Mechanism of plaque-selective inhibition of platelet inhibition under flow by ibrutinib. (A) The anti-α2β1 antibody 6F1, but not ibrutinib, inhibits platelet adhesion onto immobilized soluble collagen under arterial flow. Blood was incubated for 15 minutes at 37°C before the start of flow (shear 600/s) with DiOC6, abciximab (20 µg/mL), and DMSO (0.1%; Control), ibrutinib (1 µM), or 6F1 (20 µg/mL). Data are mean + SD (n = 4). (B) The anti-GPIbα antibody 6B4 inhibits plaque- and collagen-induced platelet aggregate formation under arterial flow. Blood samples were incubated with DiOC6, in the absence or presence of 6B4 (5 µg/mL), before perfusion at a high shear rate (1500/s). Data are mean + SD (n = 4 or 5).