ASSAYS FOR HEPATITIS B VIRUS WITH HUMAN LEUKEMIC CELL LINES

INFECTION OF HUMANS WITH THE SMALL HEPATOTROPHIC DNA VIRUS, HEPATITIS B VIRUS (HBV), CAN LEAD TO ACUTE OR CHRONIC HEPATITIS, CIRRHOSIS AND PRIMARY HEPATOCELLULAR CARCINOMA. IN SPITE OF ADVANCES IN TESTING OF BLOOD AND THE RECENT INTRODUCTION OF A SAFE EFFECTIVE VACCINE, THERE IS STILL AN INCIDENCE OF ABOUT 6% INFECTION BY HBV IN INDIVIDUALS WHO RECEIVE A BLOOD TRANSFUSION OR BLOOD PRODUCTS. THUS THERE IS STILL A NEED FOR IMPROVED METHODS FOR THE DETECTION OF INFECTIOUS HBV. RECENTLY AN HBV IN VITRO HUMAN INFECTION MODEL (HIVIM) HAS BEEN DESCRIBED IN WHICH IT HAS BEEN DEMONSTRATED THAT INTACT HBV (DANE PARTICLES) INHIBITS THE DIFFERENTIATION AND PROLIFERATION OF HEMATOPOIETIC STEM CELLS IN HIMAN BONE MARROW. THIS SYSTEM IS NOT AFFECTED BY ANY OF THE HBV ASSOCIATED ANTIGENS AND INHIBITION CAN BE SHOWN TO BE DIRECTLY PROPORTIONAL TO THE NUMBER OF VIRIONS. THE OBJECTIVE OF THE DEVELOPMENTAL WORK IN THIS PROPOSAL IS TO ADAPT THE HIVIM SYSTEM TO ESTABLISHED HUMAN LEUKEMIC CELL LINES WITH GOAL OF DEVELOPING A CELL BASED ASSAY FOR LIVE HBV THAT CAN BE USED IN AN IN VITRO SCREENINGASSAYS BASED ON THE ABILITY OF HBV TO INFECT AND INHIBIT GROWTH OF THESE CELLS. SUCH ASSAYS WOULD PROVE USEFUL IN PRECLINICAL STUDIES THAT ARE DESIGNED (1) TO ANALYZE AND DETECT NOVEL IMMUNOGENS THAT MIGHT BE THE BASIS FOR NEW VACCINES AND (2) TO DETERMINE THE ACTIVITY OF NEW ANTIVIRAL AGENTS.