TSP-dependent sickle RBC adhesion to activated endothelial cells is inhibited by scFv TSP-A10. Cytokine-stimulated endothelial cells were incubated with SFM-BSA (buffer) or TSP in SFM-BSA (5 μg/mL, TSP, whole blood) with (▦) or without (□) purified scFv TSP-A10 (2.3 μg/mL) for 20 minutes at 37°C as described in “Materials and methods.” Washed sickle RBCs (buffer, TSP) or whole blood was perfused over the treated endothelial cells and rinsed, and adherent RBCs were counted as described in Figure 3. The results are shown as the means ± SEs of adherent RBCs/mm² (n = 3 for buffer, n = 5 for TSP and whole blood). The ^* indicates a P value less than .005 comparing TSP-A10–treated assays with control assays, and σ indicates a P value of .01 or less comparing whole blood with either buffer or TSP under control conditions.