A portion of amino acids 19-188 from the human protein was used as the immunogen for the recombinant CD137 antibody.
CD137 belongs to the tumor necrosis factor receptor family and delivers a costimulatory signal to T lymphocytes. It is expressed on activated T cells and binds an inducible ligand that is found on B cells, macrophages and dendritic cells. Interactions between CD137 and its ligand are involved in antigen presentation and the generation of cytotoxic T cells. CD137 antibody may improve cancer treatment, and has been implicated in breast cancer, melanoma and lymphoma.