Figure 3.

Cytolytic activity of S. pseudintermedius PSMs. MG63 cells were incubated with increasing concentrations (from 0.1 to 100 μg.mL⁻¹) of synthetic PSMε, δ-toxin (ED99) or δ-toxin (HKU10-03) for 3 h at 37°C. Cell death was measured by staining cells with propidium iodide and detected with a fluorescence cell sorter. The percentage of cell lysis was calculated as $\%=\frac{\text{Test}-\text{Tneg}}{\text{Tpos}-\text{Tneg}}\times 100$. The values represent the means ± standard deviations derived from one experiment performed in triplicate representative of two others. NPPc, Non-professional phagocytic cells; PMNs, Polymorphonuclear neutrophils; PSM, Phenol-soluble modulins; PI, Propidium iodide.