Immunopathology of Virus Infections
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2010 |
O. Schulz, A. Pichlmair, J. Rehwinkel, N.C. Rogers, D. Scheuner, H. Kato, O. Takeuchi, S. Akira, R.J. Kaufman, C. Reis e Sousa Protein Kinase R Contributes to Immunity Against Specific Viruses by Regulating Interferon mRNA Integrity (Journal Article) Cell Host Microbe, 7 , pp. 354–361, 2010, ISSN: 1934-6069. @article{Schulz2010, title = {Protein Kinase R Contributes to Immunity Against Specific Viruses by Regulating Interferon mRNA Integrity}, author = {O. Schulz and A. Pichlmair and J. Rehwinkel and N.C. Rogers and D. Scheuner and H. Kato and O. Takeuchi and S. Akira and R.J. Kaufman and C. Reis e Sousa}, doi = {10.1016/j.chom.2010.04.007}, issn = {1934-6069}, year = {2010}, date = {2010-01-01}, journal = {Cell Host Microbe}, volume = {7}, pages = {354--361}, abstract = {Cytosolic viral RNA recognition by the helicases RIG-I and MDA5 is considered the major pathway for IFN-alpha/beta induction in response to RNA viruses. However, other cytoplasmic RNA sensors, including the double-stranded RNA-binding protein kinase R (PKR), have been implicated in IFN-alpha/beta production, although their relative contribution and mechanism have been unclear. Using cells expressing nonfunctional PKR or reduced levels of kinase, we show that PKR is required for production of IFN-alpha/beta proteins in response to a subset of RNA viruses including encephalomyocarditis, Theiler's murine encephalomyelitis, and Semliki Forest virus, but not influenza or Sendai virus. Surprisingly, although IFN-alpha/beta mRNA induction is largely normal in PKR-deficient cells, much of that mRNA lacks the poly(A) tail, indicating that its integrity is compromised. Our results suggest that PKR plays a nonredundant role in IFN-alpha/beta production in response to some but not all viruses, in part by regulating IFN-alpha/beta mRNA stability.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Cytosolic viral RNA recognition by the helicases RIG-I and MDA5 is considered the major pathway for IFN-alpha/beta induction in response to RNA viruses. However, other cytoplasmic RNA sensors, including the double-stranded RNA-binding protein kinase R (PKR), have been implicated in IFN-alpha/beta production, although their relative contribution and mechanism have been unclear. Using cells expressing nonfunctional PKR or reduced levels of kinase, we show that PKR is required for production of IFN-alpha/beta proteins in response to a subset of RNA viruses including encephalomyocarditis, Theiler's murine encephalomyelitis, and Semliki Forest virus, but not influenza or Sendai virus. Surprisingly, although IFN-alpha/beta mRNA induction is largely normal in PKR-deficient cells, much of that mRNA lacks the poly(A) tail, indicating that its integrity is compromised. Our results suggest that PKR plays a nonredundant role in IFN-alpha/beta production in response to some but not all viruses, in part by regulating IFN-alpha/beta mRNA stability. |
J. Rehwinkel, C. Tan, D. Goubau, O. Schulz, A. Pichlmair, K. Bier, N. Robb, F. Vreede, W. Barclay, E. Fodor, C. Reis e Sousa RIG-I Detects Viral Genomic RNA During Negative-strand RNA Virus Infection (Journal Article) Cell, 140 , pp. 397–408, 2010, ISSN: 1097-4172. @article{Rehwinkel2010, title = {RIG-I Detects Viral Genomic RNA During Negative-strand RNA Virus Infection}, author = {J. Rehwinkel and C. Tan and D. Goubau and O. Schulz and A. Pichlmair and K. Bier and N. Robb and F. Vreede and W. Barclay and E. Fodor and C. Reis e Sousa}, doi = {10.1016/j.cell.2010.01.020}, issn = {1097-4172}, year = {2010}, date = {2010-01-01}, journal = {Cell}, volume = {140}, pages = {397--408}, abstract = {RIG-I is a key mediator of antiviral immunity, able to couple detection of infection by RNA viruses to the induction of interferons. Natural RIG-I stimulatory RNAs have variously been proposed to correspond to virus genomes, virus replication intermediates, viral transcripts, or self-RNA cleaved by RNase L. However, the relative contribution of each of these RNA species to RIG-I activation and interferon induction in virus-infected cells is not known. Here, we use three approaches to identify physiological RIG-I agonists in cells infected with influenza A virus or Sendai virus. We show that RIG-I agonists are exclusively generated by the process of virus replication and correspond to full-length virus genomes. Therefore, nongenomic viral transcripts, short replication intermediates, and cleaved self-RNA do not contribute substantially to interferon induction in cells infected with these negative strand RNA viruses. Rather, single-stranded RNA viral genomes bearing 5'-triphosphates constitute the natural RIG-I agonists that trigger cell-intrinsic innate immune responses during infection.}, keywords = {}, pubstate = {published}, tppubtype = {article} } RIG-I is a key mediator of antiviral immunity, able to couple detection of infection by RNA viruses to the induction of interferons. Natural RIG-I stimulatory RNAs have variously been proposed to correspond to virus genomes, virus replication intermediates, viral transcripts, or self-RNA cleaved by RNase L. However, the relative contribution of each of these RNA species to RIG-I activation and interferon induction in virus-infected cells is not known. Here, we use three approaches to identify physiological RIG-I agonists in cells infected with influenza A virus or Sendai virus. We show that RIG-I agonists are exclusively generated by the process of virus replication and correspond to full-length virus genomes. Therefore, nongenomic viral transcripts, short replication intermediates, and cleaved self-RNA do not contribute substantially to interferon induction in cells infected with these negative strand RNA viruses. Rather, single-stranded RNA viral genomes bearing 5'-triphosphates constitute the natural RIG-I agonists that trigger cell-intrinsic innate immune responses during infection. |
2009 |
M. Habjan, A. Pichlmair, R.M. Elliott, A.K. Överby, T. Glatter, M. Gstaiger, G. Superti-Furga, H. Unger, F. Weber NSs Protein of Rift Valley Fever Virus Induces the Specific Degradation of the Double-stranded RNA-dependent Protein Kinase (Journal Article) J Virol, 83 , pp. 4365–4375, 2009, ISSN: 1098-5514. @article{Habjan2009, title = {NSs Protein of Rift Valley Fever Virus Induces the Specific Degradation of the Double-stranded RNA-dependent Protein Kinase}, author = {M. Habjan and A. Pichlmair and R.M. Elliott and A.K. Överby and T. Glatter and M. Gstaiger and G. Superti-Furga and H. Unger and F. Weber}, doi = {10.1128/JVI.02148-08}, issn = {1098-5514}, year = {2009}, date = {2009-01-01}, journal = {J Virol}, volume = {83}, pages = {4365--4375}, abstract = {Rift Valley fever virus (RVFV) continues to cause large outbreaks of acute febrile and often fatal illness among humans and domesticated animals in Africa, Saudi Arabia, and Yemen. The high pathogenicity of this bunyavirus is mainly due to the viral protein NSs, which was shown to prevent transcriptional induction of the antivirally active type I interferons (alpha/beta interferon [IFN-alpha/beta]). Viruses lacking the NSs gene induce synthesis of IFNs and are therefore attenuated, whereas the noninducing wild-type RVFV strains can only be inhibited by pretreatment with IFN. We demonstrate here in vitro and in vivo that a substantial part of the antiviral activity of IFN against RVFV is due to a double-stranded RNA-dependent protein kinase (PKR). PKR-mediated virus inhibition, however, was much more pronounced for the strain Clone 13 with NSs deleted than for the NSs-expressing strain ZH548. In vivo, Clone 13 was nonpathogenic for wild-type (wt) mice but could regain pathogenicity if mice lacked the PKR gene. ZH548, in contrast, killed both wt and PKR knockout mice indiscriminately. ZH548 was largely resistant to the antiviral properties of PKR because RVFV NSs triggered the specific degradation of PKR via the proteasome. The NSs proteins of the related but less virulent sandfly fever Sicilian virus and La Crosse virus, in contrast, had no such anti-PKR activity despite being efficient suppressors of IFN induction. Our data suggest that RVFV NSs has gained an additional anti-IFN function that may explain the extraordinary pathogenicity of this virus.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Rift Valley fever virus (RVFV) continues to cause large outbreaks of acute febrile and often fatal illness among humans and domesticated animals in Africa, Saudi Arabia, and Yemen. The high pathogenicity of this bunyavirus is mainly due to the viral protein NSs, which was shown to prevent transcriptional induction of the antivirally active type I interferons (alpha/beta interferon [IFN-alpha/beta]). Viruses lacking the NSs gene induce synthesis of IFNs and are therefore attenuated, whereas the noninducing wild-type RVFV strains can only be inhibited by pretreatment with IFN. We demonstrate here in vitro and in vivo that a substantial part of the antiviral activity of IFN against RVFV is due to a double-stranded RNA-dependent protein kinase (PKR). PKR-mediated virus inhibition, however, was much more pronounced for the strain Clone 13 with NSs deleted than for the NSs-expressing strain ZH548. In vivo, Clone 13 was nonpathogenic for wild-type (wt) mice but could regain pathogenicity if mice lacked the PKR gene. ZH548, in contrast, killed both wt and PKR knockout mice indiscriminately. ZH548 was largely resistant to the antiviral properties of PKR because RVFV NSs triggered the specific degradation of PKR via the proteasome. The NSs proteins of the related but less virulent sandfly fever Sicilian virus and La Crosse virus, in contrast, had no such anti-PKR activity despite being efficient suppressors of IFN induction. Our data suggest that RVFV NSs has gained an additional anti-IFN function that may explain the extraordinary pathogenicity of this virus. |
A. Pichlmair, O. Schulz, C. Tan, J. Rehwinkel, H. Kato, O. Takeuchi, S. Akira, M. Way, G. Schiavo, C. Reis e Sousa Activation of MDA5 Requires Higher-order RNA Structures Generated During Virus Infection (Journal Article) J Virol, 83 , pp. 10761–10769, 2009, ISSN: 1098-5514. @article{Pichlmair2009, title = {Activation of MDA5 Requires Higher-order RNA Structures Generated During Virus Infection}, author = {A. Pichlmair and O. Schulz and C. Tan and J. Rehwinkel and H. Kato and O. Takeuchi and S. Akira and M. Way and G. Schiavo and C. Reis e Sousa}, doi = {10.1128/JVI.00770-09}, issn = {1098-5514}, year = {2009}, date = {2009-01-01}, journal = {J Virol}, volume = {83}, pages = {10761--10769}, abstract = {Recognition of virus presence via RIG-I (retinoic acid inducible gene I) and/or MDA5 (melanoma differentiation-associated protein 5) initiates a signaling cascade that culminates in transcription of innate response genes such as those encoding the alpha/beta interferon (IFN-alpha/beta) cytokines. It is generally assumed that MDA5 is activated by long molecules of double-stranded RNA (dsRNA) produced by annealing of complementary RNAs generated during viral infection. Here, we used an antibody to dsRNA to show that the presence of immunoreactivity in virus-infected cells does indeed correlate with the ability of RNA extracted from these cells to activate MDA5. Furthermore, RNA from cells infected with encephalomyocarditis virus or with vaccinia virus and precipitated with the anti-dsRNA antibody can bind to MDA5 and induce MDA5-dependent IFN-alpha/beta production upon transfection into indicator cells. However, a prominent band of dsRNA apparent in cells infected with either virus does not stimulate IFN-alpha/beta production. Instead, stimulatory activity resides in higher-order structured RNA that contains single-stranded RNA and dsRNA. These results suggest that MDA5 activation requires an RNA web rather than simply long molecules of dsRNA.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Recognition of virus presence via RIG-I (retinoic acid inducible gene I) and/or MDA5 (melanoma differentiation-associated protein 5) initiates a signaling cascade that culminates in transcription of innate response genes such as those encoding the alpha/beta interferon (IFN-alpha/beta) cytokines. It is generally assumed that MDA5 is activated by long molecules of double-stranded RNA (dsRNA) produced by annealing of complementary RNAs generated during viral infection. Here, we used an antibody to dsRNA to show that the presence of immunoreactivity in virus-infected cells does indeed correlate with the ability of RNA extracted from these cells to activate MDA5. Furthermore, RNA from cells infected with encephalomyocarditis virus or with vaccinia virus and precipitated with the anti-dsRNA antibody can bind to MDA5 and induce MDA5-dependent IFN-alpha/beta production upon transfection into indicator cells. However, a prominent band of dsRNA apparent in cells infected with either virus does not stimulate IFN-alpha/beta production. Instead, stimulatory activity resides in higher-order structured RNA that contains single-stranded RNA and dsRNA. These results suggest that MDA5 activation requires an RNA web rather than simply long molecules of dsRNA. |
2008 |
M. Habjan, I. Andersson, J. Klingström, M. Schümann, A. Martin, P. Zimmermann, V. Wagner, A. Pichlmair, U. Schneider, E. Mühlberger, A. Mirazimi, F. Weber Processing of Genome 5' Termini as a Strategy of Negative-strand RNA Viruses to Avoid RIG-I-dependent Interferon Induction (Journal Article) PLoS One, 3 , pp. e2032, 2008, ISSN: 1932-6203. @article{Habjan2008, title = {Processing of Genome 5' Termini as a Strategy of Negative-strand RNA Viruses to Avoid RIG-I-dependent Interferon Induction}, author = {M. Habjan and I. Andersson and J. Klingström and M. Schümann and A. Martin and P. Zimmermann and V. Wagner and A. Pichlmair and U. Schneider and E. Mühlberger and A. Mirazimi and F. Weber}, doi = {10.1371/journal.pone.0002032}, issn = {1932-6203}, year = {2008}, date = {2008-01-01}, journal = {PLoS One}, volume = {3}, pages = {e2032}, abstract = {Innate immunity is critically dependent on the rapid production of interferon in response to intruding viruses. The intracellular pathogen recognition receptors RIG-I and MDA5 are essential for interferon induction by viral RNAs containing 5' triphosphates or double-stranded structures, respectively. Viruses with a negative-stranded RNA genome are an important group of pathogens causing emerging and re-emerging diseases. We investigated the ability of genomic RNAs from substantial representatives of this virus group to induce interferon via RIG-I or MDA5. RNAs isolated from particles of Ebola virus, Nipah virus, Lassa virus, and Rift Valley fever virus strongly activated the interferon-beta promoter. Knockdown experiments demonstrated that interferon induction depended on RIG-I, but not MDA5, and phosphatase treatment revealed a requirement for the RNA 5' triphosphate group. In contrast, genomic RNAs of Hantaan virus, Crimean-Congo hemorrhagic fever virus and Borna disease virus did not trigger interferon induction. Sensitivity of these RNAs to a 5' monophosphate-specific exonuclease indicates that the RIG-I-activating 5' triphosphate group was removed post-transcriptionally by a viral function. Consequently, RIG-I is unable to bind the RNAs of Hantaan virus, Crimean-Congo hemorrhagic fever virus and Borna disease virus. These results establish RIG-I as a major intracellular recognition receptor for the genome of most negative-strand RNA viruses and define the cleavage of triphosphates at the RNA 5' end as a strategy of viruses to evade the innate immune response.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Innate immunity is critically dependent on the rapid production of interferon in response to intruding viruses. The intracellular pathogen recognition receptors RIG-I and MDA5 are essential for interferon induction by viral RNAs containing 5' triphosphates or double-stranded structures, respectively. Viruses with a negative-stranded RNA genome are an important group of pathogens causing emerging and re-emerging diseases. We investigated the ability of genomic RNAs from substantial representatives of this virus group to induce interferon via RIG-I or MDA5. RNAs isolated from particles of Ebola virus, Nipah virus, Lassa virus, and Rift Valley fever virus strongly activated the interferon-beta promoter. Knockdown experiments demonstrated that interferon induction depended on RIG-I, but not MDA5, and phosphatase treatment revealed a requirement for the RNA 5' triphosphate group. In contrast, genomic RNAs of Hantaan virus, Crimean-Congo hemorrhagic fever virus and Borna disease virus did not trigger interferon induction. Sensitivity of these RNAs to a 5' monophosphate-specific exonuclease indicates that the RIG-I-activating 5' triphosphate group was removed post-transcriptionally by a viral function. Consequently, RIG-I is unable to bind the RNAs of Hantaan virus, Crimean-Congo hemorrhagic fever virus and Borna disease virus. These results establish RIG-I as a major intracellular recognition receptor for the genome of most negative-strand RNA viruses and define the cleavage of triphosphates at the RNA 5' end as a strategy of viruses to evade the innate immune response. |
2007 |
Andreas Pichlmair, Sandra S Diebold, Stephen Gschmeissner, Yasuhiro Takeuchi, Yasuhiro Ikeda, Mary K Collins, Caetano Reis e Sousa J Virol, 81 , pp. 539–547, 2007, ISSN: 0022-538X. @article{Pichlmair2007a, title = {Tubulovesicular structures within vesicular stomatitis virus G protein-pseudotyped lentiviral vector preparations carry DNA and stimulate antiviral responses via Toll-like receptor 9.}, author = {Andreas Pichlmair and Sandra S Diebold and Stephen Gschmeissner and Yasuhiro Takeuchi and Yasuhiro Ikeda and Mary K Collins and Caetano Reis e Sousa}, doi = {10.1128/JVI.01818-06}, issn = {0022-538X}, year = {2007}, date = {2007-01-01}, journal = {J Virol}, volume = {81}, pages = {539--547}, abstract = {Recombinant lentiviral vectors (LVs) are commonly used as research tools and are being tested in the clinic as delivery agents for gene therapy. Here, we show that Vesicular stomatitis virus G protein (VSV-G)-pseudotyped LV preparations produced by transient transfection are heavily contaminated with tubulovesicular structures (TVS) of cellular origin, which carry nucleic acids, including the DNA plasmids originally used for LV generation. The DNA carried by TVS can act as a stimulus for innate antiviral responses, triggering Toll-like receptor 9 and inducing alpha/beta interferon production by plasmacytoid dendritic cells (pDC). Removal of TVS markedly reduces the ability of VSV-G-pseudotyped LV preparations to activate pDC. Conversely, virus-free TVS are sufficient to stimulate pDC and act as potent adjuvants in vivo, eliciting T- and B-cell responses to coadministered proteins. These results highlight the role of by-products of virus production in determining the immunostimulatory properties of recombinant virus preparations and suggest possible strategies for diminishing responses to LVs in gene therapy and in research use.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Recombinant lentiviral vectors (LVs) are commonly used as research tools and are being tested in the clinic as delivery agents for gene therapy. Here, we show that Vesicular stomatitis virus G protein (VSV-G)-pseudotyped LV preparations produced by transient transfection are heavily contaminated with tubulovesicular structures (TVS) of cellular origin, which carry nucleic acids, including the DNA plasmids originally used for LV generation. The DNA carried by TVS can act as a stimulus for innate antiviral responses, triggering Toll-like receptor 9 and inducing alpha/beta interferon production by plasmacytoid dendritic cells (pDC). Removal of TVS markedly reduces the ability of VSV-G-pseudotyped LV preparations to activate pDC. Conversely, virus-free TVS are sufficient to stimulate pDC and act as potent adjuvants in vivo, eliciting T- and B-cell responses to coadministered proteins. These results highlight the role of by-products of virus production in determining the immunostimulatory properties of recombinant virus preparations and suggest possible strategies for diminishing responses to LVs in gene therapy and in research use. |
A. Pichlmair, C. Reis e Sousa Innate Recognition of Viruses (Journal Article) Immunity, 27 , pp. 370–383, 2007, ISSN: 1074-7613. @article{Pichlmair2007, title = {Innate Recognition of Viruses}, author = {A. Pichlmair and C. Reis e Sousa}, doi = {10.1016/j.immuni.2007.08.012}, issn = {1074-7613}, year = {2007}, date = {2007-01-01}, journal = {Immunity}, volume = {27}, pages = {370--383}, abstract = {Virus infection elicits potent responses in all cells intended to contain virus spread before intervention by the adaptive immune system. Central to this process is the virus-elicited production of type I interferons (IFNs) and other cytokines. The sensors involved in coupling recognition of viruses to the induction of the type I IFN genes have only recently been uncovered and include endosomal and cytosolic receptors for RNA and DNA. Here, we review their properties and discuss how their ability to recognize the unusual presence of atypical nucleic acids in particular subcellular compartments is used by the body to detect virus presence.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Virus infection elicits potent responses in all cells intended to contain virus spread before intervention by the adaptive immune system. Central to this process is the virus-elicited production of type I interferons (IFNs) and other cytokines. The sensors involved in coupling recognition of viruses to the induction of the type I IFN genes have only recently been uncovered and include endosomal and cytosolic receptors for RNA and DNA. Here, we review their properties and discuss how their ability to recognize the unusual presence of atypical nucleic acids in particular subcellular compartments is used by the body to detect virus presence. |
2006 |
Andreas Pichlmair, Oliver Schulz, Choon Ping Tan, Tanja I Näslund, Peter Liljeström, Friedemann Weber, Caetano Reis e Sousa RIG-I-mediated antiviral responses to single-stranded RNA bearing 5'-phosphates. (Journal Article) Science (New York, N.Y.), 314 , pp. 997–1001, 2006, ISSN: 1095-9203. @article{Pichlmair2006, title = {RIG-I-mediated antiviral responses to single-stranded RNA bearing 5'-phosphates.}, author = {Andreas Pichlmair and Oliver Schulz and Choon Ping Tan and Tanja I Näslund and Peter Liljeström and Friedemann Weber and Caetano Reis e Sousa}, doi = {10.1126/science.1132998}, issn = {1095-9203}, year = {2006}, date = {2006-01-01}, journal = {Science (New York, N.Y.)}, volume = {314}, pages = {997--1001}, abstract = {Double-stranded RNA (dsRNA) produced during viral replication is believed to be the critical trigger for activation of antiviral immunity mediated by the RNA helicase enzymes retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated gene 5 (MDA5). We showed that influenza A virus infection does not generate dsRNA and that RIG-I is activated by viral genomic single-stranded RNA (ssRNA) bearing 5'-phosphates. This is blocked by the influenza protein nonstructured protein 1 (NS1), which is found in a complex with RIG-I in infected cells. These results identify RIG-I as a ssRNA sensor and potential target of viral immune evasion and suggest that its ability to sense 5'-phosphorylated RNA evolved in the innate immune system as a means of discriminating between self and nonself.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Double-stranded RNA (dsRNA) produced during viral replication is believed to be the critical trigger for activation of antiviral immunity mediated by the RNA helicase enzymes retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated gene 5 (MDA5). We showed that influenza A virus infection does not generate dsRNA and that RIG-I is activated by viral genomic single-stranded RNA (ssRNA) bearing 5'-phosphates. This is blocked by the influenza protein nonstructured protein 1 (NS1), which is found in a complex with RIG-I in infected cells. These results identify RIG-I as a ssRNA sensor and potential target of viral immune evasion and suggest that its ability to sense 5'-phosphorylated RNA evolved in the innate immune system as a means of discriminating between self and nonself. |
2005 |
Martin Spiegel, Andreas Pichlmair, Luis Martínez-Sobrido, Jerome Cros, Adolfo García-Sastre, Otto Haller, Friedemann Weber J Virol, 79 , pp. 2079–2086, 2005, ISSN: 0022-538X. @article{Spiegel2005, title = {Inhibition of Beta interferon induction by severe acute respiratory syndrome coronavirus suggests a two-step model for activation of interferon regulatory factor 3.}, author = {Martin Spiegel and Andreas Pichlmair and Luis Martínez-Sobrido and Jerome Cros and Adolfo García-Sastre and Otto Haller and Friedemann Weber}, doi = {10.1128/JVI.79.4.2079-2086.2005}, issn = {0022-538X}, year = {2005}, date = {2005-01-01}, journal = {J Virol}, volume = {79}, pages = {2079--2086}, abstract = {Severe acute respiratory syndrome (SARS) is caused by a novel coronavirus termed SARS-CoV. We and others have previously shown that the replication of SARS-CoV can be suppressed by exogenously added interferon (IFN), a cytokine which is normally synthesized by cells as a reaction to virus infection. Here, we demonstrate that SARS-CoV escapes IFN-mediated growth inhibition by preventing the induction of IFN-beta. In SARS-CoV-infected cells, no endogenous IFN-beta transcripts and no IFN-beta promoter activity were detected. Nevertheless, the transcription factor interferon regulatory factor 3 (IRF-3), which is essential for IFN-beta promoter activity, was transported from the cytoplasm to the nucleus early after infection with SARS-CoV. However, at a later time point in infection, IRF-3 was again localized in the cytoplasm. By contrast, IRF-3 remained in the nucleus of cells infected with the IFN-inducing control virus Bunyamwera delNSs. Other signs of IRF-3 activation such as hyperphosphorylation, homodimer formation, and recruitment of the coactivator CREB-binding protein (CBP) were found late after infection with the control virus but not with SARS-CoV. Our data suggest that nuclear transport of IRF-3 is an immediate-early reaction to virus infection and may precede its hyperphosphorylation, homodimer formation, and binding to CBP. In order to escape activation of the IFN system, SARS-CoV appears to block a step after the early nuclear transport of IRF-3.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Severe acute respiratory syndrome (SARS) is caused by a novel coronavirus termed SARS-CoV. We and others have previously shown that the replication of SARS-CoV can be suppressed by exogenously added interferon (IFN), a cytokine which is normally synthesized by cells as a reaction to virus infection. Here, we demonstrate that SARS-CoV escapes IFN-mediated growth inhibition by preventing the induction of IFN-beta. In SARS-CoV-infected cells, no endogenous IFN-beta transcripts and no IFN-beta promoter activity were detected. Nevertheless, the transcription factor interferon regulatory factor 3 (IRF-3), which is essential for IFN-beta promoter activity, was transported from the cytoplasm to the nucleus early after infection with SARS-CoV. However, at a later time point in infection, IRF-3 was again localized in the cytoplasm. By contrast, IRF-3 remained in the nucleus of cells infected with the IFN-inducing control virus Bunyamwera delNSs. Other signs of IRF-3 activation such as hyperphosphorylation, homodimer formation, and recruitment of the coactivator CREB-binding protein (CBP) were found late after infection with the control virus but not with SARS-CoV. Our data suggest that nuclear transport of IRF-3 is an immediate-early reaction to virus infection and may precede its hyperphosphorylation, homodimer formation, and binding to CBP. In order to escape activation of the IFN system, SARS-CoV appears to block a step after the early nuclear transport of IRF-3. |
2004 |
Martin Spiegel, Andreas Pichlmair, Elke Mühlberger, Otto Haller, Friedemann Weber The antiviral effect of interferon-beta against SARS-coronavirus is not mediated by MxA protein. (Journal Article) Journal of clinical virology : the official publication of the Pan American Society for Clinical Virology, 30 , pp. 211–213, 2004, ISSN: 1386-6532. @article{Spiegel2004, title = {The antiviral effect of interferon-beta against SARS-coronavirus is not mediated by MxA protein.}, author = {Martin Spiegel and Andreas Pichlmair and Elke Mühlberger and Otto Haller and Friedemann Weber}, doi = {10.1016/j.jcv.2003.11.013}, issn = {1386-6532}, year = {2004}, date = {2004-01-01}, journal = {Journal of clinical virology : the official publication of the Pan American Society for Clinical Virology}, volume = {30}, pages = {211--213}, abstract = {Severe acute respiratory syndrome (SARS) is caused by a novel coronavirus termed SARS-CoV. No antiviral treatment has been established so far. Interferons are cytokines which induce the synthesis of several antivirally active proteins in the cell. In this study, we demonstrated that multiplication of SARS-CoV in cell culture can be strongly inhibited by pretreatment with interferon-beta. Interferon-alpha and interferon-gamma, by contrast, were less effective. The human MxA protein is one of the most prominent proteins induced by interferon-beta. Nevertheless, no interference with SARS-CoV replication was observed in Vero cells stably expressing MxA. Therefore, other interferon-induced proteins must be responsible for the strong inhibitory effect of interferon-beta against SARS-CoV.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Severe acute respiratory syndrome (SARS) is caused by a novel coronavirus termed SARS-CoV. No antiviral treatment has been established so far. Interferons are cytokines which induce the synthesis of several antivirally active proteins in the cell. In this study, we demonstrated that multiplication of SARS-CoV in cell culture can be strongly inhibited by pretreatment with interferon-beta. Interferon-alpha and interferon-gamma, by contrast, were less effective. The human MxA protein is one of the most prominent proteins induced by interferon-beta. Nevertheless, no interference with SARS-CoV replication was observed in Vero cells stably expressing MxA. Therefore, other interferon-induced proteins must be responsible for the strong inhibitory effect of interferon-beta against SARS-CoV. |
Andreas Pichlmair, Matthias Pollak, Andreas Bergthaler [The first answer to viral infections: type I interferon]. (Journal Article) Berl Munch Tierarztl Wochenschr, 117 , pp. 252–265, 2004, ISSN: 0005-9366. @article{Pichlmair2004a, title = {[The first answer to viral infections: type I interferon].}, author = {Andreas Pichlmair and Matthias Pollak and Andreas Bergthaler}, issn = {0005-9366}, year = {2004}, date = {2004-01-01}, journal = {Berl Munch Tierarztl Wochenschr}, volume = {117}, pages = {252--265}, abstract = {The interferon system is part of the innate immune system in vertebrates. It represents the first line of host defence against viral infections. Virus entry triggers intracellular signalling pathways which lead to the secretion of soluble factors such as interferons and other cytokines. Interferons signal to neighbouring cells that a viral infection has occurred and induce an äntiviral state" resulting in inhibition of virus replication. The first recombinant interferons were produced in the 1980ies and were considered to be a major breakthrough. At present, interferons are routinely used in the therapy of certain viral and autoimmune diseases as well as for neoplastic disorders in man. In 2001 the first interferon preparation for veterinary use was licensed in the European Union. This review summarises the molecular mechanisms of the interferon system and the viral counteractions. The current type I interferon therapies in humans are described and an overview of recent clinical studies in veterinary medicine, including cat, dog, horse, cow, sheep, pig, and poultry, is given. We review the potential application of interferons and arguments in favor or against its therapeutic use in veterinary medicine.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The interferon system is part of the innate immune system in vertebrates. It represents the first line of host defence against viral infections. Virus entry triggers intracellular signalling pathways which lead to the secretion of soluble factors such as interferons and other cytokines. Interferons signal to neighbouring cells that a viral infection has occurred and induce an äntiviral state" resulting in inhibition of virus replication. The first recombinant interferons were produced in the 1980ies and were considered to be a major breakthrough. At present, interferons are routinely used in the therapy of certain viral and autoimmune diseases as well as for neoplastic disorders in man. In 2001 the first interferon preparation for veterinary use was licensed in the European Union. This review summarises the molecular mechanisms of the interferon system and the viral counteractions. The current type I interferon therapies in humans are described and an overview of recent clinical studies in veterinary medicine, including cat, dog, horse, cow, sheep, pig, and poultry, is given. We review the potential application of interferons and arguments in favor or against its therapeutic use in veterinary medicine. |
Andreas Pichlmair, Johanna Buse, Stephanie Jennings, Otto Haller, Georg Kochs, Peter Staeheli Thogoto virus lacking interferon-antagonistic protein ML is strongly attenuated in newborn Mx1-positive but not Mx1-negative mice. (Journal Article) J Virol, 78 , pp. 11422–11424, 2004, ISSN: 0022-538X. @article{Pichlmair2004, title = {Thogoto virus lacking interferon-antagonistic protein ML is strongly attenuated in newborn Mx1-positive but not Mx1-negative mice.}, author = {Andreas Pichlmair and Johanna Buse and Stephanie Jennings and Otto Haller and Georg Kochs and Peter Staeheli}, doi = {10.1128/JVI.78.20.11422-11424.2004}, issn = {0022-538X}, year = {2004}, date = {2004-01-01}, journal = {J Virol}, volume = {78}, pages = {11422--11424}, abstract = {The Thogoto virus ML protein suppresses interferon synthesis in infected cells. Nevertheless, a virus mutant lacking ML remained highly pathogenic in standard laboratory mice. It was strongly attenuated, however, in mice carrying the interferon-responsive Mx1 gene found in wild mice, demonstrating that enhanced interferon synthesis is protective only if appropriate antiviral effector molecules are present. Our study shows that the virulence-enhancing effects of some viral interferon antagonists may escape detection in conventional animal models.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The Thogoto virus ML protein suppresses interferon synthesis in infected cells. Nevertheless, a virus mutant lacking ML remained highly pathogenic in standard laboratory mice. It was strongly attenuated, however, in mice carrying the interferon-responsive Mx1 gene found in wild mice, demonstrating that enhanced interferon synthesis is protective only if appropriate antiviral effector molecules are present. Our study shows that the virulence-enhancing effects of some viral interferon antagonists may escape detection in conventional animal models. |
2003 |
H Weissenböck, Z Hubálek, J Halouzka, A Pichlmair, A Maderner, K Fragner, J Kolodziejek, G Loupal, S Kölbl, N Nowotny Screening for West Nile virus infections of susceptible animal species in Austria. (Journal Article) Epidemiol Infect, 131 , pp. 1023–1027, 2003, ISSN: 0950-2688. @article{Weissenboeck2003, title = {Screening for West Nile virus infections of susceptible animal species in Austria.}, author = {H Weissenböck and Z Hubálek and J Halouzka and A Pichlmair and A Maderner and K Fragner and J Kolodziejek and G Loupal and S Kölbl and N Nowotny}, issn = {0950-2688}, year = {2003}, date = {2003-01-01}, journal = {Epidemiol Infect}, volume = {131}, pages = {1023--1027}, abstract = {Avian mortality and encephalomyelitis in equines are considered good indicators for West Nile virus (WNV) activity. We retrospectively tested 385 horse sera for WNV antibodies and looked for WNV nucleic acid and/or WNV antigen in paraffin embedded tissues from 12 horses with aetiologically unresolved encephalomyelitis and 102 free-living birds of different species which had been found dead. With the exception of four horses originating from eastern European countries investigated on the occasion of transit through Austria, all horse sera were negative. Nested RT-PCR of the horse tissues yielded no amplification of WNV-RNA. Also, all bird samples, examined by immunohistochemistry, in situ hybridization and nested RT-PCR were negative for WNV. These results indicate that currently WNV cannot be considered a significant pathogen in Austria.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Avian mortality and encephalomyelitis in equines are considered good indicators for West Nile virus (WNV) activity. We retrospectively tested 385 horse sera for WNV antibodies and looked for WNV nucleic acid and/or WNV antigen in paraffin embedded tissues from 12 horses with aetiologically unresolved encephalomyelitis and 102 free-living birds of different species which had been found dead. With the exception of four horses originating from eastern European countries investigated on the occasion of transit through Austria, all horse sera were negative. Nested RT-PCR of the horse tissues yielded no amplification of WNV-RNA. Also, all bird samples, examined by immunohistochemistry, in situ hybridization and nested RT-PCR were negative for WNV. These results indicate that currently WNV cannot be considered a significant pathogen in Austria. |
Prof. Dr. Andreas Pichlmair
Immunopathology of Virus Infections Laboratory,
Institute of Virology,
Technical University of Munich
Schneckenburgerstr. 8,
D-81675 Munich, Germany
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