FIG 3.

Cell-cell fusion and gH/gL cell surface expression activity for wild-type HSV-1 (KOS) gL and gL point mutants. CHO cells expressing HSV-1 gB, gD, gH, T7 polymerase and either HSV-1 (KOS) gL (wild type), a gL point mutant, or pcDNA3 (negative control [neg con]) were mixed with CHO cells expressing nectin-1 and the T7 polymerase-inducible β-Gal. The microgram ratio for gB:gD:gH:gL:T7 transfected expression plasmids was 1:1:1:0.13:1. The β-Gal activity was measured as an indication of cell-cell fusion. Cell surface gH/gL expression was measured in envelope glycoprotein-expressing cells via CELISA with the anti-gH 52S monoclonal antibody. Mean relative values and mean standard deviations from at least three independent experiments are shown. Within each experiment, values are expressed as the percentage of the transfection expressing wild-type KOS gL. There was a significant difference between the mean cell fusion activity for gLRI and that for Y26A (P = 0.041), Y26E (P = 0.0016), V27A (P = 0.024), and V27D (P = 0.0032) when the mean activity for each mutant was separately compared to that for gLRI by using a two-tailed unpaired t test.