FIG 3.

Inhibition of neutrophil phagocytosis and ROS production enhances survival of nonencapsulated K. kingae. K. kingae strains KK01 csaA and KK01 csaA pam were incubated with human neutrophils at an MOI of 0.1 for 30 min. Neutrophils were preincubated with 10 μg/ml cytochalasin D (CytoD) (A and B), 10 mM N-acetylcysteine (NAC) (C and D), or 4 μM diphenyleneiodonium (DPI) (E and F) in the presence of 1% HSA or 1% NHS. Black bars indicate survival in the absence of neutrophils, white bars represent survival in the presence of neutrophils, and gray bars represent survival in the presence of neutrophils pretreated as indicated. Survival was determined by calculating the number of recovered CFU by the number of CFU in the inoculum. A total of three biological replicates were performed (n = 3). Statistical significance was determined using two-way analysis of variance and a Tukey post hoc test. n.s., not significant; *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001.