[Performance evaluation of Abbott RealTime HBV Quantification Kit for HBV viral load by real-time PCR]

Establishment of a novel cell model of hepatitis B virus infection

AIM: To establish a hybrid cell line (by fusing HepG2 cells with primary human hepatocytes) that can be infected by hepatitis B virus (HBV) and be serially subcultured in vitro, and to evaluate the infection ability of HBV in this hybrid cell line.

METHODS: Normal human hepatocytes were isolated and cultured. Primary human hepatocytes were then fused with HGPRT-deficient HepG2 cells (induced with ethyl methanesulfonate). The hybrid cells were identified by the trypsin G-banding method. After the hybrid cells and normal HepG2 cells were infected with serum-derived HBV virions, intracellular and secreted HBV DNA as well as intracellular HBV cccDNA (covalent closed circle DNA) were detected by nested polymerase chain reaction (PCR). HBcAg in infected cells was analyzed by indirect immunofluorescence. HBsAg and HBeAg in the supernatants of infected cells were identified by electrochemiluminescence.

RESULTS: A hybrid cell line was established successfully by fusing HepG2 cells with primary human hepatocytes. This hybrid cell line could be subcultured in vitro. Karyotype analysis showed that the modal chromosome number of hybrid cells was 99. HBV DNA was detected consistently in both hybrid cells and their culture medium 4 days post-infection. HBV cccDNA was detected consistently 3 days post-infection. HBcAg, HBsAg and HBeAg were also detected consistently 4 days post-infection. In contrast, negative results were obtained in control HepG2 cells infected with HBV virions.

CONCLUSION: A new hybrid cell line that can be used for establishing an in vitro cell model of HBV infection is established successfully. This new hybrid cell line inherits the characteristics of both HepG2 cells and primary human hepatocytes.