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Inflammation. 2004 Aug;28(4):177-88.

Sialylation of ICAM-2 on platelets impairs adhesion of leukocytes via LFA-1 and DC-SIGN.

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  • 1Department of Medicine, Division of Rheumatology, Immunology & Allergy, Harvard Medical School, Boston, Massachusetts, USA.

Abstract

Intercellular adhesion molecule (ICAM)-2 is highly expressed on platelets and endothelium and is a counter-receptor for the leukocyte integrin, lymphocyte function-associated antigen-1 (LFA-1) and for the dendritic cell-specific, ICAM-grabbing non-integrin (DC-SIGN) protein. In this study, we investigated structural and functional differences between ICAM-2 from platelets and that from endothelial cells. The isoelectric point (pI) of ICAM-2 from HUVEC was pH 3.5-4.3, whereas that of platelet ICAM-2 was more acidic at pH 3.0-3.7. This charge difference was abolished by treatment with N-glycanase or neuraminidase, thus it was due to cell-specific N-linked glycosylation. Purified, immobilized platelet ICAM-2 supported 50% less adhesion of LFA-1-bearing T cells than did purified HUVEC ICAM-2 and no adhesion was observed of monocyte-derived immature dendritic cells via DC-SIGN to platelet ICAM-2. Treatment of platelet ICAM-2 with neuraminidase abolished these functional differences. These findings demonstrated that physiologic sialylation of platelet ICAM-2 renders it less able than endothelial ICAM-2 to support adherence of leukocytes.

PMID:
15673159
[PubMed - indexed for MEDLINE]
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