INDUCIBLE EXPRESSION OF HUMAN HEPATITIS-B VIRUS (HBV) IN STABLY TRANSFECTED HEPATOBLASTOMA CELLS - A NOVEL SYSTEM FOR SCREENING POTENTIAL INHIBITORS OF HBV REPLICATION

We report the development and isolation of a cell line, termed HepAD38 , that replicates human hepatitis B virus (HBV) under conditions that can be regulated with tetracycline. In the presence of the antibiotic, this cell line is free of virus due to the repression of pregenomic ( pg) RNA synthesis, Upon removal of tetracycline from the culture mediu m, the cells express viral pg RNA, accumulate subviral particles in th e cytoplasm that contain DNA intermediates characteristic of viral rep lication, and secrete virus-like particles Into the supernatant. Since the HepAD38 cell line can produce high levels of HBV DNA, it should b e useful for analyses of the viral replication cycle that depend upon viral DNA synthesis in a synchronized fashion, In addition, this cell line has been formatted into a high-throughput, cell-based assay that permits the large-scale screening of diverse compound libraries for ne w classes of inhibitors of HBV replication.