<i>S.</i> Typhi induces apoptosis in human cells.

<p>Blasts or DC were infected with <i>S.</i> Typhi at a MOI of 10∶1 and analyzed for apoptosis 3 hours after infection. DC were also exposed to heated-killed <i>S.</i> Typhi or treated with ZVA-D. Uninfected cells (media) were used as negative controls. Cells treated with staurosporine (8 µg/ml) or 1% formaldehyde were used as positive controls for apoptosis and necrosis respectively. Cell apoptosis was monitored by Annexin V and PI fluorescent dyes and by staining cells for cleaved caspase-3. (A) Blasts from volunteer A00302-5008 were stained with FITC-annexin V and PI or isotype-matched control antibodies and analyzed by flow cytometry. (B) Blasts from volunteers CVD4000#119 and CVD4000#64 and (C) DC from volunteer CVD4000#64 were surface stained for caspase-3 and <i>Salmonella</i> common structural antigens (CSA). Numbers correspond to the percentage of positive cells in the indicated quadrants or regions in each histogram. Arrows in panels B and C depict the expression of caspase 3 on cells expressing, or not, CSA.