REFERENCE TO A SEQUENCE LISTING SUBMITTED ELECTRONICALLY VIA EFS-WEB

The content of the electronically submitted sequence listing (Name: 3986.0090004_SL_ST25.txt; Size: 331,354 bytes; Date of Creation: Aug. 3, 2018) is herein incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

Field

The present disclosure relates to antibodies that specifically bind to human B7-H4 compositions comprising such antibodies, and methods of producing and using antibodies that specifically bind to B7-H4.

Description of the Related Art

B7-H4 (also known as B7x, B7-S1, and VTCN1) is an immune regulatory molecule that shares homology with other B7 family members, include PD-L1. It is a type I transmembrane protein comprised of both IgV and IgC ectodomains. While B7-H4 expression in healthy tissues is relatively limited at the protein level, B7-H4 is expressed in several solid tumors such as gynecological carcinomas of the breast, ovary, and endometrium. Expression of B7-H4 in tumors tends to correlate with poor prognosis. The receptor for B7-H4 is unknown, but it is believed to be expressed on T cells. B7-H4 is believed to directly inhibit T cell activity.

Given the expression and function of B7-H4, provided herein are antibodies that specifically bind to B7-H4 and the use of these antibodies to modulate B7-H4 activity, including, e.g., in the treatment of cancer.

SUMMARY

Provided herein is an isolated antibody or antigen-binding fragment thereof that specifically binds to human B7-H4, comprising heavy chain variable region (VH) complementarity determining region (CDR) 1, VH CDR2, VH CDR3 and light chain variable region (VL) CDR1, CDR2, and CDR3 sequences selected from the group consisting of: SEQ ID NOs:5-10, respectively; SEQ ID NOs:15-20, respectively; SEQ ID NOs:25-30, respectively; SEQ ID NOs:35-40, respectively; SEQ ID NOs:458-463, respectively; SEQ ID NOs:45-50, respectively; SEQ ID NOs:55-60, respectively; SEQ ID NOs:65-70, respectively; SEQ ID NOs:75-80, respectively; SEQ ID NOs:85-90, respectively; SEQ ID NOs:95-100, respectively; SEQ ID NOs:105-110, respectively; SEQ ID NOs:115-120, respectively; SEQ ID NOs:125-130, respectively; SEQ ID NOs:135-140, respectively; SEQ ID NOs:145-150, respectively; SEQ ID NOs:155-160, respectively; SEQ ID NOs:165-170, respectively; SEQ ID NOs:175-180, respectively; SEQ ID NOs:185-190, respectively; and SEQ ID NOs:195-200, respectively.

In one embodiment, the antibody or antigen-binding fragment thereof comprises a VH comprising the amino acid sequence of SEQ ID NO:11, 21, 31, 41, 464, 51, 61, 71, 81, 91, 101, 111, 121, 131, 141, 151, 161, 171, 181, 191, or 201.

In one embodiment, the antibody or antigen-binding fragment thereof comprises a VL comprising the amino acid sequence of SEQ ID NO:12, 22, 32, 42, 52, 62, 72, 82, 92, 102, 112, 122, 132, 142, 152, 162, 172, 182, 192, or 202.

In one embodiment, the antibody or antigen-binding fragment thereof comprises a heavy chain variable region and a light chain variable region, wherein the heavy chain variable region comprises the amino acid sequence of SEQ ID NO:11, 21, 31, 41, 464, 51, 61, 71, 81, 91, 101, 111, 121, 131, 141, 151, 161, 171, 181, 191, or 201.

Also provided herein is an isolated antibody or antigen-binding fragment thereof that specifically binds to human B7-H4, wherein the antibody comprises a heavy chain variable region and a light chain variable region, wherein the light chain variable region comprises the amino acid sequence of SEQ ID NO:12, 22, 32, 42, 52, 62, 72, 82, 92, 102, 112, 122, 132, 142, 152, 162, 172, 182, 192, or 202.

Also provided herein is an isolated antibody or antigen-binding fragment thereof that specifically binds to human B7-H4, comprising a heavy chain variable region and a light chain variable region comprising the amino acid sequences of: SEQ ID NOs:11 and 12, respectively; SEQ ID NOs:21 and 22, respectively; SEQ ID NOs:31 and 32, respectively; SEQ ID NOs:41 and 42, respectively; SEQ ID NOs:464 and 42, respectively, SEQ ID NOs:51 and 52, respectively; SEQ ID NOs:61 and 62, respectively; SEQ ID NOs:71 and 72, respectively; SEQ ID NOs:81 and 82, respectively; SEQ ID NOs:91 and 92, respectively; SEQ ID NOs:101 and 102, respectively; SEQ ID NOs:111 and 112, respectively; SEQ ID NOs:121 and 122, respectively; SEQ ID NOs:131 and 132, respectively; SEQ ID NOs:141 and 142, respectively; SEQ ID NOs:151 and 152, respectively; SEQ ID NOs:161 and 162, respectively; SEQ ID NOs:171 and 172, respectively; SEQ ID NOs:181 and 182, respectively; SEQ ID NOs:191 and 192, respectively; or SEQ ID NOs:201 and 202, respectively.

In one embodiment, the antibody or antigen-binding fragment thereof further comprises a heavy chain constant region. In one embodiment, the heavy chain constant region is selected from the group consisting of human immunoglobulins IgG1, IgG2, IgG3, IgG4, IgA1, and IgA2heavy chain constant regions.

In one embodiment, the antibody or antigen-binding fragment further comprises a light chain constant region. In one embodiment, the light chain constant region is selected from the group consisting of human immunoglobulins IgGκ and IgGλ light chain constant regions.

In one embodiment, the antibody or antigen-binding fragment further comprises a heavy chain constant region and a light chain constant region, wherein the heavy chain constant region is a human IgG1heavy chain constant region, and wherein the light chain constant region is a human IgGκ light chain constant region.

In one embodiment, the antibody or antigen-binding fragment thereof comprises a heavy chain comprising the amino acid sequence of SEQ ID NO:13, 23, 33, 43, 469, 53, 63, 73, 83, 93, 103, 113, 123, 133, 143, 153, 163, 173, 183, 193, or 203.

In one embodiment, the antibody or antigen-binding fragment thereof comprises a light chain comprising the amino acid sequence of SEQ ID NO:14, 24, 34, 44, 54, 64, 74, 84, 94, 104, 114, 124, 134, 144, 154, 164, 174, 184, 194, or 204.

In one embodiment, the antibody or antigen-binding fragment thereof comprises a heavy chain and light chain comprising the amino acid sequences of: SEQ ID NOs:13 and 14, respectively; SEQ ID NOs:23 and 24, respectively; SEQ ID NOs:33 and 34, respectively; SEQ ID NOs:43 and 44, respectively; SEQ ID NOs:469 and 44, respectively; SEQ ID NOs:53 and 54, respectively; SEQ ID NOs:63 and 64, respectively; SEQ ID NOs:73 and 74, respectively; SEQ ID NOs:83 and 84, respectively; SEQ ID NOs:93 and 94, respectively; SEQ ID NOs:103 and 104, respectively; SEQ ID NOs:113 and 114, respectively; SEQ ID NOs:123 and 124, respectively; SEQ ID NOs:133 and 134, respectively; SEQ ID NOs:143 and 144, respectively; SEQ ID NOs:153 and 154, respectively; SEQ ID NOs:163 and 164, respectively; SEQ ID NOs:173 and 174, respectively; SEQ ID NOs:183 and 184, respectively; SEQ ID NOs:193 and 194, respectively; or SEQ ID NOs:203 and 204, respectively.

Also provided herein is an isolated antibody or antigen-binding fragment thereof that specifically binds to human B7-H4, wherein the antibody or antigen-binding fragment thereof comprises the VH CDR1, VH CDR2, VH CDR3, VL CDR1, VL CDR2, and VL CDR3 of an antibody selected from the group consisting of 15461, 20500, 20501, 20502, 20502.1, 22208, 15462, 22213, 15465, 20506, 15483, 20513, 22216, 15489, 20516, 15472, 15503, 15495, 15478, 15441, and 20496. In one embodiment, the CDRs are the Kabat-defined CDRs, the Chothia-defined CDRs, or the AbM-defined CDRs.

Also provided herein is an isolated antibody or antigen-binding fragment thereof that specifically binds to human B7-H4, comprising the heavy chain variable region (VH) complementarity determining region (CDR) 1, VH CDR2, VH CDR3 and light chain variable region (VL) CDR1, CDR2, and CDR3 sequences of SEQ ID NOs:458-463, respectively. In one embodiment, (i) the antibody or antigen-binding fragment thereof comprises a variable heavy chain region comprising the amino acid sequence of SEQ ID NO:464 and a variable light chain region comprising the amino acid sequence of SEQ ID NO:42 or (ii) the antibody comprises a heavy chain comprising the amino acid sequence of SEQ ID NO:469 and a light chain comprising the amino acid sequence of SEQ ID NO:44.

Also provided herein is an isolated antibody or antigen-binding fragment thereof that specifically binds to human B7-H4, comprising the heavy chain variable region (VH) complementarity determining region (CDR) 1, VH CDR2, VH CDR3 and light chain variable region (VL) CDR1, CDR2, and CDR3 sequences of SEQ ID NOs:35-40, respectively. In one embodiment, (i) the antibody or antigen-binding fragment thereof comprises a variable heavy chain region comprising the amino acid sequence of SEQ ID NO:41 and a variable light chain region comprising the amino acid sequence of SEQ ID NO:42 or (ii) the antibody comprises a heavy chain comprising the amino acid sequence of SEQ ID NO:43 and a light chain comprising the amino acid sequence of SEQ ID NO:44.

Also provided herein is an isolated antibody or antigen-binding fragment thereof that specifically binds to human B7-H4, comprising the heavy chain variable region (VH) complementarity determining region (CDR) 1, VH CDR2, VH CDR3 and light chain variable region (VL) CDR1, CDR2, and CDR3 sequences of SEQ ID NOs:65-70, respectively. In one embodiment, (i) the antibody or antigen-binding fragment thereof comprises a variable heavy chain region comprising the amino acid sequence of SEQ ID NO:71 and a variable light chain region comprising the amino acid sequence of SEQ ID NO:72 or (ii) wherein the antibody comprises a heavy chain comprising the amino acid sequence of SEQ ID NO:73 and a light chain comprising the amino acid sequence of SEQ ID NO:74.

Also provided herein is an isolated antibody or antigen-binding fragment thereof that binds to the same epitope of human B7-H4 as the antibody or antigen-binding fragment thereof of any one of claims1-20. In one embodiment, the antibody or antigen-binding fragment thereof binds to the same epitope of human B7-H4 as determined by SPR.

In one embodiment, the antibody or antigen-binding fragment thereof is a human antibody or antigen-binding fragment thereof. In one embodiment, the antibody or antigen-binding fragment thereof is a murine, humanized, or chimeric antibody or antigen-binding fragment thereof.

In one embodiment, the antibody or antigen-binding fragment thereof induces T cell proliferation. In one embodiment, the antibody or antigen-binding fragment increases T-cell proliferation by at least 21% as compared to treatment with a control antibody. In one embodiment, the antibody or antigen-binding fragment increases T-cell proliferation by about 5% to about 35% as compared to treatment with a control antibody. In one embodiment, the antibody or antigen-binding fragment thereof induces CD4+ T cell proliferation. In one embodiment, the antibody or antigen-binding fragment thereof increases CD4+ T cell proliferation by at least 9% as compared to treatment with a control antibody. In one embodiment, the antibody or antigen-binding fragment thereof increases CD4+ T cell proliferation by about 5% to about 15% as compared to treatment with a control antibody. In one embodiment, the antibody or antigen-binding fragment thereof induces CD8+ T cell proliferation. In one embodiment, the antibody or antigen-binding fragment thereof increases CD8+ T cell proliferation by at least 11% as compared to treatment with a control antibody. In one embodiment, the antibody or antigen-binding fragment thereof increases CD8+ T cell proliferation by about 5% to about 15% as compared to treatment with a control antibody.

In one embodiment, the antibody or antigen-binding fragment thereof induces interferon-gamma (IFNγ) production. In one embodiment, the antibody or antigen-binding fragment thereof is capable of increasing production of IFNγ by at least 2 fold, at least 3 fold, at least 4 fold, and at least 5 fold, at least 6 fold, at least 7 fold, at least 8 fold, about 2 fold to about 10 fold, or about 3 fold to about 10 fold.

In one embodiment, the antibody or antigen-binding fragment thereof is capable of inducing antibody dependent cell mediated cytotoxicity (ADCC) in a B7-H4-expressing cell. In one embodiment, the antibody or antigen-binding fragment thereof induces specific lysis in at least 20%, at least 30%, at least 40%, about 20% to about 50%, or about 30% to about 50% of B7-H4 expressing cells.

In one embodiment, the antibody or antigen-binding fragment thereof inhibits tumor growth in a murine CT26 colorectal carcinoma model, a murine breast carcinoma 4T1 model, or a melanoma cell line B16-moB7-H4/H3 model. In one embodiment, the antibody or antigen-binding fragment thereof reduces tumor growth by at least 25%, at least 30%, at least 40%, at least 45%, or at least 50% as compared to treatment with a control antibody.

In one embodiment, the induction of T cell proliferation, the induction of CD4+ T cell proliferation, the induction of CD8+ T cell proliferation, the induction of IFNγ production, the ADCC activity, and/or in the inhibition of tumor growth is dose-dependent.

In one embodiment, the antibody or antigen-binding fragment thereof binds to cynomolgus monkey B7-H4. In one embodiment, the antibody or antigen-binding fragment thereof binds to rat B7-H4. In one embodiment, the antibody or antigen-binding fragment thereof binds to mouse B7-H4. In one embodiment, the antibody or antigen-binding fragment thereof binds to human B7-H4, cynomolgus monkey B7-H4, rat B7-H4 and mouse B7-H4.

In one embodiment, the antibody or antigen-binding fragment thereof binds to the IgV domain of human B7-H4.

In one embodiment, the antibody or antigen-binding fragment thereof is afucosylated.

In one embodiment, the antibody or antigen binding fragment thereof is a full length antibody. In one embodiment, the antibody or antigen binding fragment thereof is an antigen binding fragment. In one embodiment, the antigen binding fragment comprises a Fab, Fab′, F(ab)2, single chain Fv (scFv), disulfide linked Fv, V-NAR domain, IgNar, intrabody, IgGΔCH2, minibody, F(ab′)3, tetrabody, triabody, diabody, single-domain antibody, DVD-Ig, Fcab, mAb2, (scFv)2, or scFv-Fc.

In one embodiment, the antibody or antigen-binding fragment thereof further comprises a detectable label.

Also provided herein is an isolated polynucleotide comprising a nucleic acid molecule encoding the heavy chain variable region or heavy chain of an antibody or antigen-biding fragment thereof provided herein. In one embodiment, the nucleic acid molecule encodes the VH of SEQ ID NO:11, 21, 31, 41, 464, 51, 61, 71, 81, 91, 101, 111, 121, 131, 141, 151, 161, 171, 181, 191, or 201 or the heavy chain of SEQ ID NO:13, 23, 33, 43, 469, 53, 63, 73, 83, 93, 103, 113, 123, 133, 143, 153, 163, 173, 183, 193, or 203. In one embodiment, the nucleic acid molecule comprises the sequence of SEQ ID NO:213, 223, 233, 243, 470, 253, 263, 273, 283, 293, 303, 313, 323, 333, 343, 353, 363, 373, 383, 393, or 403. In one embodiment, the nucleic acid molecule comprises (i) the sequence of SEQ ID NO:213, 223, 233, 243, 470, 253, 263, 273, 283, 293, 303, 313, 323, 333, 343, 353, 363, 373, 383, 393, or 403 and (ii) the sequence of SEQ ID NO:408.

Also provided herein is an isolated polynucleotide comprising a nucleic acid molecule encoding the light chain variable region or light chain of an antibody or antigen-biding fragment thereof provided herein. In one embodiment, the nucleic acid molecule encodes the VL of SEQ ID NO:12, 22, 32, 42, 52, 62, 72, 82, 92, 102, 112, 122, 132, 142, 152, 162, 172, 182, 192, or 202 or the light chain of SEQ ID NO:14, 24, 34, 44, 54, 64, 74, 84, 94, 104, 114, 124, 134, 144, 154, 164, 174, 184, 194, or 204. In one embodiment, the nucleic acid molecule comprises the sequence of SEQ ID NO:214, 224, 234, 244, 254, 264, 274, 284, 294, 304, 314, 324, 334, 344, 354, 364, 374, 384, 394, or 404. In one embodiment, the nucleic acid molecule comprises (i) the sequence of SEQ ID NO:214, 224, 234, 244, 254, 264, 274, 284, 294, 304, 314, 324, 334, 344, 354, 364, 374, 384, 394, or 404 and (ii) the sequence of SEQ ID NO:406.

Also provided herein is an isolated polynucleotide comprising a nucleic acid molecule encoding the heavy chain variable region or heavy chain of an antibody or antigen-biding fragment provided herein and the light chain variable region or light chain of the antibody or antigen-biding fragment thereof.

Also provided herein is an isolated vector comprising a polynucleotide provided herein.

Also provided herein is a host cell comprising a polynucleotide provided herein, a vector provided herein, a first vector comprising one polynucleotide provided herein (e.g., a polynucleotide comprising a variable heavy chain or heavy chain encoding nucleic acid) and a second vector comprising another polynucleotide provided herein (e.g., a polynucleotide comprising variable light chain or light chain encoding nucleic acid). In one embodiment, the host cell is a cell selected from the group consisting ofE. coli, Pseudomonas, Bacillus, Streptomyces, yeast, CHO, YB/20, NS0, PER-C6, HEK-293T, NIH-3T3, HeLa, BHK, Hep G2, SP2/0, R1.1, B-W, L-M, COS 1, COS 7, BSC1, BSC40, BMT10 cell, plant cell, insect cell, and human cell in tissue culture. In one embodiment, the host cell is a CHO cell. In one embodiment, the host cell (e.g., a mammalian host cell, such as a CHO cell) lacks a functional alpha-1,6-fucosyltransferase gene (FUT8) gene.

Also provided herein is a method (e.g., an in vitro method) of producing an antibody or antigen-binding fragment thereof that binds to human B7-H4 comprising culturing a host cell provided herein so that the nucleic acid molecule is expressed and the antibody or antigen-biding fragment thereof is produced.

Also provided herein is an isolated antibody or antigen-binding fragment thereof that specifically binds to human B7-H4 and is encoded by a polynucleotide provided herein.

Also provided herein is a pharmaceutical composition comprising an antibody or antigen-binding fragment thereof provided herein, a polynucleotide provided herein, a vector provided herein, or a host cell provided herein; and a pharmaceutically acceptable excipient.

Also provided herein is a pharmaceutical composition comprising (i) antibodies or antigen-binding fragments provided herein and (ii) a pharmaceutically acceptable excipient, wherein at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% of the antibodies or antigen-binding fragments thereof in the composition are afucosylated.

Also provided herein is a pharmaceutical composition comprising (i) antibodies or antigen-binding fragments provided herein and (ii) a pharmaceutically acceptable excipient, wherein at least 95% of the antibodies or antigen-binding fragments thereof in the composition are afucosylated.

Also provided herein is a pharmaceutical composition comprising (i) antibodies or antigen-binding fragments thereof that specifically bind to human B7-H4 and comprise the heavy chain variable region (VH) complementarity determining region (CDR) 1, VH CDR2, VH CDR3 and light chain variable region (VL) CDR1, CDR2, and CDR3 sequences of SEQ ID NOs:458-463, respectively and (ii) a pharmaceutically acceptable excipient, wherein at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% of the antibodies or antigen-binding fragments thereof in the composition are afucosylated. In one embodiment, (i) the antibody or antigen-binding fragment thereof comprises a variable heavy chain region comprising the amino acid sequence of SEQ ID NO:464 and a variable light chain region comprising the amino acid sequence of SEQ ID NO:42 or (ii) the antibody comprises a heavy chain comprising the amino acid sequence of SEQ ID NO:469 and a light chain comprising the amino acid sequence of SEQ ID NO:44.

Also provided herein is a pharmaceutical composition comprising (i) antibodies or antigen-binding fragments thereof that specifically bind to human B7-H4 and comprise the heavy chain variable region (VH) complementarity determining region (CDR) 1, VH CDR2, VH CDR3 and light chain variable region (VL) CDR1, CDR2, and CDR3 sequences of SEQ ID NOs: 458-463, respectively and (ii) a pharmaceutically acceptable excipient, wherein at least 95% of the antibodies or antigen-binding fragments thereof in the composition are afucosylated. In one embodiment, (i) the antibody or antigen-binding fragment thereof comprises a variable heavy chain region comprising the amino acid sequence of SEQ ID NO: 464 and a variable light chain region comprising the amino acid sequence of SEQ ID NO:42 or (ii) the antibody comprises a heavy chain comprising the amino acid sequence of SEQ ID NO: 469 and a light chain comprising the amino acid sequence of SEQ ID NO:44.

Also provided herein is a pharmaceutical composition comprising (i) antibodies or antigen-binding fragments thereof that specifically bind to human B7-H4 and comprise the heavy chain variable region (VH) complementarity determining region (CDR) 1, VH CDR2, VH CDR3 and light chain variable region (VL) CDR1, CDR2, and CDR3 sequences of SEQ ID NOs:35-40, respectively and (ii) a pharmaceutically acceptable excipient, wherein at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% of the antibodies or antigen-binding fragments thereof in the composition are afucosylated. In one embodiment, (i) the antibody or antigen-binding fragment thereof comprises a variable heavy chain region comprising the amino acid sequence of SEQ ID NO:41 and a variable light chain region comprising the amino acid sequence of SEQ ID NO:42 or (ii) the antibody comprises a heavy chain comprising the amino acid sequence of SEQ ID NO:43 and a light chain comprising the amino acid sequence of SEQ ID NO:44.

Also provided herein is a pharmaceutical composition comprising (i) antibodies or antigen-binding fragments thereof that specifically bind to human B7-H4 and comprise the heavy chain variable region (VH) complementarity determining region (CDR) 1, VH CDR2, VH CDR3 and light chain variable region (VL) CDR1, CDR2, and CDR3 sequences of SEQ ID NOs:35-40, respectively and (ii) a pharmaceutically acceptable excipient, wherein at least 95% of the antibodies or antigen-binding fragments thereof in the composition are afucosylated. In one embodiment, (i) the antibody or antigen-binding fragment thereof comprises a variable heavy chain region comprising the amino acid sequence of SEQ ID NO:41 and a variable light chain region comprising the amino acid sequence of SEQ ID NO:42 or (ii) the antibody comprises a heavy chain comprising the amino acid sequence of SEQ ID NO:43 and a light chain comprising the amino acid sequence of SEQ ID NO:44.

Also provided herein is a pharmaceutical composition comprising (i) antibodies or antigen-binding fragments thereof that specifically bind to human B7-H4 and comprise the heavy chain variable region (VH) complementarity determining region (CDR) 1, VH CDR2, VH CDR3 and light chain variable region (VL) CDR1, CDR2, and CDR3 sequences of SEQ ID NOs:65-70, respectively and (ii) a pharmaceutically acceptable excipient, wherein at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% of the antibodies or antigen-binding fragments thereof in the composition are afucosylated. In one embodiment, (i) the antibody or antigen-binding fragment thereof comprises a variable heavy chain region comprising the amino acid sequence of SEQ ID NO:71 and a variable light chain region comprising the amino acid sequence of SEQ ID NO:72 or (ii) wherein the antibody comprises a heavy chain comprising the amino acid sequence of SEQ ID NO:73 and a light chain comprising the amino acid sequence of SEQ ID NO:74.

Also provided herein is a pharmaceutical composition comprising (i) antibodies or antigen-binding fragments thereof that specifically bind to human B7-H4 and comprise the heavy chain variable region (VH) complementarity determining region (CDR) 1, VH CDR2, VH CDR3 and light chain variable region (VL) CDR1, CDR2, and CDR3 sequences of SEQ ID NOs:65-70, respectively and (ii) a pharmaceutically acceptable excipient, wherein at least 95% of the antibodies or antigen-binding fragments thereof in the composition are afucosylated. In one embodiment, (i) the antibody or antigen-binding fragment thereof comprises a variable heavy chain region comprising the amino acid sequence of SEQ ID NO:71 and a variable light chain region comprising the amino acid sequence of SEQ ID NO:72 or (ii) wherein the antibody comprises a heavy chain comprising the amino acid sequence of SEQ ID NO:73 and a light chain comprising the amino acid sequence of SEQ ID NO:74.

In one embodiment, fucosylation is undetectable in the composition.

Also provided herein is a method for inducing T cell proliferation comprising contacting a T cell with an antibody or antigen-binding fragment thereof provided herein, a polynucleotide provided herein, a vector provided herein, a host cell provided herein, or a pharmaceutical composition provided herein. In one embodiment, T cell proliferation is reduced by at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, or at least 80% (e.g., as compared to treatment with a control antibody).

Also provided herein is a method for inducing CD4+ T cell proliferation comprising contacting a CD4+ T cell with an antibody or antigen-binding fragment thereof provided herein, a polynucleotide provided herein, a vector provided herein, a host cell provided herein, or a pharmaceutical composition provided herein. In one embodiment, CD4+ T cell proliferation is reduced by at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, or at least 80% (e.g., as compared to treatment with a control antibody).

Also provided herein is a method for inducing CD8+ T cell proliferation comprising contacting a CD8+ T cell with an antibody or antigen-binding fragment thereof provided herein, a polynucleotide provided herein, a vector provided herein, a host cell provided herein, or a pharmaceutical composition provided herein. In one embodiment, CD8+ T cell proliferation is reduced by at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, or at least 80% (e.g., as compared to treatment with a control antibody).

Also provided herein is a method for inducing interferon gamma production comprising contacting a T cell with an antibody or antigen-binding fragment thereof provided herein, a polynucleotide provided herein, a vector provided herein, a host cell provided herein, or a pharmaceutical composition provided herein. In one embodiment, interferon gamma production is increased by at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, or at least 80% (e.g., as compared to treatment with a control antibody).

Also provided herein is a method for killing a cell expressing B7-H4 comprising contacting the cell with an antibody or antigen-binding fragment thereof provided herein, a polynucleotide provided herein, a vector provided herein, a host cell provided herein, or a pharmaceutical composition provided herein.

Also provided herein is a method for depleting B7-H4-expressing cells from a population of cells comprising contacting the population of cells with an antibody or antigen-binding fragment thereof provided herein, a polynucleotide provided herein, a vector provided herein, a host cell provided herein, or a pharmaceutical composition provided herein.

In one embodiment, the killing or depletion occurs via ADCC.

In one embodiment, the contacting is in vitro. In one embodiment, the contacting is in a subject.

Also provided herein is a method of treating cancer in a subject, the method comprising administering to the subject an effective amount of an antibody or antigen-binding fragment thereof provided herein, a polynucleotide provided herein, a vector provided herein, a host cell provided herein, or a pharmaceutical composition provided herein. In one embodiment, the cancer is selected from the group consisting of breast cancer, such as triple negative breast cancer or invasive ductal carcinoma, endometrial carcinoma, ovarian cancer, non-small cell lung cancer, pancreatic cancer, thyroid cancer, kidney cancer and bladder cancer. In one embodiment, the breast cancer is triple negative breast cancer or wherein the non-small cell lung cancer is squamous cell carcinoma. In one embodiment, the non-small cell lung cancer is an adenocarcinoma. In one embodiment, the cancer is selected from the group consisting of head and neck cancer, small cell lung cancer, gastric cancer, and melanoma. In one embodiment, the ovarian cancer is a serous adenocarcinoma. In one embodiment, the breast cancer is a ductal adenocarcinoma.

In one embodiment, the cancer is a PD-1 inhibitor inadequate responder and/or PD-L1 inhibitor inadequate responder. In one embodiment, the cancer expresses a low level of PD-L1.

In one embodiment, the subject is human.

Also provided herein is a method for detecting B7-H4 in a sample comprising contacting said sample with an antibody or antigen-binding fragment thereof provided herein. In one embodiment, the sample is obtained from a cancer in a human subject.

Also provided herein is a kit comprising an antibody or antigen-binding fragment thereof provided herein, a polynucleotide provided herein, a vector provided herein, a host cell provided herein, or a pharmaceutical composition provided herein and a) a detection reagent, b) a B7-H4 antigen, c) a notice that reflects approval for use or sale for human administration, or d) a combination thereof.

Also provided herein is an isolated antibody or antigen-binding fragment, wherein the antibody or antigen-binding fragment thereof inhibits T cell checkpoint blockade activity of B7-H4. In one embodiment, the T cell checkpoint blockade activity is measured by an increase in IL-2 production relative to control cells.

Also provided herein is a pharmaceutical composition comprising (i) antibodies or antigen-binding fragments and (ii) a pharmaceutically acceptable excipient, wherein the antibodies or antigen-binding fragments inhibit T cell checkpoint blockade activity of B7-H4. In an embodiment, the T cell checkpoint blockade activity is measured by an increase in IL-2 production relative to control cells.

