Staphylococcal <i>α</i>-toxin was cytotoxic for DDADs.

DDAD cells were treated with various concentrations of α-toxin for 24 h. The Cell Titer 96® Aqueous One Solution Proliferation Assay and propidium iodine were used to assess the cellular toxicity and damage. (a) At 5 ug/ml and 10 ug/ml of α-toxin significant cell death occurred, while no effect was observed at lower concentrations (below 1 ug/ml). (b) Consistent with the cytotoxic effect, significant amounts of PI were incorporated into DDADs at 5 ug/ml and 10 ug/ml of α-toxin, but not at lower concentrations (*represents p<0.05, Students t-test).