title: Neonatal neutrophil interaction with P-selectin: contribution of P-selectin glycoprotein ligand-1 and sialic acid.
abstract: Previously we had determined that neonatal neutrophils had decreased interaction with monolayers expressing P-selectin compared to adult cells. In this study we examined the function of neonatal P-selectin glycoprotein ligand-1 (PSGL-1). A rabbit polyclonal antibody directed against the amino terminus of human PSGL-1 was produced and purified (3RB-PSGL-1). Neonatal neutrophils expressed the epitope recognized by 3RB-PSGL-1 and expression was decreased compared with adult neutrophils (20%, P<0.05). In addition neonatal neutrophils had decreased interaction with Chinese hamster ovary (CHO)-P-selectin under both shear conditions and static adhesion (P<0.05). Treatment of both neonatal and adult neutrophils with 3RB-PSGL-1 similarly inhibited the interaction with P-selectin monolayers under shear conditions, effects similar to treatment with O-sialoglycoprotein endopeptidase (OSGE). Neuraminidase treatment of neonatal and adult cells also markedly inhibited the interaction. In a detachment assay marked differences were noted between neonatal and adult cells treated with either 3RB-PSGL-1 or neuraminidase. Such treatments had little effect on adult neutrophils until shear stress exceeded 2.8 dynes/cm2. Treated neonatal neutrophils were exquisitely sensitive to shear stress with a marked decrease in interaction noted at a shear stress as low as 0.6 dynes/cm2. Thus the adhesive mechanisms that remain after treatment with neuraminidase or 3RB-PSGL-1 have a relatively low avidity and function less well in neonatal neutrophils compared to adult neutrophils. We speculate that this may account for the less efficient adhesion of neonatal neutrophils to P-selectin under conditions of flow.
authors.affiliation: Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030-2600, USA.
authors.forename: M H
authors.initials: MH
authors.lastname: Tcharmtchi
authors.forename: C W
authors.initials: CW
authors.lastname: Smith
authors.forename: M M
authors.initials: MM
authors.lastname: Mariscalco
mesh_terms: D000328:Adult; D000818:Animals; D016466:CHO Cells; D002448:Cell Adhesion; D006224:Cricetinae; D006801:Humans; D008562:Membrane Glycoproteins / Q000502:physiology*; D020556:Neutrophil Infiltration / Q000502:physiology*; D009504:Neutrophils / Q000166:cytology / Q000502:physiology*; D019007:P-Selectin / Q000502:physiology*; D011817:Rabbits
chemical_list: D008562:Membrane Glycoproteins; D019007:P-Selectin; C084882:P-selectin ligand protein