Abstract
Mononuclear blood cells have an important role in immunity as they produce different cytokines in response to microbial infections. We infected primary human mononuclear blood cells with a pathogenic influenza A virus (A/Beijing/353/89) and studied the activation of IFN-alpha, IFN-gamma, IRF-1, and MxA genes. IFN-alpha and IFN-gamma steady state mRNA levels peaked at 6 to 9 h after infection and declined rapidly thereafter. Only a modest (twofold) increase in IRF-1 mRNA was seen. MxA gene expression, normally strictly regulated by IFN-alpha/beta, had expression kinetics similar to those of IFN mRNA. Infection experiments done in the presence of cycloheximide showed that influenza virus infection could induce all genes studied in the absence of detectable protein synthesis. Pretreatment with IFN-alpha, but not with IFN-gamma, caused a dose-dependent inhibition of influenza virus replication in PBMC, and this inhibition correlated with increasing levels of MxA protein. Influenza virus replication was also inhibited in a stably transfected, MxA-expressing promonocytic U937 cell line. The results suggest that MxA protein significantly contributes to IFN-mediated host defence mechanisms against influenza A virus.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Antibodies, Monoclonal / immunology
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Antiviral Agents / biosynthesis
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Antiviral Agents / genetics*
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Base Sequence
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Blotting, Western
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Cells, Cultured
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Cycloheximide / pharmacology
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DNA-Binding Proteins / biosynthesis
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DNA-Binding Proteins / genetics*
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Electrophoresis, Polyacrylamide Gel
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Flow Cytometry
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GTP-Binding Proteins*
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Gene Expression Regulation / immunology
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Humans
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Influenza A virus / immunology*
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Influenza A virus / isolation & purification
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Interferon Regulatory Factor-1
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Interferon-alpha / biosynthesis
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Interferon-alpha / genetics*
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Interferon-alpha / immunology
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Interferon-gamma / biosynthesis
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Interferon-gamma / genetics*
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Interferon-gamma / immunology
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Leukocytes, Mononuclear / immunology
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Leukocytes, Mononuclear / virology
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Molecular Sequence Data
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Myxovirus Resistance Proteins
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Phosphoproteins / biosynthesis
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Phosphoproteins / genetics*
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Protein Biosynthesis
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Protein Synthesis Inhibitors / pharmacology
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Proteins / genetics*
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Viral Proteins / biosynthesis
Substances
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Antibodies, Monoclonal
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Antiviral Agents
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DNA-Binding Proteins
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IRF1 protein, human
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Interferon Regulatory Factor-1
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Interferon-alpha
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MX1 protein, human
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Myxovirus Resistance Proteins
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Phosphoproteins
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Protein Synthesis Inhibitors
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Proteins
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Viral Proteins
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Interferon-gamma
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Cycloheximide
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GTP-Binding Proteins