Fig. 1.

Pore-forming and cytolytic activities of PVL toward human and rabbit PMNs. (A) PMN pore formation [percent ethidium bromide (EtBr)-positive cells] and (B) PMN lysis [percent lactate dehydrogenase (LDH) release] assays using LukS-PV and LukF-PV purified from culture supernatants of a PVL-producing USA300 strain as described in SI Text. Results in A and B are mean of independent experiments with six human and six rabbit blood donors. (C) Pore formation caused by 1:2,000 dilutions of 8-h CCY culture supernatants of USA300 wild-type strain, Δpvl mutant, and compΔpvl strain as indicated. Results in C are mean of independent experiments with 10 human and 4 rabbit blood donors. Statistically significant differences are indicated by asterisk (P < 0.05); all other comparisons are nonsignificant.