DNA-mediated immunization of mice with plasmid encoding HBs antigen

In order to develop an experimental DNA Vaccine for the prevention and trea tment of hepatitis B virus infection, hepatitis B virus surface antigen (HB sAg) DNA was subcloned into an E. coli-eukaryotic cell shuttle vector and w as expressed in the Baculovirus expression system. Intramuscular, intraderm al, and intraperitoneal injections of 30 mu g of the plasmid DNA expressing HBsAg induced humoral and cellular immune responses in ICR mice. The first IgG antibodies were detected after ten days and specific IgG antibody tite rs peaked after two months of a single intramuscular DNA injection. Anti-HB s antibody titers gradually increased and peaked at four months following i ntradermal DNA injection, and in case of intraperitoneal injection they pea ked at seven months. Generation of HBs-specific helper T lymphocytes was al so investigated through the production of interleukin-2 by T helper cells. Boosting effects of HBs DNA were investigated without much results. In gene ral, DNA-mediated HBs immunization induced humoral and cellular immune resp onses in mice that appears to simulate immune responses in human during the course of HBV vaccination.