Interaction of GPIbα-coupled microspheres with FKN, VWF, and the combination under flow conditions. (A) Glycocalicin, the extracellular domain of GPIbα, was covalently coupled to fluorescent microspheres and combined with RBCs to obtain reconstituted blood and perfused through μ-slides coated with FKN, VWF, or FKN coimmobilized with VWF at a wall shear rate of 150, 600, or 1800 s−1. The rate of nonspecific background adhesion to the control surface was subtracted from the presented adhesion rates. Results are the mean ± SEM of 3 independent experiments with blood from different donors. ***P < .001 by 1-way analysis of variance with Bonferroni Multiple Comparison Test versus control or VWF adhesion rates. (B) GPIbα-coupled microspheres were preincubated with the neutralizing anti-GPIbα antibody HIP-1 before perfusion over VWF (open bars) and FKN coimmobilized with VWF (closed bars). The adhesion of untreated microspheres to VWF surfaces was set to 100% (dotted line). Results are the mean ± SEM of 3 independent experiments with blood from different donors. (C) GPIbα-coupled microspheres were preincubated with the neutralizing anti-GPIbα antibody HIP-1 before perfusion over FKN and control surfaces. The adhesion of untreated microspheres to control albumin surfaces for each treatment was set to 100%, and the number of microspheres adhering to FKN for untreated (closed bars) and anti-GPIbα-treated microspheres (open bars) was evaluated. Results are the mean ± SEM of 3 independent experiments with blood from different donors. **P < .01, ***P < .001 in one sample t test versus adhesion to control surface with identical treatment.
