Abstract
CD8+ T cell tolerance to self-proteins prevents autoimmunity but represents an obstacle to generating T cell responses to tumor-associated antigens. We have made a T cell receptor (TCR) transgenic mouse specific for a tumor antigen and crossed TCR-TG mice to transgenic mice expressing the tumor antigen in hepatocytes (gag-TG). TCRxgag mice showed no signs of autoimmunity despite persistence of high avidity transgenic CD8+ T cells in the periphery. Peripheral CD8+ T cells expressed phenotypic markers consistent with antigen encounter in vivo and had upregulated the antiapoptotic molecule Bcl-2. TCRxgag cells failed to proliferate in response to antigen but demonstrated cytolytic activity and the ability to produce interferon gamma. This split tolerance was accompanied by inhibition of Ca(2+) flux, ERK1/2, and Jun kinase phosphorylation, and a block in both interleukin 2 production and response to exogenous interleukin 2. The data suggest that proliferation and expression of specific effector functions characteristic of reactive cells are not necessarily linked in CD8+ T cell tolerance.
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, Neoplasm / genetics
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Antigens, Neoplasm / immunology*
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CD8-Positive T-Lymphocytes / cytology*
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CD8-Positive T-Lymphocytes / immunology*
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Calcium / metabolism
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Cell Division
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Cell Extracts
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Flow Cytometry
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Gene Expression
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Immune Tolerance / immunology*
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Interferon-gamma / metabolism
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Interleukin-2 / metabolism
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JNK Mitogen-Activated Protein Kinases
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Mice
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Mice, Transgenic
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Mitogen-Activated Protein Kinase Kinases / metabolism
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Mitogen-Activated Protein Kinases / metabolism
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Proto-Oncogene Proteins c-bcl-2 / metabolism
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Receptors, Antigen, T-Cell / genetics
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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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Spleen / cytology
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Spleen / metabolism
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Tumor Necrosis Factor-alpha / metabolism
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fas Receptor / metabolism
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ras Proteins / metabolism
Substances
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Antigens, Neoplasm
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Cell Extracts
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Interleukin-2
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Proto-Oncogene Proteins c-bcl-2
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Receptors, Antigen, T-Cell
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Tumor Necrosis Factor-alpha
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fas Receptor
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Interferon-gamma
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JNK Mitogen-Activated Protein Kinases
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Mitogen-Activated Protein Kinases
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Mitogen-Activated Protein Kinase Kinases
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ras Proteins
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Calcium