FIGURE 5.

LRP1 cluster IV, but not cluster II, competes for the binding of BDD-fVIII to LRP1. A, BDD-fVIII (20 nm) was incubated in microtiter wells coated with LRP1 in the presence of increasing concentrations of LRP1 clusters II (circles), III (squares), and IV (triangles). Following incubation, bound BDD-fVIII was detected by a fVIII-specific antibody. This experiment was repeated twice with replicates. A representative experiment is shown with replicates plotted. B, BDD-fVIII (20 nm) was incubated in microtiter wells coated with LRP1 in the presence of increasing concentrations of LRP1 cluster II (circles), IV (triangles), or clusters II and IV combined (diamonds). Following incubation, bound BDD-fVIII was detected by a fVIII-specific antibody. This experiment was performed in triplicate, and the mean values are plotted. Error bars represent S.E.