Counter-receptors on human basophils for endothelial cell adhesion molecules

Ligands on human basophils for the endothelial adhesion molecules intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), mucosal addressin cell adhesion molecule-1 (MAdCAM-1), and E-selectin were investigated. Adhesion of basophils to endothelial cells was inhibited by mAb recognizing CD18, CD11a, and/or CD11b, with the pattern and magnitude of inhibition dependent upon the activation state of the basophils and endothelium. Adhesion to recombinant VCAM-1 was completely inhibited by mAb recognizing alpha 4 integrin and partially by mAb to the beta 1 or beta 7 subunit; surface expression of these integrins was also detected. Adhesion to recombinant MAdCAM-1 expressed on Chinese hamster ovary cells was completely inhibited by mAb recognizing alpha 4 and/or beta 7 integrins. Adhesion to recombinant E-selectin was completely inhibited by basophil pretreatment with neuraminidase and partially inhibited by endo-beta-galactosidase. By flow cytometry, bimodal patterns of expression of sialyl-Lewis X- and sialyl-dimeric-Lewis X were observed, and adherent cells tended to be sialyl-dimeric-Lewis X positive. Thus, basophils express beta 1, beta 2, and beta 7 integrins along with sialylated surface ligands that may interact with the endothelium during basophil recruitment responses.