[Humoral immunization and cell-mediated immunization evoked by HBsAg and B7-2 Ag coexpression recombinant adenovirus...

To evoke cytotoxic T lymphocytes (CTL) response and seek for a more effective method to treat chronic hepatitis B.

The adenovirus vector was constructed with the foreign genes inserted in the early region 1(E1), which directed coexpression of HBV-S and B7-2 antigens by means of an internal ribosomal entry site placed between the two coding sequences. The vector was transfected into 293 cell lines by liposome and the adenovirus expressing the target antigens was obtained by plaque select. The HBsAg and B7-2 antigen expression in in vitro cell culture was measured by ELISA and Western blotting, respectively. The immune responses were measured by ELISA for antibody response and a LDH release assay for CTL activity after immunization with the recombinant adenovirus vector in C57 mice.

HBsAg and B7-2 antigens were highly expressed after infecting the 293 and HepG2 cell lines in vitro. The humoral response to hepatitis B surface antigen was mildly induced and could be enhanced by reinjecting a regular dose of HBsAg antigen vaccine. The cell-mediated immune response was highly induced by the recombinant adenovirus infection. No clear side effect was observed after immunization.

This could be a novel strategy for a development of both preventive and therapeutic vaccines against HBV infection. The recombinant adenovirus vector is an effective and safety vector system suitable to the experiments of gene immunization and gene therapy for incurable diseases.