Abstract
Modulation of intracellular signaling using cell-permeable polypeptides is a promising technology for future clinical applications. To develop a novel approach to activate innate immune signaling by synthetic polypeptides, we characterized several different polypeptides derived from the caspase recruitment domain (CARD) of IFN-beta promoter stimulator 1, each of which localizes to a different subcellular compartment. Of particular interest was, N'-CARD, which consisted of the nuclear localization signal of histone H2B and the IFN-beta promoter stimulator 1CARD and which localized to the nucleus. This polypeptide led to a strong production of type I IFNs and molecular and genetic analyses showed that nuclear DNA helicase II is critically involved in this response. N'-CARD polypeptide fused to a protein transduction domain (N'-CARD-PTD) readily transmigrated from the outside to the inside of the cell and triggered innate immune signaling. Administration of N'-CARD-PTD polypeptide elicited production of type I IFNs, maturation of bone marrow-derived dendritic cells, and promotion of vaccine immunogenicity by enhancing Ag-specific Th1-type immune responses, thereby protecting mice from lethal influenza infection and from outgrowth of transplanted tumors in vivo. Thus, our results indicate that the N'-CARD-PTD polypeptide belongs to a new class of vaccine adjuvant that directly triggers intracellular signal transduction by a distinct mechanism from those engaged by conventional vaccine adjuvants, such as TLR ligands.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing / administration & dosage
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Adaptor Proteins, Signal Transducing / genetics
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Adaptor Proteins, Signal Transducing / immunology*
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Adjuvants, Immunologic / administration & dosage
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Adjuvants, Immunologic / classification*
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Adjuvants, Immunologic / genetics
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Animals
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Carcinoma, Lewis Lung / genetics
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Carcinoma, Lewis Lung / immunology
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Carcinoma, Lewis Lung / prevention & control
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Caspases / administration & dosage
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Caspases / genetics
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Caspases / immunology*
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Cell Line
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Cells, Cultured
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Female
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HeLa Cells
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Humans
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Immunity, Innate* / genetics
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Influenza A Virus, H1N1 Subtype / genetics
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Influenza A Virus, H1N1 Subtype / immunology
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Influenza Vaccines / administration & dosage
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Influenza Vaccines / genetics
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Influenza Vaccines / immunology*
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Mice
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Mice, Inbred BALB C
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Mice, Inbred C57BL
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Moths
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Oligodeoxyribonucleotides / administration & dosage
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Oligodeoxyribonucleotides / genetics
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Oligodeoxyribonucleotides / immunology
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Peptide Fragments / administration & dosage
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Peptide Fragments / genetics
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Peptide Fragments / immunology*
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Protein Structure, Tertiary / genetics
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Protein Transport / immunology
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Signal Transduction / genetics
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Signal Transduction / immunology*
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Vaccines, DNA / administration & dosage
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Vaccines, DNA / genetics
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Vaccines, DNA / immunology*
Substances
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Adaptor Proteins, Signal Transducing
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Adjuvants, Immunologic
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CPG-oligonucleotide
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IPS-1 protein, mouse
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Influenza Vaccines
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Oligodeoxyribonucleotides
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Peptide Fragments
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Vaccines, DNA
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Caspases