LIGHT–HVEM signaling and the regulation of T cell-mediated immunity

LIGHT is a tumor necrosis factor (TNF) superfamily ligand that regulates T cell immune responses by signaling through the herpes virus entry mediator (HVEM) and the lymphotoxin β receptor (LTβR). This review will present a summary of recent advances made regarding the immunobiology of the LIGHT–HVEM and LTβR systems. LIGHT has emerged as a potent initiator of T cell co-stimulation signals effecting CTL-mediated tumor rejection, allograft rejection and graft versus host disease. Constitutive expression of LIGHT leads to tissue destruction and autoimmune-like disease syndromes. In contrast to LTαβ, LIGHT plays a minimal role in lymphoid tissue development, yet some evidence indicates a role in negative selection in the thymus. These results provide an encouraging profile for the LIGHT–HVEM–LTβR axis as a potential target for controlling cellular immune reactions.