ORAL DNA VACCINE COMPOSITION FOR HEPATITIS B VIRUS CHRONIC INFECTION

摘要

The present invention provides an oral DNA composition for improving an impaired immunity associated with chronic infection of hepatitis B virus (HBV) comprising an attenuated strain of bacterial cells which preferentially target phagocytic cells of the intestin al mucosa, and which serve as a vehicle for a plasmid vector carrying one or more genes or complementary DNA coding for at least a portion of a hepatitis B viral protein or peptide. Giv en orally, the DNA composition causes a transient and self-limiting infection of the intestinal tract through autolysis of the bacterial cells and release of the plasmid after gaining entry into infected host cells. A promotor contained within the plasmid allows for expression of the HBV gene( s) in the eurokaryotic environment, the viral products of which help to booster a cell - mediated immunity to clear the infection and reverse a state of immune tolerance characteristi c of HBV chronic infection.