Tumor Necrosis Factor β (TNF-β) is a secreted protein belonging to the tumor necrosis factor family. TNF-β binds to TNFRSF1A/TNFR1, TNFRSF1B/TNFBR and TNFRSF14/HVEM in homotrimeric form, binds to TNFRSF3/LTBR in heterotrimeric form with LTB. TNF-β forms heterotrimers with lymphotoxin-beta, which anchors TNF-β to the cell surface. TNF-β mediates the inflammatory, immunostimulatory, and antiviral response, involves in the formation of second lymphoid organs during development, has a role in apoptosis. TNF-β is produced by lymphocytes and cytotoxic for a variety of tumor cells in vitro and in vivo.