Catalase inhibited the CD95-induced and spontaneous apoptosis of normal neutrophils. (A) Neutrophils from normal donors were cultured with increasing concentrations of catalase in the presence (•) or absence (○) of 100 ng/mL anti-Fas MoAb for 12 hours and apoptosis of aged neutrophils was then estimated by flow cytometry as described in Materials and Methods. Data are expressed as mean ± SD from 4 different experiments. *P < .05, **P < 0.01 versus neutrophils cultured without addition of catalase. (B) DNA samples extracted from neutrophils cultured for 9 hours with medium alone (lane 1), 1 mg/mL of catalase (lane 2), 100 ng/mL of anti-Fas MoAb (lane 3), or catalase plus anti-Fas MoAb (lane 4) were electrophoresed through 1.7 % of agarose gel as described in Materials and Methods.