Figure 2

Flagellin delays human neutrophil apoptosis. Neutrophils were cultured with the indicated concentrations of heat-treated flagellin from either S. thyphimurium (FliC), B. cereus, or H. pylori for 24 h at 37 °C. Apoptosis was then measured (a, c, e) by fluorescence microscopy, ^*P<0.01 vs unstimulated cells, n=5 (a), n=3 (c), and n=4 (e); or (b, d, f) by flow cytometry, data are representative of 5, 3, and 4 experiments performed, respectively. Ø symbol represents Heat-treated FliC depicted in figure (a) to differenciate it from unheated FliC (No Ø). (g) Time course of apoptosis modulation by flagellin. Neutrophils were incubated in the absence or presence of FliC (10–100 ng/ml) or flagellin from B. cereus for 12 and 24 h at 37 °C. Apoptosis was then measured by fluorescence microscopy (n=6, ^*P<0.05 vs unstimulated cells).