Abstract
To elucidate potential roles of IL-15 in the maintenance of memory CD8+ T cells, we followed the fate of Ag-specific CD8+ T cells directly visualized with MHC class I tetramers coupled with listeriolysin O (LLO)(91-99) in IL-15 transgenic (Tg) mice after Listeria monocytogenes infection. The numbers of LLO(91-99)-positive memory CD8+ T cells were significantly higher at 3 and 6 wk after infection than those in non-Tg mice. The LLO(91-99)-positive CD8+ T cells produced IFN-gamma in response to LLO(91-99), and an adoptive transfer of CD8+ T cells from IL-15 Tg mice infected with L. monocytogenes conferred a higher level of resistance against L. monocytogenes in normal mice. The CD44+ CD8+ T cells from infected IL-15 Tg mice expressed the higher level of Bcl-2. Transferred CD44+ CD8+ T cells divided more vigorously in naive IL-15 Tg mice than in non-Tg mice. These results suggest that IL-15 plays an important role in long-term maintenance of Ag-specific memory CD8+ T cells following microbial exposure via promotion of cell survival and homeostatic proliferation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adoptive Transfer
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Animals
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Apoptosis / genetics
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Apoptosis / immunology
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Bacterial Proteins / administration & dosage
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Bacterial Proteins / immunology*
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Bacterial Toxins*
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CD8-Positive T-Lymphocytes / immunology*
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CD8-Positive T-Lymphocytes / microbiology
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CD8-Positive T-Lymphocytes / pathology
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CD8-Positive T-Lymphocytes / transplantation
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Cell Division / genetics
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Cell Division / immunology
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Epitopes, T-Lymphocyte / immunology*
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Heat-Shock Proteins / administration & dosage
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Heat-Shock Proteins / immunology*
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Hemolysin Proteins
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Histocompatibility Antigens Class I / immunology
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Immunologic Memory* / genetics
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Injections, Intraperitoneal
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Interleukin-15 / biosynthesis*
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Interleukin-15 / genetics
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Interleukin-15 / physiology
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Kinetics
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Listeriosis / immunology
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Listeriosis / pathology
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Listeriosis / prevention & control
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Mice
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Mice, Inbred BALB C
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Mice, Inbred C57BL
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Mice, Transgenic
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Peptide Fragments / immunology
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T-Lymphocyte Subsets / immunology*
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T-Lymphocyte Subsets / microbiology
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T-Lymphocyte Subsets / pathology
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T-Lymphocyte Subsets / transplantation
Substances
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Bacterial Proteins
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Bacterial Toxins
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Epitopes, T-Lymphocyte
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Heat-Shock Proteins
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Hemolysin Proteins
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Histocompatibility Antigens Class I
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Interleukin-15
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Peptide Fragments
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hlyA protein, Listeria monocytogenes