Fig. 6.

Neutralization of infectivity by polyclonal mouse IgG. (Left) Huh7.5 cells were inoculated with serial dilutions of virus chimeras denoted below the bars in the presence of 20 μg/ml of polyclonal IgG derived from a control mouse (Ctrl. IgG) or an animal that had been immunized with a recombinant form of the E1 glycoprotein (designated 4–80). Cells were fixed 48 h postinoculation and stained with rabbit polyclonal antibodies specific for NS3. The infectious titers were determined by counting foci of NS3-positive cells as described (11). Mean values of two independent experiments are given. The results are expressed as the mean percentages of neutralization of infectious virus relative to virus inoculation performed in the presence of a control IgG preparation. (Right) Huh7.5 cells inoculated with a Jc1 virus preparation in the presence of 4–80 or control IgG.