Development of a novel viral DNA vaccine against human papillomavirus: AcHERV-HP16L1

In this study, we developed a novel DNA vaccine for HPV; a recombinant baculovirus bearing human endogenous retrovirus (HERV) envelope protein, which cannot replicate in mammals, was used as a nano-carrier for HPV-16L1 DNA vaccine (AcHERV-HP16L1). For in vivo test, mice were injected intramuscularly with 107 particles of the constructs, with two boosts at 2-week intervals. Compared with Gardasil® (25 μL/dose), the AcHERV-HP16L1 immunized mice showed similar high levels of humoral immunity in IgG/IgA and in neutralization of HPV pseudovirions. Combined immunization (prime with AcHERV-HP16L1 and boost with Gardasil®) induced slightly higher neutralizing activity. As compared to the group treated with Gardasil®, the mice immunized with AcHERV-HP16L1 showed 450- and 490-fold increase in the IFN-γ at 5 and 20 weeks after the first priming, respectively. The combined immunization conferred lower T cell immunity than AcHERV-HP16L1 treatment. The advantages of our novel AcHERV-HP16L1 vaccine over Gardasil® include higher cellular immunogenicity, considerably lower production cost, and comparable safety. Therefore, we suggest that AcHERV-HP16L1 can be developed as an efficient prophylactic vaccine and therapeutic vaccine.