Abstract
Unlike naive T cells, memory phenotype (CD44(high)) T cells exhibit a high background rate of turnover in vivo. Previous studies showed that the turnover of memory phenotype CD8(+) (but not CD4(+)) cells in vivo can be considerably enhanced by products of infectious agents such as LPS. Such stimulation is TCR independent and hinges on the release of type I IFNs (IFN-I) which leads to the production of an effector cytokine, probably IL-15. In this study, we describe a second pathway of CD44(high) CD8(+) stimulation in vivo. This pathway is IFN-gamma rather than IFN-I dependent and is mediated by at least three cytokines, IL-12, IL-18, and IFN-gamma. As for IFN-I, these three cytokines are nonstimulatory for purified T cells and under in vivo conditions probably act via production of IL-15.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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CD8-Positive T-Lymphocytes / cytology
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CD8-Positive T-Lymphocytes / immunology*
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Cell Division / genetics
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Cell Division / immunology
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Cells, Cultured
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Immunologic Memory* / genetics
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Immunophenotyping
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Injections, Intravenous
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Interferon Type I / metabolism
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Interferon Type I / physiology
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Interferon-gamma / deficiency
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Interferon-gamma / genetics
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Interferon-gamma / physiology*
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Interleukin-12 / administration & dosage
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Interleukin-12 / physiology*
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Interleukin-18 / physiology*
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Lymphocyte Activation* / genetics
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Membrane Proteins
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Mice
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Mice, Inbred C3H
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Mice, Inbred C57BL
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Mice, Knockout
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Receptor, Interferon alpha-beta
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Receptors, Interferon / deficiency
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Receptors, Interferon / genetics
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Recombinant Proteins / administration & dosage
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Signal Transduction / genetics
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Signal Transduction / immunology*
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T-Lymphocyte Subsets / cytology
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T-Lymphocyte Subsets / immunology*
Substances
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Interferon Type I
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Interleukin-18
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Membrane Proteins
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Receptors, Interferon
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Recombinant Proteins
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Receptor, Interferon alpha-beta
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Interleukin-12
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Interferon-gamma