Effect of antioxidants on Fas-mediated eosinophil apoptosis. Eosinophils were coincubated for 19 hours with anti-Fas MoAb (2 μg/mL) and IL-3 (▪), GSH (○), NAC (•), or TAUR (□) at the concentrations indicated. Data are presented as mean ± SEM of percent apoptotic nuclei as compared with eosinophils incubated with control medium (n = 8 separate experiments). NAC and GSH inhibited Fas-mediated eosinophil apoptosis in a similar manner (optimal concentrations 5 to 10 mmol/L). Higher concentrations of GSH and NAC (15 to 20 mmol/L) induced apoptosis (not significant). Interestingly, TAUR at 10 mg/mL also significantly blocked Fas-mediated apoptosis. DMSO (0.5% to 4%) had no inhibitable effect (not shown). **P< .01 versus control (without stimulus). n.s., not significant.