The Immunotherapy Of Hepatitis B Surface Antigen With CpG Oligodeoxynucleotides In Hepatitis B Virus Transgenic Mice

Hepatitis B virus infection continues to be prevalent worldwide with more than 350 million chronic HBV carriers. Approximately 25% of these carriers develop serious liver disease, resulting in 1 to 2 million deaths per year. In our China, the HBVpatients amount to 120 million which is 1/3 of world number. Patients chronically infected with hepatitis B virus (HBV) run the risk of developing cirrhosis and hepatocellular carcinoma in later life. Antiviral treatment offers the only means of preventing such an undesirable outcome. To date, interferon-[alpha] (IFN-[alpha]), two synthetic nucleoside analogues, lamivudine and adefovir dipivoxil, are the only licensed antiviral agents for the treatment of chronic HBV infection. Long-term treatment with lamivudine or interferon is effective in suppressing viral replication, but drug-resistant mutants arise with increased length of treatment. Nevertheless, such mutants appear to be susceptible to adefovir and other nucleoside analogues. Therapeutic vaccination and other molecular approaches such as antisense oligonucleotides, ribozymes, DNA vaccines, dominant-negative proteins and aptamers are possible future antiviral therapies, which will supplement our armamentarium against chronic HBV infection. It seems certain that combination therapies involving two or more nucleoside analogues, immunomodulators or gene therapies will be the future treatment regimens for chronic HBV infection. The obejective of this experiment is to study the immunotherapy effect of hepatitis B surface antigen with CpG oligodeoxynecleotides(CpG ODN)in HBV transgenic mice, to develop a new HBV therapeutic method. We used 6-8 weeks old HBV transgenic mice were immunized by multiple sites into tibialis anterior(TA) muscles with HBsAg alone ,or combined with CpG ODN,or IFN, or NS.At various times before and after vaccine injection, blood was collected from mice by retrobulbar puncture with capillary glass pipettes. Sera recovered by centrifugation were assayed for HBsAg ,Anti-HBs Ab ,HBV DNA by IRMA,specific ELISA and fluroscene PCR respectively. The expression of HBsAg in liver tissue was detected by immunohistochemistry method (SP).The histological activity index (HAI)was calculated with Knodell`s method. Results: The anti-HBs Ab in sera could be detected in HBsAg group and HBsAg plus CpG group by 2 weeks after the last immunization; At this time,1 out of 10 mice immunized with HBsAg+CpG There were no significantly changes in induced the clearance of HBsAg in the sera, and by 4 weeks ,the number was 3; The liveral expression of HBsAg was similar with sera. The large number of lymphocytes could be found in liver tissue in HBsAg plus CpG immunization group. The histological activity index (HAI) in liver tissue from mice immunized with HBsAg plus CpG was the highest among four groups. HBsAg plus CpG injection can down regulate HBV DNA copies in sera. Conclusion: CpG ODN as an effect adjuvant can elicited the immunotherapy of recombinant HBsAg in HBV transgenic mice. CpG with HBsAg could therefore represent a potential therapeutic approach to HBV chronic infected patients. HBV DNA copies in the serum can reflect HBV replication in vivo most in the clinic diagnostics of HBV.