Abstract
Immune evasion is required for Mycobacterium tuberculosis to survive in the face of robust CD4(+) T cell responses. We have shown previously that M. tuberculosis cell wall glycolipids, including mannose capped lipoarabinomannan (ManLAM), directly inhibit polyclonal murine CD4(+) T cell activation by blocking ZAP-70 phosphorylation. We extended these studies to antigen-specific murine CD4(+) T cells and primary human T cells and found that ManLAM inhibited them as well. Lck and LAT phosphorylation also were inhibited by ManLAM without affecting their localization to lipid rafts. Inhibition of proximal TCR signaling was temperature sensitive, suggesting that ManLAM insertion into T cell membranes was required. Thus, M. tuberculosis ManLAM inhibits antigen-specific CD4(+) T cell activation by interfering with very early events in TCR signaling through ManLAM's insertion in T cell membranes.
Copyright © 2012 Elsevier Inc. All rights reserved.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing / immunology
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Adaptor Proteins, Signal Transducing / metabolism
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Animals
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Cells, Cultured
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Female
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Humans
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Lipopolysaccharides / immunology*
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Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / immunology
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Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / metabolism
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Membrane Microdomains / immunology
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Membrane Proteins / immunology
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Membrane Proteins / metabolism
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Mice
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Mice, Inbred C57BL
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Mycobacterium tuberculosis / immunology*
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Phosphoproteins / immunology
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Phosphoproteins / metabolism
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Phosphorylation
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Receptors, Antigen, T-Cell / immunology*
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Receptors, Antigen, T-Cell / metabolism
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Signal Transduction*
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T-Lymphocytes / immunology
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ZAP-70 Protein-Tyrosine Kinase / immunology
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ZAP-70 Protein-Tyrosine Kinase / metabolism
Substances
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Adaptor Proteins, Signal Transducing
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LAT protein, human
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Lat protein, mouse
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Lipopolysaccharides
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Membrane Proteins
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Phosphoproteins
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Receptors, Antigen, T-Cell
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lipoarabinomannan
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Lymphocyte Specific Protein Tyrosine Kinase p56(lck)
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ZAP-70 Protein-Tyrosine Kinase
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ZAP70 protein, human
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Zap70 protein, mouse