Abstract
The mechanism(s) controlling activation of naive B cells, their proliferation, Ag receptor affinity maturation, isotype switching, and their fate as memory or plasma cells is not fully elucidated. Here we show that between 24 and 60% of CD19+ cells in PBMC bind soluble CD14 (sCD14). Tonsillar B cells also bind sCD14, but preferentially the CD38-ve/low cells. Interaction of sCD14 with B cells resulted in higher levels of IgG1 and marked inhibition of IgE production by activated tonsillar B cells and Ag-stimulated PBMC. We found that sCD14 interfered with CD40 signaling in B cells, inhibited IL-6 production by activated B cells, and increased the kinetics and magnitude of CD40 ligand expression on T cells. Together with the previously reported effects on T cells, these findings define sCD14 as a novel soluble regulatory factor capable of modulating cellular and humoral immune responses by interacting directly with T and B cells.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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B-Lymphocyte Subsets / immunology*
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B-Lymphocyte Subsets / metabolism*
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CD40 Antigens / metabolism
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CD40 Antigens / physiology
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CD40 Ligand
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Cell Communication / immunology*
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Cells, Cultured
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DNA-Binding Proteins / antagonists & inhibitors
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DNA-Binding Proteins / metabolism
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Humans
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I-kappa B Proteins*
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Immune Tolerance
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Immunoglobulin E / biosynthesis*
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Immunoglobulin G / biosynthesis*
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Interleukin-6 / antagonists & inhibitors
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Interleukin-6 / biosynthesis
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Kinetics
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Leukocytes, Mononuclear / immunology
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Leukocytes, Mononuclear / metabolism
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Ligands
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Lipopolysaccharide Receptors / blood
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Lipopolysaccharide Receptors / metabolism*
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Lipopolysaccharide Receptors / physiology
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Lymphocyte Activation
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Membrane Glycoproteins / biosynthesis
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NF-KappaB Inhibitor alpha
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Palatine Tonsil / cytology
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Protein Binding / immunology
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Solubility
Substances
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CD40 Antigens
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DNA-Binding Proteins
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I-kappa B Proteins
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Immunoglobulin G
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Interleukin-6
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Ligands
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Lipopolysaccharide Receptors
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Membrane Glycoproteins
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NFKBIA protein, human
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NF-KappaB Inhibitor alpha
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CD40 Ligand
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Immunoglobulin E