Abstract
Activation of the CD28 surface receptor provides a major costimulatory signal for T cell activation resulting in enhanced production of interleukin-2 (IL-2) and cell proliferation. In primary T lymphocytes we show that CD28 ligation leads to the rapid intracellular formation of reactive oxygen intermediates (ROIs) which are required for CD28-mediated activation of the NF-kappa B/CD28-responsive complex and IL-2 expression. Delineation of the CD28 signaling cascade was found to involve protein tyrosine kinase activity, followed by the activation of phospholipase A2 and 5-lipoxygenase. Our data suggest that lipoxygenase metabolites activate ROI formation which then induce IL-2 expression via NF-kappa B activation. These findings should be useful for therapeutic strategies and the development of immunosuppressants targeting the CD28 costimulatory pathway.
MeSH terms
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Arachidonate 5-Lipoxygenase / metabolism*
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Arachidonic Acid / metabolism
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Base Sequence
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Benzoquinones
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CD28 Antigens / metabolism*
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Cell Division
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Cells, Cultured
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Dexamethasone / pharmacology
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Enzyme Activation
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Gene Expression Regulation / physiology
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Humans
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Interleukin-2 / metabolism*
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Lactams, Macrocyclic
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Leukotriene B4 / pharmacology
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Lipoxygenase Inhibitors
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Lymphocyte Activation
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Molecular Sequence Data
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NF-kappa B / physiology*
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Phospholipases A / antagonists & inhibitors
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Phospholipases A / metabolism
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Phospholipases A2
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Protein-Tyrosine Kinases / antagonists & inhibitors
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Protein-Tyrosine Kinases / metabolism
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Quinones / pharmacology
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Reactive Oxygen Species / metabolism*
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Receptors, Antigen, T-Cell / physiology
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Rifabutin / analogs & derivatives
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Signal Transduction / physiology*
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T-Lymphocytes / enzymology
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T-Lymphocytes / metabolism
Substances
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Benzoquinones
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CD28 Antigens
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Interleukin-2
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Lactams, Macrocyclic
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Lipoxygenase Inhibitors
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NF-kappa B
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Quinones
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Reactive Oxygen Species
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Receptors, Antigen, T-Cell
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Leukotriene B4
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Rifabutin
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Arachidonic Acid
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herbimycin
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Dexamethasone
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Arachidonate 5-Lipoxygenase
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Protein-Tyrosine Kinases
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Phospholipases A
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Phospholipases A2