FIG 9.

Dose dependence of gB or gB843 requirement for gH/gL or gp42. (A) CHO-K1 cells were transiently transfected with the T7 luciferase plasmid and a vector plasmid (control) or with the T7 luciferase plasmid and EBV gH and gL, together with wt gB or gB843. Transfected CHO-K1 cells were overlaid with Daudi B cells along with an additional 250 μl of supernatants containing different amounts of gp42, as indicated. Twenty-four hours after the overlay, luciferase activity was measured. The data are means plus standard errors of the means for three independent experiments. (B) CHO-K1 cells were transfected either with the T7 luciferase plasmid and a vector plasmid (open bars), with the T7 luciferase plasmid, wt gB, and different amounts of gH/gL, as indicated (filled bars), or with the T7 luciferase plasmid, gB843, and different amounts of gH/gL, as indicated (stippled bars). Twenty-four hours posttransfection, CHO-K1 cells were overlaid with epithelial cells expressing T7 polymerase. Luciferase activity was monitored after a 24-h overlay and was normalized to the activity of cells with wt gB and wt gH/gL levels (0.5 μg), which was set at 100%. The data are means plus standard errors of the means for three independent experiments.