Figure 3.

Human neutrophil susceptibility to death stimuli is specific, Fc-independent, and differs from responses of mouse neutrophils. Death of human (PMN^H) or mouse C57BL/6 (PMN^BL/6) polymorphonuclear neutrophils as assessed by flow cytometric ethidium bromide exclusion assay. Results of 24-h cultures of quiescent or GM-CSF primed cells are shown following treatment with (A) 20 mg/ml of whole IgG (Privigen^#B) or equimolar concentrations of Fc-, or F(ab’)₂ (Gammavenin)-fragments of pooled IgG, or with (B) stimuli known to trigger human neutrophil death including IVIG (Prigiven^#A), Fas-ligand, anti-human Fas (clone CH11) mAb or anti-Siglec-9 mAb. Bars show mean ± SEM. Data are representative of at least 3 (B), or 4 (A) independent experiments. *p < 0.05, **p < 0.01, Student t test. Specific death was calculated in comparison to untreated controls as outlined in the Materials and Methods section.