FIG. 4.
Growth analysis of mutant viruses. Flasks of DBT cells (107 cells) were infected in duplicate with wild-type A59 (♦), VUSS0 (▪), VUSS1 (▴), VUSS2 (X), and VUSS3 (•). (A) Multiplicity of infection of 5 PFU/cell. (B) Multiplicity of infection of 0.01 PFU/cell. Medium supernatant samples were obtained at 0, 4, 8, 12, 16, 24, and 32 h postinfection The plotted points represent the average of the viral titer determined by plaque assay for duplicate samples at each time point from two replicate infections.