FIG. 1.

Effects of the exogenous antioxidants NAC and GSH on the viability of monocytes after phagocytosis of S. aureus. The cells were cultured in vitro for 6 h with or without bacteria prior to PI staining. Percentages of PI positive cells are shown for control monocytes (A), monocytes exposed to FITC-labeled S. aureus (monocyte-to-bacterium ratio of 1:20) (B), and cells preincubated for 2 h with NAC (25 mM) (C) or GSH (25 mM) (D) and then exposed to FITC-labeled S. aureus. The results of a typical experiment out of five performed are presented. (The mean values ± SD of all experiments performed were 64.5% ± 9.3% PI positive in untreated cells exposed to S. aureus versus 29.8% ± 11.4% or 38.2% ± 15.6% in monocytes exposed to S. aureus after preincubation with NAC [P < 0.001] or GSH [P < 0.01].)