Abstract
The nonpolymorphic CD1 molecules present lipid antigens to T cells. In myeloid DC humans express five different CD1 proteins (CD1a-e; the corresponding CD1 genes are designated CD1A-E). A role for CD1d-restricted NKT cells in the control of virus infections has been delineated from clinical observations, mouse models and viral evasion mechanisms targeting CD1d. How NKT cells are activated by virus infections is unclear. We found that human myeloid DC differentially regulate CD1 antigen presentation in response to viral danger signals. Stimulation with type I IFN, viral TLR ligands or viruses strongly enhanced the number of CD1D transcripts in human myeloid DC but diminished the abundance of CD1A, CD1B and CD1E mRNA. These changes on the transcriptional level were mirrored by altered cellular distribution and increased surface expression of CD1d. As a consequence NKT cells were activated and showed a Th1-like response. Moreover, NKT cell activation in PBMC exposed to viral danger signals was dependent on human plasmacytoid DC which produce large amounts of IFN-alpha. In conclusion, our data indicate that viral danger signals trigger NKT cell activation by enhancing CD1d de novo synthesis through increasing the abundance of CD1D mRNA in human myeloid DC.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Aminoquinolines / pharmacology
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Antigen Presentation / drug effects
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Antigen Presentation / immunology
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Antigens, CD1 / genetics
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Antigens, CD1 / metabolism*
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Antigens, CD1d
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Cell Line
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Cell Membrane / drug effects
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Cell Membrane / metabolism
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Coculture Techniques
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Cytomegalovirus / immunology
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Dendritic Cells / drug effects
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Dendritic Cells / immunology*
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Dendritic Cells / virology
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Galactosylceramides / pharmacology
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Gene Expression / drug effects
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Herpesvirus 1, Human / immunology
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Humans
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Imiquimod
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Interferon Inducers / pharmacology
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Interferon Type I / metabolism
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Interferon Type I / pharmacology
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Interferon-alpha / pharmacology
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Interferon-gamma / metabolism
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Intracellular Space / drug effects
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Intracellular Space / metabolism
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Killer Cells, Natural / immunology*
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Killer Cells, Natural / metabolism
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Leukocytes, Mononuclear / cytology
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Leukocytes, Mononuclear / drug effects
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Leukocytes, Mononuclear / metabolism
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Lymphocyte Activation / drug effects
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Lymphocyte Activation / immunology*
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Poly I-C / pharmacology
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Toll-Like Receptors / agonists
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Virus Diseases / immunology*
Substances
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Aminoquinolines
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Antigens, CD1
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Antigens, CD1d
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CD1D protein, human
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Galactosylceramides
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Interferon Inducers
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Interferon Type I
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Interferon-alpha
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Toll-Like Receptors
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alpha-galactosylceramide
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Interferon-gamma
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Poly I-C
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Imiquimod