FIG 1.

InvS is essential for Salmonella invasion. (A) HeLa cells were infected with Salmonella strains for 15 min at an MOI of 10. Relative bacterial invasion was determined by the gentamicin protection assay as described in Materials and Methods. The invasion rate of the wild-type strain was defined as 100%. The data are the averages from three independent experiments with error bars indicating the standard deviations. (B) HeLa cells were infected with Salmonella for 15 min at an MOI of 10. Actin staining was conducted as described in Materials and Methods to indicate Salmonella-induced ruffling formation. (C) Percentages of infected cells with ruffles were calculated. The data shown were obtained from three independent experiments. Error bars indicate standard deviations. P values were calculated using the Student t test.