β 3 integrins do not modulate fibrin structure on fibroblasts, SMCs, or HUVECs. In situ thrombin generation was initiated by incubating fibroblasts, SMCs, and HUVECs with recalcified, normal, pooled PFP in the presence of 0.136μM control IgG or anti-β3 antibody (abciximab) as described in “Methods.” Three-dimensional projections show clot architecture in 10-μm stacks 0 to 10 μm from the cell surface. Each image (146 μm × 146 μm, xy) is from 1 experiment, representative of 2 to 5 separate experiments. Data (no. fibers/point, ± SD) indicate mean fibrin network density from all experiments. Fibrin density in clots formed in the presence of control IgG or abciximab was not statistically different.