FIG. 4.

Tupaia CD81 supports HCVpp infection. (A) HepG2 cells were infected with lentiviruses containing human or tupaia CD81 sequences or mock lentivirus. Three days later, the cells were probed with the anti-CD81 MAb 5A6 (left) or polyclonal antibodies (right), and CD81 expression was assessed by flow cytometry. The values on the y axis indicate counts, and those on the x axis CD81 expression. (B) Human or tupaia CD81- or mock-transduced HepG2 cells were incubated with anti-CD81 MAbs (5A6, JS81, and 1.3.3.22; 5 μg/ml), polyclonal antibodies (50 μg/ml), or mouse IgG1 (5 μg/ml) for 1 h prior to the addition of HCVpp or the control (no E1E2). At 72 h postinfection, the cells were harvested, and the level of luciferase activity (relative light units [RLU]) was determined. The values are the means ± standard deviations of results from three independent experiments.