The role of LIGHT in T cell-mediated immunity.

This review focuses on the role of homologous to lymphotoxin, exhibits inducible expression, competes with herpesvirus glycoprotein D for HVEM on T cells (LIGHT) in T-cell immunity and T cell-mediated diseases. LIGHT binds to lymphotoxin-beta receptor (LTbetaR), and cooperates with LTbeta in lymphoid organogenesis and development of lymphoid structure. Previous findings establish a crucial biological role for LIGHT, a T cell-derived costimulatory ligand, in T-cell activation and expansion via a T-T cell-dependent manner. Transgenic studies demonstrated that the dysregulation of LIGHT activity results in the disturbance of T-cell homeostasis and ultimately the breakdown of peripheral tolerance. Furthermore, the blockade of LIGHT activity ameliorates the severity of T cell-mediated diseases indicating the essential involvement of LIGHT in various pathological conditions. Here, we review the recent studies about LIGHT mainly in the context of autoimmunity and conclude with a discussion of the potential mechanisms by which LIGHT promotes autoimmunity.