Effect of VWF, VWF fragments, and VWF mutants on platelet adhesion to fibrin. (A) Human fibrin surfaces were incubated with SpII (200 μg/mL), SpIII (200 μg/mL), plasma-purified VWF (5 μg/mL), and plasma-purified VWF (5 μg/mL) in the presence of 200 μg/mL VWF fragments SpII or SpIII. (B) Human fibrin surfaces were incubated with WT-rVWF (5 μg/mL), ΔD4B-rVWF (5 μg/mL), and ΔC1C2-rVWF (5 μg/mL) and D1746G-rVWF (5 μg/mL) for 2 hours at ambient temperature. After removing nonbound material, plasma-free blood was perfused at a shear rate of 1500 s^–1 over the fibrin surfaces for 3 minutes. Platelet adhesion data are calculated relative to the mean value obtained with fibrin that was incubated with plasma-purified VWF (A) or WT-rVWF (B). Controls are nontreated fibrin layers. Error bars indicate SEM.