Adhesion of murine PECAM-1-positive and PECAM-1-negative platelets to VWF under static conditions. Calcein am-labeled platelets were incubated under static conditions at 37°C for 60 minutes in microtiter wells that had been coated with 10 μg/mL human VWF (left panel) or BSA (right panel) in the presence or absence of 4 U/mL botrocetin. Percent adhesion was calculated as follows: (bound fluorescence/total fluorescence) × 100. Some wells contained 1 mM RGDW peptide or 25 μg/mL of the antihuman VWF A1 domain antibody, AVW-3. Data shown represent the mean ± SD of triplicate determinations. No appreciable difference in the adhesion to VWF of PECAM-1-positive versus PECAM-1-negative platelets was observed under any of the conditions examined.