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 α₄ integrin and partially by mAb to the β₁ or β₇ 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 α₄ and/or β₇ integrins. Adhesion to recombinant E-selectin was completely inhibited by basophil pretreatment with neuraminidase and partially inhibited by endo-β-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 β₁, β₂, and β₇ integrins along with sialylated surface ligands that may interact with the endothelium during basophil recruitment responses.