Fig. 3.
Effect of anti-CD81 mAb on HCV binding and entry into different cells. (A) Huh-7 cells (104) were preincubated at 4°C with NLluc+env- viruses (≈100 ng/ml p24) pseudotyped with E1/E2 (HCVpv) in the presence of anti-CD81 mAb JS-81 (10 μg/ml, first bar) or a control murine IgG1 (mIgG1, 10 μg/ml, third and fourth bars). Cells were washed, and a second incubation at 4°C was performed with a control mIgG1 (10 μg/ml, second and fourth bars) or JS-81 (10 μg/ml, first and third bars). Alternatively, cells were first incubated with JS-81 followed by washing and a second incubation with HCVpv and a mlgG1 (second bar). After a second wash, cells were placed at 37°C, and luciferase activities were measured 48 h later. Results are means of three independent experiments ± SD. (B) Cells (104) indicated along the x axis were preincubated with sera of HCV+ individuals for 2 h at 4°C in the presence of JS-81 or a control murine IgG (10 μg/ml each). Viral RNA remaining bound to cells after washing was quantified. Results are expressed as % virus binding = (RNA copies in the presence of JS-81)/(RNA copies in the absence of JS-81) × 100%. Results are from a representative experiment with an assay error of ±20%.