Vaccination with a DNA vaccine encoding CD317-targeting HBs antigen elicits enhanced immunity in mice.

BACKGROUND: Conventional hepatitis B virus (HBV) vaccines fail to induce protective antibody titers in 5-10% of immune-competent vaccines. Therefore, safe and effective HBV vaccines are still clinically needed.

METHODS: In this study, we developed a plasmid DNA vaccine encoding CD317 single-chain fragment variable (α317scFv) linked with the hepatitis B surface antigen (HBsAg) and detected the humoral and cellular immune responses elicited by this vaccine in BALB/c mice.

RESULTS: Vaccination with this fusion DNA vaccine in BALB/c mice induced more robust antiviral T cell and antibody immunity against HBsAg. Compared with mice vaccinated with control vaccine encoding HBsAg, the level of serum-circulating anti-HBsAg antibody (HBsAb) was nearly double in fusion DNA-vaccinated mice. More interesting, splenic lymphocytes isolated from fusion DNA-vaccinated mice showed more potent proliferation and IFN-γ production after being re-stimulated with recombinant HBsAg in vitro. And not only that, the cytotoxicity of fusion DNA vaccine-sensitized splenocytes was ∼3-fold higher than that of controls.

CONCLUSION: Taken together, our results reveal that the fusion DNA vaccine can induce more effective immunological protection against HBV, and is a promising candidate for preventing HBV infection.