COUNTER-RECEPTORS ON HUMAN BASOPHILS FOR ENDOTHELIAL-CELL ADHESION MOLECULES

Ligands on human basophils for the endothelial adhesion molecules inte rcellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecul e-1 (VCAM-1), mucosal addressin cell adhesion molecule-1 (MAdCAM-1), a nd 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 pa rtially by mAb to the beta(1) or beta(7) subunit; surface expression o f these integrins was also detected. Adhesion to recombinant MAdCAM-1 expressed on Chinese hamster ovary cells was completely inhibited by m Ab recognizing alpha(4) and/or beta(7) integrins. Adhesion to recombin ant E-selectin was completely inhibited by basophil pretreatment with neuraminidase and partially inhibited by endo-beta-galactosidase. By f low cytometry, bimodal patterns of expression of sialyl-Lewis X- and s ialyl-dimeric-Lewis X were observed, and adherent cells tended to be s ialyl-dimeric-Lewis X positive. Thus, basophils express beta(1), beta( 2), and beta(7) integrins along with sialylated surface ligands that m ay interact with the endothelium during basophil recruitment responses .