Abstract
Little is known of how and where bacterial recognition triggers the induction of type I interferon. Whether the type of recognition receptor used in these responses is determined by the subcellular location of bacteria is not understood. Here we show that phagosomal bacteria such as group B streptococcus, but not cytosolic bacteria, potently induced interferon in conventional dendritic cells by a mechanism that required Toll-like receptor 7, the adaptor MyD88 and the transcription factor IRF1, all of which localized together with bacterial products in degradative vacuoles bearing lysosomal markers. Thus, this cell type-specific recognition pathway links lysosomal recognition of bacterial RNA with a robust, host-protective interferon response.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Animals, Newborn / immunology
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Animals, Newborn / microbiology
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Dendritic Cells / immunology
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Dendritic Cells / metabolism*
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Female
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Interferon Regulatory Factor-1 / immunology
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Interferon Regulatory Factor-1 / metabolism
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Interferon-beta / biosynthesis
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Lysosomes / immunology
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Lysosomes / metabolism*
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Macrophages / immunology
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Macrophages / metabolism
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Membrane Glycoproteins / immunology
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Membrane Glycoproteins / metabolism*
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Mice
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Mice, Knockout
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Myeloid Differentiation Factor 88 / immunology
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Myeloid Differentiation Factor 88 / metabolism
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Phagocytosis
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Phagosomes / immunology
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Phagosomes / metabolism
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RNA, Bacterial / metabolism
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Signal Transduction
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Streptococcal Infections / immunology
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Streptococcus agalactiae / immunology*
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Toll-Like Receptor 7 / immunology
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Toll-Like Receptor 7 / metabolism*
Substances
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Interferon Regulatory Factor-1
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Irf1 protein, mouse
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Membrane Glycoproteins
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Myd88 protein, mouse
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Myeloid Differentiation Factor 88
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RNA, Bacterial
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Tlr7 protein, mouse
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Toll-Like Receptor 7
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Interferon-beta