[Construction of HBV S gene recombinant and its immunity induced in mice]

OBJECTIVE: To investigate the feasibility of HBV DNA vaccines. METHODS: HBV S gene was obtained by PCR and the PCR product was cloned into pcDNA3. The recombinant was screened by antibiotics, identified by digestion and confirmed by sequencing. The plasmid was then transfected into mammalian cell COS-7 for transient expression. Then the recombinant was injected into mice and the immune responses induced in mice were investigated. RESULTS: The sequence of HBV S gene was correct and HBsAg could be detected in cells transfected with pcDNA3-S. After immunization, the positive rate in mice immunized with pcDNA3-S and pCMV-S was 70%(7/10) and 80% (8/10). The mean levels of anti-HBs were (32.14+/-13.79)mIU/ml and (28.50+/-11.87)mIU/ml respectively. There was no statistically significant difference between them P 0.05 . The mean levels of anti HBs in the control group and blank groups were both less than 10 mIU/ml. In mice immunized with pcDNA3-S and pCMV-S the results were (35.40+/-4.85)% and (38.20+/-7.69)% when E/T was 20:1, or (23.95+/-3.98)% and (24.55+/-3.59)% when E/T was 10:1, again showing no difference statistically (P>0.05). The specific CTL cytotoxicity rate of control and blank groups was both less than 5%. CONCLUSION: A specific humoral and cellular immune response can be induced in mice by intramuscular injection of pcDNA3-S.