Glycolipids support E-selectin-specific strong cell tethering under flow

This study provides functional evidence that glycosphingolipids constitute ligands for E-selectin but not P-selectin. Chinese hamster ovary (CHO) cell s expressing E-selectin (CHO-E) or P-selectin (CHO-P) were perfused over (a lpha2,3-sialyl Lewis X (alpha2,3-sLe(x)) presented as the hexaosylceramide glycosphingolipid adsorbed in a monolayer containing phosphatidylcholine an d cholesterol. CHO-E cells tethered extensively and formed slow, stable rol ling interactions with (alpha2,3-sLe(x)) glycosphingolipid but not with the comparable (2 alpha ,3-sLe(x)) glycosphingolipid. Tethering/rolling varied with wall shear stress, selectin density, and ligand density. In contrast, alpha2,3-sLe(x) glycosphingolipid supported only limited, fast CHO-P cell rolling. As calculated from a stochastic model of cell rolling, the step si ze between successive bond releases from the alpha2,3-sLe(x) glycosphingoli pid was smaller for CHO-E than CHO-P cells, whereas the opposite effect was observed for the waiting time between these events. Detachment assays reve aled stronger adhesive interactions of CHO-E than CHO-P cells with alpha2,3 -sLe(x) glycosphingolipid. These findings indicate that glycosphingolipids expressing an appropriate oligosaccharide mediate cell tethering/rolling vi a E-selectin but not P-selectin. (C) 2001 Academic Press.