Inhibition of fibrin formation with a function-blocking PDI antibody is platelet independent. Rabbit polyclonal anti-PDI antibody conjugated to Alexa Fluor 488 (0.3 μg/g body weight) and fibrin-specific mouse anti–human fibrin II β-chain monoclonal antibody conjugated to Alexa Fluor 647 (0.5 μg/g body weight) were infused into the mouse 5 minutes before arteriolar injury. (A) Representative binarized images of the appearance of fluorescence associated with PDI (green) or fibrin (red) are shown over 180 seconds after laser-induced vessel-wall injury in a wild-type mouse (left panel), a wild-type mouse treated with eptifibatide (10 μg/g body weight; middle panel), or a wild-type mouse treated with eptifibatide (10 μg/g body weight) and a function blocking anti-PDI antibody, RL90, (2 μg/g body weight; right panel). Inhibitory monoclonal anti-PDI antibody RL90 and/or eptifibatide were infused into the circulation 5 minutes before injury. Data were collected from the same mouse pre- and postinfusion of eptifibatide and/or RL90. (B) Median integrated PDI fluorescence intensity or (C) median integrated fibrin fluorescence intensity for thrombi formed before (curve 1) or after the infusion of eptifibatide (curve 2) or after the infusion of eptifibatide in the presence of RL90 (curve 3). Median fluorescence is presented versus time after vessel wall injury.