Abstract
We describe the characterization of siglec-8, a novel sialic acid-binding immunoglobulin-like lectin that is expressed specifically by eosinophils. A full-length cDNA encoding siglec-8 was isolated from a human eosinophil cDNA library. Siglec-8 is predicted to contain three extracellular immunoglobulin-like domains, a transmembrane region, and a cytoplasmic tail of 47 amino acids. The siglec-8 gene mapped on chromosome 19q13.33-41, closely linked to genes encoding CD33 (siglec-3), siglec-5, siglec-6, and siglec-7. When siglec-8 was expressed on COS cells or as a recombinant protein fused to the Fc region of human IgG(1), it was able to mediate sialic acid-dependent binding to human erythrocytes and to soluble sialoglycoconjugates. Using specific monoclonal antibodies, siglec-8 could be detected only on eosinophils and hence appears to be the first example of an eosinophil-specific transmembrane receptor.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Antigens, CD / chemistry*
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Antigens, CD / genetics*
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Antigens, CD / metabolism
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Antigens, Differentiation, B-Lymphocyte / chemistry*
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Antigens, Differentiation, B-Lymphocyte / genetics*
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Antigens, Differentiation, B-Lymphocyte / metabolism
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Antigens, Differentiation, Myelomonocytic / chemistry
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Antigens, Differentiation, Myelomonocytic / genetics
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COS Cells
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Chromosome Mapping
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Chromosomes, Human, Pair 19*
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Eosinophils / immunology*
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Erythrocytes / immunology
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Gene Library
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Genetic Linkage
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Granulocytes / immunology
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Humans
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Immunoglobulin Fc Fragments / genetics
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Immunoglobulin G / genetics
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Lectins*
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Lymphocytes / immunology
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Molecular Sequence Data
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Monocytes / immunology
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Recombinant Fusion Proteins / metabolism
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Sequence Alignment
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Sequence Homology, Amino Acid
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Sialic Acid Binding Ig-like Lectin 3
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Sialic Acids / blood
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Transfection
Substances
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Antigens, CD
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Antigens, Differentiation, B-Lymphocyte
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Antigens, Differentiation, Myelomonocytic
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CD33 protein, human
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Immunoglobulin Fc Fragments
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Immunoglobulin G
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Lectins
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Recombinant Fusion Proteins
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SIGLEC7 protein, human
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SIGLEC8 protein, human
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Sialic Acid Binding Ig-like Lectin 3
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Sialic Acids