Abstract
Multimerization of the MHC class II molecule by superantigens results in activation of cellular signal transduction pathways in macrophage and B cells. Here we show that superantigen staphylococcal enterotoxin B (SEB) induces IL-12/p40 secretion in macrophages. SEB-induced expression of the IL-12/p40 gene involves activation and nuclear translocation of nuclear factor kappaB (NF-kappaB). The NF-kappaB heterodimer bound to the NF-kappaB consensus sequence of the IL-12/p40 gene promoter is p50/C-Rel. Inhibition of PKC and PKA activation results in suppression of activation and translocation of NF-kappaB. We conclude that signals for IL-12/p40 gene transcription from MHC class II molecules follow activation of PKC and PKA, which in turn leads to the activation and translocation of NF-kappaB to the nucleus. Our study suggests that superantigens are capable of influencing the nature of the immune response by regulating cytokine production. Induction of IL-12 production by superantigens may therefore play a role in the regulation of Th 1-mediated immune response and autoimmune disease.
Copyright 2000 Academic Press.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Binding, Competitive
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Cell Nucleus / enzymology
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Cell Nucleus / metabolism
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Cells, Cultured
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Cyclic AMP-Dependent Protein Kinases / antagonists & inhibitors
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Cyclic AMP-Dependent Protein Kinases / metabolism
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DNA / genetics
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DNA / metabolism
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Genes, MHC Class II / genetics
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Genes, MHC Class II / immunology
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Histocompatibility Antigens Class II / genetics
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Histocompatibility Antigens Class II / immunology
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Interleukin-12 / biosynthesis*
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Interleukin-12 / chemistry
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Interleukin-12 / genetics
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Interleukin-12 / metabolism
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Ligands
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Lipopolysaccharides / immunology
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Macrophages / enzymology
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Macrophages / immunology*
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Macrophages / metabolism*
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Mice
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Mice, Inbred Strains
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Mice, Knockout
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NF-kappa B / antagonists & inhibitors
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NF-kappa B / chemistry
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NF-kappa B / metabolism*
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Promoter Regions, Genetic / genetics
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Protein Kinase C / antagonists & inhibitors
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Protein Kinase C / metabolism
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Receptor Aggregation
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Signal Transduction
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Superantigens / immunology*
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Up-Regulation
Substances
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Histocompatibility Antigens Class II
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Ligands
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Lipopolysaccharides
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NF-kappa B
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Superantigens
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Interleukin-12
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DNA
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Cyclic AMP-Dependent Protein Kinases
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Protein Kinase C