Binding of annexin-V, prothrombin, and factor X to isolated vesicle fractions. Microvesicles from the 10,000gfraction, exosomes from the sucrose gradient, and PS/PE/PC phopholipids were adsorbed to carbon-coated EM grids. The vesicles were incubated either with FITC-conjugated annexin-V, factor X, or prothrombin in the presence of 5 mmol/L CaCl2. After fixation, the membranes were immunolabeled with their respective antibodies and protein-A gold. (a) Annexin-V binding monitored with a polyclonal anti-FITC antibody and protein-A gold; (b) immunogold double labeling as indicated on the figure. Annexin-V binding is most prominent on the larger microvesicles. (c and d) Binding of prothrombin (c) and factor X (e) to microvesicles, but not to the exosomes (d and f); (g) binding of prothrombin to phospholipid vesicles. Bars: 100 nm.
