algorithm, test and reference sequences are input into a computer, subsequence coordinates are designated, if necessary, and sequence algorithm program parameters are designated. The sequence comparison algorithm then calculates the percent sequence identity for the test sequence(s) relative to the reference sequence, based on the designated program parameters.

[0121] Optimal alignment of sequences for comparison can be conducted, e.g., by the local homology algorithm of Smith & Waterman, Adv. Appl. Math. 2:482 (1981), by the homology alignment algorithm of Needleman & Wunsch, J. Mol. Biol. 48:443 (1970), by the search for similarity method of Pearson & Lipman, Proc. Nat’l. Acad. Sci. USA 85:2444 (1988), by computerized implementations of these algorithms (GAP, BESTFIT, FASTA, and TFASTA in the Wisconsin Genetics Software Package, Genetics Computer Group, 575 Science Dr., Madison, WI), or by visual inspection (see generally, Current Protocols in Molecular Biology, F.M. Ausubel et al., eds., Current Protocols, a joint venture between Greene Publishing Associates, Inc. and John Wiley & Sons, Inc., (1995 Supplement) (Ausubel)).

[0122] Examples of algorithms that are suitable for determining percent sequence identity and sequence similarity are the BLAST and BLAST 2.0 algorithms, which are described in Altschul et al. (1990) J. Mol. Biol. 215: 403-410 and Altschul et al. (1997) Nucleic Acids Res. 25: 3389-3402, respectively. Software for performing BLAST analyses is publicly available through the National Center for Biotechnology Information. This algorithm involves first identifying high scoring sequence pairs (HSPs) by identifying short words of length W in the query sequence, which either match or satisfy some positive-valued thresholdscore T when aligned with a word of the same length in a database sequence. T is referred to as the neighborhood word score threshold (Altschul et al., supra). These initial neighborhood word hits act as seeds for initiating searches to find longer HSPs containing them. The word hits are then extended in both directions along each sequence for as far as the cumulative alignment score can be increased.

[0123] Cumulative scores are calculated using, for nucleotide sequences, the parameters M (reward score for a pair of matching residues; always > 0) and N (penalty score for mismatching residues; always < 0). For amino acid sequences, a scoring matrix is used to calculate the cumulative score. Extension of the word hits in each direction are halted when: the cumulative alignment score falls off by the quantity X from its maximum achieved value; the cumulative score goes to zero or below, due to the accumulation of one or more negativescoring residue alignments; or the end of either sequence is reached. The BLAST algorithm parameters W, T, and X determine the sensitivity and speed of the alignment. The BLASTN program (for nucleotide sequences) uses as defaults a word length (W) of 11 , an expectation (E) of 10, M=5, N=-4, and a comparison of both strands. For amino acid sequences, the BLASTP program uses as defaults a word length (W) of 3, an expectation (E) of 10, and the BLOSUM62 scoring matrix (see Henikoff & Henikoff, Proc. Natl. Acad. Sci. USA 89:10915 (1989)).

[0124] In addition to calculating percent sequence identity, the BLAST algorithm also performs a statistical analysis of the similarity between two sequences (see, e.g., Karlin & Altschul, Proc. Nat’l. Acad. Sci. USA 90:5873-5787 (1993)). One measure of similarity provided by the BLAST algorithm is the smallest sum probability (P(N)), which provides an indication of the probability by which a match between two nucleotide or amino acid sequences would occur by chance. For example, a nucleic acid is considered similar to a reference sequence if the smallest sum probability in a comparison of the test nucleic acid to the reference nucleic acid is less than about 0.1, more preferably less than about 0.01, and most preferably less than about 0.001.

[0125] A further indication that two nucleic acid sequences or polypeptides are substantially identical is that the polypeptide encoded by the first nucleic acid is immunologically cross reactive with the polypeptide encoded by the second nucleic acid, as described below. Thus, a polypeptide is typically substantially identical to a second polypeptide, for example, where the two peptides differ only by conservative substitutions. Another indication that two nucleic acid sequences are substantially identical is that the two molecules hybridize to each other under stringent conditions.

[0126] As used herein, the term “polynucleotide,” synonymously referred to as “nucleic acid molecule,” “nucleotides” or “nucleic acids,” refers to any polyribonucleotide or poly deoxyribonucleotide, which can be unmodified RNA or DNA or modified RNA or DNA. “Polynucleotides” include, without limitation single- and double-stranded DNA, DNA that is a mixture of single- and double-stranded regions, single- and double-stranded RNA, and RNA that is mixture of single- and double-stranded regions, hybrid molecules comprising DNA and RNA that can be single-stranded or, more typically, double-stranded or a mixture of single- and double-stranded regions. In addition, “polynucleotide” refers to triple-stranded regions comprising RNA or DNA or both RNA and DNA. The term polynucleotide also includes DNAs or RNAs containing one or more modified bases and DNAs or RNAs with backbones modified for stability or for other reasons. “Modified” bases include, for example, tritylated bases and unusual bases such as inosine. A variety of modifications can be made to DNA and RNA; thus, “polynucleotide” embraces chemically, enzymatically or metabolically modified forms of polynucleotides as typically found in nature, as well as the chemical forms of DNA and RNA characteristic of viruses and cells. “Polynucleotide” also embraces relatively short nucleic acid chains, often referred to as oligonucleotides.

[0127] The term “encoding” refers to the inherent property of specific sequences of nucleotides in a polynucleotide, such as a gene, a cDNA, or an mRNA, to serve as templates for synthesis of other polymers and macromolecules in biological processes having either a defined sequence of nucleotides (e.g., rRNA, tRNA and mRNA) or a defined sequence of amino acids and the biological properties resulting therefrom. Thus, a gene, cDNA, or RNA, encodes a protein if transcription and translation of mRNA corresponding to that gene produces the protein in a cell or other biological system. Both the coding strand, the nucleotide sequence of which is identical to the mRNA sequence and is usually provided in sequence listings, and the non-coding strand, used as the template for transcription of a gene or cDNA, can be referred to as encoding the protein or other product of that gene or cDNA.

[0128] Unless otherwise specified, a “nucleotide sequence encoding an amino acid sequence” (or an equivalent phrase) includes all nucleotide sequences that are degenerate versions of each other and that encode the same amino acid sequence. The phrase nucleotide sequence that encodes a protein or an RNA may also include introns to the extent that the nucleotide sequence encoding the protein may in some version contain an intron(s).

[0129] As used herein, the term “vector” is a replicon in which another nucleic acid segment can be operably inserted so as to bring about the replication or expression of the segment.

[0130] As used herein, the term “host cell” refers to a cell comprising a nucleic acid molecule of the invention. The “host cell” can be any type of cell, e.g., a primary cell, a cell in culture, or a cell from a cell line. In one embodiment, a “host cell” is a cell transfected with a nucleic acid molecule disclosed herein. In another embodiment, a “host cell” is a progeny or potential progeny of such a transfected cell. A progeny of a cell may or may not be identical to the parent cell, e.g., due to mutations or environmental influences that can occur in succeeding generations or integration of the nucleic acid molecule into the host cell genome.

[0131] The term “expression” as used herein, refers to the biosynthesis of a gene product. The term encompasses the transcription of a gene into RNA. The term also encompasses translation of RNA into one or more polypeptides, and further encompasses all naturally occurring post-transcriptional and post-translational modifications. The expressed molecule can be within the cytoplasm of a host cell, into the extracellular milieu such as the growth medium of a cell culture or anchored to the cell membrane.

[0132] As used herein, the terms “peptide,” “polypeptide,” or “protein” can refer to a molecule comprised of amino acids and can be recognized as a protein by those of skill in the art. The conventional one-letter or three-letter code for amino acid residues is used herein.The terms “peptide,” “polypeptide,” and “protein” can be used interchangeably herein to refer to polymers of amino acids of any length. The polymer can be linear or branched, it can comprise modified amino acids, and it can be interrupted by non-amino acids. The terms also encompass an amino acid polymer that has been modified naturally or by intervention; for example, disulfide bond formation, glycosylation, lipidation, acetylation, phosphorylation, or any other manipulation or modification, such as conjugation with a labeling component. Also included within the definition are, for example, polypeptides containing one or more analogs of an amino acid (including, for example, unnatural amino acids, etc.), as well as other modifications known in the art.

[0133] The peptide sequences described herein are written according to the usual convention whereby the N-terminal region of the peptide is on the left and the C-terminal region is on the right. Although isomeric forms of the amino acids are known, it is the L-form of the amino acid that is represented unless otherwise expressly indicated.

[0134] As used herein, the terms “antibody” or “immunoglobulin” are used in a broad sense and include human, humanized, composite and chimeric antibodies and antibody fragments that are monoclonal or polyclonal. In general, antibodies are proteins or peptide chains that exhibit binding specificity to a specific antigen. A naturally occurring antibody isa Y shaped molecule that consists of two heavy chains and two light chains folded into constant and variable domains. Antibody structures, including heavy and light chains as well as constant and variable regions within each of the heavy and light chains, are well known. That is, in addition to the heavy and light constant domains, antibodies contain an antigenbinding region that is made up of a light chain variable region (VL) and a heavy chain variable region (VH), each of which contains three domains (z.e., complementarity determining regions 1 (CDR1), CDR2 and CDR3. A “CDR” refers to one of three hypervariable regions (HCDR1, HCDR2 or HCDR3) within the non- framework region of the immunoglobulin (Ig or antibody) VH P-sheet framework, or one of three hypervariable regions (LCDR1, LCDR2 or LCDR3) within the non-framework region of the antibody VL P-sheet framework. Immunoglobulins can be assigned to five major classes (z.e., IgA, IgD, IgE, IgG and IgM), depending on the heavy chain constant domain amino acid sequence. IgA and IgG are further sub-classified as the isotypes IgAl, IgA2, IgGl, IgG2, IgG3 and IgG4.

[0135] The terms “constant region” or “constant domain” refer to a carboxy terminal portion of the light and heavy chain which is not directly involved in binding of the antibody to antigen but exhibits various effector function, such as interaction with the Fc receptor. The terms refer to the portion of an immunoglobulin molecule having a more conserved amino acid sequence relative to the other portion of the immunoglobulin, the variable region, which contains the antigen binding site. The constant region may contain the CHI, CH2 and CH3 regions of the heavy chain and the CL region of the light chain.

[0136] The term “Fc region” refers to the carboxy terminal portion of an antibody’s constant region and encompasses the CH2 and CH3 regions of the heavy chains. The two CH3 domains interact with each other to form a homodimer resulting in dimerization of Fc.

[0137] As used herein, the terms “Fc monomer” or “mFc” or “Fc monomer peptide” refer to a molecule that includes the carboxy terminal portion of a monomeric Fc region that consists of the CH2 and CH3 regions of the heavy chain, or a portion thereof. In some embodiments, the Fc monomer peptide comprises a human Fc sequence. In some embodiments, the human Fc sequence comprises a sequence selected from immunoglobulins IgG, IgA, IgM, IgD, and IgE. In one embodiment, the human Fc sequence comprises an IgG sequence. In some embodiments, the IgG sequence is selected from IgGl, IgG2, IgG3, and IgG4. In some embodiments, the IgG sequence is an IgGl sequence. In some embodiments, the IgGl sequence comprises SEQ ID NOs:30 or 31, or a fragment thereof. In one embodiment, the IgGl sequence comprises SEQ ID NO:30 or a fragment thereof. In another embodiment, the IgGl sequence comprises SEQ ID NO:31 or a fragment thereof. In someembodiments, the IgG sequence comprises an IgG2 sequence. In some embodiments, the IgG2 sequence comprises SEQ ID NO:29 or a fragment thereof.

[0138] The single chain trimeric CD40L Fc fusion proteins provided herein can comprise Fc monomer peptides of any of the five major classes or corresponding sub-classes. In some embodiments, the CD40E Fc fusion protein is not in, attached to, or associated with an oncolytic virus. In specific embodiments, the Fc monomer peptides provided herein are IgGl, IgG2, IgG3 or IgG4. In further embodiments, the Fc monomer peptides provided herein are human IgGl and human IgG2 isotypes. In additional embodiments, the Fc monomer peptide component of a single chain trimeric CD40E Fc fusion protein has silenced effector functions.

[0139] Accordingly, the single chain trimeric CD40E Fc fusion proteins provided herein can contain an Fc monomer peptide corresponding to a kappa or lambda light chain constant domain. According to particular embodiments, the single chain trimeric CD40E Fc fusion proteins disclosed herein include Fc monomers with heavy and / or light chain constant regions from rat or human antibodies.

[0140] As used herein, the term “monoclonal antibody” refers to an antibody obtained from a population of substantially homogeneous antibodies, i.e., the individual antibodies comprising the population are identical except for possible naturally occurring mutations that can be present in minor amounts. The monoclonal antibodies disclosed herein can be made by the hybridoma method, phage display technology, single lymphocyte gene cloning technology, or by recombinant DNA methods. For example, the monoclonal antibodies can be produced by a hybridoma which includes a B cell obtained from a transgenic nonhuman animal, such as a transgenic mouse or rat, having a genome comprising a human heavy chain transgene and a light chain transgene. Accordingly, the single chain trimeric CD40E Fc fusion proteins provided herein can comprise Fc monomers from a monoclonal antibody.

[0141] As used herein, the term “single-chain antibody” refers to a conventional singlechain antibody in the field, which comprises a heavy chain variable region and a light chain variable region connected by a short peptide of about 15 to about 20 amino acids.Accordingly, the single chain trimeric CD40E Fc fusion proteins provided herein can comprise Fc monomers from a single-chain antibody.

[0142] As used herein, the term “human antibody” refers to an antibody produced by a human or an antibody having an amino acid sequence corresponding to an antibody produced by a human made using any technique known in the art. This definition of a human antibody includes intact or full-length antibodies, fragments thereof, and / or antibodies comprising atleast one human heavy and / or light chain polypeptide. Accordingly, the single chain trimeric CD40L Fc fusion proteins provided herein can comprise Fc monomers from a human antibody.

[0143] As used herein, the term “humanized antibody” refers to a non-human antibody that is modified to increase the sequence homology to that of a human antibody, such that the antigen-binding properties of the antibody are retained, but its antigenicity in the human body is reduced. Accordingly, the single chain trimeric CD40L Fc fusion proteins provided herein can comprise Fc monomers from a humanized antibody.

[0144] As used herein, the terms “CD40 ligand” or “CD40L” refer to a protein, or fragment of a protein, that acts as a ligand to CD40 / TNFRSF5, a costimulatory member of the tumor necrosis factor receptor (TNFR) superfamily. Particular CD40L sequences, can be obtained from publicly accessible databases such as UniProt, for example, at UniProt Accession No. P29965. CD40L consists of an extracellular domain, stalk region, transmembrane helix, and short cytoplasmic domain. The activity of CD40L is located to the 215 amino acid extracellular domain, which is characterized by a sandwich structure composed of a [3-sheet, a-helix loop, and a [3-sheet. This structure allows for the trimerization of CD40L. The term CD40L further encompasses polypeptides or any fragments thereof having at least about having at least about 50, at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, at least 90, at least 95, at least 98 or at least 99%, sequence identity and ability to act as a ligand to CD40. The term CD40L encompasses full length CD40L and any fragments thereof, e.g., extracellular domain portions of CD40L. The term further encompasses soluble CD40L (sCD40L), which has been reported in different disease settings and can exist in monomeric and multimeric forms. In the context of a single chain trimeric CD40L fusion protein or a single chain trimeric CD40L Fc fusion protein according to the present disclosure, the individual CD40L components are referred to as “CD40L subunits.” The portion of the fusion protein consisting of the three CD40L subunits fused together can also be referred to as a “CD40L trimer.”

[0145] As used herein, the term “fusion protein” refers to a protein or a polypeptide that encompasses two or more peptide segments linked together to create a sequence that is not present in the same naturally occurring polypeptide.

[0146] As used herein, the term “single chain trimeric CD40L Fc fusion protein” refers to a protein comprising a monomeric Fc region (mFc), generally linked (optionally through a peptide tether, as described herein) to three CD40L subunits, as described herein and shown in Figure 1. In particular, a single chain trimeric CD40L Fc fusion protein consists of threeCD40L extracellular domains (ECD), or fragments thereof, connected to each other with flexible peptide linkers to form a linear CD40L trimer that is connected with a peptide tether to either the N-terminus or the C-terminus of an Fc monomer peptide. Accordingly, in different embodiments, a single chain trimeric CD40L Fc fusion protein can be either a C- terminal or an N-terminal Fc fusion of the CD40E trimer.

[0147] In some embodiments, the CD40E trimer is connected to the N-terminus of the Fc monomer peptide. In some embodiments, the single chain trimeric CD40E Fc fusion protein comprises any one sequence selected from SEQ ID NOs:l-12, or a fragment thereof.

[0148] In one embodiment, the single chain trimeric CD40E Fc fusion protein comprises SEQ ID NO:1. In another embodiment, the single chain trimeric CD40E Fc fusion protein comprises SEQ ID NO:2. In another embodiment, the single chain trimeric CD40E Fc fusion protein comprises SEQ ID NO:3. In another embodiment, the single chain trimeric CD40E Fc fusion protein comprises SEQ ID NO:4. In another embodiment, the single chain trimeric CD40E Fc fusion protein comprises SEQ ID NO: 5. In another embodiment, the single chain trimeric CD40E Fc fusion protein comprises SEQ ID NO:6. In another embodiment, the single chain trimeric CD40E Fc fusion protein comprises SEQ ID NO:7. In another embodiment, the single chain trimeric CD40E Fc fusion protein comprises SEQ ID NO:8. In another embodiment, the single chain trimeric CD40E Fc fusion protein comprises SEQ ID NO:9. In another embodiment, the single chain trimeric CD40E Fc fusion protein comprises SEQ ID NO: 10. In another embodiment, the single chain trimeric CD40E Fc fusion protein comprises SEQ ID NO:11. In another embodiment, the single chain trimeric CD40E Fc fusion protein comprises SEQ ID NO: 12. In one embodiment, the single chain trimeric CD40E Fc fusion protein comprises a fragment of SEQ ID NO:1. In another embodiment, the single chain trimeric CD40E Fc fusion protein comprises a fragment of SEQ ID NO:2. In another embodiment, the single chain trimeric CD40E Fc fusion protein comprises a fragment of SEQ ID NO:3. In another embodiment, the single chain trimeric CD40E Fc fusion protein comprises a fragment of SEQ ID NO:4. In another embodiment, the single chain trimeric CD40E Fc fusion protein comprises a fragment of SEQ ID NO:5. In another embodiment, the single chain trimeric CD40E Fc fusion protein comprises a fragment of SEQ ID NO:6. In another embodiment, the single chain trimeric CD40E Fc fusion protein comprises a fragment of SEQ ID NO:7. In another embodiment, the single chain trimeric CD40E Fc fusion protein comprises a fragment of SEQ ID NO:8. In another embodiment, the single chain trimeric CD40E Fc fusion protein comprises a fragment of SEQ ID NO:9. In another embodiment, the single chain trimeric CD40E Fc fusion protein comprises afragment of SEQ ID NO: 10. In another embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO: 11. In another embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO: 12. In another embodiment, the single chain trimeric CD40L fusion protein comprises a fragment of SEQ ID NO:43. In another embodiment, the single chain trimeric CD40L fusion protein comprises a fragment of SEQ ID NO:44.

[0149] In some embodiments, the CD40L trimer is connected to the C-terminus of the Fc monomer peptide. In some embodiments, the single chain trimeric CD40L Fc fusion protein comprises any one sequence selected from SEQ ID NOs: 13-19, or a fragment thereof. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO: 16 or a fragment thereof.

[0150] In some embodiments, the CD40L trimer is connected to the C-terminus of the trimerization motif. In some embodiments, the single chain trimeric CD40L trimerization fusion protein comprises any one sequence selected from SEQ ID NOs:43 and 44, and fragments thereof.

[0151] In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO:13. In another embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO: 14. In another embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO: 15. In another embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO: 16. In another embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO: 17. In another embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO: 18. In another embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO: 19.

[0152] In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO: 13. In another embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO: 14. In another embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO: 15. In another embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO: 16. In another embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO: 17. In another embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO: 18. In another embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO: 19.

[0153] In some embodiments, the CD40 ligand subunits comprise a portion of the CD40L extracellular sequence. In some embodiments, the CD40L subunits comprise any one of thesequences selected from SEQ ID NOs:20-22, or a fragment thereof. In some embodiments, the CD40L subunits comprises SEQ ID NO: 22 or SEQ ID NO: 45, or a fragment thereof.

[0154] In one embodiment, the CD40L subunits comprise a fragment of SEQ ID NO:20. In another embodiment, the CD40L subunits comprise a fragment of SEQ ID NO:21. In another embodiment, the CD40L subunits comprise a fragment of SEQ ID NO:22. In another embodiment, the CD40L subunits comprise a fragment of SEQ ID NO:45.

[0155] In one embodiment, the CD40L subunits comprise SEQ ID NO:20. In another embodiment, the CD40L subunits comprise SEQ ID NO:21. In another embodiment, the CD40L subunits comprise SEQ ID NO:22. In another embodiment, the CD40L subunits comprise a fragment of SEQ ID NO:45.

[0156] In some instances, two single chain trimeric CD40L Fc fusion proteins can form a homodimeric Fc fusion protein or a heterodimeric Fc fusion protein with the latter being preferred. In some embodiments, the dimer is not in, attached to, or associated with an oncolytic virus. In one embodiment, two single chain trimeric CD40L Fc fusion proteins form a homodimeric Fc fusion protein. In one embodiment, two single chain trimeric CD40L Fc fusion proteins form a heterodimeric Fc fusion protein. In some cases, one monomer of the heterodimeric Fc fusion protein comprises only an Fc monomer peptide or fragment thereof and the other monomer is a single chain trimeric CD40L Fc fusion protein. In some embodiments, single chain trimeric CD40L Fc fusion proteins can include a variant Fc monomer with one or more amino acid substitutions compared to a reference or wild-type Fc monomer. In some cases, one monomer of the heterodimeric Fc fusion protein is an Fc monomer peptide or fragment thereof and a protein domain other than CD40E, such as a receptor, ligand or other binding partner. Accordingly, a single chain trimeric CD40E Fc fusion protein can be a component of a heterodimeric Fc fusion protein that is a bispecific molecule.

[0157] In some instances, three single chain trimeric CD40E fusion proteins can form a homotrimeric fusion protein complex.

[0158] The term “bispecific molecule” refers to a molecule that has two binding domains, each capable of specifically binding a target protein, ligand or fragments thereof. As such, while a bispecific molecule can include binding domains that are non- antibody proteins, ligands and fragments thereof, including recombinant antigens, that can specifically bind another protein. In an embodiment, a bispecific molecule can comprise a single chain trimeric CD40E Fc fusion protein or a single chain trimeric CD40E fusion protein.

[0159] “Agonize” as used herein refers to the activation of receptor signaling in order to induce a biological response associated with activation of the receptor. An “agonist” refers to a molecule that binds to a receptor and activates the receptor to produce a biological response. Receptors can be activated by either an endogenous or an exogenous agonist.

[0160] CD40 agonist

[0161] Cluster of differentiation 40 (CD40) is a costimulatory polypeptide expressed on numerous cell types, from antigen presenting cells (APCs) to epithelial cells. It is additionally present on various cancer cells. “CD40 agonist,” also known as cluster of differentiation 154 (CD 154), comprises 261 amino acids and is a type II membrane glycopolypeptide that is expressed on the surface of activated T cells. Native CD40 agonist promotes B cell maturation. It is additionally essential for immunoglobulin class switching, as lack of CD40 agonist is associated with hyper IgM syndrome. CD40 agonist exists as a membrane-bound form, in which the extracellular domain forms a homotrimer, and a proteolytically-cleaved, soluble form, which has been shown to be biologically active.

[0162] In some embodiments, provided herein is a polypeptide CD40 agonist. In some embodiments, polynucleotides which encode, or an expression cassette otherwise described herein or known, encode polypeptides which comprises a polynucleotide encoding CD40 agonist. In some embodiments, the CD40 agonist is a CD40 ligand. In some embodiments, the CD40 agonist comprises a CD40 ligand ectodomain. In some embodiments, the CD40 agonist is a trimer of three single -chain trimeric CD40 ligand ectodomains. In some embodiments, each of the three single -chain trimeric CD40 ligand ectodomains is fused to a trimerization motif, e.g., to direct formation of the trimer of three single-chain trimeric CD40 ligand ectodomains. In some embodiments, each of the three single -chain trimeric CD40 ligand ectodomains is fused to an Fc region, e.g., to direct formation of the trimer of three single-chain trimeric CD40 ligand ectodomains. In some embodiments, said Fc region is an IgG Fc region e.g., a human IgGl, IgG2, IgG3, or IgG4 Fc region. In some embodiments, said Fc region comprises one or more amino acid substitutions, insertions, or deletions that disfavor binding of said Fc region to another Fc region, such as an IgG Fc region, e.g., a human IgGl, IgG2, IgG3, or IgG4 Fc region. In some embodiments, said Fc region comprises a substitution of the IgG interaction domain with an IgA interaction domain. In some embodiments, each of the three single -chain trimeric CD40 ligand ectodomains is bivalent. In some embodiments, the CD40 agonist is an agonist antibody. In some embodiments, the CD40 agonist is not in, attached to, or associated with an oncolytic virus.

[0163] In some embodiments, the CD40 agonist comprises a human CD40 ligand ectodomain. In some embodiments, the human CD40 ligand ectodomain comprises the amino acid sequence set forth in SEQ ID NO:22, or an amino acid sequence having any of at least about80%, at least about 81%, at least about 82%, at least about 83%, at least about 84%, at least about85%, at least about 86%, at least about 87%, at least about 88%, at least about 89%, at least about90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% homology to the amino acid sequence set forth in SEQ ID NO:22. In some embodiments, the human CD40 ligand ectodomain comprises the amino acid sequence set forth in SEQ ID NO:45, or an amino acid sequence having any of at least about 80%, at least about 81%, at least about 82%, at least about 83%, at least about 84%, at least about 85%, at least about 86%, at least about 87%, at least about 88%, at least about 89%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% homology to the amino acid sequence set forth in SEQ ID NO:45. In some embodiments, the CD40 agonist is a trimer of three single-chain trimeric human CD40 ligand ectodomains. In some embodiments, the single-chain trimeric human CD40 ligand ectodomains comprise a polypeptide comprising three human CD40 ligand ectodomains connected by peptide linkers. In some embodiments, the single-chain trimeric human CD40 ligand ectodomain polypeptide comprises a first human CD40 ligand ectodomain connected by a peptide linker to a second human CD40 ligand ectodomain which is connected by a peptide linker to a third human CD40 ligand ectodomain. In some embodiments, the peptide linker comprises glycine and serine residues. In some embodiments, the peptide linker comprises the amino acid sequence set forth in SEQ ID NO: 39, or an amino acid sequence having any of at least about 80%, at least about 81%, at least about 82%, at least about 83%, at least about 84%, at least about85%, at least about 86%, at least about 87%, at least about 88%, at least about 89%, at least about90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% homology to the amino acid sequence set forth in SEQ ID NO:39. In some embodiments, the peptide linker comprises the amino acid sequence set forth in SEQ ID NO:25 (GGGSGGGSGGGS ) or an amino acid sequence having any of at least about 80%, at least about 81%, at least about 82%, at least about 83%, at least about 84%, at least about 85%, at least about 86%, at least about 87%, at least about 88%, at least about 89%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% homology to the amino acid sequence set forth in SEQ IDNO: 25. In some embodiments, the CD40 agonist comprises a trimerization motif operably linked to each of the three single-chain trimeric CD40 ligand ectodomains. In some embodiments, the trimerization motif is a T4 fibritin trimerization motif. In some embodiments, the T4 fibritin trimerization motif comprises the amino acid sequence set forth in SEQ ID NO:41(GYIPEAPRDGQAYVRKDGEWVLLSTFL), or an amino acid sequence having any of at least about 80%, at least about 81%, at least about 82%, at least about 83%, at least about 84%, at least about 85%, at least about 86%, at least about 87%, at least about 88%, at least about 89%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% homology to the amino acid sequence set forth in SEQ ID NO:41 In some embodiments, the trimerization motif is linked to each of the three single-chain trimeric CD40 ligand ectodomains by a peptide tether. In some embodiments, the peptide tether connecting the trimerization motif to each of the three single-chain trimeric CD40 ligand ectodomains comprises an amino acid sequence comprising glycine and / or serine residues. In some embodiments, the peptide tether comprises the amino acid sequence of SEQ ID NO:24 , or an amino acid sequence having any of about at least about 80%, at least about 81%, at least about 82%, at least about 83%, at least about 84%, at least about 85%, at least about 86%, at least about 87%, at least about 88%, at least about 89%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% homology to the amino acid sequence set forth in SEQ ID NO:24. In some embodiments, the peptide tether comprises the amino acid sequence of SEQ ID NO:26 (GGGGSGGGGS), or an amino acid sequence having any of about at least about 80%, at least about 81%, at least about 82%, at least about 83%, at least about 84%, at least about 85%, at least about 86%, at least about 87%, at least about 88%, at least about 89%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% homology to the amino acid sequence set forth in SEQ ID NO:26. In some embodiments, the CD40 agonist further comprises a signal peptide sequence operably linked to each of the three single -chain trimeric CD40 ligand ectodomains. In some embodiments, the signal peptide sequence comprises the amino acid sequence of SEQ ID NO:42 (MAWVWTLLFLMAAAQSIQA). In some embodiments, the CD40 agonist comprises a polypeptide comprising the amino acid sequence of SEQ ID NO:43 (MAWVWTLLFLMAAAQSIQAGYIPEAPRDGQAYVRKDGEWVLLSTFLGGGGSNPQIAA HVISEASSKTTSVLQWAEKGYYTMSNNLVTLENGKQLTVKRQGLYYIYAQVTFCSNREA SSQAPFIASLCLKSPGRFERILLRAANTHSSAKPCGQQSIHLGGVFELQPGASVFVNVTDPS QVSHGTGFTSFGLLKLGGGSGGGSGGGSNPQIAAHVISEASSKTTSVLQWAEKGYYTMS NNLVTLENGKQLTVKRQGLYYIYAQVTFCSNREASSQAPFIASLCLKSPGRFERILLRAA NTHSSAKPCGQQSIHLGGVFELQPGASVFVNVTDPSQVSHGTGFTSFGLLKLGGGSGGGS GGGSNPQIAAHVISEASSKTTSVLQWAEKGYYTMSNNLVTLENGKQLTVKRQGLYYIYAQVTFCSNREASSQAPFIASLCLKSPGRFERILLRAANTHSSAKPCGQQSIHLGGVFELQPG ASVFVNVTDPSQVSHGTGFTSFGLLKL), or an amino acid sequence having any of about at least about 80%, at least about 81%, at least about 82%, at least about 83%, at least about 84%, at least about 85%, at least about 86%, at least about 87%, at least about 88%, at least about 89%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% homology to the amino acid sequence set forth in SEQ ID NO:43. In some embodiments, the CD40 agonist comprises a polypeptide comprising the amino acid sequence of SEQ ID NO:44 (GYIPEAPRDGQAYVRKDGEWVLLSTFLGGGGSNPQIAAHVISEASSKTTSVLQWAEKGY YTMSNNLVTLENGKQLTVKRQGLYYIYAQVTFCSNREASSQAPFIASLCLKSPGRFERILL RAANTHSSAKPCGQQSIHLGGVFELQPGASVFVNVTDPSQVSHGTGFTSFGLLKLGGGSG GGSGGGSNPQIAAHVISEASSKTTSVLQWAEKGYYTMSNNLVTLENGKQLTVKRQGLY YIYAQVTFCSNREASSQAPFIASLCLKSPGRFERILLRAANTHSSAKPCGQQSIHLGGVFEL QPGASVFVNVTDPSQVSHGTGFTSFGLLKLGGGSGGGSGGGSNPQIAAHVISEASSKTTS VLQWAEKGYYTMSNNLVTLENGKQLTVKRQGLYYIYAQVTFCSNREASSQAPFIASLCL KSPGRFERILLRAANTHSSAKPCGQQSIHLGGVFELQPGASVFVNVTDPSQVSHGTGFTSF GLLKL), or an amino acid sequence having any of about at least about 80%, at least about 81%, at least about 82%, at least about 83%, at least about 84%, at least about 85%, at least about 86%, at least about 87%, at least about 88%, at least about 89%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% homology to the amino acid sequence set forth in SEQ ID NO: 44. In some embodiments, the CD40 agonist forms a trimer comprising three polypeptides comprising the amino acid sequence of SEQ ID NO:43, or an amino acid sequence having any of about at least about 80%, at least about 81%, at least about 82%, at least about 83%, at least about 84%, at least about 85%, at least about 86%, at least about 87%, at least about 88%, at least about 89%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% homology to the amino acid sequence set forth in SEQ ID NO:43. In some embodiments, the CD40 agonist forms a trimer comprising three polypeptides comprising the amino acid sequence of SEQ ID NO:44, or an amino acid sequence having any of about at least about 80%, at least about 81%, at least about 82%, at least about 83%, at least about 84%, at least about 85%, at least about 86%, at least about 87%, at least about 88%, at least about 89%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% homology to the amino acid sequence set forth in SEQ ID NO:44.

[0164] In some embodiments, the CD40 agonist comprises a murine CD40 ligand ectodomain. In some embodiments, the murine CD40 ligand ectodomain comprises the amino acid sequence set forth in SEQ ID NO:45 (DPQIAAHVVSEANSNAASVLQWAKKGYYTMKSNLVMLENGKQLTVKREGLYYVYTQ VTFCSNREPSSQRPFIVGLWLKPSSGSERILLKAANTHSSSQLCEQQSVHLGGVFELQAGA SVFVNVTEASQVIHRVGFSSFGEEKE), or an amino acid sequence having any of at least about 80%, at least about 81%, at least about 82%, at least about 83%, at least about 84%, at least about 85%, at least about 86%, at least about 87%, at least about 88%, at least about 89%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% homology to the amino acid sequence set forth in SEQ ID NO:45. In some embodiments, the CD40 agonist is a trimer of three single -chain trimeric murine CD40 ligand ectodomains. In some embodiments, the single-chain trimeric murine CD40 ligand ectodomains comprise a polypeptide comprising three murine CD40 ligand ectodomains connected by peptide linkers. In some embodiments, the single-chain trimeric murine CD40 ligand ectodomain polypeptide comprises a first murine CD40 ligand ectodomain connected by a peptide linker to a second murine CD40 ligand ectodomain which is connected by a peptide linker to a third murine CD40 ligand ectodomain. In some embodiments, the peptide linker comprises glycine and serine residues. In some embodiments, the peptide linker comprises the amino acid sequence set forth in SEQ ID NO:25, or an amino acid sequence having any of at least about 80%, at least about 81%, at least about 82%, at least about 83%, at least about 84%, at least about 85%, at least about 86%, at least about 87%, at least about 88%, at least about 89%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% homology to the amino acid sequence set forth in SEQ ID NO:25. In some embodiments, the CD40 agonist comprises a trimerization motif operably linked to each of the three single -chain trimeric CD40 ligand ectodomains. In some embodiments, the trimerization motif is a T4 fibritin trimerization motif. In some embodiments, the T4 fibritin trimerization motif comprises the amino acid sequence set forth in SEQ ID NO:41, or an amino acid sequence having any of at least about 80%, at least about 81%, at least about 82%, at least about 83%, at least about 84%, at least about 85%, at least about 86%, at least about 87%, at least about 88%, at least about 89%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% homology to the amino acid sequence set forth in SEQ ID NO:41. In some embodiments, the trimerization motif is linked to each of the three single -chain trimeric CD40 ligand ectodomains by a peptide tether. In some embodiments, thepeptide tether connecting the trimerization motif to each of the three single-chain trimeric CD40 ligand ectodomains comprises an amino acid sequence comprising of leucine, glycine, and / or serine residues. In some embodiments, the peptide tether comprises the amino acid sequence of SEQ ID NO:24, or an amino acid sequence having any of about at least about 80%, at least about 81%, at least about 82%, at least about 83%, at least about 84%, at least about 85%, at least about 86%, at least about 87%, at least about 88%, at least about 89%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% homology to the amino acid sequence set forth in SEQ ID NO: 24. In some embodiments, the peptide tether comprises the amino acid sequence of SEQ ID NO:26, or an amino acid sequence having any of about at least about 80%, at least about 81%, at least about 82%, at least about 83%, at least about 84%, at least about 85%, at least about 86%, at least about 87%, at least about 88%, at least about 89%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% homology to the amino acid sequence set forth in SEQ ID NO:26. In some embodiments, the CD40 agonist further comprises a signal peptide sequence operably linked to each of the three single -chain trimeric CD40 ligand ectodomains. In some embodiments, the signal peptide sequence comprises the amino acid sequence of SEQ ID NO:42. In some embodiments, the CD40 agonist comprises a polypeptide comprising the amino acid sequence of SEQ ID NO:46 (MAWVWTLLFLMAAAQSIQAGYIPEAPRDGQAYVRKDGEWVLLSTFLGGGGSGGGGSD PQIAAHVVSEANSNAASVLQWAKKGYYTMKSNLVMLENGKQLTVKREGLYYVYTQVT FCSNREPSSQRPFIVGLWLKPSSGSERILLKAANTHSSSQLCEQQSVHLGGVFELQAGASV FVNVTEASQVIHRVGFSSFGLLKLGGGSGGGSGGGSDPQIAAHVVSEANSNAASVLQWA KKGYYTMKSNLVMLENGKQLTVKREGLYYVYTQVTFCSNREPSSQRPFIVGLWLKPSS GSERILLKAANTHSSSQLCEQQSVHLGGVFELQAGASVFVNVTEASQVIHRVGFSSFGLL KLGGGSGGGSGGGSDPQIAAHVVSEANSNAASVLQWAKKGYYTMKSNLVMLENGKQL TVKREGLYYVYTQVTFCSNREPSSQRPFIVGLWLKPSSGSERILLKAANTHSSSQLCEQQS VHLGGVFELQAGASVFVNVTEASQVIHRVGFSSFGLLKL), or an amino acid sequence having any of about at least about 80%, at least about 81%, at least about 82%, at least about 83%, at least about 84%, at least about 85%, at least about 86%, at least about 87%, at least about 88%, at least about 89%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% homology to the amino acid sequence set forth in SEQ ID NO:46. In some embodiments, the CD40 agonist comprises a polypeptide comprising the amino acid sequence of SEQ ID NO:47(GYIPEAPRDGQAYVRKDGEWVLLSTFLGGGGSGGGGSDPQIAAHVVSEANSNAASVLQ WAKKGYYTMKSNLVMLENGKQLTVKREGLYYVYTQVTFCSNREPSSQRPFIVGLWLKP SSGSERILLKAANTHSSSQLCEQQSVHLGGVFELQAGASVFVNVTEASQVIHRVGFSSFG LLKLGGGSGGGSGGGSDPQIAAHVVSEANSNAASVLQWAKKGYYTMKSNLVMLENGK QLTVKREGLYYVYTQVTFCSNREPSSQRPFIVGLWLKPSSGSERILLKAANTHSSSQLCEQ QSVHLGGVFELQAGASVFVNVTEASQVIHRVGFSSFGLLKLGGGSGGGSGGGSDPQIAA HVVSEANSNAASVLQWAKKGYYTMKSNLVMLENGKQLTVKREGLYYVYTQVTFCSNR EPSSQRPFIVGLWLKPSSGSERILLKAANTHSSSQLCEQQSVHLGGVFELQAGASVFVNVT EASQVIHRVGFSSFGLLKL), or an amino acid sequence having any of about at least about 80%, at least about 81%, at least about 82%, at least about 83%, at least about 84%, at least about 85%, at least about 86%, at least about 87%, at least about 88%, at least about 89%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% homology to the amino acid sequence set forth in SEQ ID NO:47. In some embodiments, the CD40 agonist forms a trimer comprising three polypeptides comprising the amino acid sequence of SEQ ID NO:46, or an amino acid sequence having any of about at least about 80%, at least about 81%, at least about 82%, at least about 83%, at least about 84%, at least about 85%, at least about 86%, at least about 87%, at least about 88%, at least about 89%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% homology to the amino acid sequence set forth in SEQ ID NO:46. In some embodiments, the CD40 agonist forms a trimer comprising three polypeptides comprising the amino acid sequence of SEQ ID NO:47, or an amino acid sequence having any of about at least about 80%, at least about 81%, at least about 82%, at least about 83%, at least about 84%, at least about 85%, at least about 86%, at least about 87%, at least about 88%, at least about 89%, at least about 90%, at least about 91%, at least about 92%, at least about 93%, at least about 94%, at least about 95%, at least about 96%, at least about 97%, at least about 98%, or at least about 99% homology to the amino acid sequence set forth in SEQ ID NO:47.

[0165] In particular embodiments, the single chain trimeric CD40L fusion protein comprises any one sequence selected from the sequences shown in the Table 1.Table ETrimerization Fusion Protein Sequences

[0166] The terms “binds” or “binding” refer to an interaction between molecules including, for example, to form a complex. The term “binding domain” refers to a portion of a molecule responsible for a specific binding interaction with another molecule or ligand. Interactions can be, for example, non-covalent interactions including hydrogen bonds, ionic bonds, hydrophobic interactions, and / or van der Waals interactions. A complex can also include the binding of two or more molecules held together by covalent or non-covalent bonds, interactions, or forces. The strength of the total non-covalent interactions between a single antigen-binding site on an antibody and a single epitope of a target molecule, such as an antigen, is the affinity of the antibody or functional fragment for that epitope. The ratio of dissociation rate (koff) to association rate (kon) of a binding molecule (e.g., an antibody) to amonovalent antigen (koff / kon) is the dissociation constant KD, which is inversely related to affinity. The lower the KD value, the higher the affinity of the binding molecule. The value of KD varies for different complexes of binding molecules and their ligands (z.e. antibody and antigen) and depends on both konand koff. A binding domain that can specifically bind the target with a KD of 1 x 10-7M or less, such as 1 x 10-8M or less, 5 x 10-9M or less, 1 x 10“9M or less, 5 x IO-10M or less, or 1 x IO-10M or less. The dissociation constant KD for a binding molecule provided herein can be determined using any method provided herein or any other method well known to those skilled in the art. The affinity at one binding site does not always reflect the true strength of the interaction between binding molecule and its binding partner.

[0167] In connection with the binding molecules described herein terms such as “bind to,” “that specifically bind to,” and analogous terms are also used interchangeably herein and refer to binding molecules of antigen binding domains that specifically bind to an antigen, such as a polypeptide. A binding molecule or antigen binding domain that binds to or specifically binds to an antigen may be cross-reactive with related antigens. In certain embodiments, a binding molecule or antigen binding domain that binds to or specifically binds to an antigen does not cross-react with other antigens. A binding molecule or antigen binding domain that binds to or specifically binds to an antigen can be identified, for example, by immunoassays, Octet®, Biacore®, or other techniques known to those of skill in the art. In some embodiments, a binding molecule or antigen binding domain binds to or specifically binds to an antigen when it binds to an antigen with higher affinity than to any cross-reactive antigen as determined using experimental techniques, such as radioimmunoassays (RIA) and enzyme linked immunosorbent assays (ELISAs). Typically a specific or selective reaction will be at least twice background signal or noise and may be more than 10 times background. See, e.g., Fundamental Immunology 332-36 (Paul ed., 2d ed. 1989) for a discussion regarding binding specificity. In certain embodiments, the extent of binding of a binding molecule or antigen binding domain to a “non-target” protein is less than about 10% of the binding of the binding molecule or antigen binding domain to its particular target antigen, for example, as determined by fluorescence activated cell sorting (FACS) analysis or RIA. With regard terms such as “specific binding,” “specifically binds to,” or “is specific for” means binding that is measurably different from a non-specific interaction. Specific binding can be measured, for example, by determining binding of a molecule compared to binding of a control molecule, which generally is a molecule of similar structure that does not have binding activity. For example, specific binding can be determined bycompetition with a control molecule that is similar to the target, for example, an excess of non-labeled target. In this case, specific binding is indicated if the binding of the labeled target to a probe is competitively inhibited by excess unlabeled target. A binding molecule or antigen binding domain that binds to an antigen includes one that is capable of binding the antigen with sufficient affinity such that the binding molecule is useful, for example, as a diagnostic agent in targeting the antigen. In certain embodiments, a binding molecule or antigen binding domain that binds to an antigen has an equilibrium dissociation constant (KD) of less than or equal to 800 nM, 600 nM, 550 nM, 500 nM, 300 nM, 250 nM, 100 nM, 50 nM, 10 nM, 5 nM, 4 nM, 3 nM, 2 nM, 1 nM, 0.9 nM, 0.8 nM, 0.7 nM, 0.6 nM, 0.5 nM, 0.4 nM, 0.3 nM, 0.2 nM, or 0.1 nM. In certain embodiments, a binding molecule or antigen binding domain binds to an epitope of an antigen that is conserved among the antigen from different species (e.g., between human and cyno species).

[0168] “Binding affinity” generally refers to the strength of the sum total of noncovalent interactions between a single binding site of a molecule (e.g., a binding protein such as CD40L) and its binding partner (e.g., CD40 / TNFRSF5). Unless indicated otherwise, as used herein, “binding affinity” refers to intrinsic binding affinity which reflects a 1:1 interaction between members of a binding pair (e.g., antibody and antigen). The affinity of a binding molecule X for its binding partner Y can generally be represented by the equilibrium dissociation constant (KD). Affinity can be measured by common methods known in the art, including those described herein. Low-affinity antibodies generally bind antigen slowly and tend to dissociate readily, whereas high-affinity antibodies generally bind antigen faster and tend to remain bound longer. A variety of methods of measuring binding affinity are known in the art, any of which can be used for purposes of the present disclosure. Specific illustrative embodiments include the following. In one embodiment, the “KD” or “KD value” may be measured by assays known in the art, for example by a binding assay. The KD may be measured in a RIA, for example, performed with the Fab version of an antibody of interest and its antigen (Chen et al., 1999, J. Mol Biol 293:865-81). The KD or KD value may also be measured by using biolayer interferometry (BLI) or surface plasmon resonance (SPR) assays by Octet®, using, for example, an Octet®Red96 system, or by Biacore®, using, for example, a Biacore®TM-2000 or a Biacore®TM-3000. An “on-rate” or “rate of association” or “association rate” or “kon” may also be determined with the same biolayer interferometry (BLI) or surface plasmon resonance (SPR) techniques described above using, for example, the Octet®Red96, the Biacore®TM-2000, or the Biacore®TM-3000 system.

[0169] In certain embodiments, the binding molecules or antigen binding domains can comprise portions of “humanized” forms of nonhuman (e.g., camelid, murine, non-human primate) antibodies that include sequences from human immunoglobulins e.g., recipient antibody) in which the native CDR residues are replaced by residues from the corresponding CDR of a nonhuman species (e.g., donor antibody) such as camelid, mouse, rat, rabbit, or nonhuman primate having the desired specificity, affinity, and capacity. In some instances, one or more FR region residues of the human immunoglobulin sequences are replaced by corresponding nonhuman residues. Furthermore, humanized antibodies can comprise residues that are not found in the recipient antibody or in the donor antibody. These modifications are made to further refine antibody performance. A humanized antibody heavy or light chain can comprise substantially all of at least one or more variable regions, in which all or substantially all of the CDRs correspond to those of a nonhuman immunoglobulin and all or substantially all of the FRs are those of a human immunoglobulin sequence. In certain embodiments, the humanized antibody will comprise at least a portion of an immunoglobulin constant region (Fc), typically that of a human immunoglobulin. For further details, see Jones et al., 1986, Nature 321:522-25; Riechmann et al., 1988, Nature 332:323-29; Presta, 1992, Curr. Op. Struct. Biol. 2:593-96; Carter et al., 1992, Proc. Natl. Acad. Sci. USA 89:4285-89; U.S. Pat. Nos: 6,800,738; 6,719,971; 6,639,055; 6,407,213; and 6,054,297.

[0170] Techniques and procedures described or referenced herein include those that are generally well understood and / or commonly employed using conventional methodology by those skilled in the art, such as, for example, the widely utilized methodologies described in Sambrook et al., Molecular Cloning: A Laboratory Manual (3d ed. 2001); Current Protocols in Molecular Biology (Ausubel et al. eds., 2003); Therapeutic Monoclonal Antibodies: From Bench to Clinic (An ed. 2009); Monoclonal Antibodies: Methods and Protocols (Albitar ed. 2010); and Antibody Engineering Vols 1 and 2 (Kontermann and Diibel eds., 2d ed. 2010).

[0171] Unless otherwise defined herein, technical and scientific terms used in the present description have the meanings that are commonly understood by those of ordinary skill in the art. For purposes of interpreting this specification, the following description of terms will apply and whenever appropriate, terms used in the singular will also include the plural and vice versa. In the event that any description of a term set forth conflicts with any document incorporated herein by reference, the description of the term set forth below shall control.

[0172] In one aspect, provided herein is a polypeptide comprising a single chain trimeric CD40L fusion protein. In some embodiments, the single chain trimeric CD40L fusion protein is not in, attached to, or associated with an oncolytic virus. In some embodiments, the singlechain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by flexible peptide linkers. In some embodiments, the single chain trimeric CD40L fusion protein comprises three CD40L ECD domains, or fragments thereof. In particular embodiments, each CD40L subunit of the single chain trimeric CD40L fusion protein comprises any one sequence selected from Table 2.Table 2: CD40 Ligand Monomer Sequences00173] In one embodiment, a CD40L subunit of the single chain trimeric CD40L fusion protein comprises SEQ ID NO:20 or a fragment thereof. In another embodiment, a CD40L subunit of the single chain trimeric CD40L fusion protein comprises SEQ ID NO:21 or a fragment thereof. In another embodiment, a CD40L subunit of the single chain trimeric CD40L fusion protein comprises SEQ ID NO:22 or a fragment thereof. In another embodiment, a CD40L subunit of the single chain trimeric CD40L fusion protein comprises SEQ ID NO:45 or a fragment thereof. In another embodiment, a CD40L subunit of the single chain trimeric CD40L fusion protein comprises SEQ ID NO:33 or a fragment thereof. In another embodiment, a CD40L subunit of the single chain trimeric CD40L fusion protein comprises SEQ ID NO:34 or a fragment thereof. In one embodiment, a CD40L subunit of the single chain trimeric CD40L fusion protein comprises SEQ ID NO:20. In anotherembodiment, a CD40L subunit of the single chain trimeric CD40L fusion protein comprises SEQ ID NO:21. In another embodiment, a CD40L subunit of the single chain trimeric CD40L fusion protein comprises SEQ ID NO:22. In another embodiment, a CD40L subunit of the single chain trimeric CD40L fusion protein comprises SEQ ID NO:45 or a fragment thereof. In another embodiment, a CD40L subunit of the single chain trimeric CD40L fusion protein comprises SEQ ID NO:33. In another embodiment, a CD40L subunit of the single chain trimeric CD40L fusion protein comprises SEQ ID NO:34. In one embodiment, a CD40L subunit of the single chain trimeric CD40L fusion protein comprises a fragment of SEQ ID NO:20. In another embodiment, a CD40L subunit of the single chain trimeric CD40L fusion protein comprises a fragment of SEQ ID NO:21. In another embodiment, a CD40L subunit of the single chain trimeric CD40L fusion protein comprises a fragment of SEQ ID NO:22. In another embodiment, a CD40L subunit of the single chain trimeric CD40L fusion protein comprises a fragment of SEQ ID NO:33. In another embodiment, a CD40L subunit of the single chain trimeric CD40L fusion protein comprises a fragment of SEQ ID NO:34. In another embodiment, a CD40L subunit of the single chain trimeric CD40L fusion protein comprises SEQ ID NO:45 or a fragment thereof.

[0174] In one embodiment, a single chain trimeric CD40L fusion protein comprises a CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a CD40L subunit having the amino acid sequence of SEQ ID NO:22. In another embodiment, a single chain trimeric CD40L fusion protein comprises a CD40L subunit comprising the amino acid sequence of SEQ ID NO:45 or a fragment thereof. In one embodiment, a single chain trimeric CD40L fusion protein comprises a CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a CD40L subunit having the amino acid sequence of SEQ ID NO:34.

[0175] In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a second CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a second CD40L subunit having the amino acid sequence of SEQ ID NO:22. In another embodiment, a single chain trimeric CD40L fusion protein comprises a CD40L subunit comprising the amino acid sequence of SEQ ID NO:45 or afragment thereof. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a second CD40L subunit having the amino acid sequence of SEQ ID NO: 33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a second CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a second CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a second CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a second CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a second CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a second CD40L subunit having the amino acid sequence of SEQ ID NO:34.

[0176] In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and athird CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20.

[0177] In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ IDNO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20.

[0178] In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:34, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO: 34, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:34, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40Lfusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:34, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:34, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:20.

[0179] In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having theamino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having theamino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:34, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO: 34, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:34, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:34, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:34, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:21.

[0180] In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunithaving the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunithaving the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:34, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO: 34, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:34, a second CD40L subunithaving the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:34, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:34, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:22.

[0181] In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a firstCD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a firstCD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:34, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO: 34, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:34, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:34, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:34, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:33.

[0182] In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ IDNO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:20, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:21, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ IDNO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:22, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:33, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:34, a second CD40L subunit having the amino acid sequence of SEQ ID NO:20, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO: 34, a second CD40L subunit having the amino acid sequence of SEQ ID NO:21, and a third CD40L subunit having the amino acid sequence of SEQ IDNO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:34, a second CD40L subunit having the amino acid sequence of SEQ ID NO:22, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:34, a second CD40L subunit having the amino acid sequence of SEQ ID NO:33, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34. In one embodiment, a single chain trimeric CD40L fusion protein comprises a first CD40L subunit having the amino acid sequence of SEQ ID NO:34, a second CD40L subunit having the amino acid sequence of SEQ ID NO: 34, and a third CD40L subunit having the amino acid sequence of SEQ ID NO:34.

[0183] In some embodiments, the single chain trimeric CD40L fusion protein comprises three CD40L subunits, connected to each other with flexible peptide linkers to form a linear CD40L trimer. In some embodiments, the CD40L fusion protein is not in, attached to, or associated with an oncolytic virus. In particular embodiments, the flexible peptide linkers connecting the CD40L subunits in the fusion protein comprise any one sequence selected from the group consisting of EGKSSGSGS (SEQ ID NO:23) and (GaS)n (SEQ ID NO:39), wherein n is an integer from 1 to 20. In some embodiments, the integer is 1. In some embodiments, the integer is 2. In some embodiments, the integer is 3. In some embodiments, the integer is 4. In some embodiments, the integer is 5. In some embodiments, the integer is 6. In some embodiments, the integer is 7. In some embodiments, the integer is 8. In some embodiments, the integer is 9. In some embodiments, the integer is 10. In some embodiments, the integer is 11. In some embodiments, the integer is 12. In some embodiments, the integer is 13. In some embodiments, the integer is 14. In some embodiments, the integer is 15. In some embodiments, the integer is 16. In some embodiments, the integer is 17. In some embodiments, the integer is 18. In some embodiments, the integer is 19. In some embodiments, the integer is 20.

[0184] In some embodiments, the flexible linker comprises EGKSSGSGS (SEQ ID NO:23). In some embodiments, the flexible linker comprises (GaS)3 (SEQ ID NO:25). In some embodiments, the peptide linker comprises SEQ ID NO:23. In some embodiments, the peptide linker comprises SEQ ID NO:25.

[0185] In some embodiments, the peptide linker comprises the sequence EGKSSGSGS (SEQ ID NO:23). In some embodiments, the peptide linker comprises an amino acid sequence having at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 98% or at least 99% sequence identity with EGKSSGSGS (SEQ ID NO:23). In some embodiments, the peptide linker comprises an amino acid sequence having at least 50% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 55% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 60% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 65% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 70% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 75% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 80% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 85% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 90% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 95% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 98% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 99% identity. In some embodiments, the peptide linker comprises an amino acid sequence having 100% sequence identity.

[0186] In some embodiments, the peptide linker comprises the sequence (G3S)n(SEQ ID NO:39), or comprises an amino acid sequence having at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 98% or at least 99% sequence identity with (G3S)n(SEQ ID NO:39). In some embodiments, the peptide linker comprises an amino acid sequence having at least 50% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 55% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 60% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 65% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 70% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 75% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 80% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 85% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 90% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 95% identity. In some embodiments, the peptide linker comprises an amino acid sequence having at least 98% identity. In some embodiments, thepeptide linker comprises an amino acid sequence having at least 99% identity. In some embodiments, the peptide linker comprises an amino acid sequence having 100% sequence identity.

[0187] In particular embodiments, the single chain trimeric CD40L fusion protein comprises any one sequence selected from the sequences shown in the following table, where the underlined portion corresponds to the linker sequences of Table 3.Table 3: CD40L Trimer Sequences

[0188] In one embodiment, the single chain trimeric CD40L fusion protein comprises SEQ ID NO:35. In another embodiment, the single chain trimeric CD40L fusion protein comprises SEQ ID NO:36. In another embodiment, the single chain trimeric CD40L fusion protein comprises SEQ ID NO:37. In another embodiment, the single chain trimeric CD40L fusion protein comprises SEQ ID NO:38.

[0189] In some embodiments, the single chain trimeric CD40L fusion protein can also be recombinantly fused, e.g., to a heterologous peptide or polypeptide (or fragment thereof, for example, to a polypeptide of about 10, about 20, about 30, about 40, about 50, about 60, about 70, about 80, about 90, or about 100 amino acids) to generate larger fusion proteins. Accordingly, in some embodiments, provided herein are polypeptides comprising a CD40L trimer fused to a heterologous peptide or polypeptide not derived from CD40L (which is referred to as a “non-CD40L” peptide or polypeptide sometimes in this application). The connection between the CD40L trimer and the non-CD40L peptide or polypeptide can be direct or via a flexible peptide tether. In some embodiments, the non-CD40L peptide or polypeptide is fused to the N-terminus of the CD40L trimer. In some embodiments, the non- CD40L peptide or polypeptide is fused to the C-terminus of the CD40L trimer.

[0190] Accordingly, in one aspect, provided herein are fusion proteins comprising a CD40L trimer fused to a non-CD40L peptide or polypeptide, either directly or via a flexible peptide tether. In some embodiments, the non-CD40L portion of the fusion protein comprises an Fc monomer peptide.

[0191] In some embodiments, the CD40L trimer is connected to an Fc monomer peptide. In some embodiments, the CD40L Fc fusion protein is not in, attached to, or associated with an oncolytic virus. In some embodiments, the CD40L trimer is connected to a scFv or a construct comprising an scFv. In some embodiments, the scFv comprises a flexible linker for stabilizing the scFv, wherein the linker is stabilized to the scFv with disulfide bonds between the linker points and anchor points within the scFv. Stabilizing the scFv with staple technology is described in WO 2023 / 089587 and is incorporated in its entirety by reference. In some embodiments, the proteins as shown in FIG 1A, are designed with intra-subunitlinkers, tethers, Fc attachment points and scFv attachment points. In some embodiments, the CD40L trimer comprises attachment sites for binding to a cell membrane.

[0192] Provided herein is a single chain trimeric CD40L Fc fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide. In some embodiments, the CD40L Fc fusion protein is not in, attached to, or associated with an oncolytic virus.

[0193] As provided herein, the single chain trimeric CD40L Fc fusion protein can comprise an Fc region from an IgG antibody. In some embodiments, the single chain trimeric CD40L Fc fusion protein can comprise an Fc region from an IgGl, IgG2, IgG3, or IgG4 antibody. In some embodiments, the single chain trimeric CD40L Fc fusion protein can comprise an Fc region from an IgGl antibody. In some embodiments, the single chain trimeric CD40L Fc fusion protein can comprise an Fc region from an IgG2 antibody. In some embodiments, the single chain trimeric CD40L Fc fusion protein can comprise an Fc region from an IgG3 antibody. In some embodiments, the single chain trimeric CD40L Fc fusion protein can comprise an Fc region from an IgG4 antibody. In some embodiments, the single chain trimeric CD40L Fc fusion protein can comprise an Fc monomer that is a silent Fc region or a modified Fc region, that has a genetically engineered Fc domain with key mutations that abrogate binding of Fc receptors and abolish antibody directed cellular cytotoxicity (ADCC) effector function.

[0194] In some embodiments, the trimeric CD40L portion of the fusion protein is genetically fused or chemically conjugated to the C-terminus of the Fc region. In some embodiments, the trimeric CD40L portion of the fusion protein is genetically fused or chemically conjugated to the N-terminus of the Fc region.

[0195] In some embodiments, the Fc monomer peptide is covalently linked to the CD40L trimer by a peptide tether.

[0196] In some embodiments, the non-CD40L portion of the fusion protein comprises a trimerization motif.

[0197] Provided herein is a single chain trimeric CD40L trimerization fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) a trimerization motif.

[0198] As provided herein, the single chain trimeric CD40L trimerization fusion protein can comprise a trimerization motif of any origin, including biological and synthetic peptides. In some embodiments, the single chain trimeric CD40L trimerization fusion protein can comprise a synthetic trimerization motif. In some embodiments, the single chain trimericCD40L trimerization fusion protein can comprise a trimerization motif of biological origin. In some embodiments, the single chain trimeric CD40L trimerization protein can comprise a trimerization motif from a viral, bacterial, protist, plant, fungal, or animal protein. In some embodiments, the single chain trimeric CD40L trimerization protein can comprise a trimerization motif from an animal protein. In some embodiments, the single chain trimeric CD 40L trimerization protein can comprise a trimerization motif from a fungal protein. In some embodiments, the single chain trimeric CD40L trimerization protein can comprise a trimerization motif from a plant protein. In some embodiments, the single chain trimeric CD40L trimerization protein can comprise a trimerization motif from a protist protein. In some embodiments, the single chain trimeric CD40L trimerization protein can comprise a trimerization motif from a bacterial protein. In some embodiments, the single chain trimeric CD40L trimerization protein can comprise a trimerization motif from a viral protein. In some embodiments, the single chain trimeric CD40L trimerization fusion protein can comprise a trimerization motif from a T4 phage protein. In some embodiments, the single chain trimeric CD40L trimerization fusion protein can comprise a T4 fibritin trimerization motif. In some embodiments, the single chain trimeric CD40L trimerization fusion protein can comprise a trimerization motif comprising SEQ ID NO:41. In some embodiments, the trimerization motif is a tumor necrosis factor receptor-associated factor (TRAF) trimerization motif. In some embodiments, the trimerization motif is an isoleucine-zipper (ILZ) trimerization motif.

[0199] In some embodiments, the trimeric CD40L portion of the fusion protein is genetically fused or chemically conjugated to the C-terminus of the trimerization motif. In some embodiments, the trimeric CD40L portion of the fusion protein is genetically fused or chemically conjugated to the N-terminus of the trimerization motif.

[0200] In some embodiments, the trimerization motif is covalently linked to the CD40L trimer by a peptide tether.

[0201] As used herein, the term “tether” or “peptide tether” refers to the amino acid sequence that connects the trimeric CD40L portion of the fusion protein to the Fc monomer peptide or trimerization motif. In some embodiments, the peptide tether comprises between 0 and 20 amino acids (inclusive of the end points). In some embodiments, the peptide tether comprises between 0 and 1 amino acids. In some embodiments, the peptide tether comprises between 0 and 5 amino acids. In some embodiments, the peptide tether comprises between 0 and 10 amino acids. In some embodiments, the peptide tether comprises between 0 and 15 amino acids. In some embodiments, the peptide tether comprises between 5 and 10 amino acids. In some embodiments, the peptide tether comprises between 5 and 15 amino acids. Insome embodiments, the peptide tether comprises between 5 and 20 amino acids. In some embodiments, the peptide tether comprises between 10 and 15 amino acids. In some embodiments, the peptide tether comprises between 10 and 20 amino acids. In contrast, the term “linker” or peptide linker” refers to the amino acid sequence that connects the CD40L subunits to each other to form a trimer.

[0202] In one embodiment, the peptide tether that connects the trimeric CD40L portion of the fusion protein to the Fc monomer peptide or trimerization motif has the sequence (G4S)n(SEQ ID NO:40), wherein n is an integer from 1 to 20. In some embodiments, the integer is 1. In some embodiments, the integer is 2. In some embodiments, the integer is 3. In some embodiments, the integer is 4. In some embodiments, the integer is 5. In some embodiments, the integer is 6. In some embodiments, the integer is 7. In some embodiments, the integer is 8. In some embodiments, the integer is 9. In some embodiments, the integer is 10. In some embodiments, the integer is 11. In some embodiments, the integer is 12. In some embodiments, the integer is 13. In some embodiments, the integer is 14. In some embodiments, the integer is 15. In some embodiments, the integer is 16. In some embodiments, the integer is 17. In some embodiments, the integer is 18. In some embodiments, the integer is 19. In some embodiments, the integer is 20.

[0203] In one embodiment, the flexible tether does not comprise a (G4S) (SEQ ID NO:28) motif. In one embodiment, the flexible tether comprises (G4S)I (SEQ ID NO:28). In one embodiment, the flexible tether comprises (G4S)2 (SEQ ID NO:26). In one embodiment, the flexible tether comprises ('G4S)! (SEQ ID NO:24). In one embodiment, the flexible tether comprises (G4S)4(SEQ ID NO:27). In some embodiments, the peptide tether comprises SEQ ID NO:24. In some embodiments, the peptide tether comprises SEQ ID NO:26. In some embodiments, the peptide tether comprises SEQ ID NO:27. In some embodiments, the peptide tether comprises SEQ ID NO:28.

[0204] In some embodiments, the peptide tether comprises the sequence (G4S)n(SEQ ID NO:40), or comprises an amino acid sequence having at least 50, at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, at least 90, at least 95, at least 98 or at least 99%, sequence identity with (G4S)n(SEQ ID NO:40). In some embodiments, the peptide linker comprises an amino acid sequence having at least 50% identity with (G4S)n(SEQ ID NO: 40). In some embodiments, the peptide linker comprises an amino acid sequence having at least 55% identity with (G4S)n(SEQ ID NO:40). In some embodiments, the peptide linker comprises an amino acid sequence having at least 60% identity with (G4S)n(SEQ ID NO:40). In some embodiments, the peptide linker comprises an amino acid sequence having at least65% identity with (G4S)n(SEQ ID NO:40). In some embodiments, the peptide linker comprises an amino acid sequence having at least 70% identity with (G4S)n(SEQ ID NO:40). In some embodiments, the peptide linker comprises an amino acid sequence having at least 75% identity with (G4S)n(SEQ ID NO:40). In some embodiments, the peptide linker comprises an amino acid sequence having at least 80% identity with (G4S)n(SEQ ID NO:40). In some embodiments, the peptide linker comprises an amino acid sequence having at least 85% identity with (G4S)n(SEQ ID NO:40). In some embodiments, the peptide linker comprises an amino acid sequence having at least 90% identity with (G4S)n(SEQ ID NO:40). In some embodiments, the peptide linker comprises an amino acid sequence having at least 95% identity with (G4S)n(SEQ ID NO:40). In some embodiments, the peptide linker comprises an amino acid sequence having at least 98% identity with (G4S)n(SEQ ID NO:40). In some embodiments, the peptide linker comprises an amino acid sequence having at least 99% identity with (G4S)n(SEQ ID NO:40). In some embodiments, the peptide linker comprises an amino acid sequence having 100% sequence identity with (G4S)n(SEQ ID NO:40).

[0205] In one embodiment, the peptide linker that connects the CD40L subunits to each other to form the trimeric CD40L portion of the fusion protein may be a flexible linker comprising a sequence selected from the group consisting of EGKSSGSGS (SEQ ID NO:23) and (G3S)n(SEQ ID NO: 39), wherein n is an integer from 1 to 20. In some embodiments, the integer is 1. In some embodiments, the integer is 2. In some embodiments, the integer is 3. In some embodiments, the integer is 4. In some embodiments, the integer is 5. In some embodiments, the integer is 6. In some embodiments, the integer is 7. In some embodiments, the integer is 8. In some embodiments, the integer is 9. In some embodiments, the integer is 10. In some embodiments, the integer is 11. In some embodiments, the integer is 12. In some embodiments, the integer is 13. In some embodiments, the integer is 14. In some embodiments, the integer is 15. In some embodiments, the integer is 16. In some embodiments, the integer is 17. In some embodiments, the integer is 18. In some embodiments, the integer is 19. In some embodiments, the integer is 20. In one embodiment, the flexible linker comprises EGKSSGSGS (SEQ ID NO:23). In one embodiment, the flexible linker comprises (GaS)3 (SEQ ID NO:25). In some embodiments, the peptide linker comprises SEQ ID NO:23. In some embodiments, the peptide linker comprises SEQ ID NO:25.

[0206] In some embodiments, the peptide linker comprises the sequence EGKSSGSGS(SEQ ID NO:23), or comprises an amino acid sequence having at least 50, atleast 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, at least 90, at least 95, at least 98 or at least 99%, sequence identity with EGKSSGSGS (SEQ ID NO:23). In some embodiments, the peptide linker comprises an amino acid sequence having at least 50% identity with EGKSSGSGS (SEQ ID NO:23). In some embodiments, the peptide linker comprises an amino acid sequence having at least 55% identity with EGKSSGSGS (SEQ ID NO:23). In some embodiments, the peptide linker comprises an amino acid sequence having at least 60% identity with EGKSSGSGS (SEQ ID NO:23). In some embodiments, the peptide linker comprises an amino acid sequence having at least 65% identity with EGKSSGSGS (SEQ ID NO:23). In some embodiments, the peptide linker comprises an amino acid sequence having at least 70% identity with EGKSSGSGS (SEQ ID NO:23). In some embodiments, the peptide linker comprises an amino acid sequence having at least 75% identity with EGKSSGSGS (SEQ ID NO:23). In some embodiments, the peptide linker comprises an amino acid sequence having at least 80% identity with EGKSSGSGS (SEQ ID NO:23). In some embodiments, the peptide linker comprises an amino acid sequence having at least 85% identity with EGKSSGSGS (SEQ ID NO:23). In some embodiments, the peptide linker comprises an amino acid sequence having at least 90% identity with EGKSSGSGS (SEQ ID NO:23). In some embodiments, the peptide linker comprises an amino acid sequence having at least 95% identity with EGKSSGSGS (SEQ ID NO:23). In some embodiments, the peptide linker comprises an amino acid sequence having at least 98% identity with EGKSSGSGS (SEQ ID NO:23). In some embodiments, the peptide linker comprises an amino acid sequence having at least 99% identity with EGKSSGSGS (SEQ ID NO:23). In some embodiments, the peptide linker comprises an amino acid sequence having 100% sequence identity with EGKSSGSGS (SEQ ID NO:23).

[0207] In some embodiments, the peptide linker comprises the sequence (G3S)n(SEQ ID NO:39), or comprises an amino acid sequence having at least 50, at least 55, at least 60, at least 65, at least 70, at least 75, at least 80, at least 85, at least 90, at least 95, at least 98 or at least 99%, sequence identity with (G3S)n(SEQ ID NO:39). In some embodiments, the peptide linker comprises an amino acid sequence having at least 50% identity with (G3S)n(SEQ ID NO:39). In some embodiments, the peptide linker comprises an amino acid sequence having at least 55% identity with (G3S)n(SEQ ID NO:39). In some embodiments, the peptide linker comprises an amino acid sequence having at least 60% identity with (G3S)n(SEQ ID NO:39). In some embodiments, the peptide linker comprises an amino acid sequence having at least 65% identity with (G3S)n(SEQ ID NO:39). In some embodiments, the peptide linker comprises an amino acid sequence having at least 70% identity with (G3S)n(SEQ ID NO:39).In some embodiments, the peptide linker comprises an amino acid sequence having at least 75% identity with (G3S)n(SEQ ID NO:39). In some embodiments, the peptide linker comprises an amino acid sequence having at least 80% identity with (G3S)n(SEQ ID NO:39). In some embodiments, the peptide linker comprises an amino acid sequence having at least 85% identity with (G3S)n(SEQ ID NO:39). In some embodiments, the peptide linker comprises an amino acid sequence having at least 90% identity with (G3S)n(SEQ ID NO:39). In some embodiments, the peptide linker comprises an amino acid sequence having at least 95% identity with (G3S)n(SEQ ID NO:39). In some embodiments, the peptide linker comprises an amino acid sequence having at least 98% identity with (G3S)n(SEQ ID NO:39). In some embodiments, the peptide linker comprises an amino acid sequence having at least 99% identity with (G3S)n(SEQ ID NO:39). In some embodiments, the peptide linker comprises an amino acid sequence having 100% sequence identity with (G3S)n(SEQ ID NO:39).

[0208] In particular embodiments, the Fc monomer in the fusion protein according to the present disclosure comprises any one sequence selected from Table 4.Table 4: Fc Monomer Sequences

[0209] In some embodiments, the CD40L trimer is connected to the N-terminus of the Fc monomer peptide. In some embodiments, the single chain trimeric CD40E Fc fusion protein comprises any one sequence selected from SEQ ID NOs:l-12, or a fragment thereof.

[0210] In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO:1. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO:2. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO:3. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO:4. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO:5. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO:6. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO:7. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO: 8. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO:9. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO: 10. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO: 11. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO: 12. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO:1. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO:2. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO:3. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO:4. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO:5. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO:6. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO:7. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO:8. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO:9. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO: 10. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO: 11. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO: 12.

[0211] In some embodiments, the CD40L trimer is connected to the C-terminus of the Fc monomer peptide. In some embodiments, the single chain trimeric CD40L Fc fusion protein comprises any one sequence selected from SEQ ID NOs: 13-19, or a fragment thereof. In one embodiment, the single chain trimeric CD40E Fc fusion protein comprises SEQ ID NO: 16 or a fragment thereof. In one embodiment, the single chain trimeric CD40E Fc fusion protein comprises SEQ ID NO: 13. In one embodiment, the single chain trimeric CD40E Fc fusionprotein comprises SEQ ID NO: 14. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO: 15. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO: 16. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO: 17. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO: 18. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises SEQ ID NO: 19. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO:13. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO: 14. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO: 15. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO: 16. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO: 17. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO: 18. In one embodiment, the single chain trimeric CD40L Fc fusion protein comprises a fragment of SEQ ID NO: 19.

[0212] In some embodiments, the CD40 ligand subunits comprise a portion of the CD40L extracellular sequence. In some embodiments, the CD40L subunits comprise any one of the sequences selected from SEQ ID NOs:20-22, or a fragment thereof. In one embodiment, the CD40L subunits comprises SEQ ID NO:20. In one embodiment, the CD40L subunits comprises SEQ ID NO:21. In one embodiment, the CD40L subunits comprises SEQ ID NO:22. In one embodiment, the CD40L subunits comprises a fragment of SEQ ID NO:20. In one embodiment, the CD40L subunits comprises a fragment of SEQ ID NO:21. In one embodiment, the CD40L subunits comprises a fragment of SEQ ID NO:22.

[0213] In some instances, two single chain trimeric CD40L Fc fusion proteins can form a homodimeric Fc fusion protein or a heterodimeric Fc fusion protein with the latter being preferred. In one embodiment, two single chain trimeric CD40L Fc fusion proteins form a homodimeric Fc fusion protein. In one embodiment, two single chain trimeric CD40L Fc fusion proteins form a heterodimeric Fc fusion protein. In some cases, one monomer of the heterodimeric Fc fusion protein comprises only an Fc monomer peptide or fragment thereof and the other monomer is a single chain trimeric CD40E Fc fusion protein. In one embodiment, one monomer of the heterodimeric Fc fusion protein comprises only an Fc monomer peptide and the other monomer is a single chain trimeric CD40E Fc fusion protein. In one embodiment, one monomer of the heterodimeric Fc fusion protein comprises only a fragment of a Fc monomer peptide and the other monomer is a single chain trimeric CD40EFc fusion protein. In some embodiments, single chain trimeric CD40L Fc fusion proteins include a variant Fc monomer with one or more amino acid substitutions compared to a reference or wild-type Fc monomer. In some embodiments, one monomer of the heterodimeric Fc fusion protein comprises an Fc monomer peptide or fragment thereof and a protein domain other than CD40L, such as a receptor, ligand or other binding partner. In one embodiment, one monomer of the heterodimeric Fc fusion protein comprises an Fc monomer peptide and a protein domain other than CD40L. In one embodiment, one monomer of the heterodimeric Fc fusion protein comprises a fragment of Fc monomer peptide and a protein domain other than CD40L. In one embodiment, the protein domain other than CD40L is a receptor. In one embodiment, the protein domain other than CD40L is a ligand. In one embodiment, the protein domain other than CD40L is another binding partner. Accordingly, a single chain trimeric CD40L Fc fusion protein can be a component of a heterodimeric Fc fusion protein that is a bispecific molecule. Thus, in some embodiments, provided is a bispecific molecule that comprises a single chain trimeric CD40L Fc fusion protein provided herein.

[0214] In some embodiments, the CD40L trimer is connected to the C-terminus of the trimerization motif. In some embodiments, the single chain trimeric CD40L trimerization fusion protein comprises any one sequence selected from SEQ ID NOs:43, 44, 46, and 47, and fragments thereof. A schematic is shown in FIG. 8A, demonstrating a mouse surrogate CD40 agonist payload, and FIG. 9A, demonstrating a human CD40 agonist payload, which are trimerized, C-terminal fusion protein consisting of trimeric bundles of CD40L ectodomains.

[0215] In one embodiment, the single chain trimeric CD40L trimerization fusion protein comprises SEQ ID NO:43. In one embodiment, the single chain trimeric CD40L trimerization fusion protein comprises SEQ ID NO:44. In one embodiment, the single chain trimeric CD40L trimerization fusion protein comprises SEQ ID NO:46. In one embodiment, the single chain trimeric CD40L trimerization fusion protein comprises SEQ ID NO:47. In one embodiment, the single chain trimeric CD40L trimerization fusion protein comprises a fragment of SEQ ID NO: 43. In one embodiment, the single chain trimeric CD40L trimerization fusion protein comprises a fragment of SEQ ID NO:44. In one embodiment, the single chain trimeric CD40L trimerization fusion protein comprises a fragment of SEQ ID NO:46. In one embodiment, the single chain trimeric CD40L trimerization fusion protein comprises a fragment of SEQ ID NO:47.

[0216] In some embodiments, the CD40L trimer is connected to the N-terminus of the trimerization motif.

[0217] In some embodiments, the CD40 ligand subunits comprise a portion of the CD40L extracellular sequence. In some embodiments, the CD40L subunits comprise any one of the sequences selected from SEQ ID NOs:20-22, and fragments thereof. In one embodiment, the CD40L subunits comprises SEQ ID NO:20. In one embodiment, the CD40L subunits comprises SEQ ID NO:21. In one embodiment, the CD40L subunits comprises SEQ ID NO:22. In one embodiment, the CD40L subunits comprises a fragment of SEQ ID NO:20. In one embodiment, the CD40L subunits comprises a fragment of SEQ ID NO:21. In one embodiment, the CD40L subunits comprises a fragment of SEQ ID NO:22.

[0218] In some embodiments, an CD40L trimer provided herein is recombinantly fused or chemically conjugated (covalent or non-covalent conjugations) to a target antigen. In one embodiment, an CD40L trimer provided herein is recombinantly fused to a target antigen. In one embodiment, an CD40L trimer provided herein is chemically conjugated to a target antigen. In one embodiment, the chemical conjugation is a covalent conjugation. In one embodiment, the chemical conjugation is a non-covalent conjugation. In some embodiments, the target antigen is recombinantly fused to the C-terminus of the CD40L trimer. In other embodiments, the target antigen is recombinantly fused to the N-terminus of the CD40L trimer. In some embodiments, the CD40L trimer and the target antigen is covalently linked via a peptide tether.

[0219] In specific embodiments, provided herein is a single chain trimeric CD40L-target antigen fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) a target antigen.

[0220] In some embodiments, the target antigen is for eliciting an immune response. In some embodiments, the target antigen is originated or derived from a pathogen or a diseased cell. As used herein, a target antigen “originated” from a pathogen or a diseased cell refers to a native antigen that is produced by the pathogen or the diseased cell under conditions naturally existing or artificially created. Examples of antigens originated from a pathogen or diseased cell include but are not limited to native proteins expressed by the pathogen or diseased cell in vivo or in vitro. As used herein, a target antigen “derived” from a pathogen or a diseased cell refers to a variant of the native antigen originated therefrom. For example, a variant of a protein or peptide may result from one or more (such as, for example, about 1 to about 25, about 1 to about 20, about 1 to about 15, about 1 to about 10, or about 1 to about 5) changes to an amino acid sequence of the native or unmodified sequence of such protein orpeptide. Variants of a native protein may be naturally occurring (such as allelic or splice variants, or fragmented or processed by an immune cell), or may be artificially constructed. In some embodiments, the target antigen is originated from a pathogen. In some embodiments, the target antigen is originated from a diseased cell. In some embodiments, the target antigen is derived from a pathogen. In some embodiments, the target antigen is derived from a diseased cell.

[0221] In some embodiments, the target antigen is originated or derived from a protein expressed by an infective pathogen, such as a virus, a bacterial, a fungus, or a parasite. In one embodiment, the target antigen is originated from a protein expressed by an infective pathogen. In one embodiment, the target antigen is derived from a protein expressed by an infective pathogen. In one embodiment, the pathogen is a virus. In another embodiment, the pathogen is a bacteria. In one embodiment, the pathogen is a fungus. In another embodiment, the pathogen is a parasite.

[0222] In some embodiments, the target antigen is originated or derived from a protein expressed by a diseased host cell that is infected by the infective pathogen. In one embodiment, the target antigen is originated from a protein expressed by a diseased host cell. In one embodiment, the target antigen is derived from a protein expressed by a diseased host cell. In some embodiments, the diseased host cell is infected by an infective pathogen. In one embodiment, the pathogen is a virus. In another embodiment, the pathogen is a bacteria. In one embodiment, the pathogen is a fungus. In another embodiment, the pathogen is a parasite.

[0223] In some embodiments, the target antigen is originated or derived from a protein produced by an infective pathogen. In some embodiments, the target antigen is originated from a protein produced by an infective pathogen. In some embodiments, the target antigen is derived from a protein produced by an infective pathogen. In some embodiments, the infective pathogen mediates host entry by the pathogen. In one embodiment, the pathogen is a virus. In another embodiment, the pathogen is a bacteria. In one embodiment, the pathogen is a fungus. In another embodiment, the pathogen is a parasite.

[0224] In some embodiments, the target antigen is originated or derived from a protein produced by a cancer cell or a tumor stromal cell. In some embodiments, the target antigen is originated from a protein produced by a cancer cell. In some embodiments, the target antigen is originated from a protein produced by a tumor stromal cell. In some embodiments, the target antigen is derived from a protein produced by a cancer cell. In some embodiments, the target antigen is derived from a protein produced by a tumor stromal cell.

[0225] In specific embodiments, the target antigen is a tumor associated antigen (TAA), or an antigenic fragment thereof. In one embodiment, the target antigen is a TAA. In one embodiment, the target antigen is an antigenic fragment of a TAA.

[0226] In some embodiments, the target antigen is recognized by the innate immune system of a subject. In some embodiments, the target antigen is processed and presented by antigen presenting cells. In some embodiments, the target antigen is processed and presented by antigen presenting cells in vitro. In some embodiments, the target antigen is processed and presented by antigen presenting cells in vivo. In some embodiments, the antigen presenting cells are B cells, dendritic cells, macrophages, natural killer cells, monocytes, granulocytes, eosinophils, neutrophil, or a combination thereof. In some embodiments, the antigen presenting cells are dendritic cells. In some embodiments, the antigen presenting cells are B cells. In some embodiments, the antigen presenting cells are dendritic cells. In some embodiments, the antigen presenting cells are macrophages. In some embodiments, the antigen presenting cells are natural killer cells. In some embodiments, the antigen presenting cells are monocytes. In some embodiments, the antigen presenting cells are granulocytes. In some embodiments, the antigen presenting cells are eosinophils. In some embodiments, the antigen presenting cells are neutrophils.

[0227] In some embodiments, the target antigen is derived from a protein expressed on the surface of a cell, where the expression marks the cell for apoptosis (e.g., via cell- mediated cytotoxicity or antibody-dependent cellular toxicity).

[0228] In some embodiments, the target antigen is derived from a protein expressed on the surface of a cell. In certain embodiments, the protein that is marked on the surface of a cell marks the cell for apoptosis. In some embodiments, the apoptosis is via cell-mediated cytotoxicity. In other embodiments, the apoptosis is via antibody-dependent cellular toxicity.

[0229] In some embodiments, the target antigen is derived from a protein expressed on the surface of a cell, wherein the expression marks the cell for phagocytosis. In some embodiments, the target antigen is derived from a protein specifically recognized by circulating antibodies in a subject.

[0230] In some embodiments, the single chain trimeric CD40L fusion protein can also be chemically conjugated (covalent or non-covalent conjugations) or recombinantly fused, e.g., to a diagnostic agent or detectable agent. In some embodiments, the CD40L fusion protein conjugated or fused to a diagnostic agent or detectable agent is not in, attached to, or associated with an oncolytic virus. In one embodiment, the single chain trimeric CD40L fusion protein is chemically conjugated to another molecule. In one embodiment, theconjugation is a covalent conjugation. In another embodiment, the conjugation is a non- covalent conjugation. In one embodiment, the single chain trimeric CD40L fusion protein is recombinantly fused to another molecule. In some embodiments, the CD40L Fc fusion protein is not in, attached to, or associated with an oncolytic virus. In some embodiments the other molecule is a diagnostic agent. In some embodiments the other molecule is a detectable agent. In particular embodiments, the single chain trimeric CD40L fusion protein of the present disclosure is coupled with detectable substances including, but not limited to, various enzymes, such as, but not limited to, horseradish peroxidase, alkaline phosphatase, betagalactosidase, or acetylcholinesterase; prosthetic groups, such as, but not limited to, streptavidin / biotin or avidin / biotin; fluorescent materials, such as, but not limited to, umbelliferone, fluorescein, fluorescein isothiocynate, rhodamine, dichlorotriazinylamine fluorescein, dansyl chloride, or phycoerythrin; luminescent materials, such as, but not limited to, luminol; bioluminescent materials, such as, but not limited to, luciferase, luciferin, or aequorin; chemiluminescent material, such as, but not limited to, an acridinium based compound or a HALOTAG; radioactive materials, such as, but not limited to, iodine (131I,125I,123I, and121I,), carbon (14C), sulfur (35S), tritium (3H), indium (115In,113In,112In, andluIn), technetium (99Tc), thallium (201Ti), gallium (68Ga and67Ga), palladium (103Pd), molybdenum (99Mo), xenon (133Xe), fluorine (18F),153Sm,177Lu,159Gd,149Pm,140La,175Yb,166HO,90Y,47SC,186Re,188Re,142Pr,105Rh,97Ru,68Ge,57Co,65Zn,85Sr,32P,153Gd,169Yb,51Cr,54Mn,75Se,113Sn, or117Sn; positron emitting metals using various positron emission tomographies; and non-radioactive paramagnetic metal ions.

[0231] In some embodiments, fusion proteins provided herein can be fused to marker or “tag” sequences, such as a peptide, to facilitate purification. In specific embodiments, the marker or tag amino acid sequence is a hexa-histidine peptide (SEQ ID NO: 50), such as the tag provided in a pQE vector (see, e.g., QIAGEN, Inc.), among others, many of which are commercially available. For example, as described in Gentz et al., 1989, Proc. Natl. Acad. Sci. USA 86:821-24, hexa-histidine (SEQ ID NO: 50) provides for convenient purification of the fusion protein. Other peptide tags useful for purification include, but are not limited to, the hemagglutinin (“HA”) tag, which corresponds to an epitope derived from the influenza hemagglutinin protein (Wilson et al., 1984, Cell 37:767-78), and the “FLAG” tag.

[0232] Methods for fusing or conjugating moieties (including polypeptides) are known see, e.g., Arnon et al., Monoclonal Antibodies for Immunotargeting of Drugs in Cancer Therapy, in Monoclonal Antibodies and Cancer Therapy 243-56 (Reisfeld et al. eds., 1985); Hellstrom et al., Antibodies for Drug Delivery, in Controlled Drug Delivery 623-53(Robinson et al. eds., 2d ed. 1987); Thorpe, Antibody Carriers of Cytotoxic Agents in Cancer Therapy: A Review, in Monoclonal Antibodies: Biological and Clinical Applications 475-506 (Pinchera et al. eds., 1985); Analysis, Results, and Future Prospective of the Therapeutic Use of Radiolabeled Antibody in Cancer Therapy, in Monoclonal Antibodies for Cancer Detection and Therapy 303-16 (Baldwin et al. eds., 1985); Thorpe et al., 1982, Immunol. Rev. 62:119-58; U.S. Pat. Nos. 5,336,603; 5,622,929; 5,359,046; 5,349,053; 5,447,851;5,723,125; 5,783,181; 5,908,626; 5,844,095; and 5,112,946; EP 307,434; EP 367,166; EP 394,827; PCT publications WO 91 / 06570, WO 96 / 04388, WO 96 / 22024, WO 97 / 34631, and WO 99 / 04813; Ashkenazi et al., 1991, Proc. Natl. Acad. Sci. USA, 88: 10535-39; Traunecker et al., 1988, Nature, 331:84-86; Zheng et al., 1995, J. Immunol. 154:5590-600; and Vil et al., 1992, Proc. Natl. Acad. Sci. USA 89: 11337-41).

[0233] In some embodiments, a polypeptide comprising the single chain trimeric CD40L fusion protein provided herein can modulate CD40 upon binding to CD40. In certain embodiments, a polypeptide comprising the single chain trimeric CD40L fusion protein provided herein can activate CD40 upon binding to CD40.

[0234] In one aspect, the CD40 is activated upon binding the single chain trimeric CD40L fusion protein. In some embodiments, the single chain trimeric CD40L fusion protein activates CD40 with an ECso of less than about 4 nM. In some embodiments, the single chain trimeric CD40L fusion protein activates CD40 with an ECso of less than about 3 nM. In some embodiments, the single chain trimeric CD40L fusion protein activates CD40 with an ECso of less than about 1 nM. In some embodiments, the single chain trimeric CD40L fusion protein activates CD40 with an ECso of less than about 500 pM. In some embodiments, the single chain trimeric CD40L fusion protein activates CD40 with an ECso of less than about 100 pM.

[0235] In one aspect, the CD40 is activated upon binding the single chain trimeric CD40L Fc fusion protein. In some embodiments, the single chain trimeric CD40L Fc fusion protein activates CD40 with an ECso of less than about 4 nM. In some embodiments, the single chain trimeric CD40L Fc fusion protein activates CD40 with an ECso of less than about 3 nM. In some embodiments, the single chain trimeric CD40L Fc fusion protein activates CD40 with an ECso of less than about 1 nM. In some embodiments, the single chain trimeric CD40L Fc fusion protein activates CD40 with an ECso of less than about 500 pM. In some embodiments, the single chain trimeric CD40L Fc fusion protein activates CD40 with an ECso of less than about 100 pM.

[0236] In certain embodiments, the ECso is less than about 1 nM. In one embodiment, the ECso is less than about 0.9 nM. In one embodiment, the ECso is less than about 0.8 nM. Inone embodiment, the ECso is less than about 0.7 nM. In one embodiment, the ECso is less than about 0.6 nM. In one embodiment, the ECso is less than about 0.5 nM. In one embodiment, the ECso is less than about 0.4 nM. In one embodiment, the ECso is less than about 0.300 nM. In one embodiment, the ECso is less than about 0.2 nM. In one embodiment, the ECso is less than about 0.19 nM. In one embodiment, the ECso is less than about 0.18 nM. In one embodiment, the ECso is less than about 0.17 nM. In one embodiment, the ECso is less than about 0.16 nM. In one embodiment, the ECso is less than about 0.15 nM. In one embodiment, the ECso is less than about 0.14 nM. In one embodiment, the ECso is less than about 0.13 nM. In one embodiment, the ECso is less than about 0.12 nM. In one embodiment, the ECso is less than about 0.11 nM. In one embodiment, the ECso is less than about 0.1 nM. In one embodiment, the ECso is less than about 0.09 nM. In one embodiment, the ECso is less than about 0.08 nM. In one embodiment, the ECso is less than about 0.07 nM. In one embodiment, the ECso is less than about 0.06 nM. In one embodiment, the ECso is less than about 0.05 nM. In one embodiment, the ECso is less than about 0.04 nM. In one embodiment, the ECso is less than about 0.03 nM. In one embodiment, the ECso is less than about 0.02 nM. In one embodiment, the ECso is or less than about 0.01 nM. In certain embodiments. In one embodiment, the ECso is the ECso is less than about 1 pM. In one embodiment, the ECso is less than about 0.9 pM. In one embodiment, the ECso is less than about 0.8 pM. In one embodiment, the ECso is less than about 0.7 pM. In one embodiment, the ECso is less than about 0.6 pM. In one embodiment, the ECso is less than about 0.5 pM. In one embodiment, the ECso is less than about 0.4 pM. In one embodiment, the ECso is less than about 0.300 pM. In one embodiment, the ECso is less than about 0.2 pM. In one embodiment, the ECso is less than about 0.19 pM. In one embodiment, the ECso is less than about 0.18 pM. In one embodiment, the ECso is less than about 0.17 pM. In one embodiment, the ECso is less than about 0.16 pM. In one embodiment, the ECso is less than about 0.15 pM. In one embodiment, the ECso is less than about 0.14 pM. In one embodiment, the ECso is less than about 0.13 pM. In one embodiment, the ECso is less than about 0.12 pM. In one embodiment, the ECso is less than about 0.11 pM. In one embodiment, the ECso is less than about 0.1 pM. In one embodiment, the ECso is less than about 0.09 pM. In one embodiment, the ECso is less than about 0.08 pM. In one embodiment, the ECso is less than about 0.07 pM. In one embodiment, the ECso is less than about 0.06 pM. In one embodiment, the ECso is less than about 0.05 pM. In one embodiment, the ECso is less than about 0.04 pM. In one embodiment, the ECso is less than about 0.03 pM. In one embodiment, the ECso is less than about 0.02 pM. In one embodiment, the ECso is or less than about 0.01 pM. In certain embodiments. In oneembodiment, the ECso is less than about 1000 pM. In one embodiment, the ECso is less than about 900 pM. In one embodiment, the ECso is less than about 800 pM. In one embodiment, the ECso is less than about 700 pM. In one embodiment, the ECso is less than about 600 pM. In one embodiment, the ECso is less than about 500 pM. In one embodiment, the ECso is less than about 400 pM. In one embodiment, the ECso is less than about 300 pM. In one embodiment, the ECso is less than about 200 pM. In one embodiment, the ECso is less than about 190 pM. In one embodiment, the ECso is less than about 180 pM. In one embodiment, the ECso is less than about 170 pM. In one embodiment, the ECso is less than about 160 pM. In one embodiment, the ECso is less than about 150 pM. In one embodiment, the ECso is less than about 140 pM. In one embodiment, the ECso is less than about 130 pM. In one embodiment, the ECso is less than about 120 pM. In one embodiment, the ECso is less than about 110 pM. In one embodiment, the ECso is less than about 100 pM. In one embodiment, the ECso is less than about 90 pM. In one embodiment, the ECso is less than about 80 pM. In one embodiment, the ECso is less than about 70 pM. In one embodiment, the ECso is less than about 60 pM. In one embodiment, the ECso is less than about 50 pM. In one embodiment, the ECso is less than about 40 pM. In one embodiment, the ECso is less than about 30 pM. In one embodiment, the ECso is less than about 20 pM. In one embodiment, the ECso is less than about 10 pM.

[0237] Also provided herein are methods of modulating a CD40 polypeptide comprising contacting the CD40 polypeptide with a polypeptide comprising the single chain trimeric CD40L fusion protein provided herein. In some embodiments, the single chain trimeric CD40L fusion protein is not in, attached to, or associated with an oncolytic virus. Also provided herein are methods of activating a CD40 polypeptide comprising contacting the CD40 polypeptide with a polypeptide comprising the single chain trimeric CD40L fusion protein provided herein.

[0238] Also provided are methods of activating a CD40 polypeptide comprising contacting the CD40 polypeptide with a single chain trimeric CD40L Fc fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide, wherein said single chain trimeric CD40L Fc fusion protein activates the CD40 polypeptide upon binding. In some embodiments, the single chain trimeric CD40L fusion protein is not in, attached to, or associated with an oncolytic virus.

[0239] Also provided are methods of activating a CD40 polypeptide comprising contacting the CD40 polypeptide with a single chain trimeric CD40L trimerization fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptidelinkers; and (b) a trimerization motif, wherein said single chain trimeric CD40L trimerization fusion protein activates the CD40 polypeptide upon binding. In some embodiments, the single chain trimeric CD40L fusion protein is not in, attached to, or associated with an oncolytic virus.

[0240] Also provided are method of activating a target cell expressing a CD40 polypeptide comprising contacting the target cell with a polypeptide comprising the single chain trimeric CD40L fusion protein according to the present disclosure, thereby producing an activated target cell. In some embodiments, the single chain trimeric CD40L fusion protein is not in, attached to, or associated with an oncolytic virus. In specific embodiments, the polypeptide contacted with the target cell is a single chain trimeric CD40L Fc fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide, wherein the polypeptide activates the target cell upon binding CD40. In some embodiments, the polypeptide contacted with the target cell is a single chain trimeric CD40L trimerization fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an trimerization motif, wherein the polypeptide activates the target cell upon binding CD40. In some embodiments, the activated target cell in turn activates another cell. In some embodiments, the activated target cell activates a T cell. In some embodiments, the activated target cell activates a population of T cells.

[0241] In some embodiments, the target cell is an antigen presenting cell. In some embodiments, the target cell is an immune cell. In some embodiments, the target cell is B cells, natural killer cells, dendritic cells, macrophages, monocytes, granulocytes, eosinophils, neutrophils, or a combination thereof. In one embodiment, the target cell is a dendritic cell. In one embodiment, the target cell is a macrophage. In one embodiment, the target cell is a natural killer cell. In one embodiment, the target cell is a monocyte. In one embodiment, the target cell is a granulocyte. In one embodiment, the target cell is an eosinophil. In one embodiment, the target cell is a granulocyte. In one embodiment, the target cell is a neutrophil. In some embodiments the target cell is a Langerhans cell. In some embodiments the target cell is a prostatic glandular cell. In some embodiments the target cell is a B cell. In some embodiments the target cell is a naive B cell. In some embodiments the target cell is a memory B cell. In some embodiments the target cell is a basal respiratory cell.

[0242] In some embodiments, the activated target cell activates another cell. In some embodiments, the activated target cell activates another cell that does not express the CD40 polypeptide. In some embodiments, the activated target cell activates an immune cell. Insome embodiments, the activated target cell activates a T cell. In some embodiments, the activated target cell activates CD4+T cells, CD8+ T cells, MAIT, natural killer cells, neutrophils, or a combination thereof. In one embodiment, the activated target cell activates a CD4+ T cell. In one embodiment, the activated target cell activates a CD8+ T cell. In one embodiment, the activated target cell activates a MAIT. In one embodiment, the activated target cell activates a natural killer cell. In one embodiment, the activated target cell activates a neutrophil.

[0243] In some embodiments, activation of the target cell is measured as increased proliferation or maturation of the target cell. In one embodiment, activation of the target cell is measured as increased proliferation of the target cell. In one embodiment, activation of the target cell is measured as increased maturation of the target cell. In particular embodiments, proliferation or maturation of the target cell is increased by about 10%, 20%, 30%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 125%, 150%, 175%, 200%, 250%, 300%, 400%, 500%, 600%, 700%, 800%, 900%, or 1000%. In one embodiment, proliferation of the target cell is increased by about 10-100%. In another embodiment, proliferation of the target cell is increased by about 100-200%. In another embodiment, proliferation of the target cell is increased by about 200-300%. In another embodiment, proliferation of the target cell is increased by about 300-400%. In another embodiment, proliferation of the target cell is increased by about 400-500%. In another embodiment, proliferation of the target cell is increased by about 500-600%. In another embodiment, proliferation of the target cell is increased by about 600-700%. In another embodiment, proliferation of the target cell is increased by about 700-800%. In another embodiment, proliferation of the target cell is increased by about 800-900%. In another embodiment, proliferation of the target cell is increased by about 900-1000%. In one embodiment, proliferation of the target cell is increased by about 10%. In one embodiment, proliferation of the target cell is increased by about 20%. In one embodiment, proliferation of the target cell is increased by about 30%. In one embodiment, proliferation of the target cell is increased by about 40%. In one embodiment, proliferation of the target cell is increased by about 45%. In one embodiment, proliferation of the target cell is increased by about 50%. In one embodiment, proliferation of the target cell is increased by about 55%. In one embodiment, proliferation of the target cell is increased by about 60%. In one embodiment, proliferation of the target cell is increased by about 65%. In one embodiment, proliferation of the target cell is increased by about 70%. In one embodiment, proliferation of the target cell is increased by about 75%. In one embodiment, proliferation of the target cell is increased byabout 80%. In one embodiment, proliferation of the target cell is increased by about 85%. In one embodiment, proliferation of the target cell is increased by about 90%. In one embodiment, proliferation of the target cell is increased by about 95%. In one embodiment, proliferation of the target cell is increased by about 100%. In one embodiment, proliferation of the target cell is increased by about 125%. In one embodiment, proliferation of the target cell is increased by about 150%. In one embodiment, proliferation of the target cell is increased by about 175%. In one embodiment, proliferation of the target cell is increased by about 200%. In one embodiment, proliferation of the target cell is increased by about 250%. In one embodiment, proliferation of the target cell is increased by about 300%. In one embodiment, proliferation of the target cell is increased by about 400%. In one embodiment, proliferation of the target cell is increased by about 500%. In one embodiment, proliferation of the target cell is increased by about 600%. In one embodiment, proliferation of the target cell is increased by about 700%. In one embodiment, proliferation of the target cell is increased by about 800%. In one embodiment, proliferation of the target cell is increased by about 900%. In one embodiment, proliferation of the target cell is increased by about 1000%. In one embodiment, maturation of the target cell is increased by about 10-100%. In another embodiment, maturation of the target cell is increased by about 100-200%. In another embodiment, maturation of the target cell is increased by about 200-300%. In another embodiment, maturation of the target cell is increased by about 300-400%. In another embodiment, maturation of the target cell is increased by about 400-500%. In another embodiment, maturation of the target cell is increased by about 500-600%. In another embodiment, maturation of the target cell is increased by about 600-700%. In another embodiment, maturation of the target cell is increased by about 700-800%. In another embodiment, maturation of the target cell is increased by about 800-900%. In another embodiment, maturation of the target cell is increased by about 900-1000%. In one embodiment, maturation of the target cell is increased by about 10%. In one embodiment, maturation of the target cell is increased by about 20%. In one embodiment, maturation of the target cell is increased by about 30%. In one embodiment, maturation of the target cell is increased by about 40%. In one embodiment, maturation of the target cell is increased by about 45%. In one embodiment, maturation of the target cell is increased by about 50%. In one embodiment, maturation of the target cell is increased by about 55%. In one embodiment, maturation of the target cell is increased by about 60%. In one embodiment, maturation of the target cell is increased by about 65%. In one embodiment, maturation of the target cell is increased by about 70%. In one embodiment, maturation of the target cell is increased byabout 75%. In one embodiment, maturation of the target cell is increased by about 80%. In one embodiment, maturation of the target cell is increased by about 85%. In one embodiment, maturation of the target cell is increased by about 90%. In one embodiment, maturation of the target cell is increased by about 95%. In one embodiment, maturation of the target cell is increased by about 100%. In one embodiment, maturation of the target cell is increased by about 125%. In one embodiment, maturation of the target cell is increased by about 150%. In one embodiment, maturation of the target cell is increased by about 175%. In one embodiment, maturation of the target cell is increased by about 200%. In one embodiment, maturation of the target cell is increased by about 250%. In one embodiment, maturation of the target cell is increased by about 300%. In one embodiment, maturation of the target cell is increased by about 400%. In one embodiment, maturation of the target cell is increased by about 500%. In one embodiment, maturation of the target cell is increased by about 600%. In one embodiment, maturation of the target cell is increased by about 700%. In one embodiment, maturation of the target cell is increased by about 800%. In one embodiment, maturation of the target cell is increased by about 900%. In one embodiment, maturation of the target cell is increased by about 1000%.

[0244] In some embodiments, activation of the target cell is measured as prolonged survival time of the target cell. In particular embodiments, survival time of the target cell is increased by about 10%, 20%, 30%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 125%, 150%, 175%, 200%, 250%, 300%, 400%, 500%, 600%, 700%, 800%, 900%, or 1000%. In one embodiment, survival time of the target cell is increased by about 10-100%. In another embodiment, survival time of the target cell is increased by about 100-200%. In another embodiment, survival time of the target cell is increased by about 200-300%. In another embodiment, survival time of the target cell is increased by about 300-400%. In another embodiment, survival time of the target cell is increased by about 400-500%. In another embodiment, survival time of the target cell is increased by about 500-600%. In another embodiment, survival time of the target cell is increased by about 600-700%. In another embodiment, survival time of the target cell is increased by about 700-800%. In another embodiment, survival time of the target cell is increased by about 800-900%. In another embodiment, survival time of the target cell is increased by about 900-1000%. In one embodiment, survival time of the target cell is increased by about 10%. In one embodiment, survival time of the target cell is increased by about 20%. In one embodiment, survival time of the target cell is increased by about 30%. In one embodiment, survival time of the target cell is increased by about 40%. In oneembodiment, survival time of the target cell is increased by about 45%. In one embodiment, survival time of the target cell is increased by about 50%. In one embodiment, survival time of the target cell is increased by about 55%. In one embodiment, survival time of the target cell is increased by about 60%. In one embodiment, survival time of the target cell is increased by about 65%. In one embodiment, survival time of the target cell is increased by about 70%. In one embodiment, survival time of the target cell is increased by about 75%. In one embodiment, survival time of the target cell is increased by about 80%. In one embodiment, survival time of the target cell is increased by about 85%. In one embodiment, survival time of the target cell is increased by about 90%. In one embodiment, survival time of the target cell is increased by about 95%. In one embodiment, survival time of the target cell is increased by about 100%. In one embodiment, survival time of the target cell is increased by about 125%. In one embodiment, survival time of the target cell is increased by about 150%. In one embodiment, survival time of the target cell is increased by about 175%. In one embodiment, survival time of the target cell is increased by about 200%. In one embodiment, survival time of the target cell is increased by about 250%. In one embodiment, survival time of the target cell is increased by about 300%. In one embodiment, survival time of the target cell is increased by about 400%. In one embodiment, survival time of the target cell is increased by about 500%. In one embodiment, survival time of the target cell is increased by about 600%. In one embodiment, survival time of the target cell is increased by about 700%. In one embodiment, survival time of the target cell is increased by about 800%. In one embodiment, survival time of the target cell is increased by about 900%. In one embodiment, survival time of the target cell is increased by about 1000%.

[0245] Also provided are methods of activating a T cell comprising contacting the T cell with an antigen presenting cell in the presence of a single chain trimeric CD40L Fc fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide, wherein the antigen presenting cell expresses a CD40 polypeptide, wherein said single chain trimeric CD40L Fc fusion protein activates the T-cell upon binding the CD40 polypeptide. In some embodiments, the single chain trimeric CD40L Fc fusion protein is not in, attached to, or associated with an oncolytic virus. Further provided are methods of activating a T cell comprising contacting the T cell with an antigen presenting cell in the presence of a single chain trimeric CD40L trimerization fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) a trimerization motif, wherein the antigen presenting cell expresses a CD40 polypeptide, wherein said single chain trimeric CD40L trimerization fusion protein activates the T-cellupon binding the CD40 polypeptide. In some embodiments, the antigen presenting cell presents an antigen to the T cell.

[0246] In some embodiments, activation of a population of T cells is measured by increased secretion of pro-inflammatory cytokines by the T cells. In some embodiments, the pro-inflammatory cytokines are selected from IL-1, IL-2, IL-6, IL-12, IL-17, IL-22, IL-23, GM-CSF, TNF-a, IFN-yor any combination thereof. In one embodiment, the cytokine is IL- 1. In one embodiment, the cytokine is IL-2. In one embodiment, the cytokine is IL-6. In one embodiment, the cytokine is IL-12. In one embodiment, the cytokine is IL-17. In one embodiment, the cytokine is IL-22. In one embodiment, the cytokine is IL-23. In one embodiment, the cytokine is GM-CSF. In one embodiment, the cytokine is TNF-a. In one embodiment, the cytokine is IFN-y.

[0247] In some embodiments, the antigen presenting cell presents an antigen to the T cell. In some embodiments, upon activation of the antigen presenting cell by the single chain trimeric CD40L Fc fusion protein, presentation of the antigen by the antigen presenting cell to the T cell is increased. In some embodiments, the population of antigen presenting cells comprises B cells, dendritic cells, macrophages, natural killer cells, monocytes, granulocytes, eosinophils, neutrophils, or a combination thereof. In some embodiments, the population of antigen presenting cells comprise B cells. In some embodiments, the population of antigen presenting cells comprise macrophages. In some embodiments, the population of antigen presenting cells comprise dendritic cells. In some embodiments, the population of antigen presenting cells comprise natural killer cells. In some embodiments, the population of antigen presenting cells comprise monocytes. In some embodiments, the population of antigen presenting cells comprise granulocytes. In some embodiments, the population of antigen presenting cells comprise eosinophils. In some embodiments, the population of antigen presenting cells comprise neutrophils.

[0248] In some embodiments, upon activation of the antigen presenting cell by the single chain trimeric CD40L trimerization fusion protein, presentation of the antigen by the antigen presenting cell to the T cell is increased. In some embodiments, the population of antigen presenting cells comprises B cells, dendritic cells, macrophages, natural killer cells, monocytes, granulocytes, eosinophils, neutrophils or a combination thereof. In some embodiments, the population of antigen presenting cells comprise B cells. In some embodiments, the population of antigen presenting cells comprise macrophages. In some embodiments, the population of antigen presenting cells comprise dendritic cells. In someembodiments, the population of antigen presenting cells comprise natural killer cells. In some embodiments, the population of antigen presenting cells comprise monocytes. In some embodiments, the population of antigen presenting cells comprise granulocytes. In some embodiments, the population of antigen presenting cells comprise eosinophils. In some embodiments, the population of antigen presenting cells comprise neutrophils.

[0249] Also provided are methods of activating a dendritic cell comprising contacting a CD40 polypeptide with a single chain trimeric CD40L Fc fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide, wherein said single chain trimeric CD40L Fc fusion protein activates the dendritic cell polypeptide upon binding CD40. In some embodiments, the single chain trimeric CD40L Fc fusion protein is not in, attached to, or associated with an oncolytic virus. Further provided are methods of activating a dendritic cell comprising contacting a CD40 polypeptide with a single chain trimeric CD40L trimerization fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) a trimerization motif, wherein said single chain trimeric CD40L trimerization fusion protein activates the dendritic cell polypeptide upon binding CD40.

[0250] In some embodiments, the methods comprise contacting the CD40 polypeptide with a dimer comprising two single chain trimeric CD40L Fc fusion proteins, each comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide. In some embodiments, the dimer is not in, attached to, or associated with an oncolytic virus. In some embodiments, the methods comprise contacting the CD40 polypeptide with a trimer comprising three single chain trimeric CD40L trimerization fusion proteins, each comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) a trimerization motif.

[0251] In some embodiments, provided herein is a method for promoting antibody production by a population of B cells, comprising contacting the B cells with a polypeptide comprising the single chain trimeric CD40L fusion protein according to the present disclosure. In some embodiments, the single chain trimeric CD40L fusion protein is not in, attached to, or associated with an oncolytic virus. In specific embodiments, the polypeptide contacted with the population of B cells is a single chain trimeric CD40L Fc fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide. In specific embodiments, the polypeptide contacted with the population of B cells is a single chain trimeric CD40L trimerization fusion proteincomprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) a trimerization motif.

[0252] In some embodiments, the B cells are contacted with the polypeptide comprising the single chain trimeric CD40L fusion protein in the presence of a target antigen, and wherein the antibody produced by the B cells specifically binds to the antigen. In some embodiments, the single chain trimeric CD40L fusion protein is not in, attached to, or associated with an oncolytic virus. In some embodiments, the target antigen is chemically conjugated or recombinantly fused to the single chain trimeric CD40L fusion protein. In some embodiments, the target antigen is presented by an antigen-presenting cell. In some embodiments, the target antigen is associated with an MHC class I complex. In some embodiments, the target antigen is associated with an MHC class II complex. In some embodiments, the target antigen is originated or derived from an infectious pathogen. In some embodiments, the target antigen is originated or derived from a diseased cell. In some embodiments, the diseased cell is a cancer cell. In some embodiments, the diseased cell is a cell infected by an infectious pathogen. In some embodiments, the infectious pathogen is a virus, a bacterial, a fungus or a parasite.

[0253] In some embodiments, antibody production by the population of B cells is increased by about 10%, 20%, 30%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 125%, 150%, 175%, 200%, 250%, 300%, 400%, 500%, 600%, 700%, 800%, 900%, or 1000%. In one embodiment, antibody production by a population of B cells is increased by about 10-100%. In another embodiment, antibody production by a population of B cells is increased by about 100-200%. In another embodiment, antibody production by a population of B cells is increased by about 200-300%. In another embodiment, antibody production by a population of B cells is increased by about 300-400%. In another embodiment, antibody production by a population of B cells is increased by about 400-500%. In another embodiment, antibody production by a population of B cells is increased by about 500-600%. In another embodiment, antibody production by a population of B cells is increased by about 600-700%. In another embodiment, antibody production by a population of B cells is increased by about 700-800%. In another embodiment, antibody production by a population of B cells is increased by about 800-900%. In another embodiment, antibody production by a population of B cells is increased by about 900- 1000%. In one embodiment, antibody production by a population of B cells is increased by about 10%. In one embodiment, antibody production by a population of B cells is increased by about 20%. In one embodiment, antibody production by a population of B cells isincreased by about 30%. In one embodiment, antibody production by a population of B cells is increased by about 40%. In one embodiment, antibody production by a population of B cells is increased by about 45%. In one embodiment, antibody production by a population of B cells is increased by about 50%. In one embodiment, antibody production by a population of B cells is increased by about 55%. In one embodiment, antibody production by a population of B cells is increased by about 60%. In one embodiment, antibody production by a population of B cells is increased by about 65%. In one embodiment, antibody production by a population of B cells is increased by about 70%. In one embodiment, antibody production by a population of B cells is increased by about 75%. In one embodiment, antibody production by a population of B cells is increased by about 80%. In one embodiment, antibody production by a population of B cells is increased by about 85%. In one embodiment, antibody production by a population of B cells is increased by about 90%. In one embodiment, antibody production by a population of B cells is increased by about 95%. In one embodiment, antibody production by a population of B cells is increased by about 100%. In one embodiment, antibody production by a population of B cells is increased by about 125%. In one embodiment, antibody production by a population of B cells is increased by about 150%. In one embodiment, antibody production by a population of B cells is increased by about 175%. In one embodiment, antibody production by a population of B cells is increased by about 200%. In one embodiment, antibody production by a population of B cells is increased by about 250%. In one embodiment, antibody production by a population of B cells is increased by about 300%. In one embodiment, antibody production by a population of B cells is increased by about 400%. In one embodiment, antibody production by a population of B cells is increased by about 500%. In one embodiment, antibody production by a population of B cells is increased by about 600%. In one embodiment, antibody production by a population of B cells is increased by about 700%. In one embodiment, antibody production by a population of B cells is increased by about 800%. In one embodiment, antibody production by a population of B cells is increased by about 900%. In one embodiment, antibody production by a population of B cells is increased by about 1000%. In one embodiment, antibody production by a population of B cells is increased by about 10-100%. In another embodiment, antibody production by a population of B cells is increased by about 100-200%. In another embodiment, antibody production by a population of B cells is increased by about 200-300%. In another embodiment, antibody production by a population of B cells is increased by about 300-400%. In another embodiment, antibody production by a population of B cells is increased by about 400-500%. In anotherembodiment, antibody production by a population of B cells is increased by about 500-600%. In another embodiment, antibody production by a population of B cells is increased by about 600-700%. In another embodiment, antibody production by a population of B cells is increased by about 700-800%. In another embodiment, antibody production by a population of B cells is increased by about 800-900%. In another embodiment, antibody production by a population of B cells is increased by about 900-1000%. In some embodiments, the method further promotes formation of memory B cells capable of producing the antibody in response to the antigen.

[0254] In some embodiments, provided herein is a method for increasing secretion of pro-inflammatory cytokines by a population of immune cells, comprising contacting the population of immune cells with a population of antigen presenting cells in the presence of a polypeptide comprising the single chain trimeric CD40L fusion protein according to the present disclosure. In some embodiments, the single chain trimeric CD40L fusion protein is not in, attached to, or associated with an oncolytic virus. In specific embodiments, the polypeptide contacted with the population of antigen presenting cells is a single chain trimeric CD40L Fc fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide. In some embodiments, the polypeptide contacted with the population of antigen presenting cells is a single chain trimeric CD40L trimerization fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) a trimerization motif. In some embodiments, the population of antigen presenting cells present an antigen to the population of immune cells. In some embodiments, the population of immune cells comprises T cells. In some embodiments, the population of immune cells is a population of T cells. In specific embodiments, upon activation of the antigen presenting cells, the presentation of the antigen by the population of antigen presenting cells to the population of immune cells is increased. In some embodiments, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 10%, 20%, 30%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99%. In one embodiment, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 10-20%. In another embodiment, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 20-30%. In another embodiment, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 30-40%. In another embodiment, a minimal percentageof antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 40-50%. In another embodiment, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 50-60%. In another embodiment, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 60-70%. In another embodiment, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 70-80%. In another embodiment, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 80-90%. In another embodiment, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 90-99%. In some embodiments, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 10%. In some embodiments, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 20%. In some embodiments, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 30%. In some embodiments, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 40%. In some embodiments, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 45%. In some embodiments, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 50%. In some embodiments, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 55%. In some embodiments, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 60%. In some embodiments, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 65%. In some embodiments, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 70%. In some embodiments, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 75%. In some embodiments, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 80%. In some embodiments, a minimal percentage ofantigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 85%. In some embodiments, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 90%. In some embodiments, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 95%. In some embodiments, a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about or 99%. In some embodiments, the population of antigen presenting cells comprises B cells, dendritic cells, macrophages, natural killer cells, monocytes, granulocytes, eosinophils, neutrophils, or a combination thereof. In some embodiments, the population of antigen presenting cells comprise B cells. In some embodiments, the population of antigen presenting cells comprise macrophages. In some embodiments, the population of antigen presenting cells comprise dendritic cells. In some embodiments, the population of antigen presenting cells comprise natural killer cells. In some embodiments, the population of antigen presenting cells comprise monocytes. In some embodiments, the population of antigen presenting cells comprise granulocytes. In some embodiments, the population of antigen presenting cells comprise eosinophils. In some embodiments, the population of antigen presenting cells comprise neutrophils. In some embodiments, the cytokine is IL-1, IL-2, IL-6, IL-12, IL-17, IL-22, IL-23, GM-CSF, TNF-a, IFN-yor any combination thereof. In one embodiment, the cytokine is IL-1. In one embodiment, the cytokine is IL-2. In one embodiment, the cytokine is IL-6. In one embodiment, the cytokine is IL-12. In one embodiment, the cytokine is IL-17. In one embodiment, the cytokine is IL-22. In one embodiment, the cytokine is IL-23. In one embodiment, the cytokine is GM-CSF. In one embodiment, the cytokine is TNF-a. In one embodiment, the cytokine is IFN-y. In some embodiments, the cytokine production is increased by about 10%, 20%, 30%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 125%, 150%, 175%, 200%, 250%, 300%, 400%, 500%, 600%, 700%, 800%, 900%, or 1000%. In one embodiment, cytokine production is increased by about 10-100%. In another embodiment, cytokine production is increased by about 100- 200%. In another embodiment, cytokine production is increased by about 200-300%. In another embodiment, cytokine production is increased by about 300-400%. In another embodiment, cytokine production is increased by about 400-500%. In another embodiment, cytokine production is increased by about 500-600%. In another embodiment, cytokine production is increased by about 600-700%. In another embodiment, cytokine production isincreased by about 700-800%. In another embodiment, cytokine production is increased by about 800-900%. In another embodiment, cytokine production is increased by about 900- 1000%. In another embodiment, cytokine production is increased by about 10-1000%. In one embodiment, cytokine production is increased by about 20%. In one embodiment, cytokine production is increased by about 30%. In one embodiment, cytokine production is increased by about 40%. In one embodiment, cytokine production is increased by about 45%. In one embodiment, cytokine production is increased by about 50%. In one embodiment, cytokine production is increased by about 55%. In one embodiment, cytokine production is increased by about 60%. In one embodiment, cytokine production is increased by about 65%. In one embodiment, cytokine production is increased by about 70%. In one embodiment, cytokine production is increased by about 75%. In one embodiment, cytokine production is increased by about 80%. In one embodiment, cytokine production is increased by about 85%. In one embodiment, cytokine production is increased by about 90%. In one embodiment, cytokine production is increased by about 95%. In one embodiment, cytokine production is increased by about 100%. In one embodiment, cytokine production is increased by about 125%. In one embodiment, cytokine production is increased by about 150%. In one embodiment, cytokine production is increased by about 175%. In one embodiment, cytokine production is increased by about 200%. In one embodiment, cytokine production is increased by about 250%. In one embodiment, cytokine production is increased by about 300%. In one embodiment, cytokine production is increased by about 400%. In one embodiment, cytokine production is increased by about 500%. In one embodiment, cytokine production is increased by about 600%. In one embodiment, cytokine production is increased by about 700%. In one embodiment, cytokine production is increased by about 800%. In one embodiment, cytokine production is increased by about 900%. In one embodiment, cytokine production is increased by about 1000%.

[0255] In some embodiments, provided herein is a method for increasing phagocytosis of diseased cells by a population of macrophages, comprising contacting the diseased cells, the macrophages, or both the diseased cells and the macrophage with a polypeptide comprising the single chain trimeric CD40L fusion protein according to the present disclosure. In some embodiments, the single chain trimeric CD40L fusion protein is not in, attached to, or associated with an oncolytic virus. In specific embodiments, the polypeptide contacted with the population of macrophages is a single chain trimeric CD40L Fc fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide. In specific embodiments, the polypeptide contacted with the population of macrophages is a single chain trimeric CD40L trimerization fusion protein comprising (a)three CD40L subunits covalently linked to one another by peptide linkers; and (b) a trimerization motif.

[0256] In some embodiments, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 10%, 20%, 30%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99%. In one embodiment, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 10-20%. In another embodiment, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 20-30%. In another embodiment, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 30-40%. In another embodiment, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 40-50%. In another embodiment, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 50-60%. In another embodiment, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 60-70%. In another embodiment, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 70-80%. In another embodiment, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 80- 90%. In another embodiment, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 90-99%. In some embodiments, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 10%. In some embodiments, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 20%. In some embodiments, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 30%. In some embodiments, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 40%. In some embodiments, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 45%. In some embodiments, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 50%. In some embodiments, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 55%. In some embodiments, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 60%. In some embodiments, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 65%. In some embodiments, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 70%. In some embodiments, a minimalpercentage of phagocytotic macrophages in the population of macrophages is increased by about 75%. In some embodiments, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 80%. In some embodiments, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 85%. In some embodiments, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 90%. In some embodiments, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 95%. In some embodiments, a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about or 99%.

[0257] In some embodiments, the phagocytosis by macrophages is measured by coculturing macrophages labeled with a first fluorescent dye and diseased cells labeled with a second fluorescent dye, wherein the first fluorescent dye and the second fluorescent dye are different. In some embodiments, the percentage of phagocytotic macrophages is measured by determining the percentage of macrophages comprising the diseased cells. In specific embodiments, the diseased cells are cancer cells. In specific embodiments, the diseased cells are cells infected by an infectious pathogen. In some embodiments, the infectious pathogen is a virus, a bacterial, a fungus or a parasite.

[0258] In some embodiments, provided herein is a method for increasing antigen presentation by a population of dendritic cells, comprising contacting the dendritic cells with a polypeptide comprising the single chain trimeric CD40L fusion protein according to the present disclosure. In some embodiments, the single chain trimeric CD40L fusion protein is not in, attached to, or associated with an oncolytic virus. In specific embodiments, the polypeptide contacted with the population of dendritic cells is a single chain trimeric CD40L Fc fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide. In some embodiments, the polypeptide contacted with the population of dendritic cells is a single chain trimeric CD40L trimerization fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) a trimerization motif. In some embodiments, the antigen is originated or derived from an infectious pathogen. In some embodiments, the antigen is originated or derived from a diseased cell. In some embodiments, the diseased cell is a cancer cell. In some embodiments, the diseased cell is a cell infected by an infectious pathogen. In some embodiments, the infectious pathogen is a virus, a bacteria, a fungus, a parasite, or a combination thereof. In some embodiments, the antigen is chemically conjugated orrecombinantly fused to the polypeptide comprising the single chain trimeric CD40L fusion protein.

[0259] In some embodiments, the antigen presentation by the dendritic cells is measured by co-culturing dendritic cells labeled with a first fluorescent dye and the antigen labeled with a second fluorescent dye, wherein the first fluorescent dye and the second fluorescent dye are different. In some embodiments, percentage of dendritic cells presenting the antigen is measured by determining the percentage of dendritic cells co-localizing with the antigen in the population of dendritic cells. In some embodiments, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 10%, 20%, 30%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99%. In one embodiment, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 10-20%. In another embodiment, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 20-30%. In another embodiment, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 30-40%. In another embodiment, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 40-50%. In another embodiment, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 50-60%. In another embodiment, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 60-70%. In another embodiment, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 70-80%. In another embodiment, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 80-90%. In another embodiment, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 90-99%. In some embodiments, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 10%. In some embodiments, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 20%. In some embodiments, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 30%. In some embodiments, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 40%. In some embodiments, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 45%. In some embodiments, a minimal percentage ofdendritic cells presenting the antigen in the population of dendritic cells is increased by about 50%. In some embodiments, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 55%. In some embodiments, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 60%. In some embodiments, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 65%. In some embodiments, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 70%. In some embodiments, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 75%. In some embodiments, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 80%. In some embodiments, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 85%. In some embodiments, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 90%. In some embodiments, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 95%. In some embodiments, a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about or 99%.

[0260] In some embodiments, provided herein is a method for increasing expression of a CD40 polypeptide by a target cell, comprising contacting the target cell with a polypeptide comprising the single chain trimeric CD40L fusion protein according to the present disclosure. In some embodiments, the single chain trimeric CD40L fusion protein is not in, attached to, or associated with an oncolytic virus. In specific embodiments, the polypeptide contacted with the target cell is a single chain trimeric CD40L Fc fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide. In some embodiments, the polypeptide contacted with the target cell is a single chain trimeric CD40L trimerization fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) a trimerization motif.

[0261] In some embodiments, the target cell is a diseased cell. In some embodiments, the diseased cell is a cancer cell. In some embodiments, the diseased cell is a cell infected by an infectious pathogen. In some embodiments, the infectious pathogen is a virus, a bacteria, a fungus, a parasite, or a combination thereof. In some embodiments, the target cell is an immune cell selected from B cells, natural killer cells, dendritic cells, macrophages, monocytes, granulocytes, eosinophils, neutrophils, or a combination thereof.

[0262] In some embodiments, the population of the diseased cells is reduced by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 99%. In one embodiment, the population of the diseased cells is reduced by about 10-20%. In another embodiment, the population of the diseased cells is reduced by about 20-30%. In another embodiment, the population of the diseased cells is reduced by about 30-40%. In another embodiment, the population of the diseased cells is reduced by about 40-50%. In another embodiment, the population of the diseased cells is reduced by about 50-60%. In another embodiment, the population of the diseased cells is reduced by about 60-70%. In another embodiment, the population of the diseased cells is reduced by about 70-80%. In another embodiment, the population of the diseased cells is reduced by about 80-90%. In another embodiment, the population of the diseased cells is reduced by about 90-99%. In one embodiment, the population of the diseased cells is reduced by about 10%. In one embodiment, the population of the diseased cells is reduced by about 20%. In one embodiment, the population of the diseased cells is reduced by about 30%. In one embodiment, the population of the diseased cells is reduced by about 40%. In one embodiment, the population of the diseased cells is reduced by about 45%. In one embodiment, the population of the diseased cells is reduced by about 50%. In one embodiment, the population of the diseased cells is reduced by about 55%. In one embodiment, the population of the diseased cells is reduced by about 60%. In one embodiment, the population of the diseased cells is reduced by about 65%. In one embodiment, the population of the diseased cells is reduced by about 70%. In one embodiment, the population of the diseased cells is reduced by about 75%. In one embodiment, the population of the diseased cells is reduced by about 80%. In one embodiment, the population of the diseased cells is reduced by about 85%. In one embodiment, the population of the diseased cells is reduced by about 90%. In one embodiment, the population of the diseased cells is reduced by about 95%. In one embodiment, the population of the diseased cells is reduced by about 99%. In one embodiment, the population of the diseased cells is reduced by about 100%.

[0263] In some embodiments, provided herein is a method for forming a pro- inflammatory milieu in a tissue surrounding a population of diseased cells, comprising contacting the tissue with a polypeptide comprising the single chain trimeric CD40L fusion protein according to the present disclosure. In some embodiments, the single chain trimeric CD40L fusion protein is not in, attached to, or associated with an oncolytic virus. In specificembodiments, the polypeptide contacted with the tissue is a single chain trimeric CD40L Fc fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide. In some embodiments, the polypeptide contacted with the tissue is a single chain trimeric CD40L trimerization fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) a trimerization motif.

[0264] In some embodiments, infiltration of activated B cells, CD4+ T cells, CD8+ T cells, MAITs, dendritic cells, macrophages, natural killer cells, monocytes, granulocytes, eosinophils and / or neutrophils in the tissue is increased. In some embodiments, infiltration of activated B cells is increased. In some embodiments, infiltration of CD4+ T cells is increased. In some embodiments, infiltration of CD8+ T cells is increased. In some embodiments, infiltration of dendritic cells is increased. In some embodiments, infiltration of macrophages is increased. In some embodiments, infiltration of natural killer cells is increased. In some embodiments, infiltration of monocytes is increased. In some embodiments, infiltration of granulocytes is increased. In some embodiments, infiltration of eosinophils is increased. In some embodiments, infiltration of neutrophils is increased.

[0265] In some embodiments, concentration of a pro-inflammatory cytokine is increased in the tissue. In some embodiments, the pro-inflammatory cytokine is IL-1, IL-2, IL-6, IL-12, IL-17, IL-22, IL-23, GM-CSF, TNF-a, IFN-y, or any combination thereof. In one embodiment, the cytokine is IL-1. In one embodiment, the cytokine is IL-2. In one embodiment, the cytokine is IL-6. In one embodiment, the cytokine is IL-12. In one embodiment, the cytokine is IL-17. In one embodiment, the cytokine is IL-22. In one embodiment, the cytokine is IL-23. In one embodiment, the cytokine is GM-CSF. In one embodiment, the cytokine is TNF-a. In one embodiment, the cytokine is IFN-y.

[0266] In some embodiments, presentation of antigens originated or derived from the diseased cells by antigen presentation cells is increased in the tissue. In some embodiments, phagocytosis of the diseased cells is increased in the tissue. In some embodiments, apoptosis of the diseased cells induced by cell-mediated cytotoxicity is increased in the tissue. In some embodiments, apoptosis of the diseased cells induced by antibody-dependent cellular cytotoxicity is increased in the tissue. In some embodiments, the population of the diseased cells is reduced in the tissue. In some embodiments, the population of the diseased cells is reduced by about 10%, 20%, 30%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99% in the tissue. In one embodiment, the population of the diseased cells isreduced by about 10-20%. In another embodiment, the population of the diseased cells is reduced by about 20-30%. In another embodiment, the population of the diseased cells is reduced by about 30-40%. In another embodiment, the population of the diseased cells is reduced by about 40-50%. In another embodiment, the population of the diseased cells is reduced by about 50-60%. In another embodiment, the population of the diseased cells is reduced by about 60-70%. In another embodiment, the population of the diseased cells is reduced by about 70-80%. In another embodiment, the population of the diseased cells is reduced by about 80-90%. In another embodiment, the population of the diseased cells is reduced by about 90-99%. In one embodiment, the population of the diseased cells is reduced by about 10%. In one embodiment, the population of the diseased cells is reduced by about 20%. In one embodiment, the population of the diseased cells is reduced by about 30%. In one embodiment, the population of the diseased cells is reduced by about 40%. In one embodiment, the population of the diseased cells is reduced by about 45%. In one embodiment, the population of the diseased cells is reduced by about 50%. In one embodiment, the population of the diseased cells is reduced by about 55%. In one embodiment, the population of the diseased cells is reduced by about 60%. In one embodiment, the population of the diseased cells is reduced by about 65%. In one embodiment, the population of the diseased cells is reduced by about 70%. In one embodiment, the population of the diseased cells is reduced by about 75%. In one embodiment, the population of the diseased cells is reduced by about 80%. In one embodiment, the population of the diseased cells is reduced by about 85%. In one embodiment, the population of the diseased cells is reduced by about 90%. In one embodiment, the population of the diseased cells is reduced by about 95%. In one embodiment, the population of the diseased cells is reduced by about 99%. In one embodiment, the population of the diseased cells is reduced by about 100%.

[0267] Methods of use

[0268] According to certain embodiments, the described single chain trimeric CD40L Fc fusion protein or single chain trimeric CD40L trimerization fusion protein can be provided in a buffered composition for storage or use. In some embodiments, the single chain trimeric CD40L Fc fusion protein or single chain trimeric CD40L trimerization fusion protein is not in, attached to, or associated with an oncolytic virus. Suitable buffers for the storage of the described single chain trimeric CD40L Fc fusion protein or single chain trimeric CD40L trimerization fusion protein would serve to maintain the stability of the fusion proteins whilebeing acceptable for pharmaceutical use. In some embodiments, the composition does not comprise an oncolytic virus.

[0269] In one aspect, provided herein is a method of treating a disease.

[0270] Also provided herein is a single chain trimeric CD40L Fc fusion protein and a single chain trimeric CD40L trimerization fusion protein as described herein for use in therapy. In some embodiments, the single chain trimeric CD40L Fc fusion protein or single chain trimeric CD40L trimerization fusion protein is not in, attached to, or associated with an oncolytic virus. Such therapy includes those in accordance with the methods of treatment and therapeutic uses defined herein and all embodiments thereof.

[0271] Also provided herein is a single chain trimeric CD40L Fc fusion protein and a single chain trimeric CD40L trimerization fusion protein as described herein for use in the treatment of a disease or disorder. In some embodiments, the single chain trimeric CD40L Fc fusion protein or single chain trimeric CD40L trimerization fusion protein is not in, attached to, or associated with an oncolytic virus. Such method includes those in accordance with the methods of treatment of a disease or disorder defined herein and all embodiments thereof

[0272] In some embodiments, provided herein is a method for eliminating a diseased cell in a subject, comprising administering an effective amount of a polypeptide comprising the single chain trimeric CD40L fusion protein according to the present disclosure to the subject. In some embodiments, the polypeptide is not in, attached to, or associated with an oncolytic virus. In specific embodiments, the polypeptide administered to the subject is a single chain trimeric CD40L Fc fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide. In some embodiments, the polypeptide administered to the subject is a single chain trimeric CD40L trimerization fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) a trimerization motif. In some embodiments, the diseased cell does not express a CD40 polypeptide. In some embodiments, the diseased cell expresses a CD40 polypeptide. In some embodiments, the diseased cell is a cancer cell. In some embodiments, the diseased cell is a cell infected by an infectious pathogen. In some embodiments, the infectious pathogen is a virus, a bacteria, a fungus, a parasite, or a combination thereof.

[0273] Also provided herein is a single chain trimeric CD40L Fc fusion protein as described herein for use in the elimination of a diseased cell in a subject. Further provided herein is a single chain trimeric CD40L trimerization fusion protein as described herein for use in the elimination of a diseased cell in a subject. In certain embodiments, the diseased cell is a cancer cell. In other embodiments, the diseased cell is a cell infected with a pathogen.

[0274] In some embodiments, provided herein is a method for treating cancer in a subject in need thereof, comprising administering an effective amount of a polypeptide comprising the single chain trimeric CD40L fusion protein according to the present disclosure to the subject. In some embodiments, the polypeptide is not in, attached to, or associated with an oncolytic virus. In specific embodiments, the polypeptide administered to the subject is a single chain trimeric CD40L Fc fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide. In some embodiments, the polypeptide administered to the subject is a single chain trimeric CD40L trimerization fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) a trimerization motif.

[0275] Also provided are methods of treating cancer in a subject comprising administering to the subject a therapeutically effective amount of a dimer comprising two single chain trimeric CD40L Fc fusion proteins, each comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide. In some embodiments, the dimer is not in, attached to, or associated with an oncolytic virus. In some embodiments, the method comprises administering a homodimer. In some embodiments, the method comprises administering a homodimer.

[0276] Also provided are methods of treating cancer in a subject comprising administering to the subject a therapeutically effective amount of a trimer comprising three single chain trimeric CD40L trimerization fusion proteins, each comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) a trimerization domain. In some embodiments, the trimer is not in, attached to, or associated with an oncolytic virus. In some embodiments, the method comprises administering a homotrimer. In some embodiments, the method comprises administering a heterotrimer.

[0277] Also provided herein is a polypeptide comprising the single chain trimeric CD40L fusion protein as described herein for use in the treatment of a cancer. Such treatment includes those in accordance with the methods of treating cancer defined herein and all embodiments thereof. In specific embodiments, the polypeptide for use in the treatment of a cancer is a single chain trimeric CD40L Fc fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide. In some embodiments, the polypeptide for use in the treatment of a cancer is a single chain trimeric CD40L trimerization fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) a trimerization motif.

[0278] Also provided herein is a single chain trimeric CD40L Fc fusion protein as described herein for use in the treatment of a cancer. Such treatment includes those in accordance with the methods of treating cancer defined herein and all embodiments thereof.

[0279] Also provided herein is a dimer comprising two single chain trimeric CD40L Fc fusion proteins as described herein for use in the treatment of a cancer. Such treatment includes those in accordance with the methods of treating cancer defined herein and all embodiments thereof.

[0280] Also provided herein is a single chain trimeric CD40L trimerization fusion protein as described herein for use in the treatment of a cancer. Such treatment includes those in accordance with the methods of treating cancer defined herein and all embodiments thereof.

[0281] Also provided herein is a trimer comprising three single chain trimeric CD40L trimerization fusion proteins as described herein for use in the treatment of a cancer. Such treatment includes those in accordance with the methods of treating cancer defined herein and all embodiments thereof.

[0282] In some embodiments, the cancer is a solid cancer. In some embodiments, the cancer is a liquid cancer. In some embodiments, the cancer is selected from the group consisting of melanoma, mesothelioma, advanced solid tumor, and lymphoma. In one embodiment, the cancer is a melanoma. In one embodiment, the cancer is a mesothelioma. In one embodiment, the cancer is an advanced solid tumor. In one embodiment, the cancer is a lymphoma.

[0283] In some embodiments, the method comprises administering a pharmaceutical composition comprising a pharmaceutically acceptable carrier and a single chain trimeric CD40L Fc fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) an Fc monomer peptide. In some embodiments, the composition does not comprise an oncolytic virus. In some embodiments, the method comprises administering a homodimer. In some embodiments, the method comprises administering a heterodimer. In some embodiments, the composition does not comprise an oncolytic virus.

[0284] In some embodiments, the method comprises administering a pharmaceutical composition comprising a pharmaceutically acceptable carrier and a single chain trimeric CD40L trimerization fusion protein comprising (a) three CD40L subunits covalently linked to one another by peptide linkers; and (b) a trimerization motif. In some embodiments, the composition does not comprise an oncolytic virus. In some embodiments, the method comprises administering a homotrimer. In some embodiments, the method comprisesadministering a heterotrimer. In some embodiments, the composition does not comprise an oncolytic virus.

[0285] In some embodiments, the method of treating cancer enhances an innate anti- neoplastic immune response. An “anti-neoplastic immune response,” as used herein, refers to immune cells such as, for example, T cells, B cells, or other antigen presenting cells (e.g., dendritic cells (DCs)) of an individual being recruited, primed and / or activated to mount an immune response against a specific tumor target. In some embodiments, antigen presenting cells activated by the polypeptide comprising the single chain trimeric CD40L fusion protein according to the present disclosure can in turn activates additional cell types, such as T-cells. Alternatively, the anti-neoplastic immune response comprises a reduction in tumor burden. The term also encompasses recruitment of cytokines, such as granulocyte macrophage colony stimulating factor (GM-CSF) are to amplify immune activation and / or induce migration of the primed cells to lymph nodes.

[0286] In one embodiment, the disease is cancer. In some embodiments, the cancer is selected from the group consisting of melanoma, mesothelioma, advanced solid tumor, and lymphoma. In some embodiments, the cancer is a solid tumor cancer. In other embodiments, the cancer is a blood cancer.

[0287] In some embodiments, the cancer is an adrenal cancer, anal cancer, appendix cancer, bile duct cancer, bladder cancer, bone cancer, brain cancer, breast cancer, cervical cancer, colorectal cancer, esophageal cancer, gallbladder cancer, gestational trophoblastic, head and neck cancer, Hodgkin lymphoma, intestinal cancer, kidney cancer, leukemia, liver cancer, lung cancer, melanoma, mesothelioma, multiple myeloma, neuroendocrine tumor, non-Hodgkin lymphoma, oral cancer, ovarian cancer, pancreatic cancer, prostate cancer, sinus cancer, skin cancer, soft tissue sarcoma spinal cancer, stomach cancer, testicular cancer, throat cancer, thyroid cancer, uterine cancer endometrial cancer, vaginal cancer, or vulvar cancer.

[0288] In some embodiments, the adrenal cancer is an adrenocortical carcinoma (ACC), adrenal cortex cancer, pheochromocytoma, or neuroblastoma. In some embodiments, the anal cancer is a squamous cell carcinoma, cloacogenic carcinoma, adenocarcinoma, basal cell carcinoma, or melanoma. In some embodiments, the appendix cancer is a neuroendocrine tumor (NET), mucinous adenocarcinoma, goblet cell carcinoid, intestinal-type adenocarcinoma, or signet-ring cell adenocarcinoma. In some embodiments, the bile duct cancer is an extrahepatic bile duct cancer, adenocarcinomas, hilar bile duct cancer, perihilar bile duct cancer, distal bile duct cancer, or intrahepatic bile duct cancer. In someembodiments, the bladder cancer is transitional cell carcinoma (TCC), papillary carcinoma, flat carcinoma, squamous cell carcinoma, adenocarcinoma, small-cell carcinoma, or sarcoma. In some embodiments, the bone cancer is a primary bone cancer, sarcoma, osteosarcoma, chondrosarcoma, sarcoma, fibrosarcoma, malignant fibrous histiocytoma, giant cell tumor of bone, chordoma, or metastatic bone cancer. In some embodiments, the brain cancer is an astrocytoma, brain stem glioma, glioblastoma, meningioma, ependymoma, oligodendroglioma, mixed glioma, pituitary carcinoma, pituitary adenoma, craniopharyngioma, germ cell tumor, pineal region tumor, medulloblastoma, or primary CNS lymphoma. In some embodiments, the breast cancer is a breast adenocarcinoma, invasive breast cancer, noninvasive breast cancer, breast sarcoma, metaplastic carcinoma, adenocystic carcinoma, phyllodes tumor, angiosarcoma, HER2 -positive breast cancer, triple-negative breast cancer, or inflammatory breast cancer. In some embodiments, the cervical cancer is a squamous cell carcinoma, or adenocarcinoma. In some embodiments, the colorectal cancer is a colorectal adenocarcinoma, primary colorectal lymphoma, gastrointestinal stromal tumor, leiomyosarcoma, carcinoid tumor, mucinous adenocarcinoma, signet ring cell adenocarcinoma, gastrointestinal carcinoid tumor, or melanoma. In some embodiments, the esophageal cancer is an adenocarcinoma or squamous cell carcinoma. In some embodiments, the gall bladder cancer is an adenocarcinoma, papillary adenocarcinoma, adenosquamous carcinoma, squamous cell carcinoma, small cell carcinoma, or sarcoma. In some embodiments, the gestational trophoblastic disease (GTD) is a hydatidiform mole, gestational trophoblastic neoplasia (GTN), choriocarcinoma, placental-site trophoblastic tumor (PSTT), or epithelioid trophoblastic tumor (ETT). In some embodiments, the head and neck cancer is a laryngeal cancer, nasopharyngeal cancer, hypopharyngeal cancer, nasal cavity cancer, paranasal sinus cancer, salivary gland cancer, oral cancer, oropharyngeal cancer, or tonsil cancer. In some embodiments, the Hodgkin lymphoma is a classical Hodgkin lymphoma, nodular sclerosis, mixed cellularity, lymphocyte-rich, lymphocyte-depleted, or nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL). In some embodiments, the intestinal cancer is a small intestine cancer, small bowel cancer, adenocarcinoma, sarcoma, gastrointestinal stromal tumors, carcinoid tumors, or lymphoma. In some embodiments, the kidney cancer is a renal cell carcinoma (RCC), clear cell RCC, papillary RCC, chromophobe RCC, collecting duct RCC, unclassified RCC, transitional cell carcinoma, urothelial cancer, renal pelvis carcinoma, or renal sarcoma. In some embodiments, the leukemia is an acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), chronic myeloid leukemia (CML), hairy cell leukemia (HCL), or amyelodysplastic syndrome (MDS). In a specific embodiment, the leukemia is AML. In some embodiments, the liver cancer is a hepatocellular carcinoma (HCC), fibrolamellar HCC, cholangiocarcinoma, angiosarcoma, or liver metastasis. In some embodiments, the lung cancer is a small cell lung cancer, small cell carcinoma, combined small cell carcinoma, nonsmall cell lung cancer, lung adenocarcinoma, squamous cell lung cancer, large-cell undifferentiated carcinoma, pulmonary nodule, metastatic lung cancer, adenosquamous carcinoma, large cell neuroendocrine carcinoma, salivary gland-type lung carcinoma, lung carcinoid, mesothelioma, sarcomatoid carcinoma of the lung, or malignant granular cell lung tumor. In some embodiments, the melanoma is a superficial spreading melanoma, nodular melanoma, acral-lentiginous melanoma, lentigo maligna melanoma, amelanotic melanoma, desmoplastic melanoma, ocular melanoma, or metastatic melanoma. In some embodiments, the mesothelioma is a pleural mesothelioma, peritoneal mesothelioma, pericardial mesothelioma, or testicular mesothelioma. In some embodiments, the multiple myeloma is an active myeloma or smoldering myeloma. In some embodiments, the neuroendocrine tumor, is a gastrointestinal neuroendocrine tumor, pancreatic neuroendocrine tumor, or lung neuroendocrine tumor. In some embodiments, the non-Hodgkin’s lymphoma is an anaplastic large-cell lymphoma, lymphoblastic lymphoma, peripheral T cell lymphoma, follicular lymphoma, cutaneous T cell lymphoma, lymphoplasmacytic lymphoma, marginal zone B-cell lymphoma, MALT lymphoma, small-cell lymphocytic lymphoma, Burkitt lymphoma, chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma (SLL), precursor T- lymphoblastic leukemia / lymphoma, acute lymphocytic leukemia (ALL), adult T cell lymphoma / leukemia (ATLL), hairy cell leukemia, B-cell lymphomas, diffuse large B-cell lymphoma (DLBCL), primary mediastinal B-cell lymphoma, primary central nervous system (CNS) lymphoma, mantle cell lymphoma (MCL), marginal zone lymphomas, mucosa- associated lymphoid tissue (MALT) lymphoma, nodal marginal zone B-cell lymphoma, splenic marginal zone B-cell lymphoma, lymphoplasmacytic lymphoma, B-cell non-Hodgkin lymphoma, T cell non-Hodgkin lymphoma, natural killer cell lymphoma, cutaneous T cell lymphoma, Alibert-Bazin syndrome, Sezary syndrome, primary cutaneous anaplastic largecell lymphoma, peripheral T cell lymphoma, angioimmunoblastic T cell lymphoma (AITL), anaplastic large-cell lymphoma (ALCL), systemic ALCL, enteropathy-type T cell lymphoma (EATL), or hepatosplenic gamma / delta T cell lymphoma. In some embodiments, the oral cancer is a squamous cell carcinoma, verrucous carcinoma, minor salivary gland carcinomas, lymphoma, benign oral cavity tumor, eosinophilic granuloma, fibroma, granular cell tumor, karatoacanthoma, leiomyoma, osteochondroma, lipoma, schwannoma, neurofibroma,papilloma, condyloma acuminatum, verruciform xanthoma, pyogenic granuloma, rhabdomyoma, odontogenic tumors, leukoplakia, erythroplakia, squamous cell lip cancer, basal cell lip cancer, mouth cancer, gum cancer, or tongue cancer. In some embodiments, the ovarian cancer is a ovarian epithelial cancer, mucinous epithelial ovarian cancer, endometrioid epithelial ovarian cancer, clear cell epithelial ovarian cancer, undifferentiated epithelial ovarian cancer, ovarian low malignant potential tumors, primary peritoneal carcinoma, fallopian tube cancer, germ cell tumors, teratoma, dysgerminoma ovarian germ cell cancer, endodermal sinus tumor, sex cord-stromal tumors, sex cord-gonadal stromal tumor, ovarian stromal tumor, granulosa cell tumor, granulosa-theca tumor, Sertoli-Leydig tumor, ovarian sarcoma, ovarian carcinosarcoma, ovarian adenosarcoma, ovarian leiomyosarcoma, ovarian fibrosarcoma, Krukenberg tumor, or ovarian cyst. In some embodiments, the pancreatic cancer is a pancreatic exocrine gland cancer, pancreatic endocrine gland cancer, or pancreatic adenocarcinoma, islet cell tumor, or neuroendocrine tumor. In some embodiments, the prostate cancer is a prostate adenocarcinoma, prostate sarcoma, transitional cell carcinoma, small cell carcinoma, or neuroendocrine tumor. In some embodiments, the sinus cancer is a squamous cell carcinoma, mucosa cell carcinoma, adenoid cystic cell carcinoma, acinic cell carcinoma, sinonasal undifferentiated carcinoma, nasal cavity cancer, paranasal sinus cancer, maxillary sinus cancer, ethmoid sinus cancer, or nasopharynx cancer. In some embodiments, the skin cancer is a basal cell carcinoma, squamous cell carcinoma, melanoma, Merkel cell carcinoma, Kaposi sarcoma (KS), actinic keratosis, skin lymphoma, or keratoacanthoma. In some embodiments, the soft tissue cancer is an angiosarcoma , dermatofibrosarcoma, epithelioid sarcoma, Ewing’ s sarcoma, fibrosarcoma, gastrointestinal stromal tumors (GISTs), Kaposi sarcoma, leiomyosarcoma, liposarcoma, dedifferentiated liposarcoma (DL), myxoid / round cell liposarcoma (MRCL), well-differentiated liposarcoma (WDL), malignant fibrous histiocytoma, neurofibrosarcoma, rhabdomyosarcoma (RMS), or synovial sarcoma. In some embodiments, the spinal cancer is a spinal metastatic tumor. In some embodiments, the stomach cancer is a stomach adenocarcinoma, stomach lymphoma, gastrointestinal stromal tumors, carcinoid tumor, gastric carcinoid tumors, Type I ECL-cell carcinoid, Type II ECL-cell carcinoid, or Type III ECL-cell carcinoid. In some embodiments, the testicular cancer is a seminoma, nonseminoma, embryonal carcinoma, yolk sac carcinoma, choriocarcinoma, teratoma, gonadal stromal tumor, ley dig cell tumor, or sertoli cell tumor. In some embodiments, the throat cancer is a squamous cell carcinoma, adenocarcinoma, sarcoma, laryngeal cancer, pharyngeal cancer, nasopharynx cancer, oropharynx cancer, hypopharynx cancer, laryngeal cancer,laryngeal squamous cell carcinoma, laryngeal adenocarcinoma, lymphoepithelioma, spindle cell carcinoma, verrucous cancer, undifferentiated carcinoma, or lymph node cancer. In some embodiments, the thyroid cancer is a papillary carcinoma, follicular carcinoma, Hurthle cell carcinoma, medullary thyroid carcinoma, or anaplastic carcinoma. In some embodiments, the uterine cancer is an endometrial cancer, endometrial adenocarcinoma, endometroid carcinoma, serous adenocarcinoma, adenosquamous carcinoma, uterine carcinosarcoma, uterine sarcoma, uterine leiomyosarcoma, endometrial stromal sarcoma, or undifferentiated sarcoma. In some embodiments, the vaginal cancer is a squamous cell carcinoma, adenocarcinoma, melanoma, or sarcoma. In some embodiments, the vulvar cancer is a squamous cell carcinoma or adenocarcinoma.

[0289] In one aspect, the subject is a subject in need thereof. In another aspect, the subject is a human.

[0290] As used herein, the terms “effective amount” or “therapeutically effective amount” refer to an amount of an active ingredient or component that elicits the desired biological or medicinal response in a subject. The term refers to an amount that is sufficient, when administered to a subject suffering from or susceptible to a disease, disorder, and / or condition, to treat, diagnose, prevent, and / or delay the onset of the symptom(s) of the disease, disorder, and / or condition. It will be appreciated by those of ordinary skill in the art that a therapeutically effective amount is typically administered via a dosing regimen comprising at least one unit dose.

[0291] According to particular embodiments, a therapeutically effective amount refers to the amount of therapy which is sufficient to achieve one or more, two or more, three or more, four or more, or five or more of the following effects: (i) reduce or ameliorate the severity of the disease, disorder or condition to be treated or a symptom associated therewith; (ii) reduce the duration of the disease, disorder or condition to be treated, or a symptom associated therewith; (iii) prevent the progression of the disease, disorder or condition to be treated, or a symptom associated therewith; (iv) cause regression of the disease, disorder or condition to be treated, or a symptom associated therewith; (v) prevent the development or onset of the disease, disorder or condition to be treated, or a symptom associated therewith; (vi) prevent the recurrence of the disease, disorder or condition to be treated, or a symptom associated therewith; (vii) reduce hospitalization of a subject having the disease, disorder or condition to be treated, or a symptom associated therewith; (viii) reduce hospitalization length of a subject having the disease, disorder or condition to be treated, or a symptom associated therewith; (ix) increase the survival of a subject with the disease, disorder or condition to be treated, or asymptom associated therewith; (xi) inhibit or reduce the disease, disorder or condition to be treated, or a symptom associated therewith in a subject; and / or (xii) enhance or improve the prophylactic or therapeutic effect(s) of another therapy.

[0292] The therapeutically effective amount or dosage can vary according to various factors, such as the disease,...

Claims

CLAIMSWhat is Claimed is:

1. A polypeptide comprising a single chain trimeric CD40 ligand (CD40L) fusion protein, wherein the single chain trimeric CD40L fusion protein comprises three CD40L subunits covalently linked to one another by peptide linkers (CD40L trimer) and a trimerization motif, optionally wherein the CD40L subunits comprise a portion of the CD40L extracellular domain.

2. The polypeptide of claim 1, wherein the CD40L subunits comprise SEQ ID NO:22 or 45, or a fragment thereof.

3. The polypeptide of claim 1, wherein at least one of the peptide linkers consists of (G3S)3(SEQ ID NO:25), optionally wherein at least two of the peptide linkers have the same sequence.

4. The polypeptide of claim 1 , wherein the CD40L fusion protein is fused to a peptide tether, wherein the peptide tether is selected from (G4S)3 (SEQ ID NO:24) and (G4S)2 (SEQ ID NO:26.

5. The polypeptide of claim 1, wherein the trimerization motif comprises a T4 fibritin trimerization motif.

6. The polypeptide of claim 5, wherein the trimerization motif comprises SEQ ID NO:41.

7. The polypeptide of claim 1, wherein the polypeptide comprises SEQ ID NO:44 or 47.

8. The polypeptide of claim 1, wherein the polypeptide further comprises a signal peptide.

9. The polypeptide of claim 8, wherein the signal peptide comprises the amino acid sequence of SEQ ID NO:42.

10. The polypeptide of claim 9, wherein the polypeptide comprises SEQ ID NO:43 or46.

11. The polypeptide of claim 1, wherein the single chain trimeric CD40L fusion protein is fused to an Fc monomer peptide.

12. The polypeptide of claim 11, wherein the Fc monomer peptide comprises an Fc sequence from a human IgG, IgA, IgM, IgD, or IgE Fc sequence, optionally wherein the IgG sequence is selected from IgGl, IgG2, IgG3, and IgG4, optionally wherein the IgGl sequence comprises SEQ ID NO:30 or 31, or a fragment thereof, or the IgG2 sequence comprises SEQ ID NO:29.

13. The polypeptide of claim 11, wherein the single chain trimeric CD40E fusion protein is fused to the Fc monomer peptide via a peptide tether, wherein the peptide tether comprises 1 to 20 amino acids, optionally wherein the peptide tether is selected from the group consisting of (G4S)3(SEQ ID NO:24), (G4S)2(SEQ ID NO:26), (G4S)4(SEQ ID NO:27), and G4S (SEQ ID NO:28).

14. The polypeptide of claim 11, wherein the CD40L trimer is fused to: a) the N-terminus of the Fc monomer peptide, wherein the CD40L Fc fusion protein comprises the amino acid sequence of any one of SEQ ID NOs: 43, 44, 46, and 57; or b) the C-terminus of the Fc monomer peptide, wherein the CD40L Fc fusion protein comprises the amino acid sequence of any one of SEQ ID NOs: 13-19.

15. The polypeptide of claim 1, wherein the single chain trimeric CD40L fusion protein: a) enhances activation of a CD40 polypeptide compared to wild-type CD40L, optionally wherein the activation of the CD40 polypeptide comprises i) enhanced immune-stimulatory functions of T cells and / or B cells; ii) enhanced activation of B cells, CD4+ T cells, CD8+ T cells, dendritic cells, macrophages, natural killer cells, monocytes, granulocytes, eosinophils and / or neutrophils compared to wild- type CD40L; and / or iii) increased expression of the CD40 polypeptide.(b) enhances anti-tumor activity compared to wild- type CD40L;(c) enhances pro-inflammatory activity compared to wild- type CD40L;(d) enhances clearance of an infectious pathogen compared to wild-type CD40L;(e) increases antibody production by a population of B cells by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, about 100%, about 125%, about 150%, about 175%, about 200%, about 250%, about 300%, about 400%, about 500%, about 600%, about 700%, about 800%, about 900% or about 1000%;(f) increases secretion of a pro-inflammatory cytokine by a population of T cells by at least about 10%, optionally wherein the pro-inflammatory cytokine is IL- 1, IL-2, IL-6, IL-12, IL-17, IL-22, IL-23, GM-CSF, TNF-a, IFN-g, or any combination thereof, wherein the cytokine production is increased by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, about 100%, about 125%, about 150%, about 175%, about 200%, about 250%, about 300%, about 400%, about 500%, about 600%, about 700%, about 800%, about 900% or about 1000%;(g) increases a minimal percentage of phagocytotic macrophages in a population of macrophages to about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 99%; and / or(h) increases a minimal percentage of antigen-presenting dendritic cells in a population of dendritic cells to about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 99%.

16. The polypeptide of claim 1, wherein the polypeptide is conjugated to an agent, wherein the agent is selected from the group consisting of a radioisotope, a metal chelator, an enzyme, a fluorescent compound, a bioluminescent compound, or a chemiluminescent compound.

17. The polypeptide of any one of claims 1-16, wherein the polypeptide is not in, attached to, or associated with an oncolytic virus.

18. A polynucleotide encoding the polypeptide of any one of claims 1-16.

19. The polynucleotide of claim 18, wherein the polynucleotide is not in, attached to, or associated with an oncolytic virus.

20. A vector comprising the polynucleotide of claim 18.

21. The vector of claim 20, wherein the vector does not comprise an oncolytic virus.

22. A host cell comprising the vector of claim 20.

23. A composition comprising the polypeptide of any one of claims 1-16 and a pharmaceutically acceptable carrier.

24. The composition of claim 23, wherein the composition does not comprise an oncolytic virus.

25. A method of activating a CD40 polypeptide or a target cell comprising contacting the CD40 polypeptide or target cell with the polypeptide of any one of claims 1-16, wherein binding of the polypeptide of any one of claims 1-16 to the CD40 polypeptide or target cell activates the CD40 polypeptide or target cell.

26. The method of claim 25, wherein the target cell is selected from the group consisting of: an antigen presenting cell (APC) selected from the group consisting of a B cell, a dendritic cell, a macrophage, a monocyte, a granulocyte, an eosinophil, and a combination thereof.

27. The method of claim 25, wherein upon activation, the target cell activates a second cell, wherein the second cell is selected from the group consisting of a CD4+T cell, a CD8+T cell, a mucosal associated invariant T (MAIT) cell, a natural killer (NK) cell, a neutrophil, and a combination thereof.

28. The method of claim 25, wherein the activation of the target cell is measured as a) increased proliferation or maturation of the target cell, optionally wherein proliferation or maturation of the target cell is increased by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, about 100%, about 125%, about 150%, about 175%, about 200%, about 250%, about 300%, about 400%, about 500%, about 600%, about 700%, about 800%, about 900% or about 1000%; or b) prolonged survival time of the target cell, optionally wherein survival time of the target cell is increased by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, about 100%, about 125%, about 150%, about 175%, about 200%, about 250%, about 300%, about 400%, about 500%, about 600%, about 700%, about 800%, about 900% or about 1000%.

29. A method of treating cancer in a subject comprising administering to the subject a therapeutically effective amount of the polypeptide of any one of claims 1-16.

30. The method of claim 29, wherein the therapeutically effective amount of the polypeptide is administered in a pharmaceutical composition, wherein the pharmaceutical composition further comprises a pharmaceutically acceptable carrier, optionally wherein the administration enhances an innate anti-neoplastic immune response.

31. The method of claim 30, wherein the composition does not comprise an oncolytic virus.

32. The method of claim 29, wherein the cancer is selected from the group consisting of melanoma, mesothelioma, advanced solid tumor, and lymphoma.

33. A method of promoting antibody production in a population of B cells comprising contacting the population of B cells with the polypeptide of any one of claims 1-16, wherein binding of the polypeptide activates the B cells upon binding, optionally wherein the antibody production is increased by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, about 100%, about 125%, about 150%, about 175%, about 200%, about 250%, about 300%, about 400%, about 500%, about 600%, about 700%, about 800%, about 900% or about 1000%.

34. The method of claim 33, wherein the polypeptide is contacted with the population of B cells in the presence of an antigen, wherein the antibody produced by the B cells specifically binds to the antigen, optionally wherein the method further promotes formation of memory B cells capable of producing the antibody in response to the antigen.

35. The method of claim 33, wherein the polypeptide is in a vaccine composition or adjuvant composition.

36. The method of claim 35, wherein the vaccine or adjuvant composition does not comprise an oncolytic virus.

37. The method of claim 34, wherein the antigen is in a vaccine composition.

38. The method of claim 34, wherein the antigen is originated or derived from an infectious pathogen, a cell infected with an infectious pathogen, a diseased cell, optionally wherein the infectious pathogen is a virus, a bacteria, a fungus, a parasite, or a combination thereof, or wherein the diseased cell is a cancer cell.

39. The method of claim 34, wherein the antigen is presented by an antigen presenting cell, wherein the antigen is associated with an MHC class I or MHC class II complex, optionally wherein the antigen presenting cell is a dendritic cell.

40. A method of increasing antigen presentation by a population of dendritic cells, comprising contacting the dendritic cells in the presence of the antigen with an effective amount of the polypeptide of any one of claims 1 to 16; optionally wherein a minimal percentage of dendritic cells presenting the antigen in the population of dendritic cells is increased by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 99%.

41. The method of claim 40, wherein the antigen presentation by the dendritic cells is measured by co-culturing dendritic cells labeled with a first fluorescent dye and the antigen labeled with a second fluorescent dye, wherein the first fluorescent dye and the second fluorescent dye are different; optionally wherein the percentage of dendritic cells presenting the antigen is measured by determining the percentage of dendritic cells co-localizing with the antigen in the population of dendritic cells.

42. The method of claim 40, wherein the polypeptide is in a vaccine composition or adjuvant composition.

43. The method of claim 42, wherein the vaccine composition does not comprise an oncolytic virus.

44. The method of claim 40, wherein the antigen is in a vaccine composition.

45. The method of claim 44, wherein the vaccine composition does not comprise an oncolytic virus.

46. The method of claim 40, wherein the antigen is originated or derived from an infectious pathogen or a diseased cell, wherein the diseased cell is a cancer cell or a cell infected with the infectious pathogen, optionally wherein the infectious pathogen is a virus, a bacteria, a fungus, a parasite, or a combination thereof.

47. The method of claim 40, wherein the antigen is presented by an antigen presenting cell, wherein the antigen is associated with an MHC class I or MHC class II complex, optionally wherein the antigen presenting cell is a dendritic cell.

48. A method of increasing secretion of pro-inflammatory cytokines by a population of immune cells, comprising contacting the population of immune cells with a population of antigen presenting cells in the presence of the polypeptide of any one of claims 1 to 16, wherein said single chain trimeric CD40L fusion protein activates the antigen presenting cells upon binding, and wherein upon activation, the antigen presenting cells activate the population of immune cells, optionally wherein the cytokine is IL-1, IL-2, IL-6, IL-12, IL-17, IL- 22, IL-23, GM-CSF, TNF-a, IFN-g, or any combination thereof.49.The method of claim 48, wherein the cytokine production is increased by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, about 100%, about 125%, about 150%, about 175%, about 200%, about 250%, about 300%, about 400%, about 500%, about 600%, about 700%, about 800%, about 900% or about 1000%;50. The method of claim 48, wherein, upon activation of the antigen presenting cells, the population of antigen presenting cells that present an antigen to the population of immune cells is increased, wherein a minimal percentage of antigen presenting cells presenting the antigen in the population of antigen presenting cells is increased by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 99%;51. The method of claim 48, wherein the antigen presenting cells comprise dendritic cells, macrophages, B cells, or a combination thereof.

52. The method of claim 48, wherein the population of immune cells comprise T cells, neutrophils, or a combination thereof.

53. The method of claim 48, wherein the polypeptide is in a vaccine composition or adjuvant composition.

54. The method of claim 53, wherein the vaccine composition does not comprise an oncolytic virus.

55. The method of claim 48, wherein the antigen is in a vaccine composition.

56. The method of claim 55, wherein the vaccine composition does not comprise an oncolytic virus.

57. The method of claim 48, wherein the antigen is originated or derived from an infectious pathogen or a diseased cell, wherein the diseased cell is a cancer cell or a cell infected with the infectious pathogen, optionally wherein the infectious pathogen is a virus, a bacteria, a fungus, a parasite, or a combination thereof.

58. The method of claim 48, wherein the antigen is presented by an antigen presenting cell, wherein the antigen is associated with an MHC class I or MHC class II complex, optionally wherein the antigen presenting cell is a dendritic cell.

59. A method of increasing phagocytosis of diseased cells by a population of macrophages, comprising contacting the diseased cells, the macrophages, or both the diseased cells and the population of macrophages with an effective amount of the polypeptide of any one of claims 1 to 16, wherein a minimal percentage of phagocytotic macrophages in the population of macrophages is increased by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 99%.

60. The method of claim 59, wherein the polypeptide is not in, attached to, or associated with an oncolytic virus.

61. The method of claim 59, wherein the phagocytosis by macrophages is measured by co-culturing macrophages labeled with a first fluorescent dye and diseased cells labeled with a second fluorescent dye, wherein the first fluorescent dye and the second fluorescent dye are different.

62. The method of claim 59, wherein the percentage of phagocytotic macrophages is measured by determining the percentage of macrophages comprising the diseased cells; wherein the diseased cells are cancer cells or cells infected by an infectious pathogen; optionally wherein the infectious pathogen is a virus, a bacteria, a fungus, a parasite, or a combination thereof.

63. A method of increasing expression of a CD40 polypeptide by a target cell, comprising contacting the target cell with an effective amount of the polypeptide of any one of claims 1 to 16.

64. The method of claim 63, wherein the polypeptide is not in, attached to, or associated with an oncolytic virus.

65. The method of claim 63, wherein the target cell is: a) a diseased cell, wherein the diseased cell is a cancer cell or a cell infected by an infectious pathogen; optionally wherein the infectious pathogen is a virus, a bacteria, a fungus, a parasite, or a combination thereof; or b) a B cell, natural killer cell, dendritic cell, macrophage, monocyte, granulocyte, eosinophil, neutrophil, or a combination thereof; optionally wherein the population of the diseased cells is reduced by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 99%.

66. A method of forming a pro-inflammatory milieu in a tissue surrounding a population of diseased cells, comprising contacting the tissue with an effective amount of the polypeptide of any one of claims 1 to 16;optionally wherein: a) infiltration of activated B cells, CD4+ T cells, CD8+ T cells, dendritic cells, macrophages, natural killer cells, monocytes, granulocytes, eosinophils and / or neutrophils in the tissue is increased; b) concentration of a pro-inflammatory cytokine is increased in the tissue; optionally wherein the pro-inflammatory cytokine is IL-1, IL-2, IL-6, IL-12, IL-17, IL-22, IL-23, GM-CSF, TNF-a, IFN-g, or any combination thereof; c) presentation of antigens originated or derived from the diseased cells by antigen presentation cells is increased in the tissue; d) phagocytosis of the diseased cells is increased in the tissue; e) apoptosis of the diseased cells induced by cell-mediated cytotoxicity is increased in the tissue; f) apoptosis of the diseased cells induced by antibody-dependent cellular cytotoxicity is increased in the tissue; and / or g) the population of the diseased cells is reduced in the tissue; optionally wherein the population of the diseased cells is reduced by about 10%, about 20%, about 30%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 99% in the tissue.

67. The method of claim 66, wherein the polypeptide is not in, attached to, or associated with an oncolytic virus.

68. A method of eliminating a diseased cell in a subject, comprising administering to the subject an effective amount of the polypeptide of any one of claims 1 to 16, wherein, the diseased cell is a cancer cell or a cell infected by an infectious pathogen; optionally wherein the infectious pathogen is a virus, a bacteria, a fungus, a parasite, or a combination thereof.

69. The method of claim 68, wherein the polypeptide is not in, attached to, or associated with an oncolytic virus.

70. A method of treating cancer in a subject in need thereof, comprising administering to the subject an effective amount of the polypeptide of any one of claims 1 to 16; optionally wherein: a) the treatment enhances an innate, humoral or cell-mediated anti- neoplastic immune response; b) the method further comprises co-administration of a second therapy; and / or c) the cancer is selected from the group consisting of melanoma, mesothelioma, advanced solid tumor, and lymphoma.

71. The method of claim 70, wherein the polypeptide is not in, attached to, or associated with an oncolytic virus.

72. A method of treating an infection in a subject in need thereof, comprising administering to the subject an effective amount of the polypeptide of any one of claims 1 to 16; optionally wherein: a) the treatment enhances an innate, humoral, or cell-mediated anti- infective immune response; and / or b) a vaccine composition for preventing the infection is coadministered to the subject; optionally wherein, the vaccine composition is co- administered simultaneously or sequentially.

73. The method of claim 72, wherein the polypeptide is not in, attached to, or associated with an oncolytic virus.

74. The method of claim 72, wherein the vaccine does not comprise an oncolytic virus.

75. A method of increasing the response to an antigen in a subject in need thereof, comprising administering to the subject an effective amount of the polypeptide of any one of claims 1 to 16,optionally wherein the antigen is an antigen of a cancer, tumor, pathogen, or allergen.

76. The method of claim 75, wherein the polypeptide is not in, attached to, or associated with an oncolytic virus.

77. A method of increasing a response to a vaccine in a subject in need thereof, comprising administering to the subject the vaccine and an effective amount of the polypeptide of any one of claims 1 to 16, optionally wherein: a) the vaccine is a vaccine against a tumor, cancer, pathogen or allergen; and / or b) the peptide is co-formulated with the vaccine.

78. The method of claim 77, wherein the polypeptide is not in, attached to, or associated with an oncolytic virus.

79. The method of claim 77, wherein the vaccine does not comprise an oncolytic virus.

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