FIG 5.

Entry of revertant viruses. BAC-derived WT HSV-1 (GS3217), gB3A virus, or gB3A revertant viruses were added to Vero cells at 37°C for 2 h and then rinsed with citric acid buffer to inactivate extracellular virus. As a positive control, duplicate samples were rinsed with PBS instead of acid. Methylcellulose was overlaid onto the cells, and plaques were counted after 3 days. For each virus, the number of plaques present after the citric acid rinse is expressed as a percentage of the number of plaques present in the duplicate control samples that received a PBS rinse only. The means and standard deviations from at least four independent experiments are shown. Asterisks indicate that the difference in the numbers of plaques formed between the mutant and WT viruses was statistically significant (P < 0.05 using a t test). The difference between the mutant and gB3A viruses was not significant.