Figure 2.

SA-13, SA-15, and SA-17 neutralize cytotoxicity caused by Staphylococcus aureus USA300 strains during ex vivo infection of primary human neutrophils. A, Primary human neutrophils (PMNs) from 5 donors were inoculated with wild-type (WT) USA300 S. aureus strains LAC and BK18807 and isogenic lukAB mutants (multiplicity of infection = 25) for 2 hours, and toxicity was measured in a LDH release assay (measurement of significant membrane damage/pore formation and cell lysis). Killing of PMNs in a LukAB-dependent manner is evident. B,Primary human neutrophils were inoculated with WT S. aureus strains (i: LAC; ii: BK18807) in the presence or absence of monoclonal antibodies, 2.5 μg/mL, for 2 hours, and cell death was evaluated by measuring LDH release. Bars represent mean ± SEM, with n = 5 donors. *P < .05 using 1-way analysis of variance with Tukey’s post hoc test correction for multiple comparisons. Abbreviations: IgG, immunoglobulin G; LDH, lactate dehydrogenase; WT, wild-type.