Fig 3. Infection with toxingenic S. typhimurium promotes cell spreading.

A. U2OS cells were left untreated or infected for 24h with the S. typhimurium strains carrying the active typhoid toxin (MC71TT) or an isogenic strain carrying a deletion mutant of the active subunit, thus lacking the genotoxic activity (MC71ΔcdtB). Cells were detached with 2.5 mM EDTA in PBS, seeded on fibronectin-coated glasses for 20 minutes, prior fixation and immunofluorescence analysis. The actin cytoskeleton was visualized by phalloidin staining. B. Quantification of cell spreading of U2OS or HeLa cells left untreated or infected, as described in Fig 1. The area of 50 adherent cells per experiment was measured using the ImageJ software. The data are presented as the mean ± SEM of three independent experiments. Statistical analysis was performed using the Student t-test. *** p value < 0.001.