ULVWF-coated beads adhered to immobilized P-selectin under flow. Polystyrene beads coated with ULVWF were perfused over immobilized P-selectin under a 2.5-dyn/cm² shear stress for 5 minutes at room temperature (A). Control experiments were perfusion of ULVWF-coated beads and BSA-coated beads over BSA and immobilized P-selectin, respectively (A). At the end of perfusion, the numbers of beads adhered to P-selectin were counted. Panel B is a summary of 6 separate experiments. Figures are means ± SEM (the studentt test).