FIG 2.

ROS pathway inhibitors reverse IFN-γ and ceftazidime synergy. NAC (A) and GSH (D) reverse the intracellular killing effect of IFN-γ (10 ng/ml) and ceftazidime (10 μg/ml) combination therapy on B. thailandensis-infected macrophages in a dose-dependent manner. Statistical differences compared to the group treated with IFN-γ and ceftazidime were assessed by one-way ANOVA with Tukey's posttest (*, P < 0.05). (B) Mean fluorescent intensity of mBCl after treatment of uninfected RAW cells with NAC (20 mM) for 2 h (***, P = 0.0004); (C) intracellular ROS levels (as detected by carboxy-H2DCFDA) in RAW 264.7 cells after 10 h of treatment with ceftazidime and IFN-γ, with or without NAC (20 mM); (E and F) histogram overlays of intracellular ROS responses as measured with carboxy-H2DCFDA by flow cytometry; (E) IFN-γ-elicited ROS responses from uninfected RAW 264.7 macrophages, various hours after stimulation; (F) intracellular ROS responses of B. thailandensis-infected RAW 264.7 macrophages 18 h after treatment with ceftazidime (10 μg/ml) or IFN-γ (10 ng/ml). Results are representative of data from at least two independent experiments.