Abstract. The selectins (lectin-EGF-complement binding-cell adhesion molecules [LEC-CAMs]) are a family of mammalian receptors implicated in the initial interactions between leukocytes and vascular endothelia, leading to lymphocyte homing, platelet binding, and neutrophil extravasation. The three known selectins, L-selectin (leukocyte adhesion molecule-1 [LECAM-1]), E-selectin (endothelial-leukocyte adhesion molecule-1 [ELAM-1]), and P-selectin

Complex carbohydrates coat the surfaces of cells and have the potential to carry the information necessary for cell-cell recognition. Sugar-specific receptors (lectins) are also present on cells, and can interact with sugars on apposing cells. This may result in the adhesion of the two cells via carbohydrates and specific cell-surface receptors. Such carbohydrate-directed cell adhesion appears to be important in many intercellular activities including infection by bacteria and viruses, communication among cells of lower eukaryotes, specific binding of sperm to egg; and recirculation of lymphocytes, among others. New approaches involving synthesis of chemically defined cell-surface analogs, in conjunction with inhibition experiments, are beginning to reveal the mechanics of a potential carbohydrate "language" involved in intercellular interactions.

No abstract

The acute inflammatory response requires that circulating leukocytes bind to and penetrate the vascular wall to access the site of injury. Several receptors have been implicated in this interaction, including a family of putative carbohydrate-binding proteins. We report here the identification of an endogenous carbohydrate ligand for one of these receptors, endotheial-leukocyte adhesion molecule 1 (ELAM-1). Radiolabeled COS cells transfected with a plasmid containing the cDNA for ELAM-1 were used as probes to screen glycolipids extracted from human leukocytes. COS cells transfected with this plasmid adhered to a subset of sialylated glycolipids resolved on TLC plates or adsorbed on polyvinyl chloride microtiter wells. Adhesion to these glycolipids required calcium but was not inhibited by heparin, chondroitin sulfate, keratan sulfate, or yeast phosphomannan. Monosaccharide composition, linkage analysis, and fast atom bombardment mass spectrometry of the glycolipids indicate that the ligands for ELAM-1 are terminally sialylated lactosylceramides with a variable number ofN-acetyllactosamine repeats and at least one fucosylated N-acetylglucosamine residue.