Functional and structural characterization of the eosinophil P-selectin ligand

F A Symon, M B Lawrence, M L Williamson, Garry Michael Walsh, A J Wardlaw

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Abstract

Our recent studies have indicated an important role for P-selectin in eosinophil adhesion, We have therefore compared eosinophil and neutrophil binding with nasal polyp endothelium as well as purified P-selectin. We have also compared the structure and expression of the eosinophil and neutrophil P-selectin ligands. Using the frozen section assay, eosinophils bound to 2-fold more blood vessels within the nasal polyp tissue than neutrophils. Up to 10-fold more eosinophils than neutrophils bound per unit length of endothelium, Neutrophil and eosinophil binding was inhibited by a mAb against P-selectin and a P-selectin chimera which binds to the P-selectin ligand. Eosinophils bound with approximately 2-fold greater avidity to purified P-selectin under now conditions, Using SDS-PAGE we characterized the eosinophil P-selectin ligand as a sialylated, homodimeric glycoprotein consistent with the known structure of PSGL-1. However, expression of PSGL-1 by eosinophils was significantly greater than on neutrophils. The eosinophil ligand had a calculated molecular mass by SDS-PACE of approximately 10 kDa greater than the neutrophil ligand, which was not due to differences in N-glycosylation. Eosinophils expressed the 15-decapeptide repeat form of PSGL-1 compared with neutrophils that have the 16-decapeptide repeat form, The increased binding of eosinophils, compared with neutrophils, to P-selectin in both an ex-vivo and in vitro assay suggests that P-selectin may have a role directing the specific migration of eosinophils in diseases such as asthma. The increased avidity may be due to increased expression of PSGL-1 by eosinophils, differences in the peptide backbone, or post-translational modifications.

Original languageEnglish
Pages (from-to)1711-1719
Number of pages9
JournalThe Journal of Immunology
Volume157
Issue number4
Publication statusPublished - 15 Aug 1996

Keywords

  • VASCULAR ENDOTHELIAL-CELLS
  • INTERCELLULAR-ADHESION MOLECULE-1
  • GLYCOPROTEIN LIGAND
  • HUMAN-LEUKOCYTES
  • BRONCHIAL-MUCOSA
  • AMINO-TERMINUS
  • EXPRESSION
  • NEUTROPHILS
  • RECEPTOR
  • MECHANISMS

Cite this

Symon, F. A., Lawrence, M. B., Williamson, M. L., Walsh, G. M., & Wardlaw, A. J. (1996). Functional and structural characterization of the eosinophil P-selectin ligand. The Journal of Immunology, 157(4), 1711-1719.