FIG 4.

gB^B4.1 contains fusion-enhancing mutations. To test for fusion activity of gB^B4.1, RK13 cells were cotransfected with combinations of plasmids expressing the different glycoproteins as indicated. Results from assays with gB^Ka, gH^Ka, and gL were set as 100%, and those with the gB^Ka expression plasmid only (together with empty vector) served as negative control. Shown are the mean values and corresponding standard deviations from three independent experiments (these data, originating from a larger data set testing multiple variables, are also included in Fig. 7).