Blocking of LRP1-impaired MK binding to PMNs. (A) Binding of Alexa Fluor 488-labeled MK to WT PMNs using flow cytometry. For control, PMNs were left unstained. PMNs were treated with LRPAP (3 µM, blocked) for 20 minutes at RT or left untreated, and cells were subsequently left unstimulated (w/o) or stimulated with TNF-α (100 ng/ml), or CXCL1 (100 ng/ml) for 20 minutes at 37°C. Histograms are representative of 3 independent experiments. (B) Analysis of the high affinity conformation of β₂ integrins of human PMNs using the mAb24 antibody following incubation with ICAM1 and MK-coated microparticles for 15 minutes at 37°C. Prior to exposure to microparticles, PMNs were treated with LRPAP (3, 6, 9 µM) or left untreated for control (w/o). Data represents percentage of median fluorescence intensity of PMNs interacting with beads after LRP1 blockade in comparison with unblocked samples (n = 5). (B) Shows median ± SEM. *P < .05.