Platelets (2 × 10⁸ cells/mL) were first activated by thrombin, and then incubated with various concentrations of A11 for 4 hours at 37°C. Twenty microliters of A11-treated activated platelets were added to an equal volume of human monocytes (2 × 10⁶ cells/mL) and incubated at room temperature for 30 minutes followed by inspection and scoring of the monocytes with various numbers of attached platelets: monocytes with less than 5, between 5 and 10, and more than 10 attached platelets.