CCR3-active chemokines promote rapid detachment of eosinophils from VCAM-1 in vitro

H Tachimoto, MM Burdick, SA Hudson… - The Journal of …, 2000 - journals.aai.org
H Tachimoto, MM Burdick, SA Hudson, M Kikuchi, K Konstantopoulos, BS Bochner
The Journal of Immunology, 2000journals.aai.org
Selective eosinophil recruitment is the result of orchestrated events involving cell adhesion
molecules, chemokines, and their receptors. The mechanisms by which chemokines
regulate eosinophil adhesion and migration via integrins are not fully understood. In our
study, we examined the effect of CCR3-active chemokines on eosinophil adhesion to VCAM-
1 and BSA under both static and flow conditions. When eotaxin-2 or other CCR3-active
chemokines were added to adherent eosinophils, it induced rapid and sustained eosinophil …
Abstract
Selective eosinophil recruitment is the result of orchestrated events involving cell adhesion molecules, chemokines, and their receptors. The mechanisms by which chemokines regulate eosinophil adhesion and migration via integrins are not fully understood. In our study, we examined the effect of CCR3-active chemokines on eosinophil adhesion to VCAM-1 and BSA under both static and flow conditions. When eotaxin-2 or other CCR3-active chemokines were added to adherent eosinophils, it induced rapid and sustained eosinophil detachment from VCAM-1 in a concentration-dependent manner. Adhesion was detectably reduced within 3 min and was further reduced at 10–60 min. Simultaneously, eotaxin-2 enhanced eosinophil adhesion to BSA. Preincubation of eosinophils with the CCR3-blocking mAb 7B11 completely prevented chemokine-induced changes in adhesion to VCAM-1 and BSA. Using a different protocol, pretreatment of eosinophils with chemokines for 0–30 min before their use in adhesion assays resulted in inhibition of VCAM-1 adhesion and enhancement of BSA adhesion. By flow cytometry, expression of α 4 integrins and a β 1 integrin activation epitope on eosinophils was decreased by eotaxin-2. In a flow-based adhesion assay, eotaxin-2 reduced eosinophil accumulation and the strength of attachment to VCAM-1. These results show that eotaxin-2 rapidly reduced α 4 integrin function while increasing β 2 integrin function. These findings suggest that chemokines facilitate migration of eosinophils by shifting usage away from β 1 integrins toward β 2 integrins.
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