Immunization with adenovirus LIGHT-engineered dendritic cells induces potent T cell responses and therapeutic immunity in HBV transgenic mice

LIGHT, a TNF superfamily member (TNFSF14), is a type II transmembrane protein expressed on activated T cells and immature dendritic cells (DCs). However, the expression of LIGHT on mature DCs is down-regulated. Recent studies demonstrated that LIGHT provides potent costimulatory activity for T cells, enhancing proliferation and the production of Th1 cytokines independently of the B7-CD28 pathway. Here, we evaluated the effectiveness of peptide-pulsed DC-mediated antiviral immunity in HBV transgenic mice and the immunoadjuvant effect of LIGHT. The bone marrow-derived DCs were modified in vitro with an adenovirus (Ad) vector expressing mouse LIGHT (Ad-LIGHT), the expression of costimulatory molecules was up-regulated and the secretion of cytokines IL-12 and IFN-γ increased. LIGHT-modified DCs enhanced allostimulation for T cells in mixed lymphocyte reaction (MLR). HBV peptide-pulsed DCs elicited HBV specific CD8+ T cell response and reduced the level of HBsAg and HBV DNA in sera of HBV transgenic mice. Importantly, LIGHT-modified DCs could induce stronger antiviral immunity. These results support the concept that genetic modification of DCs with a recombinant LIGHT adenovirus vector may be a useful strategy for antiviral immunotherapy.