Phagocytosis of platelet-derived microvesicles by macrophages. BODIPY-maleimide–labeled human platelet-derived microvesicles (80 μg) were incubated with THP-1–derived macrophages (106 cells/well) for 30 minutes. The nonadherent and the surface-bound microvesicles were detached with trypsin-EDTA solution. The macrophages were washed and analyzed by flow cytometry. The macrophages were identified by PE-labeled CD11b and gated. Phagocytosis was quantified by measuring the percentage of BODIPY (green) fluorescence-positive macrophages. (A) Phagocytosis in the absence of lactadherin. (B) Phagocytosis in the presence of lactadherin (0.8 μg/mL). (C) Lactadherin concentration-dependent phagocytosis of microvesicles. Each point represents the mean and SD of 3 or more separate experiments.