Rate constants for killing of S aureus by human neutrophils. Opsonized bacteria were mixed with neutrophils in a 1:1 ratio. Numbers of extracellular and viable intracellular bacteria were measured at 0, 10, 20, and 30 minutes, and from these independent first-order rate constants for phagocytosis and killing were measured. Superoxide dismutase was conjugated to IgG (IgG-SOD) and attached to the bacteria through binding to the protein A on their surface. ABAH, the myeloperoxidase inhibitor 4-aminobenzoic acid hydrazide. The shaded area represents the contribution of nonoxidative killing measured in the presence of diphenyleneiodonium (DPI) or anaerobically (N₂). The data are taken from Hampton,117 and show the mean and SD of at least three experiments.