ABSTRACT
Objective:To construct a DNA vaccine co-expressing the HBV compound multi-epitope antigen gene, the hIL-12 and the anti-HBV siRNA genes, and to express this DNA vaccine in HepG2 cells. Methods:The HBV multi-epitope antigen gene was designed and synthesized before it was fused with enhanced green fluorescent protein(EGFP) gene, and cloned into the multi-clone site(MCS) of the eukaryotic expression vector pVAX1. The expressinig units of hIL-12 and siRNA were cloned into the BspH I and Mlu I site of pVAX1 respectively. Then the recombinant plasmid pVAX1-siHBV-HB-EGFP-hIL12 was transiently transfected HepG2 cells. The expression of HBV compound multi-epitope gene was observed through EGFP report gene. The expression of hIL-12 was analyzed by ELISA and the effects of anti-HBV siRNA was confirmed with rtPCR . Results: The analysis of enzyme digestion and sequencing both demonstrated that the trible-expressing HBV DNA vaccine has been constructed successfully. The green fluorescent image was detected in the transfected cells which could confirm the expression of the multi-epitope antigen gene. The amount of hIL-12 secretion was 1289pg/ml in supernatant at 48h after transfection and 1712pg/ml at 72h after transfection. The mRNA amount of HBV S gene, which was the siRNA target, had been obviously knockdown. Conclusion: The DNA vaccine co-expressing the HBV compound multi-epitope antigen gene, the hIL-12 and the siRNA genes was constructed and transiently expressed in HepG2 cells, and siRNA had shown us a good anti-HBV effect. It laid a foundation of further study on anti-HBV effect of the new DNA vaccine.