Antitumor Effects of HPV DNA Vaccine Adjuvanted with Beclin-1 as an Autophagy Inducer in a Mice Model

BACKGROUND: There is a growing interest in development of an effective adjuvant system for improving DNA vaccines. Recent findings have confirmed an important role for autophagy in both innate and adaptive immunity. The current study was undertaken to determine the efficacy of autophagy induction with Beclin-1, as a novel adjuvant system, in mice immunized with human papilloma virus (HPV) DNA vaccine. METHODS: To determine whether autophagy induction with Beclin-1 enhances the efficacy of HPV DNA vaccine, female C57BL/6 mice were challenged with TC-1 tumor cells and were immunized three times at one-week intervals. Two weeks after the final immunization, the mice were sacrificed, and the antitumor effects were assessed by measurement of lymphocyte proliferation, cytotoxicity, cytokine production, and tumor regression. RESULTS: Beclin-1 in combination with HPV-16 DNA vaccine encoding the E7 antigen induced a higher level of lymphocyte proliferation and cytotoxicity than the DNA vaccine alone. The novel combination increased the production of IFN-γ and highly inhibited tumor progression in comparison with DNA vaccine alone. CONCLUSION: Administration of Beclin-1, as an autophagy inducer, with HPV DNA vaccine produces antitumor effects, providing an effective adjuvant for the induction of a strong antitumor immune response.