Successful Generation of Hepatitis B virus (HBV) Pseudotype Particle; A Versatile Tool for Identification of the HBV Receptor and Investigation of HBV Infectivity

It is near a half century since hepatitis B virus (HBV) was identified. HBV receptor molecules and the entry mechanism of HBV into hepatocytes have not been elucidated completely, though there are some reports on infection systems and on the receptor molecules. Thus, we still have not reached finding a real HBV receptor and there have been no useful and convenient infection system in vitro and in vivo for HBV, which makes it impossible for us to understand a precise HBV life cycle and HBV involved related diseases. An HBV infection system is really needed to explore ways and means of treatment of HBV related diseases based on evidence as well. Here, we designed and tried to generate an HBV pseudotype, which has a viral particle containing a retrovirus capsid and a genome inside surrounded by HBV membrane proteins. We proved successful generation of this pseudotype by immunoprecipitation with anti-HBVs antibodies and by CsCl density gradient ultracentrifugation, followed by RT-PCR targeting a retroviral gene, an EGFP gene in this case, respectively. Though our established system is constructed on growth dependent integration of retroviral genomes and thus was very hard to observe its infection in a primary human hepatocytes culture system, successful generation of the HBV pseudotype will make it possible for us to perform a biological assay to clone an HBV receptor based on infectivity and will facilitate its separation and identification