FIG 2.

ROS production by macrophages is required for optimal S. gordonii survival. (A) Survival of S. gordonii within RAW264.7 macrophages, with increasing amounts of diphenyleneiodonium (DPI) added to inhibit NOX2 ROS production within the phagosome. Increasing levels of DPI led to significant reductions in survival of DL1, to levels not significantly different from SK12 survival in macrophages with or without DPI added. (B) Survival of S. gordonii within polarized human monocyte-derived macrophages. DL1 survived significantly better in GM-CSF-matured, IFN-γ/LPS-polarized (M1) macrophages than SK12 did, while both strains were equally killed by M-CSF-matured, IL-4-polarized (M2) macrophages. (C) Survival of DL1 within M1 polarized human monocyte-derived macrophages, with 20 μM DPI added to inhibit NOX2 ROS production within the phagosome. The data were normalized by setting DL1 survival at 1. All data are means and standard errors for 4 to 8 independent experiments, with a minimum of 2 technical replicates per experiment. P values were calculated by one-way ANOVA with the Sidak multiple-comparison test (A and B) or by unpaired t test (C).