Fig. 3.

ExoT activates the mitochondrial/cytochrome c-dependent apoptosis.

A. HeLa cells were infected with the indicated strains at an moi of ca. 10 for 5 h, bacteria were removed and medium containing MitoCapture^™ stain was added to stain cells. Cells were imaged by IF microscopy without fixation. Punctate mitochondrial staining is apparent in uninfected, PA103pscJ-infected and PA103ΔUΔT-infected cells. In contrast, PA103ΔU-infected or camptothecin-treated cells exhibit diffuse cytoplasmic staining, consistent with disruption of the mitochondrial membrane potential.

B. The fraction of cells with diffuse staining from six random fields for each sample is tabulated and shown as the mean ± SEM (*P < 0.001).

C. HeLa cells were infected with the indicated strains in the presence or absence of ZVAD as described in Fig. 2. Bacteria were removed 5 h post infection, cells were harvested at 20 h post infection, and triplicate samples were analysed for activated caspase-3 by flow cytometry using APO ACTIVE 3^™.

The mean ± SEM is shown (*P < 0.001).