Platelet-associated human IgG during Sk-induced platelet aggregation.

Following agonist treatment, platelets were incubated with an FITC-labeled antibody against human IgG and platelet-associated fluorescence measured using flow cytometry. (A) Platelets stirred in the absence of agonist. (B) Subthreshold concentration of ADP. (C) 500 U/mL Sk alone. (D) ADP in the presence of 500 U/mL Sk. (E) Treated with the Fc receptor-blocking antibody IV.3 prior to the addition of Sk and ADP.