OBJECTIVETo observe the immune effect of DNA vaccines encoding mutated HBV pre-c/c gene (VE2,VE4) in mice.

METHODSThree kinds of plasmid VEC(DNA vaccines encoding HBV pre-c/c gene), VE2 and VE4 were injected into the thigh muscles of different group of BALB/c mice.Blood and splenocytes from mice were isolated at 4 weeks after immunization. We also have mouse groups immunized with three of these plasmid combined with IFN-gamma gene plasmids. The anti-HBc and anti-HBe antibody in peripheral blood in mice were detected by enzyme linked immunosorbent assay (ELISA), antigen-specific cell immune responses were detected by CTL test and enzyme linked immunospot assay(ELISpot).

RESULTSWe found that anti-HBe titers of VE2 and VE4 immunizing groups are higher than VEC group (P < 0.05). We also observed that VE2 and VE4 could induce stronger antigen-specific immune responses than VEC and when combined with IFN-gamma plasmid,the antigen-specific immune responses are stronger than those without combination immunization in mice (P < 0.05).

CONCLUSIONSThe DNA vaccine VE2 and VE4 could induces stronger antigen-specific immune responses than VEC, and when combined with IFN-gamma plasmid,the antigen-specific immune responses are improved in mice.