Receptors that support neutrophil adhesion to ICAM-1.

Neutrophils (1 × 10⁶ cells/mL) were preincubated with saturation concentrations of blocking antibodies, mixed with either I_high or parent 300.19 cells (2 × 10⁶ cells/mL), stimulated with 1 μmol/L fMLP, and sheared in the cone-plate viscometer. (A) Peak heterotypic aggregation at 1 minute after stimulation with fMLP and initiation of shear at 600 s⁻¹ is compared for saturating concentrations of blocking antibodies as denoted. The open bar depicts binding to the nontransfected parent 300.19 cell. *P > .05 compared with other bars with the same symbol. (B) Adhesion efficiency for aggregation mediated through CD11a/CD18 and CD11b/CD18. The kinetics of heterotypic aggregation over the first 60 seconds after stimulation with fMLP and initiation of shear were fit with a mathematical model at each shear rate. Smooth lines represent curves fit to experimental data with a first-order exponential decay function. *P < .05 compared with control at the same shear rate. Data are presented as mean ± SEM from 3 to 6 separate experiments.