MoAb PAC-1 and fibrinogen binding to ADP-, thrombin-, or PMA-stimulated washed platelets. Washed platelets prepared from control (□) or patient blood (▪) were activated with either thrombin (0.2 U/mL; panel A), PMA (100 nM; panel B), or ADP (10 μM; panel C) in the presence of FITC-conjugated MoAb PAC-1 and FITC-labeled fibrinogen (Fg) for 60 minutes and binding assessed by flow cytometry. Results are shown as median fluorescence ± SEM obtained from quadruplicate determinations from 1 experiment representative of 2 performed.