Effect of soluble recombinant CD31 on endothelial CD31-induced enhancement of eosinophil adhesion to IL-4–stimulated vascular endothelial cells. IL-4–stimulated HUVECs were preincubated with anti-CD31 MoAb or control mouse IgG (10 μg/mL each) for 10 minutes at 37°C. After washing HUVECs, the adhesion assay of⁵¹Cr-labeled eosinophils to HUVECs was performed in the presence (▪) or absence (□) of soluble recombinant CD31 (1, 5, and 50 μg/mL). Data are the means ± SD for 4 experiments. *Significantly different from the mean value of the control response (*P < .005). **Significantly different from the mean value of the control response of anti-CD31 MoAb-pretreated HUVECs (**P< .005).