Quantitative comparison of C3-exoenzyme treatment on platelet shape change induced by various agonists. Platelets were incubated with vehicle (□) or C3-exoenzyme (400 μg/mL; ▪) before stimulation with YFLLRNP (300 μmol/L), ADP (2 μmol/L), or ionomycin (200 nmol/L). The shape change responses (measured by the maximal decrease in light-transmission) induced by the different agonists were similar. Values are mean ± SD of three experiments with different platelet donors.