title: Functional characterization of L-selectin ligands on human neutrophils and leukemia cell lines: evidence for mucinlike ligand activity distinct from P-selectin glycoprotein ligand-1.
abstract: Recent reports have shown that leukocyte-leukocyte adhesion is dependent on L-selectin and that leukocyte recognition of L-selectin may be mediated by P-selectin glycoprotein ligand-1 (PSGL-1). We show that the specific attachment and rolling of human neutrophils and the leukemia cell lines HL-60 and U937 on immobilized, purified L-selectin under continuous shear stress is only partially inhibited by treatment with the PSGL-1 monoclonal antibody (MoAb), KPL1 (41% to 53% inhibition), suggesting that L-selectin ligand activity in addition to PSGL-1 may mediate myeloid cell rolling on L-selectin. K562 cells cotransfected with cDNAs encoding alpha (1,3)fucosyltransferase-VII (FucT-VII) and PSGL-1 rolled on L-selectin. Adhesion of FucT-VII-PSGL-1 transfectants to L-selectin was completely blocked by MoAb KPL1, indicating that both L-selectin and P-selectin bind similar sites on PSGL-1. In support of existence of a non-PSGL-1 L-selectin ligand activity on leukocytes, an HL-60 membrane preparation immunodepleted of PSGL-1 supported rolling of L-selectin, but not P-selectin transfectants. Treatment of HL-60 cells with O-sialoglycoprotein endopeptidase inhibited attachment and rolling on L-selectin and P-selectin. However, neuraminidase treatment completely blocked HL-60 rolling on L-selectin, but not P-selectin, suggesting L-selectin and P-selectin ligand activities have different contributions of sialic acid. These findings indicate that myeloid cells express sialylated, O-linked glycoprotein ligand activity independent of PSGL-1 that supports L-selectin-mediated rolling.
authors.affiliation: Department of Biomedical Engineering, University of Virginia Health Sciences Center, Charlottesville 22908, USA.
authors.forename: C L
authors.initials: CL
authors.lastname: Ramos
authors.forename: M J
authors.initials: MJ
authors.lastname: Smith
authors.forename: K R
authors.initials: KR
authors.lastname: Snapp
authors.forename: G S
authors.initials: GS
authors.lastname: Kansas
authors.forename: G W
authors.initials: GW
authors.lastname: Stickney
authors.forename: K
authors.initials: K
authors.lastname: Ley
authors.forename: M B
authors.initials: MB
authors.lastname: Lawrence
mesh_terms: D000911:Antibodies, Monoclonal / Q000494:pharmacology; D002448:Cell Adhesion; D005647:Fucosyltransferases / Q000235:genetics; D018922:HL-60 Cells; D006801:Humans; D019041:L-Selectin / Q000235:genetics / Q000378:metabolism*; D007938:Leukemia / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D009077:Mucins / Q000378:metabolism*; D009504:Neutrophils / Q000378:metabolism*; D012212:Rheology; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D000911:Antibodies, Monoclonal; D008562:Membrane Glycoproteins; D009077:Mucins; C084882:P-selectin ligand protein; D019041:L-Selectin; D005647:Fucosyltransferases