The T5-39 antibody recognizes human LIGHT (CD258) also known as ligand for herpesvirus entry mediator, tumor necrosis factor receptor-like-2 ligand, TR2 ligand, and tumor necrosis factor ligand superfamily member 14 (TNFSF14). LIGHT is a type 2 transmembrane protein, and a member of the tumor necrosis factor ligand superfamily. LIGHT can be proteolytically cleaved and two isofoms have been shown to be produced by alternative splicing. The apparent molecular weight of LIGHT us approximately 30 kD. LIGHT expression has been observed in spleen, brain and kidney; expression is upregulated on activated T cells (particularly CD8+ cells). LIGHT stimulates proliferation of T cells and inhibits growth of some tumor cells. This protein has been shown to play a role in intestinal inflammation and contribute to IgA nephropathy. LIGHT is a ligand for HVEM, and LTbetaR and has also been shown to bind DcR3 and modulate function. In addition, LIGHT has been shown to interact with other proteins including TRAF2, TRAF3, and DIABLO. The T5-39 antibody has been shown to be useful for flow cytometry and ELISA.