In vitro culture systems for hepatitis B and delta viruses

The development of tissue culture technology has led to invaluable information in many fields of modern virology. Until recently, the lack of an in vitro culture system for the hepatitis B virus (HBV) was a considerable impediment to the study of its life cycle at the cellular and molecular levels. However, it did not prevent its isolation and molecular cloning. Such has been the case also for the hepatitis delta virus (HDV), the genome of which was cloned and sequenced before its replication could be observed in cultured cells. In recent years, tissue culture systems for HBV and HDV have been developed progressively by the identification of permissive, established cell lines for production of virions and susceptible primary hepatocyte cultures for infection assays. I will briefly review here the recent experiments that have contributed to replicate HBV and HDV in cell culture systems.