The percentage of adult (A) and neonatal (B) of those initially attached to CHO-P-selectin in the absence of shear stress that remain interacting as shear stress is applied. Adult and neonatal neutrophils were treated with the anti-CD11a (▾) or anti-CD18 (▴) MoAb or left untreated (•). Data are expressed as the mean percentage of initially interacting cells remaining ± SEM from 7 to 14 experiments. *P < .05 compared with control neutrophils. **P < .005 compared with control neutrophils.