In vitro study on hepatitis B virus infecting human choriocarcinoma JEG3 cells and its mechanism.

AIM To build a hepatitis B virus (HBV)-infected human trophoblast cell model in vitro and determine the mechanism of intrauterine HBV infection. METHODS Serum from hepatitis B-infected patients containing HBV DNA >10(9) was drawn, subsequently inoculated into human trophoblast cells in vitro (JEG3) and passage-cultured. The supernatants and intracellular HBV viral load of inoculated cells were tested by real-time PCR, and HBV DNA was determined by Southern blot. RESULTS From inoculation of the 1st passage JEG3 cells, the supernatant viral load of the 1st passage was seen increasing over time, which peaked at 120 h, whereas the HBV viral load was seen decreasing gradually in subsequent passages, and tested negative after the 6th passage. In addition, infected cells of HBV DNA were tested by Southern blot, and showed continual expression in the subsequent cell passages 1-5 while passage 6 was negative. HBsAg was tested as positive from different passages 1-5, and its concentration was also seen decreasing with each subsequent passage cultured until the 6th passage when it tested negative. CONCLUSION HBV could infect human trophoblast cells (JEG3) in vitro, and it showed continual expression in subsequent cell passages 1-5.