FIG. 3.
Purified PLY is a strong activator of the NADPH oxidase. Neutrophils were stimulated with various concentrations of highly purified PLY and the kinetics of the NADPH oxidative response were measured. Data are from a representative experiment (n = 3). (Inset) Neutrophils (5 × 105/ml) were incubated at 37°C for 30 min with various concentrations of native PLY, PdT, or 50 μl of undiluted S. pneumoniae A17 suspension. After being washed, the cells were stained with 7-amino-actinomycin D and the numbers of viable neutrophils were determined by flow cytometry. The experiment was performed on neutrophils from three blood donors and data show the average numbers of viable cells (± standard deviations) after the various stimulations. S. pneum, S. pneumoniae.