Development of a dendritic cell vaccine encoding multiple cytotoxic T lymphocyte epitopes targeting hepatitis C virus

The aim of the present study was to develop a dendritic cell (DC) vaccine encoding hepatitis C virus (HCV) multiple cytotoxic T lymphocyte (CTL) epitopes that can stimulate T cell responses in vitro, and can be used for immunization in vivo. DCs were infected with recombinant replication-defective adenoviruses (Ads) expressing 2 HCV sequences fused with green fluorescent protein (GFP) and FLAG tags. One sequence (sequence 1) contained the HCV CTL epitopes, NS4B 1793-1801 and P7 774-782, as well as the HCV Th epitope, NS3 1248-1261. A second sequence (sequence 2) was the positive epitope control which contained HCV core 35-44, core 132-140 and NS3 1248-1261. The efficiency of infection was detected by flow cytometry and the expression of HCV epitopes in the DCs was confirmed by RT-PCR and western blot analysis. Ad infection significantly enhanced DC maturation and interleukin (IL)-12p70 production, resulting in T cell proliferation and increased interferon-γ secretion. The CTLs stimulated by Ad-infected DCs specifically killed Huh7.5 human hepatoma cells. The recombinant Ad-expressing multiple CTL HCV epitopes effectively infected the DCs in vitro and promoted T cell antiviral immune responses, thereby laying the foundation for the development of anti-HCV DC vaccines.