Specific expression of human interferon-gamma controls hepatitis B virus replication in vitro in secreting hepatitis B surface antigen hepatocytes

Interferon-gamma (IFN-γ) has been reported to have antiviral activity against Hepatitis B virus (HBV) and to suppress HBV replication noncytolytically in vivo. Since systemic administration of IFN-γ may cause severe adverse effects, studies of the effects of liver-specific IFN-γ expression from adenoviral vectors in vivo have been investigated. In this study, a novel strategy has been described that drives specific expression of human IFN-γ in HBsAg-secreting hepatocytes. A bicistronic expression vector has been developed, pcDNA3.1-HBV antisense S gene-HCV core protein gene-HCV internal ribosome entry sites (IRES)-IFN-γ (pcDNA-SCIγ), by inserting four DNA fragments into pcDNA3.1. Tight modulation of HCV IRES-dependent translation by the HCV core protein was achieved using an antisense RNA technique with a bicistronic expression vector. HepG2 cells and HepG2.2.15 cells stably expressing HBV were transduced with pcDNA-SCIγ to test the responsiveness of IFN-γ to HBsAg expression. Gene transfer resulted in a low background and a 30-fold induction of IFN-γ expression from pcDNA-SCIγ in a cell-specific fashion. Hepatocyte-specific IFN-γ expression controlled effectively HBV replication in HBsAg-secreting HepG2.2.15 cells without cell toxicity.