Suppression of the antigen-specific T cell immune response by co-immunization with the HBV DNA vaccine and recombinant HBsAg

Abstract:

Abstract: [Objective] To explore a new therapeutic strategy against acute hepatitis B and fulminant hepatitis B, we studied effect of co-immunization with HBV DNA and HBsAg on the T cell proliferation reaction. [Methods] We immunized the BALB/c mice with HBV DNA vaccine (pcDS2) plus HBsAg by intramuscular injection. The immunization was performed on week 0, 2 and 4. The anti-HBs（IgG）antibody titer, T lymphocyte proliferation reaction , and the expression of IL-10 and Foxp3 in CD3+ T cell were detected on week 6. [Results] The anti-HBs IgG titer induced by pcDS2 plus HBsAg group was higher than that induced by pcDS2, or HBsAg alone. Compared to mice immunized with pcDS2, or HBsAg alone, the stimulated index (SI) of T cell proliferation induced by the pcDS2 plus HBsAg group tested by MTT methods decreased. Besides, the immune suppression of T cell proliferation response induced by co-immunization group was further confirmed by flow cytometry. Finally, the expression of IL-10 and Foxp3 in CD3+ T cell was up-regulated in the co-immunization group significantly. [Conclusion] The co-immunization of HBV DNA vaccine and HBsAg can induce the humoral immune response, but cannot induce antigen specific T cell proliferation reaction. Besides, the immune suppression induced by co-immunization may be correlated with the expression of IL-10 and Foxp3.