Figure 4.

Oxidation of GSH in P. aeruginosa during phagocytosis by human neutrophils and its dependence on active MPO and NADPH oxidase. Neutrophils (1 × 10⁷/ml) were preincubated with inhibitors of the NADPH oxidase (10 μm DPI) and MPO (10 μm AZM198 and 100 μm sodium azide) and a scavenger of extracellular HOCl (0.5 mm methionine) before the addition of ¹³C-grown PAO1 (1 × 10⁸/ml). After 30 min at 37 °C with end–over–end rotation. [¹³C]GSH (A), [¹³C]GSSG (B), [¹³C]GSSX (C), and [¹³C]GSA (D) were measured by LC-MS. Bars represent means ± S.D. from five separate experiments using different donors. A significant difference when compared with the untreated control was identified by repeated measures ANOVA with Dunnett's multiple comparison test and is indicated by * (p < 0.05), ** (p < 0.01), or *** (p < 0.001).