Inhibition of ¹²⁵I-VWF binding to fibrin by polyclonal antibodies against VWF and its proteolytic fragments SpII and SpIII. Polyclonal antibodies to VWF(□), SpII (•), or SpIII (▴) were preincubated with 250 ng/mL ¹²⁵I-VWF before addition to filters without and with fibrin (37 μg) for 2 hours at 37°C. For each point nonspecific binding (< 3% of total binding) was subtracted from the total binding to obtain the specific binding. Results are expressed as percentages of specific binding of ¹²⁵I-VWF measured in the absence of antibody. Error bars indicate SEM.