CD258, also known as LIGHT and tumor necrosis factor superfamily member 14 (TNFSF14), is a secreted protein belonging to the TNF superfamily. It is a type II transmembrane protein expressed on activated T cells and immature dendritic cells and recognized by the herpes virus invasion mediator (HVEM) and decoy receptor 3. The protein can be used as a co-stimulatory factor of lymphocyte activation and an inhibitor of herpes virus infection, which can stimulate the proliferation of T cells, cause apoptosis of various tumor cells and prevent virus invasion. It has also been reported to prevent TNF-α-mediated apoptosis in primary hepatocytes. In addition, CD258 is involved in T cell development and homeostasis, dendritic cell maturation, and atherosclerosis, and plays a significant role in diseases involving T cells such as graft-versus-host disease (GVHD) and autoimmune diseases.