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West Nile Virus: An Update on Pathobiology, Epidemiology, Diagnostics, Control and "One Health" Implications. Pathogens 2020; 9:pathogens9070589. [PMID: 32707644 PMCID: PMC7400489 DOI: 10.3390/pathogens9070589] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 07/16/2020] [Accepted: 07/16/2020] [Indexed: 02/06/2023] Open
Abstract
West Nile virus (WNV) is an important zoonotic flavivirus responsible for mild fever to severe, lethal neuroinvasive disease in humans, horses, birds, and other wildlife species. Since its discovery, WNV has caused multiple human and animal disease outbreaks in all continents, except Antarctica. Infections are associated with economic losses, mainly due to the cost of treatment of infected patients, control programmes, and loss of animals and animal products. The pathogenesis of WNV has been extensively investigated in natural hosts as well as in several animal models, including rodents, lagomorphs, birds, and reptiles. However, most of the proposed pathogenesis hypotheses remain contentious, and much remains to be elucidated. At the same time, the unavailability of specific antiviral treatment or effective and safe vaccines contribute to the perpetuation of the disease and regular occurrence of outbreaks in both endemic and non-endemic areas. Moreover, globalisation and climate change are also important drivers of the emergence and re-emergence of the virus and disease. Here, we give an update of the pathobiology, epidemiology, diagnostics, control, and “One Health” implications of WNV infection and disease.
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Lopez-Denman AJ, Russo A, Wagstaff KM, White PA, Jans DA, Mackenzie JM. Nucleocytoplasmic shuttling of the West Nile virus RNA-dependent RNA polymerase NS5 is critical to infection. Cell Microbiol 2018; 20:e12848. [PMID: 29582535 DOI: 10.1111/cmi.12848] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 03/08/2018] [Accepted: 03/16/2018] [Indexed: 01/05/2023]
Abstract
West Nile virus (WNV) is a single-stranded, positive sense RNA virus of the family Flaviviridae and is a significant pathogen of global medical importance. Flavivirus replication is known to be exclusively cytoplasmic, but we show here for the first time that access to the nucleus of the WNV strain Kunjin (WNVKUN ) RNA-dependent RNA polymerase (protein NS5) is central to WNVKUN virus production. We show that treatment of cells with the specific nuclear export inhibitor leptomycin B (LMB) results in increased NS5 nuclear accumulation in WNVKUN -infected cells and NS5-transfected cells, indicative of nucleocytoplasmic shuttling under normal conditions. We used site-directed mutagenesis to identify the nuclear localisation sequence (NLS) responsible for WNVKUN NS5 nuclear targeting, observing that mutation of this NLS resulted in exclusively cytoplasmic accumulation of NS5 even in the presence of leptomycin B. Introduction of NS5 NLS mutations into FLSDX, an infectious clone of WNVKUN , resulted in lethality, suggesting that the ability of NS5 to traffic into the nucleus in integral to WNVKUN replication. This study thus shows for the first time that NLS-dependent trafficking into the nucleus during infection of WNVKUN NS5 is critical for viral replication. Excitingly, specific inhibitors of NS5 nuclear import reduce WNVKUN virus production, proving the principle that inhibition of WNVKUN NS5 nuclear import is a viable therapeutic avenue for antiviral drug development in the future.
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Affiliation(s)
- Adam J Lopez-Denman
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia.,Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, Victoria, Australia
| | - Alice Russo
- Faculty of Science, Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Kylie M Wagstaff
- Department of Biochemistry, Monash University, Melbourne, Victoria, Australia
| | - Peter A White
- Faculty of Science, Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - David A Jans
- Department of Biochemistry, Monash University, Melbourne, Victoria, Australia
| | - Jason M Mackenzie
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
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Prow NA, Edmonds JH, Williams DT, Setoh YX, Bielefeldt-Ohmann H, Suen WW, Hobson-Peters J, van den Hurk AF, Pyke AT, Hall-Mendelin S, Northill JA, Johansen CA, Warrilow D, Wang J, Kirkland PD, Doggett S, Andrade CC, Brault AC, Khromykh AA, Hall RA. Virulence and Evolution of West Nile Virus, Australia, 1960-2012. Emerg Infect Dis 2018; 22:1353-62. [PMID: 27433830 PMCID: PMC4982165 DOI: 10.3201/eid2208.151719] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Despite the absence of disease in humans and animals, virulent virus strains have been circulating for >30 years. Worldwide, West Nile virus (WNV) causes encephalitis in humans, horses, and birds. The Kunjin strain of WNV (WNVKUN) is endemic to northern Australia, but infections are usually asymptomatic. In 2011, an unprecedented outbreak of equine encephalitis occurred in southeastern Australia; most of the ≈900 reported cases were attributed to a newly emerged WNVKUN strain. To investigate the origins of this virus, we performed genetic analysis and in vitro and in vivo studies of 13 WNVKUN isolates collected from different regions of Australia during 1960–2012. Although no disease was recorded for 1984, 2000, or 2012, isolates collected during those years (from Victoria, Queensland, and New South Wales, respectively) exhibited levels of virulence in mice similar to that of the 2011 outbreak strain. Thus, virulent strains of WNVKUN have circulated in Australia for >30 years, and the first extensive outbreak of equine disease in Australia probably resulted from a combination of specific ecologic and epidemiologic conditions.
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McLean BJ, Hobson-Peters J, Webb CE, Watterson D, Prow NA, Nguyen HD, Hall-Mendelin S, Warrilow D, Johansen CA, Jansen CC, van den Hurk AF, Beebe NW, Schnettler E, Barnard RT, Hall RA. A novel insect-specific flavivirus replicates only in Aedes-derived cells and persists at high prevalence in wild Aedes vigilax populations in Sydney, Australia. Virology 2015; 486:272-83. [PMID: 26519596 DOI: 10.1016/j.virol.2015.07.021] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 06/16/2015] [Accepted: 07/31/2015] [Indexed: 01/16/2023]
Abstract
To date, insect-specific flaviviruses (ISFs) have only been isolated from mosquitoes and increasing evidence suggests that ISFs may affect the transmission of pathogenic flaviviruses. To investigate the diversity and prevalence of ISFs in Australian mosquitoes, samples from various regions were screened for flaviviruses by ELISA and RT-PCR. Thirty-eight pools of Aedes vigilax from Sydney in 2007 yielded isolates of a novel flavivirus, named Parramatta River virus (PaRV). Sequencing of the viral RNA genome revealed it was closely related to Hanko virus with 62.3% nucleotide identity over the open reading frame. PaRV failed to grow in vertebrate cells, with only Aedes-derived mosquito cell lines permissive to replication, suggesting a narrow host range. 2014 collections revealed that PaRV had persisted in A. vigilax populations in Sydney, with 88% of pools positive. Further investigations into its mode of transmission and potential to influence vector competence of A. vigilax for pathogenic viruses are warranted.
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Affiliation(s)
- Breeanna J McLean
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Queensland, Australia.
| | - Jody Hobson-Peters
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Queensland, Australia.
| | - Cameron E Webb
- Medical Entomology, Marie Bashir Institute of Infectious Diseases and Biosecurity, The University of Sydney, NSW, Australia.
| | - Daniel Watterson
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Queensland, Australia.
| | - Natalie A Prow
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Queensland, Australia.
| | - Hong Duyen Nguyen
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Queensland, Australia.
| | - Sonja Hall-Mendelin
- Virology, Public and Environmental Health, Forensic and Scientific Services, Department of Health, Queensland Government, Queensland, Australia.
| | - David Warrilow
- Virology, Public and Environmental Health, Forensic and Scientific Services, Department of Health, Queensland Government, Queensland, Australia.
| | - Cheryl A Johansen
- School of Pathology and Laboratory Medicine, The University of Western Australia, Western Australia, Australia.
| | - Cassie C Jansen
- Virology, Public and Environmental Health, Forensic and Scientific Services, Department of Health, Queensland Government, Queensland, Australia.
| | - Andrew F van den Hurk
- Virology, Public and Environmental Health, Forensic and Scientific Services, Department of Health, Queensland Government, Queensland, Australia.
| | - Nigel W Beebe
- School of Biological Sciences, University of Queensland, Queensland, Australia; CSIRO Biosecurity Flagship, Dutton Park, Queensland, Australia.
| | - Esther Schnettler
- MRC - University of Glasgow Centre for Virus Research, Glasgow, United Kingdom.
| | - Ross T Barnard
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Queensland, Australia.
| | - Roy A Hall
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Queensland, Australia.
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Paradkar PN, Duchemin JB, Rodriguez-Andres J, Trinidad L, Walker PJ. Cullin4 Is Pro-Viral during West Nile Virus Infection of Culex Mosquitoes. PLoS Pathog 2015; 11:e1005143. [PMID: 26325027 PMCID: PMC4556628 DOI: 10.1371/journal.ppat.1005143] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 08/12/2015] [Indexed: 01/01/2023] Open
Abstract
Although mosquitoes serve as vectors of many pathogens of public health importance, their response to viral infection is poorly understood. It also remains to be investigated whether viruses deploy some mechanism to be able to overcome this immune response. Here, we have used an RNA-Seq approach to identify differentially regulated genes in Culex quinquefasciatus cells following West Nile virus (WNV) infection, identifying 265 transcripts from various cellular pathways that were either upregulated or downregulated. Ubiquitin-proteasomal pathway genes, comprising 12% of total differentially regulated genes, were selected for further validation by real time RT-qPCR and functional analysis. It was found that treatment of infected cells with proteasomal inhibitor, MG-132, decreased WNV titers, indicating importance of this pathway during infection process. In infection models, the Culex ortholog of mammalian Cul4A/B (cullin RING ubiquitin ligase) was found to be upregulated in vitro as well as in vivo, especially in midguts of mosquitoes. Gene knockdown using dsRNA and overexpression studies indicated that Culex Cul4 acts as a pro-viral protein by degradation of CxSTAT via ubiquitin-proteasomal pathway. We also show that gene knockdown of Culex Cul4 leads to activation of the Jak-STAT pathway in mosquitoes leading to decrease viral replication in the body as well as saliva. Our results suggest a novel mechanism adopted by WNV to overcome mosquito immune response and increase viral replication. Mosquitoes are responsible for transmitting a large number of human and livestock viruses, like West Nile, dengue and Japanese encephalitis viruses. Infection of female mosquitoes with these viruses during blood feeding elicits an immune response. It is not known how the viruses manage to replicate in spite of this antiviral response. We used an unbiased transcriptome sequencing approach to identify genes differentially regulated after WNV infection resulting in 265 transcripts from various cellular pathways. Ubiquitin-proteasomal pathway, responsible for protein degradation, was found to be important during viral infection in mosquito cells. Using in vitro and in vivo infection models, we identified Culex Cul4 to be acting as pro-viral protein, increasing viral titers. Knockdown of Cul4 in Culex mosquitoes decreased viral titers in mosquito saliva. Identification of this novel immune evasion mechanism adopted by WNV provides new insights into transmission of arbovirus and interaction of WNV with its mosquito vector.
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Affiliation(s)
- Prasad N. Paradkar
- CSIRO Health and Biosecurity, Australian Animal Health Laboratory, Geelong, Victoria, Australia
- * E-mail:
| | - Jean-Bernard Duchemin
- CSIRO Health and Biosecurity, Australian Animal Health Laboratory, Geelong, Victoria, Australia
| | - Julio Rodriguez-Andres
- CSIRO Health and Biosecurity, Australian Animal Health Laboratory, Geelong, Victoria, Australia
| | - Lee Trinidad
- CSIRO Health and Biosecurity, Australian Animal Health Laboratory, Geelong, Victoria, Australia
| | - Peter J. Walker
- CSIRO Health and Biosecurity, Australian Animal Health Laboratory, Geelong, Victoria, Australia
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Aktepe TE, Pham H, Mackenzie JM. Differential utilisation of ceramide during replication of the flaviviruses West Nile and dengue virus. Virology 2015; 484:241-250. [PMID: 26122470 DOI: 10.1016/j.virol.2015.06.015] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 04/05/2015] [Accepted: 06/12/2015] [Indexed: 01/22/2023]
Abstract
It is well established that +ssRNA viruses manipulate cellular lipid homoeostasis and distribution to facilitate efficient replication. Here, we show that the cellular lipid ceramide is redistributed to the West Nile virus strain Kunjin virus (WNVKUN) replication complex (RC) but not to the dengue virus serotype 2 strain New Guinea C (DENVNGC) RC. We show that prolonged chemical inhibition of serine palmitoyltransferase with myriocin had a significant deleterious effect on WNVKUN replication but enhanced DENVNGC replication. Additionally, inhibition of ceramide synthase with Fumonisin B1 had a detrimental effect on WNVKUN replication and release of infectious virus particles but contrastingly an enhancing effect on DENVNGC replication and virus production. These observations suggest that ceramide production via the de novo and salvage pathway is a requirement for WNVKUN replication but inhibitory for DENVNGC replication. Thus, although these two viruses are from the same genus, they have a differential ceramide requirement for replication.
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Affiliation(s)
- Turgut E Aktepe
- Department of Microbiology and Immunology, University of Melbourne, Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Helen Pham
- Department of Microbiology, La Trobe University, Melbourne, VIC, Australia
| | - Jason M Mackenzie
- Department of Microbiology and Immunology, University of Melbourne, Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia.
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Goh LYH, Hobson-Peters J, Prow NA, Baker K, Piyasena TBH, Taylor CT, Rana A, Hastie ML, Gorman JJ, Hall RA. The Chikungunya Virus Capsid Protein Contains Linear B Cell Epitopes in the N- and C-Terminal Regions that are Dependent on an Intact C-Terminus for Antibody Recognition. Viruses 2015; 7:2943-64. [PMID: 26061335 PMCID: PMC4488721 DOI: 10.3390/v7062754] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 04/02/2015] [Accepted: 05/29/2015] [Indexed: 01/14/2023] Open
Abstract
Chikungunya virus (CHIKV) is an arthropod-borne agent that causes severe arthritic disease in humans and is considered a serious health threat in areas where competent mosquito vectors are prevalent. CHIKV has recently been responsible for several millions of cases of disease, involving over 40 countries. The recent re-emergence of CHIKV and its potential threat to human health has stimulated interest in better understanding of the biology and pathogenesis of the virus, and requirement for improved treatment, prevention and control measures. In this study, we mapped the binding sites of a panel of eleven monoclonal antibodies (mAbs) previously generated towards the capsid protein (CP) of CHIKV. Using N- and C-terminally truncated recombinant forms of the CHIKV CP, two putative binding regions, between residues 1–35 and 140–210, were identified. Competitive binding also revealed that five of the CP-specific mAbs recognized a series of overlapping epitopes in the latter domain. We also identified a smaller, N-terminally truncated product of native CP that may represent an alternative translation product of the CHIKV 26S RNA and have potential functional significance during CHIKV replication. Our data also provides evidence that the C-terminus of CP is required for authentic antigenic structure of CP. This study shows that these anti-CP mAbs will be valuable research tools for further investigating the structure and function of the CHIKV CP.
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Affiliation(s)
- Lucas Y H Goh
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
| | - Jody Hobson-Peters
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
| | - Natalie A Prow
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
| | - Kelly Baker
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
| | - Thisun B H Piyasena
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
| | - Carmel T Taylor
- Public Health Virology, Queensland Health Forensic and Scientific Services, Coopers Plain, Queensland 4108, Australia.
| | - Ashok Rana
- Protein Discovery Centre, QIMR Berghofer Medical Research Institute, Herston, Queensland 4029, Australia.
| | - Marcus L Hastie
- Protein Discovery Centre, QIMR Berghofer Medical Research Institute, Herston, Queensland 4029, Australia.
| | - Jeff J Gorman
- Protein Discovery Centre, QIMR Berghofer Medical Research Institute, Herston, Queensland 4029, Australia.
| | - Roy A Hall
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia.
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Kao YT, Chang BL, Liang JJ, Tsai HJ, Lee YL, Lin RJ, Lin YL. Japanese encephalitis virus nonstructural protein NS5 interacts with mitochondrial trifunctional protein and impairs fatty acid β-oxidation. PLoS Pathog 2015; 11:e1004750. [PMID: 25816318 PMCID: PMC4376648 DOI: 10.1371/journal.ppat.1004750] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 02/17/2015] [Indexed: 01/16/2023] Open
Abstract
Infection with Japanese encephalitis virus (JEV) can induce the expression of pro-inflammatory cytokines and cause acute encephalitis in humans. β-oxidation breaks down fatty acids for ATP production in mitochondria, and impaired β-oxidation can induce pro-inflammatory cytokine expression. To address the role of fatty-acid β-oxidation in JEV infection, we measured the oxygen consumption rate of mock- and JEV-infected cells cultured with or without long chain fatty acid (LCFA) palmitate. Cells with JEV infection showed impaired LCFA β-oxidation and increased interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) expression. JEV nonstructural protein 5 (NS5) interacted with hydroxyacyl-CoA dehydrogenase α and β subunits, two components of the mitochondrial trifunctional protein (MTP) involved in LCFA β-oxidation, and NS5 proteins were detected in mitochondria and co-localized with MTP. LCFA β-oxidation was impaired and higher cytokines were induced in cells overexpressing NS5 protein as compared with control cells. Deletion and mutation studies showed that the N-terminus of NS5 was involved in the MTP association, and a single point mutation of NS5 residue 19 from methionine to alanine (NS5-M19A) reduced its binding ability with MTP. The recombinant JEV with NS5-M19A mutation (JEV-NS5-M19A) was less able to block LCFA β-oxidation and induced lower levels of IL-6 and TNF-α than wild-type JEV. Moreover, mice challenged with JEV-NS5-M19A showed less neurovirulence and neuroinvasiveness. We identified a novel function of JEV NS5 in viral pathogenesis by impairing LCFA β-oxidation and inducing cytokine expression by association with MTP.
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Affiliation(s)
- Yu-Ting Kao
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Bi-Lan Chang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Jian-Jong Liang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Hang-Jen Tsai
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Yi-Ling Lee
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Ren-Jye Lin
- Department of General Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Department of Primary Care Medicine, Taipei Medical University Hospital, Taipei, Taiwan
| | - Yi-Ling Lin
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
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O’Brien CA, Hobson-Peters J, Yam AWY, Colmant AMG, McLean BJ, Prow NA, Watterson D, Hall-Mendelin S, Warrilow D, Ng ML, Khromykh AA, Hall RA. Viral RNA intermediates as targets for detection and discovery of novel and emerging mosquito-borne viruses. PLoS Negl Trop Dis 2015; 9:e0003629. [PMID: 25799391 PMCID: PMC4370754 DOI: 10.1371/journal.pntd.0003629] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 02/19/2015] [Indexed: 12/15/2022] Open
Abstract
Mosquito-borne viruses encompass a range of virus families, comprising a number of significant human pathogens (e.g., dengue viruses, West Nile virus, Chikungunya virus). Virulent strains of these viruses are continually evolving and expanding their geographic range, thus rapid and sensitive screening assays are required to detect emerging viruses and monitor their prevalence and spread in mosquito populations. Double-stranded RNA (dsRNA) is produced during the replication of many of these viruses as either an intermediate in RNA replication (e.g., flaviviruses, togaviruses) or the double-stranded RNA genome (e.g., reoviruses). Detection and discovery of novel viruses from field and clinical samples usually relies on recognition of antigens or nucleotide sequences conserved within a virus genus or family. However, due to the wide antigenic and genetic variation within and between viral families, many novel or divergent species can be overlooked by these approaches. We have developed two monoclonal antibodies (mAbs) which show co-localised staining with proteins involved in viral RNA replication in immunofluorescence assay (IFA), suggesting specific reactivity to viral dsRNA. By assessing binding against a panel of synthetic dsRNA molecules, we have shown that these mAbs recognise dsRNA greater than 30 base pairs in length in a sequence-independent manner. IFA and enzyme-linked immunosorbent assay (ELISA) were employed to demonstrate detection of a panel of RNA viruses from several families, in a range of cell types. These mAbs, termed monoclonal antibodies to viral RNA intermediates in cells (MAVRIC), have now been incorporated into a high-throughput, economical ELISA-based screening system for the detection and discovery of viruses from mosquito populations. Our results have demonstrated that this simple system enables the efficient detection and isolation of a range of known and novel viruses in cells inoculated with field-caught mosquito samples, and represents a rapid, sequence-independent, and cost-effective approach to virus discovery.
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Affiliation(s)
- Caitlin A. O’Brien
- Australian Infectious Disease Research Centre, School of Chemical and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Jody Hobson-Peters
- Australian Infectious Disease Research Centre, School of Chemical and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Alice Wei Yee Yam
- Australian Infectious Disease Research Centre, School of Chemical and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Agathe M. G. Colmant
- Australian Infectious Disease Research Centre, School of Chemical and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Breeanna J. McLean
- Australian Infectious Disease Research Centre, School of Chemical and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Natalie A. Prow
- Australian Infectious Disease Research Centre, School of Chemical and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Daniel Watterson
- Australian Infectious Disease Research Centre, School of Chemical and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Sonja Hall-Mendelin
- Public Health Virology Laboratory, Forensic and Scientific Services, Department of Health, Archerfield, Queensland, Australia
| | - David Warrilow
- Public Health Virology Laboratory, Forensic and Scientific Services, Department of Health, Archerfield, Queensland, Australia
| | - Mah-Lee Ng
- Department of Microbiology, National University Health System, National University of Singapore, Singapore
| | - Alexander A. Khromykh
- Australian Infectious Disease Research Centre, School of Chemical and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Roy A. Hall
- Australian Infectious Disease Research Centre, School of Chemical and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
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Goh LY, Hobson-Peters J, Prow NA, Gardner J, Bielefeldt-Ohmann H, Pyke AT, Suhrbier A, Hall RA. Neutralizing monoclonal antibodies to the E2 protein of chikungunya virus protects against disease in a mouse model. Clin Immunol 2013; 149:487-97. [DOI: 10.1016/j.clim.2013.10.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 09/09/2013] [Accepted: 10/02/2013] [Indexed: 12/26/2022]
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11
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The changing epidemiology of Kunjin virus in Australia. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2013; 10:6255-72. [PMID: 24287851 PMCID: PMC3881112 DOI: 10.3390/ijerph10126255] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 11/04/2013] [Accepted: 11/07/2013] [Indexed: 12/02/2022]
Abstract
West Nile virus (WNV) is a mosquito-borne virus responsible for outbreaks of viral encephalitis in humans and horses, with particularly virulent strains causing recent outbreaks of disease in Eastern Europe, the Middle East and North America. A strain of WNV, Kunjin (WNVKUN), is endemic in northern Australia and infection with this virus is generally asymptomatic. However in early 2011, an unprecedented outbreak of encephalitis in horses occurred in south-eastern Australia, resulting in mortality in approximately 10%–15% of infected horses. A WNV-like virus (WNVNSW2011) was isolated and found to be most closely related to the indigenous WNVKUN, rather than other exotic WNV strains. Furthermore, at least two amino acid changes associated with increased virulence of the North American New York 99 strain (WNVNY99) compared to the prototype WNVKUN were present in the WNVNSW2011 sequence. This review summarizes our current understanding of WNVKUN and how the epidemiology and ecology of this virus has changed. Analysis of virulence determinants of contemporary WNVKUN isolates will provide clues on where virulent strains have emerged in Australia. A better understanding of the changing ecology and epidemiology associated with the emergence of virulent strains is essential to prepare for future outbreaks of WNV disease in Australia.
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García-Cordero J, Carrillo-Halfon S, León-Juárez M, Romero-Ramírez H, Valenzuela-León P, López-González M, Santos-Argumedo L, Gutiérrez-Castañeda B, González-Y-Merchand JA, Cedillo-Barrón L. Generation and characterization of a rat monoclonal antibody against the RNA polymerase protein from Dengue Virus-2. Immunol Invest 2013; 43:28-40. [DOI: 10.3109/08820139.2013.833622] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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13
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Mann RA, Fegan M, O'Riley K, Motha J, Warner S. Molecular characterization and phylogenetic analysis of Murray Valley encephalitis virus and West Nile virus (Kunjin subtype) from an arbovirus disease outbreak in horses in Victoria, Australia, in 2011. J Vet Diagn Invest 2013; 25:35-44. [PMID: 23345269 DOI: 10.1177/1040638712467985] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Virus was detected in the central nervous system (CNS) tissue of 11 horses from Victoria that died displaying neurological symptoms during an outbreak of disease in Australia in 2011. Five horses were identified as being infected with Murray Valley encephalitis virus (MVEV) and 6 as being infected with West Nile virus subtype Kunjin (WNV(KUN)). Analysis of partial sequence information from the NS5 and E genes indicated that the MVEVs within the samples were highly homogenous and all belonged to lineage I, which is enzootic to the tropical regions of northern Australia. Likewise, analysis of partial NS5 and E gene and full genome sequences indicated that the WNV(KUN) within the samples were also highly homogenous and clustered with WNV lineage 1, clade b, which is consistent with other WNV(KUN) isolates. Full genomes of 1 MVEV isolate and 2 WNV(KUN) isolates were sequenced and characterized. The genome sequences of Victorian WNV(KUN) are almost identical (3 amino acid differences) to that of the recently sequenced WNV isolate WNV(NSW2011). Metagenome sequencing directly from CNS tissue identified the presence of WNV(KUN) and MVEV within infected CNS tissue.
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Affiliation(s)
- Rachel A Mann
- Biosciences Research Division, Department of Primary Industries, AgriBio, 5 Ring Road, Bundoora, VIC, 3083, Australia
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14
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Tan CSE, Hobson-Peters JM, Stoermer MJ, Fairlie DP, Khromykh AA, Hall RA. An interaction between the methyltransferase and RNA dependent RNA polymerase domains of the West Nile virus NS5 protein. J Gen Virol 2013; 94:1961-1971. [PMID: 23740481 DOI: 10.1099/vir.0.054395-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The flavivirus nonstructural protein 5 (NS5) is a large protein that is structurally conserved among members of the genus, making it an attractive target for antiviral drug development. The protein contains a methyltransferase (MTase) domain and an RNA dependent RNA polymerase (POL) domain. Previous studies with dengue viruses have identified a genetic interaction between residues 46-49 in the αA3-motif in the MTase and residue 512 in POL. These genetic interactions are consistent with structural modelling of these domains in West Nile virus (WNV) NS5 that predict close proximity of these regions of the two domains, and potentially a functional interaction mediated via the αA3-motif. To demonstrate an interaction between the MTase and POL domains of the WNV NS5 protein, we co-expressed affinity-tagged recombinant MTase and POL proteins in human embryonic kidney cells with simian virus 40 large T antigen (HEK293T cells) and performed pulldown assays using an antibody to the flag tag on POL. Western blot analysis with an anti-MTase mAb revealed that the MTase protein was specifically co-immunoprecipitated with POL, providing the first evidence of a specific interaction between these domains. To further assess the role of the αA3 helix in this interaction, selected residues in this motif were mutated in the recombinant MTase and the effect on POL interaction determined by the pulldown assay. These mutations were also introduced into a WNV infectious clone (FLSDX) and the replication properties of these mutant viruses assessed. While none of the αA3 mutations had a significant effect on the MTase-POL association in pulldown assays, suggesting that these residues were not specific to the interaction, an E46L mutation completely abolished virus viability indicating a critical requirement of this residue in replication. Failure to generate compensatory mutations in POL to rescue replication, even after several passages of the transfection supernatant in Vero cells, precluded further conclusion of the role of this residue in the context of MTase-POL interactions.
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Affiliation(s)
- Cindy S E Tan
- Institute of Molecular Biosciences, University of Queensland, St Lucia 4072, Australia.,Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia 4072, Australia
| | - Jody M Hobson-Peters
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia 4072, Australia
| | - Martin J Stoermer
- Institute of Molecular Biosciences, University of Queensland, St Lucia 4072, Australia
| | - David P Fairlie
- Institute of Molecular Biosciences, University of Queensland, St Lucia 4072, Australia
| | - Alexander A Khromykh
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia 4072, Australia
| | - Roy A Hall
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia 4072, Australia
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15
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Song KY, Zhao H, Li SH, Li XF, Deng YQ, Wang HJ, Ye Q, Zhu SY, Jiang ZY, Zhang FC, Qin ED, Qin CF. Identification and characterization of a linearized B-cell epitope on the pr protein of dengue virus. J Gen Virol 2013; 94:1510-1516. [PMID: 23559476 DOI: 10.1099/vir.0.052084-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The four serotypes of dengue virus (DENV) represent one of the major mosquito-borne pathogens globally; so far no vaccine or specific antiviral is available. During virion maturation, the pr protein is cleaved from its precursor form the prM protein on the surface of immature DENV by host protease. Recent findings have demonstrated that the pr protein not only played critical roles in virion assembly and maturation, but was also involved in antibody-dependent enhancement of DENV infection. However, the B-cell epitopes on the pr protein of DENV have not been well characterized. In this study, a set of 11 partially overlapping peptides spanning the entire pr protein of DENV-2 were fused with glutathione S-transferase and expressed in Escherichia coli. ELISA screening with murine hyperimmune antiserum against immature DENV identified the P8 peptide (⁵⁷KQNEPEDIDCWCNST⁷¹) in the pr protein as the major immunodominant epitope. Fine mapping by truncated protein assays confirmed the 8-e peptide ⁵⁷KQNEPEDI⁶⁴ was the smallest unit capable of antibody binding. Importantly, the 8-e epitope reacted with sera from dengue fever patients. Site-directed mutagenesis revealed the asparagine residue at position 59 was important for epitope recognition. The 8-e epitope coincided well with the B-cell epitopes predicted by Immune Epitope Database analysis, and 3D structural modelling mapped the 8-e peptide on the surface of prM-E heterodimers. Overall, our findings characterized a linearized B-cell epitope on the pr protein of DENV, which will help to understand the life cycle of DENV and pathogenesis of dengue infections in human.
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Affiliation(s)
- Ke-Yu Song
- Guangzhou No. 8 People's Hospital, Guangzhou Medical College, Guangzhou 510060, China.,Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Hui Zhao
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Shi-Hua Li
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Xiao-Feng Li
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Yong-Qiang Deng
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Hong-Jiang Wang
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Qing Ye
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Shun-Ya Zhu
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Zhen-You Jiang
- Department of Microbiology and Immunology, School of Medicine Jinan University, Guangzhou 510632, China
| | - Fu-Chun Zhang
- Guangzhou No. 8 People's Hospital, Guangzhou Medical College, Guangzhou 510060, China
| | - E-De Qin
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Cheng-Feng Qin
- Department of Virology, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
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16
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Frost MJ, Zhang J, Edmonds JH, Prow NA, Gu X, Davis R, Hornitzky C, Arzey KE, Finlaison D, Hick P, Read A, Hobson-Peters J, May FJ, Doggett SL, Haniotis J, Russell RC, Hall RA, Khromykh AA, Kirkland PD. Characterization of virulent West Nile virus Kunjin strain, Australia, 2011. Emerg Infect Dis 2013; 18:792-800. [PMID: 22516173 PMCID: PMC3358055 DOI: 10.3201/eid1805.111720] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
To determine the cause of an unprecedented outbreak of encephalitis among horses in New South Wales, Australia, in 2011, we performed genomic sequencing of viruses isolated from affected horses and mosquitoes. Results showed that most of the cases were caused by a variant West Nile virus (WNV) strain, WNV(NSW2011), that is most closely related to WNV Kunjin (WNV(KUN)), the indigenous WNV strain in Australia. Studies in mouse models for WNV pathogenesis showed that WNV(NSW2011) is substantially more neuroinvasive than the prototype WNV(KUN) strain. In WNV(NSW2011), this apparent increase in virulence over that of the prototype strain correlated with at least 2 known markers of WNV virulence that are not found in WNV(KUN). Additional studies are needed to determine the relationship of the WNV(NSW2011) strain to currently and previously circulating WNV(KUN) strains and to confirm the cause of the increased virulence of this emerging WNV strain.
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Affiliation(s)
- Melinda J Frost
- Elizabeth Macarthur Agriculture Institute, Menangle, New South Wales, Australia
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17
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A novel bacterium-free method for generation of flavivirus infectious DNA by circular polymerase extension reaction allows accurate recapitulation of viral heterogeneity. J Virol 2012; 87:2367-72. [PMID: 23236063 DOI: 10.1128/jvi.03162-12] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
A novel bacterium-free approach for rapid assembly of flavivirus infectious cDNAs using circular polymerase extension reaction was applied to generate infectious cDNA for the virulent New South Wales isolate of the Kunjin strain of West Nile virus (KUNV) that recently emerged in Australia. Recovered virus recapitulated the genetic heterogeneity present in the original isolate. The approach was utilized to generate viral mutants with designed phenotypic properties and to identify E protein glycosylation as one of the virulence determinants.
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18
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Identification of a novel antiviral inhibitor of the flavivirus guanylyltransferase enzyme. J Virol 2012; 86:8730-9. [PMID: 22674988 DOI: 10.1128/jvi.00384-12] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Arthropod-borne flavivirus infection causes serious morbidity and mortality worldwide, but there are currently no effective antiflaviviral chemotherapeutics available for human use. Therefore, it is critical that new therapeutics against virus-specific targets be developed. To identify new compounds that may be used as broadly active flavivirus therapeutics, we have performed a high-throughput screening of 235,456 commercially available compounds for small-molecule inhibitors of the dengue virus NS5 RNA capping enzyme. We identified a family of compounds, the 2-thioxothiazolidin-4-ones, that show potent biochemical inhibition of capping enzyme GTP binding and guanylyltransferase function. During the course of structure-activity relationship analysis, a molecule within this family, (E)-{3-[5-(4-tert-butylbenzylidene)-4-oxo-2-thioxo-1,3-thiazolidin-3-yl]propanoic acid} (BG-323), was found to possess significant antiviral activity in a dengue virus subgenomic replicon assay. Further testing of BG-323 demonstrated that this molecule is able to reduce the replication of infectious West Nile virus and yellow fever virus in cell culture with low toxicity. The results of this study describe the first inhibitor that targets the GTP-binding/guanylyltransferase activity of the flavivirus RNA capping enzyme.
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Sedegah M, Kim Y, Peters B, McGrath S, Ganeshan H, Lejano J, Abot E, Banania G, Belmonte M, Sayo R, Farooq F, Doolan DL, Regis D, Tamminga C, Chuang I, Bruder JT, King CR, Ockenhouse CF, Faber B, Remarque E, Hollingdale MR, Richie TL, Sette A. Identification and localization of minimal MHC-restricted CD8+ T cell epitopes within the Plasmodium falciparum AMA1 protein. Malar J 2010; 9:241. [PMID: 20735847 PMCID: PMC2939619 DOI: 10.1186/1475-2875-9-241] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Accepted: 08/24/2010] [Indexed: 12/14/2022] Open
Abstract
Background Plasmodium falciparum apical membrane antigen-1 (AMA1) is a leading malaria vaccine candidate antigen that is expressed by sporozoite, liver and blood stage parasites. Since CD8+ T cell responses have been implicated in protection against pre-erythrocytic stage malaria, this study was designed to identify MHC class I-restricted epitopes within AMA1. Methods A recombinant adenovirus serotype 5 vector expressing P. falciparum AMA1 was highly immunogenic when administered to healthy, malaria-naive adult volunteers as determined by IFN-γ ELISpot responses to peptide pools containing overlapping 15-mer peptides spanning full-length AMA1. Computerized algorithms (NetMHC software) were used to predict minimal MHC-restricted 8-10-mer epitope sequences within AMA1 15-mer peptides active in ELISpot. A subset of epitopes was synthesized and tested for induction of CD8+ T cell IFN-γ responses by ELISpot depletion and ICS assays. A 3-dimensional model combining Domains I + II of P. falciparum AMA1 and Domain III of P. vivax AMA1 was used to map these epitopes. Results Fourteen 8-10-mer epitopes were predicted to bind to HLA supertypes A01 (3 epitopes), A02 (4 epitopes), B08 (2 epitopes) and B44 (5 epitopes). Nine of the 14 predicted epitopes were recognized in ELISpot or ELISpot and ICS assays by one or more volunteers. Depletion of T cell subsets confirmed that these epitopes were CD8+ T cell-dependent. A mixture of the 14 minimal epitopes was capable of recalling CD8+ T cell IFN-γ responses from PBMC of immunized volunteers. Thirteen of the 14 predicted epitopes were polymorphic and the majority localized to the more conserved front surface of the AMA1 model structure. Conclusions This study predicted 14 and confirmed nine MHC class I-restricted CD8+ T cell epitopes on AMA1 recognized in the context of seven HLA alleles. These HLA alleles belong to four HLA supertypes that have a phenotypic frequency between 23% - 100% in different human populations.
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Affiliation(s)
- Martha Sedegah
- USMMVP, Malaria Department, NMRC, Silver Spring, MD 20910, USA
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20
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The NS5 protein of the virulent West Nile virus NY99 strain is a potent antagonist of type I interferon-mediated JAK-STAT signaling. J Virol 2010; 84:3503-15. [PMID: 20106931 DOI: 10.1128/jvi.01161-09] [Citation(s) in RCA: 172] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Flaviviruses transmitted by arthropods represent a tremendous disease burden for humans, causing millions of infections annually. All vector-borne flaviviruses studied to date suppress host innate responses to infection by inhibiting alpha/beta interferon (IFN-alpha/beta)-mediated JAK-STAT signal transduction. The viral nonstructural protein NS5 of some flaviviruses functions as the major IFN antagonist, associated with inhibition of IFN-dependent STAT1 phosphorylation (pY-STAT1) or with STAT2 degradation. West Nile virus (WNV) infection prevents pY-STAT1 although a role for WNV NS5 in IFN antagonism has not been fully explored. Here, we report that NS5 from the virulent NY99 strain of WNV prevented pY-STAT1 accumulation, suppressed IFN-dependent gene expression, and rescued the growth of a highly IFN-sensitive virus (Newcastle disease virus) in the presence of IFN, suggesting that this protein can function as an efficient IFN antagonist. In contrast, NS5 from Kunjin virus (KUN), a naturally attenuated subtype of WNV, was a poor suppressor of pY-STAT1. Mutation of a single residue in KUN NS5 to the analogous residue in WNV-NY99 NS5 (S653F) rendered KUN NS5 an efficient inhibitor of pY-STAT1. Incorporation of this mutation into recombinant KUN resulted in 30-fold greater inhibition of JAK-STAT signaling than with the wild-type virus and enhanced KUN replication in the presence of IFN. Thus, a naturally occurring mutation is associated with the function of NS5 in IFN antagonism and may influence virulence of WNV field isolates.
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