Effect of β1 integrin activation on eosinophil rolling and detachment from VCAM-1 in vitro.
Eosinophils (preincubated with a β1 integrin–activating Ab or control Ab) were infused into a parallel plate flow chamber containing VCAM-1– or BSA-coated coverslip. The number of (A) rolling eosinophils during continuous flow periods of 2 minutes was recorded and subjected to offline analysis. To evaluate the influence of the β1-activating antibody on the resistance of eosinophils to detachment from VCAM-1 (B), stepwise increases in shear stress were applied for 15 seconds at each shear force (2 to 20 dyn/cm2) to eosinophils adherent to VCAM-1 in the flow chamber. The number of eosinophils firmly adherent to VCAM-1 per field was recorded before and after each stepwise increase in shear stress. The number of detached eosinophils is expressed as a percentage of the total number of eosinophils adherent to VCAM-1 before stepwise increases in shear stress were applied to the coverslip in the flow chamber. Results of experiments performed at a flow rate of 0.7 dyn/cm2 are presented as the mean ± SEM (n = 3 experiments). Solid bar, mAb 8A2 treated; hatched bar, control.
