Anti-VCAM-1 mAb Rb 1/9 blocks eosinophil rolling in venular endothelium in vivo.

Fluorescently labeled eosinophils were injected into the superior mesenteric artery and their baseline rolling on IL-1β–stimulated venular endothelium determined. The flow of the mesenteric circulation was temporarily occluded and an anti-VCAM-1 (Rb 1/9) or control (mouse IgG1) mAb infused. After a 10-minute incubation of the mAb with the endothelial surface, the blood flow was restored and the CFDA-labeled eosinophils injected. The flux of rolling eosinophils was determined at different time points (up to 1 hour postinfusion of eosinophils into the antibody treated mesenteric venules) by frame-by-frame analysis of recorded video images. The effect of mAb blockade lasted for up to about 30 minutes after resumption of flow. The results are expressed as percent rolling of eosinophils compared with rolling observed before mAb treatment (% of average control). The values represent mean ± SD. There was significant inhibition of eosinophil rolling 10 to 15 minutes posttreatment with mAb Rb 1/9 (P = .05 vs control) but not with mouse IgG (P = not significant vs control). •, mAb Rb 1/9; ○, mouse IgG1.