Induction of Tc1 response and enhanced cytotoxic T lymphocyte activity in mice by dendritic cells transduced with adenovirus expressing HBsAg

We evaluated the potential of dendritic cells (DCs) engineered to express antigen of hepatitis B virus (HBV) in priming Th/Tc and HBV-specific CTL responses in mice. Recombinant adenovirus expressing hepatitis B surface antigen (HBsAg) (Ad-S) was constructed, and bone marrow-derived DCs were transduced with Ad-S or pulsed with HBsAg protein. Mice were injected with either Ad-S-transduced DCs or HBsAg-pulsed DCs or plasmid DNA encoding HBsAg twice at 3-week intervals. We showed that adenovirus infection had no further effect on the phenotype, the ability to induce IFN-γ-producing Th1/Tc1 response or the T cell stimulatory capacity of already mature DCs in vitro. We also showed that immunization with Ad-S-transduced DCs effectively induced Tc1 cells and HBsAg-specific CTLs in vivo and down-regulated the circulating HBsAg and HBV DNA in HBV transgenic mice. Furthermore, these efficacies were stronger than that of HBsAg-pulsed DCs and plasmid DNA. Thus, DCs transduced with recombinant adenovirus may be a promising candidate for an effective CTL-based therapeutic vaccine against HBV.