Objective: To rational design HBV therapeutic vaccine candidate and evaluate their specific immunity to HBV in mice.
Methods: Based on our previous data of HBV protein vaccine consisting of S-PreS1 fusion particle. We first construct a novel DNA vaccine candidate, pVRC-HBSS1, which consisting of S (aa: 1-223) and PreS1 (aa: 21-47) fuse gene,then confirm the expression of the DNA vaccine by Western blotting, and followed by vaccination using prime boost strategy, ie, Intradermal injection of DNA vaccine with gene electroporation (EP) in BALB/c mice after twice injection of different HBSS1 protein vaccines (combination with different adjuvants). The immune response was measured by ELISA and IFN-gamma ELISPOT.
Result: The novel DNA vaccine candidate could effectively express in vitro, boost with single intradermal injection of HBV DNA vaccine via EP can significantly enhance the surface antigen (S)-specific cellular immune responses (IFN-gamma ELISpot analysis) and PreS1-specific antibody levels, especially in the group primed with protein vaccine in combination with alum adjuvant.
Conclusion: Boost with the novel HBV DNA vaccine followed prime with HBV protein vaccine could induced a higher anti-HBV T cell response in mice than vaccination with the HBSS1 particle-like protein vaccine only. This prime-boost vaccination may serve as a promising way to develop and optimize the novel HBV therapeutic vaccine.