Impact of different adjuvant on immunogenicity of the HBV particle vaccine containing the S + PreS1 fusion antigen in Balb/C mice

Abstract:

We previous reported the development of novel hepatitis B virus(HBV) vaccine containing the surface antigen(S) plus PreS1 fusion derived from Chinese hamster ovary (CHO) cells system. In this study, we analyzed the impact of different adjuvants on immunogenicity of the HBV particle vaccine in Balb/C mice, including alum alone, CpG oligodeoxynucleotides (CpG-ODN) alone and CpG-ODN in combination with alum adjuvant. We first detected the antigen specific humoral response in mice, including total IgG antibody and IgG subtyping. Then, we characterized the specific cell-mediated immune (CMI) response by detection of γ-interfon secreting splenocytes after stimulating with S or PreS1 peptide pool. Our results showed that: CpG-ODN adjuvanted vaccine could rapidly induce higher level of anti-PreS1 and anti-S antibodies, and a higher ratio of IgG2a/IgG1 antibody than that of alum adjuvanted vaccine. At the same time, CpG-ODN adjuvanted vaccine induced robust antigen-specific cellular immune responses in mice, which was superior to that of alum adjuvanted vaccine and CpG-ODN in combination with alum adjuvanted vaccine; however, the vaccine candidate with CpG-ODN in combination with alum adjuvant induced highest anti-S antibody and mixed IgG subclasses in mice after twice immunization. There exists dominant HBV CMI epitopes in the N-terminal of S antigen. These results provided important evidence that CpG-ODN adjuvanted HBSS1 particles vaccine may serve as a novel method in the development of new preventive and therapeutic agents against hepatitis B infection.