Effect of anti-fXII antibodies on fibrin formation in human blood under flow. (A) Immunofluorescent images (Zeiss LSM 710, objective lenses: 20×/0.80 Plan-Apochromat, ×20 magnification) showing the effects of the anti-fXI IgG O1A6 (300 nM) or the anti-fXII IgGs 9A2 and 15H8 (4 μM) on fibrin deposition over time in recalcified human blood flowing across collagen-coated surfaces with an initial average shear rate of 300 s−1. Direction of flow is indicated at the bottom of the image. Fibrin appears orange in these images and platelet aggregates appear green. (B) Collagen-coated glass capillary tubes were perfused with recalcified human blood driven by a constant pressure gradient under the force of gravity. Shown are times to capillary occlusion in the presence of varying concentrations of 9A2 (□) or 15H8 (▪). Each bar represent means for 3 separate measurements ± standard error.
