[Hepatitis B immunoglobulins blocking hepatitis B virus infection of trophoblast cell culture in vitro].

Objective: To determine the role of hepatitis B Immunoglobulins (HBIG) in blocking hepatitis B virus (HBV) infection of trophoblast cell culture in vitro.

Methods: Trophoblast cells were placed in the six-well cluster dishes and incubated with 10% fetal calf serum/Dubecco's modified Eagle's Medium (10% FCS DMEM) at 37 degrees C with 5% CO2 in air. At 24 h after plating cells were subjected to experiment. Group A: cells were cultured with 0.5 ml HBV positive serum plus 3 ml 2% FCS DMEM; Group B: cells were cultured with 3 ml 2% FCS DMEM plus 0.5 ml HBV positive serum pretreated with 80 U HBIG for 30 min at 37 degrees C; Group C: cells were cultured with 3 ml 2% FCS DMEM plus 0.5 ml HBV positive serum pretreated with 40 U HBIG for 30 min at 37 degrees C; Group D: cells were cultured with 3 ml 2% FCS DMEM plus 40 U HBIG for 30 min before 0.5 ml HBV positive serum was added; Group E: cells were cultured with 40 U HBIG plus 3 ml 2% FCS DMEM; Group F: cells were cultured with HBV negative serum plus 3 ml 2% FCS DMEM. Twenty-four hours later the inoculums were removed, and the cells were extensively washed with 0.01 mol/L phosphate-buffered saline (PBS). After PBS washing, 4 ml 2% FCS DMEM was added to each well and the medium was collected every 12 hours. Enzyme-Linked Immunosorbent Assay (ELISA) method was used to detect HBsAg in culture medium (absorption value, A). HBV DNA in cell culture medium was detected by polymerase chain reaction (PCR).

Results: Before PBS washing, the A value of groups A, B, C, D, E, F were 2.697, 0.040, 0.102, 0.198, 0.036, 0.040 respectively. The cell culture medium in groups of A, B, C, and D were HBV DNA positive, groups of E, F were HBV DNA negative. From 12 hours to 84 hours, the average A value of groups A, B, C, D, E and F was 1.55 +/- 0.27, 0.032 +/- 0.016, 0.100 +/- 0.087, 0.052 +/- 0.044, 0.034 +/- 0.020, 0.034 +/- 0.022 respectively. The A value of groups A was significantly higher than those of other groups (P < 0.01). Cell culture medium at 84 hours of group A was HBV DNA positive and those of group B, C, D, E, F were HBV DNA negative.

Conclusion: HBIG could effectively block HBV infection of trophoblast cell culture in vitro.