Elastase release from neutrophils that were unstimulated and continuously rolling (□), stimulated with 10⁻⁷mol/L PAF (▧), or stimulated with 10⁻⁷ mol/L fMLP (▪) while adherent to platelet monolayers (Platelets) or 5 μg/mL purified recombinant P-selectin coimmobilized with 1% BSA (P-sel/Alb). Data are the mean ± SEM of three experiments. ANOVA showed that there was a significant effect of treatment on release of elastase but that adherent substrate did not affect release. Paired t-test showed that elastase release from fMLP-but not PAF-treated cells was significantly increased (**P < .01) compared with rolling unstimulated control cells on either adhesive substrate.