Abstract
A20 is a zinc finger protein with ubiquitin-modifying activity. A20 has been described as negatively regulating signaling induced by the TNF receptor and TLR family in a number of cell types, including mouse bone marrow-derived dendritic cells (DCs). However, the expression and effect of A20 in activated human monocyte-derived DCs have not been previously evaluated. We report that DCs activated with the TLR3 ligand poly(I:C) up-regulate A20. Down-regulating A20 demonstrated its role in the functional activation of DCs. A20 down-regulated DCs showed higher activation of the transcription factors NF-kappaB and activator protein-1, which resulted in increased and sustained production of IL-6, IL-10, and IL-12p70. We additionally silenced the immunosuppressive cytokine IL-10 and demonstrated that IL-10 inhibits T cell proliferation. We further demonstrated that A20 down-regulated DCs skew naive CD4+ T cells toward IFN-gamma producing Th1 cells, a process which is dependent on IL-12p70 and which is unaffected by IL-10. Furthermore, A20 and/or IL-10 down-regulated DCs had an enhanced capacity to prime Melan-A/MART-1 specific CD8+ T cells. Finally, we demonstrated that potent T cell stimulatory DCs are generated by the simultaneous delivery of poly(I:C12U), A20, or A20/IL-10 small interfering RNA and Ag-encoding mRNA, introducing a one step approach to improve DC-based vaccines. Together these findings demonstrate that A20 negatively regulates NF-kappaB and activator protein-1 in DCs and that down-regulation of A20 results in DCs with enhanced T cell stimulatory capacity.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adjuvants, Immunologic / biosynthesis
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Adjuvants, Immunologic / genetics*
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Adjuvants, Immunologic / physiology
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CD4-Positive T-Lymphocytes / immunology
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Cancer Vaccines / genetics*
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Cancer Vaccines / immunology*
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Cells, Cultured
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Coculture Techniques
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DNA-Binding Proteins
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Dendritic Cells / immunology
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Dendritic Cells / metabolism
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Dendritic Cells / transplantation*
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Down-Regulation / genetics
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Down-Regulation / immunology*
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Humans
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Interleukin-10 / biosynthesis
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Interleukin-12 / biosynthesis
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Interleukin-6 / biosynthesis
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Intracellular Signaling Peptides and Proteins / antagonists & inhibitors
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Intracellular Signaling Peptides and Proteins / genetics*
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Lymphocyte Activation / genetics
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Lymphocyte Activation / immunology
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Monocytes / immunology
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Monocytes / metabolism
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NF-kappa B / antagonists & inhibitors
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NF-kappa B / biosynthesis
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Nuclear Proteins / antagonists & inhibitors
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Nuclear Proteins / biosynthesis
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Nuclear Proteins / genetics*
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RNA Interference / immunology
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RNA, Double-Stranded / physiology*
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RNA, Small Interfering / physiology
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Transcription Factor AP-1 / antagonists & inhibitors
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Transcription Factor AP-1 / biosynthesis
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Tumor Necrosis Factor alpha-Induced Protein 3
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Up-Regulation / genetics
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Up-Regulation / immunology*
Substances
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Adjuvants, Immunologic
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Cancer Vaccines
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DNA-Binding Proteins
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Interleukin-6
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Intracellular Signaling Peptides and Proteins
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NF-kappa B
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Nuclear Proteins
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RNA, Double-Stranded
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RNA, Small Interfering
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Transcription Factor AP-1
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Interleukin-10
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Interleukin-12
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TNFAIP3 protein, human
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Tumor Necrosis Factor alpha-Induced Protein 3