FIGURE 6.
P-selectin (P-sel) is responsible for Efb and fibrinogen binding by thrombin-stimulated platelets. A, FITC-labeled FGN binding by platelets (107 ml−1) in resting or thrombin- (Thr) stimulated (0.25 unit/ml) states was measured in the presence of 50 μg/ml P-selectin-Fc and/or 50 μg/ml integrin αIIbβ3 inhibitory anti-CD41 antibody (CD41 Ab). B, FITC-labeled Efb was incubated at 1 μm concentration on human platelets (107 platelets/ml) in resting (control (CTRL)) or thrombin-stimulated (0.25 units/ml) conditions. Where indicated, 50 μg/ml P-selectin-Fc and/or 50 μg/ml integrin αIIbβ3 inhibitory anti-CD41 antibody (CD41 Ab) were added to the platelet suspension, and Efb binding was assessed by flow cytometry using a FACSAria III (n = 4). Representative FITC-labeling histograms are shown in the right panels with the percentage of events above 1000 rfu (indicated as R1). Mean fluorescence value ± S.E. from four independent experiments is reported in left panels. Statistical significance was tested by one-way ANOVA with Bonferroni post test (* = p < 0.01, n = 4).