Abstract
alpha-Galactosylceramide (alpha-GalCer), a glycolipid antigen, specifically activates natural killer T (NKT) cells by a CD1d-restricted mechanism. In this work, we found that in vivo administration of alpha-GalCer resulted in the activation of B cells in addition to NKT cells, namely, alpha-GalCer administration caused upregulation of the early activation marker, CD69, on both NKT and B cells. In addition, expression of B7.2 and I-A(b) on B cells was greatly upregulated by alpha-GalCer. However, serum levels of IgE, IgG1, and IgG2a were not significantly changed within 48 h. In the present experiments, it was also demonstrated that the upregulation of CD69 expression by alpha-GalCer was strongly blocked by anti-IL-4 monoclonal antibody. Moreover, B-cell activation by alpha-GalCer was not observed in NKT-deficient mice. These results suggested that antigen-stimulated NKT cells might play a critical role not only in early defense mechanisms but also in early B-cell activation through IL-4 production.
Copyright 2000 Academic Press.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Antibodies, Monoclonal / immunology
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Antigens / administration & dosage
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Antigens / immunology
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Antigens, CD / metabolism
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Antigens, Differentiation, T-Lymphocyte / metabolism
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B-Lymphocytes / immunology*
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B-Lymphocytes / metabolism
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Cells, Cultured
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Coculture Techniques
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Galactosylceramides / administration & dosage
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Galactosylceramides / antagonists & inhibitors
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Galactosylceramides / immunology*
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Gene Deletion
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Immunoglobulin E / biosynthesis
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Immunoglobulin E / blood
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Immunoglobulin G / biosynthesis
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Immunoglobulin G / blood
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Interferon-gamma / biosynthesis
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Interferon-gamma / blood
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Interferon-gamma / immunology
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Interleukin-4 / biosynthesis*
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Interleukin-4 / blood
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Killer Cells, Natural / immunology
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Killer Cells, Natural / metabolism
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Lectins, C-Type
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Lymphocyte Activation / immunology*
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Lymphocyte Subsets / immunology*
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Lymphocyte Subsets / metabolism
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Mice
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Mice, Inbred C57BL
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Receptors, Antigen, T-Cell / immunology
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Receptors, Immunologic / immunology
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Up-Regulation / drug effects
Substances
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Antibodies, Monoclonal
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Antigens
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Antigens, CD
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Antigens, Differentiation, T-Lymphocyte
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CD69 antigen
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Galactosylceramides
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Immunoglobulin G
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Lectins, C-Type
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Nktr protein, mouse
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Receptors, Antigen, T-Cell
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Receptors, Immunologic
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Interleukin-4
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Immunoglobulin E
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Interferon-gamma