Human antibodies that bind lymphocyte activation gene-3 (lag-3), and uses thereof

Abstract

The present disclosure provides isolated monoclonal antibodies that specifically bind to LAG-3 with high affinity, particularly human monoclonal antibodies. Preferably, the antibodies bind human LAG-3. In certain embodiments, the antibodies bind both human and monkey LAG-3 but do not bind mouse LAG-3. The invention provides anti-LAG-3 antibodies that can inhibit the binding of LAG-3 to MHC Class II molecules and that can stimulate antigen-specific T cell responses. Nucleic acid molecules encoding the antibodies of the invention, expression vectors, host cells and methods for expressing the antibodies of the invention are also provided. Immunoconjugates, bispecific molecules and pharmaceutical compositions comprising the antibodies of the invention are also provided. This disclosure also provides methods for detecting LAG-3, as well as methods for treating stimulating immune responses using an anti-LAG-3 antibody of the invention. Combination therapy, in which an anti-LAG-3 antibody is co-administered with at least one additional immunostimulatory antibody, is also provided.

1 - 62 . (canceled) 
     
     
         63 . A method for assessing the potency of an antibody that specifically binds human lymphocyte activation gene-3 (LAG-3) comprising:
 (a) providing a cell culture containing murine T cells that express a human LAG-3 polypeptide, and major histocompatibility complex (MHC)-matched antigen presenting cells;   (b) contacting said cell culture with the anti-human LAG-3 antibody;   (c) contacting said cell culture with a T cell activating agent; and   (d) detecting cytokine secretion from the T cells, wherein the level of cytokine secretion indicates the potency of the anti-human LAG-3 antibody.   
     
     
         64 . The method of  claim 63 , wherein the cell culture contains a 3:1 ratio of murine T cells to MHC-matched antigen presenting cells. 
     
     
         65 . The method of  claim 63 , wherein the cell culture contains about 5.0×10 4  murine T cells. 
     
     
         66 . The method of  claim 63 , wherein the cell culture contains about 2.5×10 4  MHC-matched antigen presenting cells. 
     
     
         67 . The method of  claim 63 , wherein cell culture is contacted with about 25 μg/mL of the anti-human LAG-3 antibody. 
     
     
         68 . The method of  claim 64  wherein the murine T cells express a human LAG-3 at least 90% identical to the amino acid sequence of SEQ ID NO:29. 
     
     
         69 . The method of  claim 68 , wherein the T cells express the human LAG-3 polypeptide of SEQ ID NO:29. 
     
     
         70 . The method of  claim 63 , wherein the murine T cell is an antigen-specific T cell hybridoma. 
     
     
         71 . The method of  claim 63 , wherein the T cell hybridoma expresses a T cell receptor that is activated by the antigen presenting cells. 
     
     
         72 . The method of  claim 63 , wherein the murine T cell is a 3A9 hybridoma. 
     
     
         73 . The method of  claim 72 , wherein the 3A9 hybridoma expresses a T cell receptor specific for the peptide HEL48-62 from hen egg lysozyme. 
     
     
         74 . The method of  claim 63 , wherein the antigen presenting cells are murine B cell hybridomas. 
     
     
         75 . The method of  claim 63 , wherein the murine B cell hybridomas are LK35.2 cells. 
     
     
         76 . The method of  claim 63 , wherein the T cell activating agent is a peptide. 
     
     
         77 . The method of  claim 63 , wherein the peptide is a hen egg lysozyme peptide. 
     
     
         78 . The method of  claim 77 , wherein the peptide is HEL48-62. 
     
     
         79 . The method of  claim 78 , wherein the peptide is added at a concentration from about 323 nM to about 357 nM. 
     
     
         80 . The method of  claim 79 , wherein the peptide is added at a concentration of about 340 nM. 
     
     
         81 . The method of  claim 63 , wherein the anti-LAG-3 antibody comprises: (a) a heavy chain variable region CDR1 comprising the sequence set forth in SEQ ID NO:15; (b) a heavy chain variable region CDR2 comprising the sequence set forth in SEQ ID NO:16; (c) a heavy chain variable region CDR3 comprising the sequence set forth in SEQ ID NO:17; (d) a light chain variable region CDR1 comprising the sequence set forth in SEQ ID NO:18; (e) a light chain variable region CDR2 comprising the sequence set forth in SEQ ID NO:19; and (f) a light chain variable region CDR3 comprising the sequence set forth in SEQ ID NO:20. 
     
     
         82 . The method of  claim 63 , wherein the cytokine is selected from the group consisting of interleukin-2 (IL-2), interferon, IL-21, GM-CSF, TNFα, and G-CSF. 
     
     
         83 . The method of  claim 63 , wherein the cytokine secretion is detected using an enzyme-linked immunosorbent assay (ELISA). 
     
     
         84 . The method of  claim 83 , wherein the ELISA is performed in a 96 well plate. 
     
     
         85 . The method of  claim 83 , wherein the ELISA assay is automated. 
     
     
         86 . A murine T cell hybridoma that expresses human LAG-3 polypeptide. 
     
     
         87 . The murine T cell hybridoma of  claim 86 , wherein the T cell hybridoma is a 3A9 cell that stably expresses human LAG-3 polypeptide. 
     
     
         88 . An assay for assessing the potency of an antibody that specifically binds human lymphocyte activation gene-3 (LAG-3), said assay comprising:
 (a) providing a cell culture containing murine T cells that express a human LAG-3 polypeptide, and major histocompatibility complex (MHC)-matched antigen presenting cells;   (b) contacting said cell culture with the anti-human LAG-3 antibody;   (c) contacting said cell culture with a T cell activating agent; and   (d) detecting cytokine secretion from the T cells, wherein the level of cytokine secretion indicates the potency of the anti-human LAG-3 antibody.