Fig 5.

Focus formation by vGPE⁻, mutant viruses, and ALD/A76 in SK-L cell cultures. SK-L cells were inoculated at an MOI of 0.001 with the parent and mutant viruses as indicated. The cell monolayers were overlaid with MEM containing 1.0% Bacto agar and incubated at 37°C in the presence of 5% CO₂. After 72 h of incubation, the cells were fixed with acetone and viral NS3 was detected by immunofluorescence using MAb 46/1. The number of infected cells per focus was counted for 30 independent foci (n = 30). Error bars represent the standard deviations, and the significance of the differences was calculated with the t test. *, P < 0.05.