Abstract
TLR9 is expressed in cells of the innate immune system, as well as in B lymphocytes and their progenitors. We investigated the effect of the TLR9 ligand CpG DNA on the proliferation of pro-B cells. CpG DNA inhibits the proliferation of pro-B, but not pre-B, cells by inducing caspase-independent cell death through a pathway that requires the expression of cathepsin B. This pathway is operative in Rag-deficient mice carrying an SP6 transgene, in which B lymphopoiesis is compromised, to reduce the size of the B lymphocyte precursor compartments in the bone marrow. Thus, TLR9 signals can regulate B lymphopoiesis in vivo.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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B-Lymphocyte Subsets / cytology*
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B-Lymphocyte Subsets / immunology*
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B-Lymphocyte Subsets / metabolism
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Caspases / physiology
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Cathepsin B / deficiency
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Cathepsin B / genetics
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Cathepsin B / physiology*
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Cell Death / immunology
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Cell Differentiation / genetics
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Cell Differentiation / immunology*
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Cell Line
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Cell Proliferation
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Cells, Cultured
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CpG Islands / physiology*
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Homeostasis / immunology
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Interleukin-7 / physiology
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Ligands
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Mice
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Mice, Inbred C57BL
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Mice, Knockout
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Mice, Transgenic
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Signal Transduction / immunology
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Stem Cells / cytology*
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Stem Cells / immunology*
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Stem Cells / metabolism
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Toll-Like Receptor 9 / deficiency
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Toll-Like Receptor 9 / genetics
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Toll-Like Receptor 9 / physiology
Substances
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Interleukin-7
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Ligands
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Tlr9 protein, mouse
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Toll-Like Receptor 9
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Caspases
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Cathepsin B
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Ctsb protein, mouse