Visualization of platelet/THP-1 complexes. Fluorescently labeled activated platelets were added to the suspension of nonlabeled THP-1 cells in a ratio of 3:1. Complex formation between platelets and THP-1 cells was assessed by combined light and fluorescence microscopy. The panels in row (A) depict micrographs of THP-1/platelet complexes adhering to the endothelial monolayer (40×). Row (B) shows typical examples of sparsely decorated THP-1 cells in the suspension after passage through the flow chamber (40×).