| Autor: |
Welply, Joseph K., Abbas, S. Zaheer, Scudder, Peter, Keene, Jeffery L., Broschat, Kay, Casnocha, Susan, Gorka, Chris, Steininger, Christina, Howard, Susan C., Schmuke, Jon J., Graneto, Matthew, Rotsaert, J.M., Manger, Ian D., Jacob, Gary S. |
| Zdroj: |
Glycobiology; May1994, Vol. 4 Issue 3, p259-265, 7p |
| Abstrakt: |
Free, monovalent SLeX (Neu5Acα2-3GalβI-4(Fucαl-3)-GlcNAc), SLn (Neu5Acα2-3Galβ1-4GlcNAc) and corresponding BSA-conjugated forms—displaying different ratios of SLeX and SLn to protein—were tested for their ability to inhibit binding of HL-60 cells to Immobilized E-selectin. Free SLeX and conjugated SLeX-BSA inhibited cell binding in a dose-dependent manner. SLn and SLn-BSA did not inhibit binding. SLeXBSA (16 mol tetrasaccharide/mol BSA) and monovalent SLeX inhibited cell binding with measured inhibitory concentrations (s) of 1 μM and 1 mM, respectively, demonstrating a three-order-of-magnitude enhancement of inhibitory activity with the multivalent form of SLeX. A SLexBSA conjugate was 10-fold less potent than those with 11 or 16 mol SLeX/mol BSA. An assay which measured neutrophil rolling on interleukin (IL)-1β-activated human umbilical vein endothelial cells (HUVECs) showed 50% reduction in the number of rolling neutrophils in the presence of 1 μM SLeXBSA, whereas the level of free, monovalent SLeX oligosaccharide required to produce the same effect was ˜0.3 mM. SLeX–BSA was found to be an excellent reagent for staining endothelial cells expressing E-selectin. Biotinylated SLeX–BSA in conjunction with Texas red avidin-stained lipopolysaccharide (LPS)-activated HUVECs, and co-incubation of activated cells with anti-E-selectin, specifically blocked staining. The distribution of E-selectin, as determined by binding of SLeX–BSA, was virtually identical with that obtained by binding of anti-E-selectin antibody. The pattern was punctate in nature, rather than being diffuse, suggesting that E-selectin may be organized as clusters within the plasma membrane. The results suggest that multivalent forms of SLeX bind to E-selectin with higher affinity than do monovalent glycans. Clustering of E-selectin in the membrane may be important for binding to counter-receptors on leukocyte cell surfaces. [ABSTRACT FROM PUBLISHER] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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