Effect of NNKY5-5 on platelet aggregation. Platelet aggregation was measured from the changes of light transmission using PRP anticoagulated with citrate and maintained at 37°C with constant stirring. (A) Effect of ristocetin (1.5 mg/mL). (B) NNKY5-5 (10 μg/mL) was added 2 minutes before ristocetin. (C) and (D) NNKY5-5 was added to PRP in the absence (C) or the presence (D) of MoAb IV.3 (10 μg/mL). The traces shown are representative ones from at least 4 experiments. (E) and (F ) NNKY5-5 Fab′ (10 μg/mL) was added 5 minutes before ristocetin (E) or of goat anti-mouse antibody (F ).