Replication of hepatitis B virus which carries foreign DNA in vitro

Targeting a specific DNA sequence to the desired tissues is an important st ep in gene therapy. The hepatitis B virus (HBV) is the only DNA virus that has hepatocyte specificity. We attempted to construct an HBV-based vector f or targeting the liver. me observed the replication and secretion of virus particles in an HBV construct that lacks X gene and carries an extra 63 bp DNA fragment in vitro. Replication was observed in the cell line HuH-7 but not HepG2. From this construct, we designed an HBV-based vector that could carry foreign DNA. HBV based vectors provide for the possibilities of gener ating therapeutic agents for individual patients. Our host vector system ma y be used to clear out the HBV from the HBV carrier or chronic hepatitis B patients by introducing a genetically engineered HBV into these patients. ( C) 1999 Academic Press.