FIG 1.

The EBV CTD truncation mutant gB843 has increased fusion activity. (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 gB or gB843. Twenty-four hours posttransfection, transfected CHO-K1 cells were overlaid with epithelial cells expressing T7 polymerase. Luciferase activity was monitored 24 h after the overlay and was normalized to the activity in cells with wt gB and gH/gL, which was set at 100%. (B) 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, gL, and gp42, together with gB or the gB843 mutant. Twenty-four hours posttransfection, CHO-K1 cells were overlaid with Daudi B cells expressing T7 polymerase. Luciferase activity was monitored 24 h after the overlay and was normalized to the activity in cells with wt gB and gH/gL, set at 100%. The data are means plus standard errors of the means for three independent experiments. (C and D) Expression of gB and gH/gL. Twenty-four hours posttransfection, 4 × 10⁴ cells were seeded into 96-well plates in triplicate. CELISA was performed with anti-gH/gL monoclonal antibody E1D1 or anti-gB monoclonal antibody CL55.