Abstract
Most hemopoietic cells express one or more members of the Ly-6 supergene family of small glycosylphosphatidylinositol-linked proteins. Although levels of Ly-6 proteins vary with stages of differentiation and activation, their function largely remains unknown. To ascertain whether ligands for Ly-6 proteins exist, chimeric proteins were constructed in which Ly-6E, Ly-6C, and Ly-6I were fused to the murine IgM heavy chain. These chimeras specifically stained both developing and mature B lymphocytes, as assessed by flow cytometry. Analysis of variants of the CH27 B cell lymphoma revealed that Ly-6A/E and Ly-6I recognized different molecules. CH27 cells with low levels of Ly-6A/E ligand activity also lost expression of CD22, and cells transfected with CD22 gained the ability to bind the Ly-6A/E chimera and, to a lesser extent, the Ly-6C and Ly-6I chimeric proteins. As many mature B cells coexpress Ly-6A/E and CD22, the function of Ly-6 molecules may be to associate with other membrane proteins, possibly concentrating these ligands in lipid rafts, rather than acting directly as cell:cell adhesion molecules.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Antigens, CD / genetics
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Antigens, CD / metabolism*
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Antigens, Differentiation, B-Lymphocyte / genetics
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Antigens, Differentiation, B-Lymphocyte / metabolism*
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Antigens, Ly / genetics
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Antigens, Ly / metabolism*
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B-Lymphocyte Subsets / immunology*
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B-Lymphocyte Subsets / metabolism*
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CD59 Antigens / biosynthesis
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CD59 Antigens / genetics
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CD59 Antigens / isolation & purification
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CD59 Antigens / metabolism*
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CHO Cells
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COS Cells
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Cell Adhesion Molecules*
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Cricetinae
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Genetic Variation / immunology
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Immunoglobulin Constant Regions / genetics
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Immunoglobulin mu-Chains / genetics
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Lectins / genetics
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Lectins / metabolism*
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Ligands
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Membrane Proteins / genetics
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Membrane Proteins / metabolism*
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Mice
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Mice, Inbred C57BL
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Multigene Family / immunology*
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Myeloid Cells / immunology
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Myeloid Cells / metabolism
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Protein Binding / genetics
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Protein Binding / immunology
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Recombinant Fusion Proteins / biosynthesis
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / isolation & purification
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Recombinant Fusion Proteins / metabolism
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Sialic Acid Binding Ig-like Lectin 2
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Transfection
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Tumor Cells, Cultured
Substances
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Antigens, CD
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Antigens, Differentiation, B-Lymphocyte
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Antigens, Ly
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CD59 Antigens
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Cd22 protein, mouse
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Cell Adhesion Molecules
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Immunoglobulin Constant Regions
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Immunoglobulin mu-Chains
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Lectins
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Ligands
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Ly6a protein, mouse
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Ly6i protein, mouse
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Membrane Proteins
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Recombinant Fusion Proteins
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Sialic Acid Binding Ig-like Lectin 2