High affinity binding of the leucocyte adhesion molecule L-selectin to 3'-sulphated-Le(a) and -Le(x) oligosaccharides and the predominance of sulphate in this interaction demonstrated by binding studies with a series of lipid-linked oligosaccharides.

The binding of the leucocyte adhesion molecule L-selectin has been investigated toward several structurally defined lipid-linked oligosaccharides immobilized on silica gel chromatograms or plastic wells. In both assay systems the 3'-sulphated Le(a)/Le(x) type tetrasaccharides [formula: see text] were more strongly bound than 3'-sialyl analogues. A considerable binding was observed to the 3'-sulphated oligosaccharide backbone in the absence of fucose but not to a 3'-sialyl analogue or fuco-oligosaccharide analogues lacking sulphate or sialic acid. Affinity for other sulphated saccharides: 3'-sulphoglucuronyl neolactotetraosyl ceramide and glycolipids with sulphate 3'-linked to terminal or sub-terminal galactose or N-acetylgalactosamine was detected in the chromatogram assay only. These studies, together with earlier reports that L-selectin binding to endothelium is inhibited by sulphatide, highlight the relative importance of sulphate in the adhesive specificity of this protein.