Replication of hepatitis B virus in culture systems with adult human hepatocytes

We developed a technique for isolation and primary culture of adult human hepatocytes from surgical liver biopsy specimens by in situ perfusion and a shaking method. Cultured hepatocytes were maintained in monolayers for more than three weeks and showed morphological and functional characteristics in vivo. The cultured human hepatocytes were inoculated with hepatitis B virus (HBV). Hepatitis B surface antigen (HBsAg) in the medium was detected for about three weeks after inoculation, which was longer than that reported in previous studies. In one case of high attachment efficiency, hepatitis B e antigen (HBeAg) was detected in the medium five to eight days after inoculation. HBsAg and HBeAg were also detected in the extracts of inoculated human hepatocytes. Immunofluorescence study revealed HBsAg in 20-30% of hepatocytes and hepatitis B core antigen (HBcAg) in 2-3% of the cultured human hepatocytes four days after inoculation. Free HBV DNA was identified in the human hepatocytes for at least two weeks after inoculation, although single-stranded HBV DNA was not detected. These studies suggest that HBsAg was actively produced and that HBV replicated in a small number of inoculated adult human hepatocytes in primary culture. However, further improvement of culture systems is needed for active replication of HBV in vitro.