The high affinity conformation of β₂integrins was promoted by immobilized MK. (A-C) Flow cytometric analysis of the high affinity conformation of β₂ integrins of human PMNs using the mAb24 antibody. (A) Quantitative analysis of median fluorescence intensity of isolated PMNs left unstimulated (w/o) or stimulated with soluble MK at various concentrations (100 ng/ml or 30 μg/ml), or TNF-α (100 ng/ml) for 15 minutes at 37°C (n = 4). (B) Analysis of the high affinity conformation of β₂ integrins of human PMNs using the mAb24 antibody or control antibody following incubation with microparticles coated with ICAM1 (ICAM1), ICAM1 and MK (ICAM1-MK), or MK (MK), and left untreated (w/o) or after stimulation with soluble MK (100 ng/ml), or TNF-α (100 ng/ml) for 15 minutes at 37°C. Histograms are representative of 6 independent experiments. (C) Quantitative analysis of median fluorescence intensity of mAb24 epitope expression of PMNs binding or nonbinding to coated microparticles (n = 6). (A, C) Show median ± SEM. ***P < .001.