FIGURE 9.
F2M2-desensitized FPR2 can be reactivated to release superoxide upon stimulation with Lat A or PAF in human neutrophils. A, naive neutrophils (105 cells) were desensitized with WKYMVM (100 nm; solid line) or F2M2 (500 nm; dashed line), and subsequently FPR2 reactivation was achieved with the actin cytoskeleton-disrupting agent Lat A. A representative experiment is shown, and the time point for the addition of agonists is indicated by the first arrow, whereas the time point for Lat A stimulation (10 ng/ml) is indicated by the second arrow. Abscissa, time of study (min); ordinate, superoxide production (106 × counts/min (Mcpm)). B, naive neutrophils (105 cells) were first desensitized with F2M2 (500 nm) and subsequently stimulated with PAF as indicated by the arrow (100 nm; solid line), and release of superoxide anions was recorded continuously. When required, the FPR2-specific inhibitor PBP10 (1 μm) was added 1 min before PAF stimulation (dashed line). The PAF responses induced in naive cells (dotted line) are shown for comparison. Abscissa, time of study (min); ordinate, superoxide production (106 × counts/min).