The study of immune response of IL-2 preS DNA vaccine on BALB/c mice and HBV transgenic mice

Objective To investigate the feasibility and functional mechanism of hIL-2 preS DNA vaccine as prevention and therapeutic vaccine for hepatitis B. Methods hIL-2 and preS eukaryon expression vector was constructed by using DNA recombinant technology. Normal BALB/c mice and HBV transgenic mice were injected with gene gun. The antibody of anti-preS2 and anti-HBs was detected by ELISA. The HBV DNA copies in HBV transgenic mice serum and liver tissue were detected by real-time PCR. The inflammatory activity, liver function and transaminase were detected at the same time. Results (1) preS1 antibody can be detected at the 4~(th) and 6~(th) week, which can maintain up to 10 wk after the injection of immune-normal mice with eukaryotic expressive plasmid. (2) The injection of eukaryotic plasmid into muscle using gene gun is better than normal muscle injection and subcutaneous. The quality of plasmid (10μg per mouse) is only one tenth of the later (100μg per mouse). (3) When detecting IgG subset at the peak stage of the 4~(th) week, it is a reaction that mainly induces cellular immunity of T_H1 IgG2a cells. (4) After the transgenic mouse was immuned by injection of eukaryotic expression plasmid (1μg per mouse) using gene gun, 80% mice got the antibody, and the copied of HBV DNA decreased. (5) HE stain of liver tissue showed there were obviously inflammatory cells infiltration and hepatocyte liver cell swelling and particulate degeneration. Conclusion Humoral and cellular immunity can be produced and immunological tolerance can be broken partly after the injection of IL-2 preS DNA vaccine. All these provide experimental foundation for the further research of therapeutic HBV DNA vaccine. [