Figure 7.

FcγRIIIb-induced NET formation requires Syk but is independent of PI-3K. (a) Human neutrophils (PMN) were not stimulated (None) or were restimulated with 20 nM phorbol 12-myristate 13-acetate (PMA) or by cross-linking FcγRIIIb with mAb 3G8. PMN were previously treated with solvent alone (—) or with the Syk inhibitor piceatannol (50 μM) or with the PI-3K inhibitor wortmannin (50 nM). After four hours, PMN were fixed and stained for DNA (DAPI). Microphotographs were taken at 200x magnification and are representative of three experiments. Bar is 50 μm. (b) The relative amount of NETs was estimated from SYTOX Green fluorescence in relative fluorescent units (RFU) at 4 hours after stimulation. Data are mean ± SEM of 5 experiments. Asterisks denote conditions that are statistically different from control (p < 0.05).