The TNF superfamily members LIGHT and CD154 (CD40 ligand) costimulate induction of dendritic cell maturation and elicit specific CTL activity

LIGHT is a recently identified member of the TNF superfamily that is up-reg ulated upon activation of T cells. Herpesvirus entry mediator, one of its r eceptors, is constitutively expressed on immature dendritic cells (DCs). In this report, we demonstrate that LIGHT induces partial DC maturation as de monstrated by Ag presentation and up-regulation of adhesion and costimulato ry molecules. LIGHT-stimulated DCs show reduced macropinocytosis and enhanc ed allogeneic stimulatory capacity but fail to produce significant amounts of IL-12, IL-6, IL-1 beta, or TNF-alpha compared with unstimulated DCs. How ever, LIGHT cooperates with CD154 (CD40 ligand) in DC maturation, with part icular potentiation of allogeneic T cell proliferation and cytokine secreti on of IL-12, IL-6, and TNF-alpha. Moreover, LIGHT costimulation allows DCs to prime in vitro-enhanced specific CTL responses. Our results suggest that LIGHT plays an important role in DC-mediated immune responses by regulatin g CD154 signals and represents a potential tool for DC-based cancer immunot herapy.