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AbuBakar U, Amrani L, Kamarulzaman FA, Karsani SA, Hassandarvish P, Khairat JE. Avian Influenza Virus Tropism in Humans. Viruses 2023; 15:833. [PMID: 37112812 PMCID: PMC10142937 DOI: 10.3390/v15040833] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 03/12/2023] [Accepted: 03/17/2023] [Indexed: 03/29/2023] Open
Abstract
An influenza pandemic happens when a novel influenza A virus is able to infect and transmit efficiently to a new, distinct host species. Although the exact timing of pandemics is uncertain, it is known that both viral and host factors play a role in their emergence. Species-specific interactions between the virus and the host cell determine the virus tropism, including binding and entering cells, replicating the viral RNA genome within the host cell nucleus, assembling, maturing and releasing the virus to neighboring cells, tissues or organs before transmitting it between individuals. The influenza A virus has a vast and antigenically varied reservoir. In wild aquatic birds, the infection is typically asymptomatic. Avian influenza virus (AIV) can cross into new species, and occasionally it can acquire the ability to transmit from human to human. A pandemic might occur if a new influenza virus acquires enough adaptive mutations to maintain transmission between people. This review highlights the key determinants AIV must achieve to initiate a human pandemic and describes how AIV mutates to establish tropism and stable human adaptation. Understanding the tropism of AIV may be crucial in preventing virus transmission in humans and may help the design of vaccines, antivirals and therapeutic agents against the virus.
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Affiliation(s)
- Umarqayum AbuBakar
- Institute of Biological Sciences (ISB), Faculty of Science, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Lina Amrani
- Institute of Biological Sciences (ISB), Faculty of Science, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Farah Ayuni Kamarulzaman
- Institute of Biological Sciences (ISB), Faculty of Science, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Saiful Anuar Karsani
- Institute of Biological Sciences (ISB), Faculty of Science, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Pouya Hassandarvish
- Tropical Infectious Diseases Research and Education Center, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Jasmine Elanie Khairat
- Institute of Biological Sciences (ISB), Faculty of Science, Universiti Malaya, Kuala Lumpur 50603, Malaysia
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2
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Pushan SS, Samantaray M, Rajagopalan M, Ramaswamy A. Evolution of Indian Influenza A (H1N1) Hemagglutinin Strains: A Comparative Analysis of the Pandemic Californian HA Strain. Front Mol Biosci 2023; 10:1111869. [PMID: 37006623 PMCID: PMC10061220 DOI: 10.3389/fmolb.2023.1111869] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 02/20/2023] [Indexed: 03/18/2023] Open
Abstract
The need for a vaccine/inhibitor design has become inevitable concerning the emerging epidemic and pandemic viral infections, and the recent outbreak of the influenza A (H1N1) virus is one such example. From 2009 to 2018, India faced severe fatalities due to the outbreak of the influenza A (H1N1) virus. In this study, the potential features of reported Indian H1N1 strains are analyzed in comparison with their evolutionarily closest pandemic strain, A/California/04/2009. The focus is laid on one of its surface proteins, hemagglutinin (HA), which imparts a significant role in attacking the host cell surface and its entry. The extensive analysis performed, in comparison with the A/California/04/2009 strain, revealed significant point mutations in all Indian strains reported from 2009 to 2018. Due to these mutations, all Indian strains disclosed altered features at the sequence and structural levels, which are further presumed to be associated with their functional diversity as well. The mutations observed with the 2018 HA sequence such as S91R, S181T, S200P, I312V, K319T, I419M, and E523D might improve the fitness of the virus in a new host and environment. The higher fitness and decreased sequence similarity of mutated strains may compromise therapeutic efficacy. In particular, the mutations observed commonly, such as serine-to-threonine, alanine-to-threonine, and lysine-to-glutamine at various regions, alter the physico-chemical features of receptor-binding domains, N-glycosylation, and epitope-binding sites when compared with the reference strain. Such mutations render diversity among all Indian strains, and the structural and functional characterization of these strains becomes inevitable. In this study, we observed that mutational drift results in the alteration of the receptor-binding domain, the generation of new variant N-glycosylation along with novel epitope-binding sites, and modifications at the structural level. Eventually, the pressing need to develop potentially distinct next-generation therapeutic inhibitors against the HA strains of the Indian influenza A (H1N1) virus is also highlighted here.
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Affiliation(s)
- Shilpa Sri Pushan
- Department of Bioinformatics, Pondicherry University, Puducherry, India
| | - Mahesh Samantaray
- Department of Bioinformatics, Pondicherry University, Puducherry, India
| | - Muthukumaran Rajagopalan
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur, India
| | - Amutha Ramaswamy
- Department of Bioinformatics, Pondicherry University, Puducherry, India
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Zhang Y, Zhang L, Wu J, Yu Y, Liu S, Li T, Li Q, Ding R, Wang H, Nie J, Cui Z, Wang Y, Huang W, Wang Y. A second functional furin site in the SARS-CoV-2 spike protein. Emerg Microbes Infect 2022; 11:182-194. [PMID: 34856891 PMCID: PMC8741242 DOI: 10.1080/22221751.2021.2014284] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The ubiquitously-expressed proteolytic enzyme furin is closely related to the pathogenesis of SARS-CoV-2 and therefore represents a key target for antiviral therapy. Based on bioinformatic analysis and pseudovirus tests, we discovered a second functional furin site located in the spike protein. Furin still increased the infectivity of mutated SARS-CoV-2 pseudovirus in 293T-ACE2 cells when the canonical polybasic cleavage site (682-686) was deleted. However, K814A mutation eliminated the enhancing effect of furin on virus infection. Furin inhibitor prevented infection by 682-686-deleted SARS-CoV-2 in 293T-ACE2-furin cells, but not the K814A mutant. K814A mutation did not affect the activity of TMPRSS2 and cathepsin L but did impact the cleavage of S2 into S2' and cell-cell fusion. Additionally, we showed that this functional furin site exists in RaTG13 from bat and PCoV-GD/GX from pangolin. Therefore, we discovered a new functional furin site that is pivotal in promoting SARS-CoV-2 infection.
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Affiliation(s)
- Yue Zhang
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
- National Vaccine & Serum Institute, Beijing, People's Republic of China
| | - Li Zhang
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Jiajing Wu
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Yuanling Yu
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Shuo Liu
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Tao Li
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Qianqian Li
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Ruxia Ding
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Haixin Wang
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Jianhui Nie
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Zhimin Cui
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Yulin Wang
- National Vaccine & Serum Institute, Beijing, People's Republic of China
| | - Weijin Huang
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Youchun Wang
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
- Lead Contact
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de Bruin ACM, Funk M, Spronken MI, Gultyaev AP, Fouchier RAM, Richard M. Hemagglutinin Subtype Specificity and Mechanisms of Highly Pathogenic Avian Influenza Virus Genesis. Viruses 2022; 14:v14071566. [PMID: 35891546 PMCID: PMC9321182 DOI: 10.3390/v14071566] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 07/08/2022] [Accepted: 07/11/2022] [Indexed: 02/04/2023] Open
Abstract
Highly Pathogenic Avian Influenza Viruses (HPAIVs) arise from low pathogenic precursors following spillover from wild waterfowl into poultry populations. The main virulence determinant of HPAIVs is the presence of a multi-basic cleavage site (MBCS) in the hemagglutinin (HA) glycoprotein. The MBCS allows for HA cleavage and, consequently, activation by ubiquitous proteases, which results in systemic dissemination in terrestrial poultry. Since 1959, 51 independent MBCS acquisition events have been documented, virtually all in HA from the H5 and H7 subtypes. In the present article, data from natural LPAIV to HPAIV conversions and experimental in vitro and in vivo studies were reviewed in order to compile recent advances in understanding HA cleavage efficiency, protease usage, and MBCS acquisition mechanisms. Finally, recent hypotheses that might explain the unique predisposition of the H5 and H7 HA sequences to obtain an MBCS in nature are discussed.
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Affiliation(s)
- Anja C. M. de Bruin
- Department of Viroscience, Erasmus Medical Center, 3000 CA Rotterdam, The Netherlands; (A.C.M.d.B.); (M.F.); (M.I.S.); (A.P.G.); (R.A.M.F.)
| | - Mathis Funk
- Department of Viroscience, Erasmus Medical Center, 3000 CA Rotterdam, The Netherlands; (A.C.M.d.B.); (M.F.); (M.I.S.); (A.P.G.); (R.A.M.F.)
| | - Monique I. Spronken
- Department of Viroscience, Erasmus Medical Center, 3000 CA Rotterdam, The Netherlands; (A.C.M.d.B.); (M.F.); (M.I.S.); (A.P.G.); (R.A.M.F.)
| | - Alexander P. Gultyaev
- Department of Viroscience, Erasmus Medical Center, 3000 CA Rotterdam, The Netherlands; (A.C.M.d.B.); (M.F.); (M.I.S.); (A.P.G.); (R.A.M.F.)
- Group Imaging and Bioinformatics, Leiden Institute of Advanced Computer Science (LIACS), Leiden University, 2300 RA Leiden, The Netherlands
| | - Ron A. M. Fouchier
- Department of Viroscience, Erasmus Medical Center, 3000 CA Rotterdam, The Netherlands; (A.C.M.d.B.); (M.F.); (M.I.S.); (A.P.G.); (R.A.M.F.)
| | - Mathilde Richard
- Department of Viroscience, Erasmus Medical Center, 3000 CA Rotterdam, The Netherlands; (A.C.M.d.B.); (M.F.); (M.I.S.); (A.P.G.); (R.A.M.F.)
- Correspondence:
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Feng T, Zhang J, Chen Z, Pan W, Chen Z, Yan Y, Dai J. Glycosylation of viral proteins: Implication in virus-host interaction and virulence. Virulence 2022; 13:670-683. [PMID: 35436420 PMCID: PMC9037552 DOI: 10.1080/21505594.2022.2060464] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Glycans are among the most important cell molecular components. However, given their structural diversity, their functions have not been fully explored. Glycosylation is a vital post-translational modification for various proteins. Many bacteria and viruses rely on N-linked and O-linked glycosylation to perform critical biological functions. The diverse functions of glycosylation on viral proteins during viral infections, including Dengue, Zika, influenza, and human immunodeficiency viruses as well as coronaviruses have been reported. N-linked glycosylation is the most common form of protein modification, and it modulates folding, transportation and receptor binding. Compared to N-linked glycosylation, the functions of O-linked viral protein glycosylation have not been comprehensively evaluated. In this review, we summarize findings on viral protein glycosylation, with particular attention to studies on N-linked glycosylation in viral life cycles. This review informs the development of virus-specific vaccines or inhibitors.
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Affiliation(s)
- Tingting Feng
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Jinyu Zhang
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Zhiqian Chen
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Wen Pan
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Zhengrong Chen
- Department of Respiratory Medicine, Children's Hospital of Soochow University, Soochow University, Suzhou, China
| | - Yongdong Yan
- Department of Respiratory Medicine, Children's Hospital of Soochow University, Soochow University, Suzhou, China
| | - Jianfeng Dai
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Suzhou, China
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Gischke M, Bagato O, Breithaupt A, Scheibner D, Blaurock C, Vallbracht M, Karger A, Crossley B, Veits J, Böttcher-Friebertshäuser E, Mettenleiter TC, Abdelwhab EM. The role of glycosylation in the N-terminus of the hemagglutinin of a unique H4N2 with a natural polybasic cleavage site in virus fitness in vitro and in vivo. Virulence 2021; 12:666-678. [PMID: 33538209 PMCID: PMC7872060 DOI: 10.1080/21505594.2021.1881344] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 01/11/2021] [Accepted: 01/21/2021] [Indexed: 02/07/2023] Open
Abstract
To date, only low pathogenic (LP) H5 and H7 avian influenza viruses (AIV) have been observed to naturally shift to a highly pathogenic (HP) phenotype after mutation of the monobasic hemagglutinin (HA) cleavage site (HACS) to polybasic motifs. The LPAIV monobasic HACS is activated by tissue-restricted trypsin-like enzymes, while the HPAIV polybasic HACS is activated by ubiquitous furin-like enzymes. However, glycosylation near the HACS can affect proteolytic activation and reduced virulence of some HPAIV in chickens. In 2012, a unique H4N2 virus with a polybasic HACS was isolated from quails but was LP in chickens. Whether glycosylation sites (GS) near the HACS hinder the evolution of HPAIV H4N2 remains unclear. Here, we analyzed the prevalence of potential GS in the N-terminus of HA1, 2NYT4 and 18NGT20, in all AIV sequences and studied their impact on H4N2 virus fitness. Although the two motifs are conserved, some non-H5/H7 subtypes lack one or both GS. Both sites were glycosylated in this H4N2 virus. Deglycosylation increased trypsin-independent replication in cell culture, cell-to-cell spread and syncytium formation at low-acidic pH, but negatively affected the thermostability and receptor-binding affinity. Alteration of 2NYT4 with or without 18NGT20 enabled systemic spread of the virus to different organs including the brain of chicken embryos. However, all intranasally inoculated chickens did not show clinical signs. Together, although the conserved GS near the HACS are important for HA stability and receptor binding, deglycosylation increased the H4N2 HA-activation, replication and tissue tropism suggesting a potential role for virus adaptation in poultry.
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Affiliation(s)
- Marcel Gischke
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Ola Bagato
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
- Center of Scientific Excellence for Influenza Viruses, National Research Centre (NRC), Dokki, Giza, Egypt
| | - Angele Breithaupt
- Department of Experimental Animal Facilities and Biorisk Management, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - David Scheibner
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Claudia Blaurock
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Melina Vallbracht
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Axel Karger
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Beate Crossley
- California Animal Health and Food Safety Laboratory, School of Veterinary Medicine, University of California, Davis, United States
| | - Jutta Veits
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | | | - Thomas C. Mettenleiter
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Elsayed M. Abdelwhab
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
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Seidah NG, Pasquato A, Andréo U. How Do Enveloped Viruses Exploit the Secretory Proprotein Convertases to Regulate Infectivity and Spread? Viruses 2021; 13:v13071229. [PMID: 34202098 PMCID: PMC8310232 DOI: 10.3390/v13071229] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/09/2021] [Accepted: 06/18/2021] [Indexed: 12/14/2022] Open
Abstract
Inhibition of the binding of enveloped viruses surface glycoproteins to host cell receptor(s) is a major target of vaccines and constitutes an efficient strategy to block viral entry and infection of various host cells and tissues. Cellular entry usually requires the fusion of the viral envelope with host plasma membranes. Such entry mechanism is often preceded by “priming” and/or “activation” steps requiring limited proteolysis of the viral surface glycoprotein to expose a fusogenic domain for efficient membrane juxtapositions. The 9-membered family of Proprotein Convertases related to Subtilisin/Kexin (PCSK) serine proteases (PC1, PC2, Furin, PC4, PC5, PACE4, PC7, SKI-1/S1P, and PCSK9) participate in post-translational cleavages and/or regulation of multiple secretory proteins. The type-I membrane-bound Furin and SKI-1/S1P are the major convertases responsible for the processing of surface glycoproteins of enveloped viruses. Stefan Kunz has considerably contributed to define the role of SKI-1/S1P in the activation of arenaviruses causing hemorrhagic fever. Furin was recently implicated in the activation of the spike S-protein of SARS-CoV-2 and Furin-inhibitors are being tested as antivirals in COVID-19. Other members of the PCSK-family are also implicated in some viral infections, such as PCSK9 in Dengue. Herein, we summarize the various functions of the PCSKs and present arguments whereby their inhibition could represent a powerful arsenal to limit viral infections causing the present and future pandemics.
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Affiliation(s)
- Nabil G. Seidah
- Laboratory of Biochemical Neuroendocrinology Montreal Clinical Research Institute, University of Montreal, Montreal, QC H2W1R7, Canada;
- Correspondence: ; Tel.: +1-514-987-5609
| | - Antonella Pasquato
- Antonella Pasquato, Department of Industrial Engineering, University of Padova, Via Marzolo 9, 35131 Padova, Italy;
| | - Ursula Andréo
- Laboratory of Biochemical Neuroendocrinology Montreal Clinical Research Institute, University of Montreal, Montreal, QC H2W1R7, Canada;
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Abstract
Introduction: As the pathogen that caused the first influenza virus pandemic in this century, the swine-origin A(H1N1) pdm09 influenza virus has caused continuous harm to human public health. The evolution of hemagglutinin protein glycosylation sites, including the increase in number and positional changes, is an important way for influenza viruses to escape host immune pressure. Based on the traditional influenza virus molecular monitoring, special attention should be paid to the influence of glycosylation evolution on the biological characteristics of virus antigenicity, transmission and pathogenicity. The epidemiological significance of glycosylation mutants should be analyzed as a predictive tool for early warning of new outbreaks and pandemics, as well as the design of vaccines and drug targets.Areas covered: We review on the evolutionary characteristics of glycosylation on the HA protein of the A(H1N1)pdm09 influenza virus in the last ten years.Expert opinion: We discuss the crucial impact of evolutionary glycosylation on the biological characteristics of the virus and the host immune responses, summarize studies revealing different roles of glycosylation play during host adaptation. Although these studies show the significance of glycosylation evolution in host-virus interaction, much remains to be discovered about the mechanism.
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Affiliation(s)
- Pan Ge
- Center for Vaccines and Immunology, University of Georgia, Athens, GA, USA
| | - Ted M Ross
- Center for Vaccines and Immunology, University of Georgia, Athens, GA, USA.,Department of Infectious Diseases, University of Georgia, Athens, GA USA
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Seekings AH, Howard WA, Nuñéz A, Slomka MJ, Banyard AC, Hicks D, Ellis RJ, Nuñéz-García J, Hartgroves LC, Barclay WS, Banks J, Brown IH. The Emergence of H7N7 Highly Pathogenic Avian Influenza Virus from Low Pathogenicity Avian Influenza Virus Using an in ovo Embryo Culture Model. Viruses 2020; 12:v12090920. [PMID: 32839404 PMCID: PMC7552004 DOI: 10.3390/v12090920] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/15/2020] [Accepted: 08/18/2020] [Indexed: 01/19/2023] Open
Abstract
Outbreaks of highly pathogenic avian influenza virus (HPAIV) often result in the infection of millions of poultry, causing up to 100% mortality. HPAIV has been shown to emerge from low pathogenicity avian influenza virus (LPAIV) in field outbreaks. Direct evidence for the emergence of H7N7 HPAIV from a LPAIV precursor with a rare di-basic cleavage site (DBCS) was identified in the UK in 2008. The DBCS contained an additional basic amino acid compared to commonly circulating LPAIVs that harbor a single-basic amino acid at the cleavage site (SBCS). Using reverse genetics, outbreak HPAIVs were rescued with a DBCS (H7N7DB), as seen in the LPAIV precursor or an SBCS representative of common H7 LPAIVs (H7N7SB). Passage of H7N7DB in chicken embryo tissues showed spontaneous evolution to a HPAIV. In contrast, deep sequencing of extracts from embryo tissues in which H7N7SB was serially passaged showed retention of the LPAIV genotype. Thus, in chicken embryos, an H7N7 virus containing a DBCS appears naturally unstable, enabling rapid evolution to HPAIV. Evaluation in embryo tissue presents a useful approach to study AIV evolution and allows a laboratory-based dissection of molecular mechanisms behind the emergence of HPAIV.
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Affiliation(s)
- Amanda H. Seekings
- Virology Department, Animal and Plant Health Agency (APHA-Weybridge), Addlestone, Surrey KT15 3NB, UK; (W.A.H.); (M.J.S.); (A.C.B.); (J.B.); (I.H.B.)
- Correspondence:
| | - Wendy A. Howard
- Virology Department, Animal and Plant Health Agency (APHA-Weybridge), Addlestone, Surrey KT15 3NB, UK; (W.A.H.); (M.J.S.); (A.C.B.); (J.B.); (I.H.B.)
| | - Alejandro Nuñéz
- Pathology Department, Animal and Plant Health Agency (APHA-Weybridge), Addlestone, Surrey KT15 3NB, UK; (A.N.); (D.H.)
| | - Marek J. Slomka
- Virology Department, Animal and Plant Health Agency (APHA-Weybridge), Addlestone, Surrey KT15 3NB, UK; (W.A.H.); (M.J.S.); (A.C.B.); (J.B.); (I.H.B.)
| | - Ashley C. Banyard
- Virology Department, Animal and Plant Health Agency (APHA-Weybridge), Addlestone, Surrey KT15 3NB, UK; (W.A.H.); (M.J.S.); (A.C.B.); (J.B.); (I.H.B.)
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, UK
- Institute for Infection and Immunity, St. George’s Hospital Medical School, University of London, London SW17 0RE, UK
| | - Daniel Hicks
- Pathology Department, Animal and Plant Health Agency (APHA-Weybridge), Addlestone, Surrey KT15 3NB, UK; (A.N.); (D.H.)
| | - Richard J. Ellis
- Surveillance and Laboratory Services Department, Animal and Plant Health Agency (APHA-Weybridge), Addlestone, Surrey KT15 3NB, UK; (R.J.E.); (J.N.-G.)
| | - Javier Nuñéz-García
- Surveillance and Laboratory Services Department, Animal and Plant Health Agency (APHA-Weybridge), Addlestone, Surrey KT15 3NB, UK; (R.J.E.); (J.N.-G.)
| | | | - Wendy S. Barclay
- Virology Department, Imperial College, London W2 1NY, UK; (L.C.H.); (W.S.B.)
| | - Jill Banks
- Virology Department, Animal and Plant Health Agency (APHA-Weybridge), Addlestone, Surrey KT15 3NB, UK; (W.A.H.); (M.J.S.); (A.C.B.); (J.B.); (I.H.B.)
| | - Ian H. Brown
- Virology Department, Animal and Plant Health Agency (APHA-Weybridge), Addlestone, Surrey KT15 3NB, UK; (W.A.H.); (M.J.S.); (A.C.B.); (J.B.); (I.H.B.)
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Ghabeshi S, Ebrahimie E, Salimi V, Ghanizadeh A, Khodakhah F, Yavarian J, Norouzbabaei Z, Sasani F, Rezaie F, Azad TM. Experimental direct-contact transmission of influenza A/H9N2 virus in the guinea pig model in Iran. Future Virol 2020. [DOI: 10.2217/fvl-2019-0141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aim: The present study aims to evaluate risk factors for the transmission of A/H9N2 viruses in guinea pig model. Materials & methods: Lung tissue samples were collected from the chicken clinically infected with influenza A/H9N2 virus in 2018. Next, virus isolation and titration, as well as reverse transcription PCR were performed. Then, hemagglutnation and neuraminidase genes was sequenced to identify different positions (hotspots) involved in transmission and host adaptation. Results: Influenza A/H9N2 virus could replicate in low titers in the nasal turbinate and transmit from infected to noninfected guinea pigs. Conclusion: Hotspots on the surface glycoproteins had the potential to alter transmission properties in the new host.
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Affiliation(s)
- Soad Ghabeshi
- Virology Department, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Esmaeil Ebrahimie
- School of Animal and VeterinarySciences, The University of Adelaide, South Australia, Adelaide, Australia
- Genomics Research Platform, Schoolof Life Sciences, La Trobe University, Melbourne, Victoria, Australia
| | - Vahid Salimi
- Virology Department, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Arash Ghanizadeh
- Department of Biotechnology, Razi Vaccine & Serum Research Institute, Karaj, Alborz, Iran
| | - Farshad Khodakhah
- Virology Department, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Jila Yavarian
- Virology Department, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Zahra Norouzbabaei
- Virology Department, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Farhang Sasani
- Department of Pathology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - Farhad Rezaie
- Virology Department, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Talat Mokhtari Azad
- Virology Department, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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Insertion of Basic Amino Acids in the Hemagglutinin Cleavage Site of H4N2 Avian Influenza Virus (AIV)-Reduced Virus Fitness in Chickens is Restored by Reassortment with Highly Pathogenic H5N1 AIV. Int J Mol Sci 2020; 21:ijms21072353. [PMID: 32231159 PMCID: PMC7178042 DOI: 10.3390/ijms21072353] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 03/25/2020] [Accepted: 03/27/2020] [Indexed: 02/02/2023] Open
Abstract
Highly pathogenic (HP) avian influenza viruses (AIVs) are naturally restricted to H5 and H7 subtypes with a polybasic cleavage site (CS) in hemagglutinin (HA) and any AIV with an intravenous pathogenicity index (IVPI) ≥ 1.2. Although only a few non-H5/H7 viruses fulfill the criteria of HPAIV; it remains unclear why these viruses did not spread in domestic birds. In 2012, a unique H4N2 virus with a polybasic CS 322PEKRRTR/G329 was isolated from quails in California which, however, was avirulent in chickens. This is the only known non-H5/H7 virus with four basic amino acids in the HACS. Here, we investigated the virulence of this virus in chickens after expansion of the polybasic CS by substitution of T327R (322PEKRRRR/G329) or T327K (322PEKRRKR/G329) with or without reassortment with HPAIV H5N1 and H7N7. The impact of single mutations or reassortment on virus fitness in vitro and in vivo was studied. Efficient cell culture replication of T327R/K carrying H4N2 viruses increased by treatment with trypsin, particularly in MDCK cells, and reassortment with HPAIV H5N1. Replication, virus excretion and bird-to-bird transmission of H4N2 was remarkably compromised by the CS mutations, but restored after reassortment with HPAIV H5N1, although not with HPAIV H7N7. Viruses carrying the H4-HA with or without R327 or K327 mutations and the other seven gene segments from HPAIV H5N1 exhibited high virulence and efficient transmission in chickens. Together, increasing the number of basic amino acids in the H4N2 HACS was detrimental for viral fitness particularly in vivo but compensated by reassortment with HPAIV H5N1. This may explain the absence of non-H5/H7 HPAIV in poultry.
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12
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Braun E, Sauter D. Furin-mediated protein processing in infectious diseases and cancer. Clin Transl Immunology 2019; 8:e1073. [PMID: 31406574 PMCID: PMC6682551 DOI: 10.1002/cti2.1073] [Citation(s) in RCA: 197] [Impact Index Per Article: 39.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 07/10/2019] [Accepted: 07/13/2019] [Indexed: 12/17/2022] Open
Abstract
Proteolytic cleavage regulates numerous processes in health and disease. One key player is the ubiquitously expressed serine protease furin, which cleaves a plethora of proteins at polybasic recognition motifs. Mammalian substrates of furin include cytokines, hormones, growth factors and receptors. Thus, it is not surprising that aberrant furin activity is associated with a variety of disorders including cancer. Furthermore, the enzymatic activity of furin is exploited by numerous viral and bacterial pathogens, thereby enhancing their virulence and spread. In this review, we describe the physiological and pathophysiological substrates of furin and discuss how dysregulation of a simple proteolytic cleavage event may promote infectious diseases and cancer. One major focus is the role of furin in viral glycoprotein maturation and pathogenicity. We also outline cellular mechanisms regulating the expression and activation of furin and summarise current approaches that target this protease for therapeutic intervention.
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Affiliation(s)
- Elisabeth Braun
- Institute of Molecular VirologyUlm University Medical CenterUlmGermany
| | - Daniel Sauter
- Institute of Molecular VirologyUlm University Medical CenterUlmGermany
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13
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Influenza virus N-linked glycosylation and innate immunity. Biosci Rep 2019; 39:BSR20171505. [PMID: 30552137 PMCID: PMC6328934 DOI: 10.1042/bsr20171505] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/03/2018] [Accepted: 12/13/2018] [Indexed: 12/21/2022] Open
Abstract
Influenza viruses cause seasonal epidemics and sporadic pandemics in humans. The virus’s ability to change its antigenic nature through mutation and recombination, and the difficulty in developing highly effective universal vaccines against it, make it a serious global public health challenge. Influenza virus’s surface glycoproteins, hemagglutinin and neuraminidase, are all modified by the host cell’s N-linked glycosylation pathways. Host innate immune responses are the first line of defense against infection, and glycosylation of these major antigens plays an important role in the generation of host innate responses toward the virus. Here, we review the principal findings in the analytical techniques used to study influenza N-linked glycosylation, the evolutionary dynamics of N-linked glycosylation in seasonal versus pandemic and zoonotic strains, its role in host innate immune responses, and the prospects for lectin-based therapies. As the efficiency of innate immune responses is a critical determinant of disease severity and adaptive immunity, the study of influenza glycobiology is of clinical as well as research interest.
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14
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Su H, Yang X, Wang S, Shi H, Liu X. Effect of annexin II-mediated conversion of plasmin from plasminogen on airborne transmission of H9N2 avian influenza virus. Vet Microbiol 2018; 223:100-106. [PMID: 30173734 DOI: 10.1016/j.vetmic.2018.08.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 08/01/2018] [Accepted: 08/02/2018] [Indexed: 11/16/2022]
Abstract
Airborne transmission plays an important role in dissemination of H9N2 subtype avian influenza virus. Annexin II (A2)-mediated activation of plasminogen (PLG) promotes cleavage of the influenza virus HA protein and viral replication, resulting in enhanced pathogenesis. In this study, airborne transmission competent and defective strains of H9N2 influenza virus, SH7 and SH14, respectively, were used to investigate the effect of A2 on airborne spread. The results showed that A2 protein was increased in SH7 virions compared with SH14 particles, the binding ability of the SH7-infected MDCK cells to PLG was significantly higher than the SH14-infected cells, and influence efficiency of the PLG on replicated ability of SH7 virus was significantly stronger than that of SH14 virus, who spread without airborne route, indicating that the annexin 2 (A2) can bind PLG and contributes to SH7 with high replication ability. Furthermore, the copies of SH7 in the airborne infected chickens under inhibited by 6-AHA were significantly decreased, suggesting that the release of H9N2 avian influenza virus were reduced by inhibiting the conversion of PLG to PL, ultimately resulting in reduced airborne transmission of H9N2 avian influenza virus. In summary, A2-mediated conversion of PLG to PL plays a role in the airborne transmission capacity of H9N2 avian influenza viruses, and this interaction may represent potential targets for prevention and treatment of influenza virus infection.
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Affiliation(s)
- Hailong Su
- College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, Jiangsu, China; Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China.
| | - Xueqin Yang
- College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, Jiangsu, China; Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China.
| | - Shifeng Wang
- Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611-0880, USA.
| | - Huoying Shi
- College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, Jiangsu, China; Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China.
| | - Xiufan Liu
- College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, Jiangsu, China; Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China.
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15
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Richard M, Fouchier R, Monne I, Kuiken T. Mechanisms and risk factors for mutation from low to highly pathogenic avian influenza virus. ACTA ACUST UNITED AC 2017. [DOI: 10.2903/sp.efsa.2017.en-1287] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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16
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A Unique Multibasic Proteolytic Cleavage Site and Three Mutations in the HA2 Domain Confer High Virulence of H7N1 Avian Influenza Virus in Chickens. J Virol 2015; 90:400-11. [PMID: 26491158 DOI: 10.1128/jvi.02082-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 10/11/2015] [Indexed: 12/29/2022] Open
Abstract
UNLABELLED In 1999, after circulation for a few months in poultry in Italy, low-pathogenic (LP) avian influenza (AI) H7N1 virus mutated into a highly pathogenic (HP) form by acquisition of a unique multibasic cleavage site (mCS), PEIPKGSRVRR*GLF (asterisk indicates the cleavage site), in the hemagglutinin (HA) and additional alterations with hitherto unknown biological function. To elucidate these virulence-determining alterations, recombinant H7N1 viruses carrying specific mutations in the HA of LPAI A/chicken/Italy/473/1999 virus (Lp) and HPAI A/chicken/Italy/445/1999 virus (Hp) were generated. Hp with a monobasic CS or carrying the HA of Lp induced only mild or no disease in chickens, thus resembling Lp. Conversely, Lp with the HA of Hp was as virulent and transmissible as Hp. While Lp with a multibasic cleavage site (Lp_CS445) was less virulent than Hp, full virulence was exhibited when HA2 was replaced by that of Hp. In HA2, three amino acid differences consistently detected between LP and HP H7N1 viruses were successively introduced into Lp_CS445. Q450L in the HA2 stem domain increased virulence and transmission but was detrimental to replication in cell culture, probably due to low-pH activation of HA. A436T and/or K536R restored viral replication in vitro and in vivo. Viruses possessing A436T and K536R were observed early in the HPAI outbreak but were later superseded by viruses carrying all three mutations. Together, besides the mCS, stepwise mutations in HA2 increased the fitness of the Italian H7N1 virus in vivo. The shift toward higher virulence in the field was most likely gradual with rapid optimization. IMPORTANCE In 1999, after 9 months of circulation of low-pathogenic (LP) avian influenza virus (AIV), a devastating highly pathogenic (HP) H7N1 AIV emerged in poultry, marking the largest epidemic of AIV reported in a Western country. The HPAIV possessed a unique multibasic cleavage site (mCS) complying with the minimum motif for HPAIV. The main finding in this report is the identification of three mutations in the HA2 domain that are required for replication and stability, as well as for virulence, transmission, and tropism of H7N1 in chickens. In addition to the mCS, Q450L was required for full virulence and transmissibility of the virus. Nonetheless, it was detrimental to virus replication and required A436T and/or K536R to restore replication, systemic spread, and stability. These results are important for better understanding of the evolution of highly pathogenic avian influenza viruses from low-pathogenic precursors.
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17
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A mutant H3N2 influenza virus uses an alternative activation mechanism in TMPRSS2 knockout mice by loss of an oligosaccharide in the hemagglutinin stalk region. J Virol 2015; 89:5154-8. [PMID: 25673722 DOI: 10.1128/jvi.00124-15] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 02/02/2015] [Indexed: 11/20/2022] Open
Abstract
The host protease TMPRSS2 plays an essential role in proteolytic activation of the influenza A virus (IAV) hemagglutinin (HA) protein possessing a monobasic cleavage site. However, after passages in TMPRSS2 knockout mice, an H3N2 subtype IAV began to undergo cleavage activation of HA, showing high virulence in the mice due to the loss of an oligosaccharide at position 8 in the HA stalk region. Thus, the H3N2 IAV acquired cleavability by an alternative HA activation mechanism/protease(s).
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18
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Berhane Y, Joseph T, Kehler H, Hisanaga T, Embury-Hyatt C, Diederich S, McGreevy KH, Handel K, Cottam-Birt C, Pasick J. Characterization of a Low Pathogenic Avian Influenza H5N2 Virus Isolated from a Turkey Breeder Flock in Manitoba, Canada. Avian Dis 2014; 58:1-7. [DOI: 10.1637/10591-061213-reg.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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19
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Abdelwhab ESM, Veits J, Mettenleiter TC. Genetic changes that accompanied shifts of low pathogenic avian influenza viruses toward higher pathogenicity in poultry. Virulence 2013; 4:441-52. [PMID: 23863606 PMCID: PMC5359749 DOI: 10.4161/viru.25710] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 07/09/2013] [Accepted: 07/10/2013] [Indexed: 11/19/2022] Open
Abstract
Avian influenza viruses (AIV) of H5 and H7 subtypes exhibit two different pathotypes in poultry: infection with low pathogenic (LP) strains results in minimal, if any, health disturbances, whereas highly pathogenic (HP) strains cause severe morbidity and mortality. LPAIV of H5 and H7 subtypes can spontaneously mutate into HPAIV. Ten outbreaks caused by HPAIV are known to have been preceded by circulation of a predecessor LPAIV in poultry. Three of them were caused by H5N2 subtype and seven involved H7 subtype in combination with N1, N3, or N7. Here, we review those outbreaks and summarize the genetic changes which resulted in the transformation of LPAIV to HPAIV under natural conditions. Mutations that were found directly in those outbreaks are more likely to be linked to virulence, pathogenesis, and early adaptation of AIV.
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Affiliation(s)
- El-Sayed M Abdelwhab
- Friedrich-Loeffler-Institut; Federal Research Institute for Animal Health; Institute of Molecular Biology; Greifswald-Insel Riems, Germany
| | - Jutta Veits
- Friedrich-Loeffler-Institut; Federal Research Institute for Animal Health; Institute of Molecular Biology; Greifswald-Insel Riems, Germany
| | - Thomas C Mettenleiter
- Friedrich-Loeffler-Institut; Federal Research Institute for Animal Health; Institute of Molecular Biology; Greifswald-Insel Riems, Germany
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20
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Böttcher-Friebertshäuser E, Klenk HD, Garten W. Activation of influenza viruses by proteases from host cells and bacteria in the human airway epithelium. Pathog Dis 2013; 69:87-100. [PMID: 23821437 PMCID: PMC7108517 DOI: 10.1111/2049-632x.12053] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 06/03/2013] [Indexed: 11/28/2022] Open
Abstract
Influenza is an acute infection of the respiratory tract, which affects each year millions of people. Influenza virus infection is initiated by the surface glycoprotein hemagglutinin (HA) through receptor binding and fusion of viral and endosomal membranes. HA is synthesized as a precursor protein and requires cleavage by host cell proteases to gain its fusion capacity. Although cleavage of HA is crucial for virus infectivity, little was known about relevant proteases in the human airways for a long time. Recent progress in the identification and characterization of HA‐activating host cell proteases has been considerable however and supports the idea of targeting HA cleavage as a novel approach for influenza treatment. Interestingly, certain bacteria have been demonstrated to support HA activation either by secreting proteases that cleave HA or due to activation of cellular proteases and thereby may contribute to virus spread and enhanced pathogenicity. In this review, we give an overview on activation of influenza viruses by proteases from host cells and bacteria with the main focus on recent progress on HA cleavage by proteases HAT and TMPRSS2 in the human airway epithelium. In addition, we outline investigations of HA‐activating proteases as potential drug targets for influenza treatment. The authors, who are leading experts in this field, present a timely, authoritative review on the proteolytic cleavage of the influenza hemagglutinin (HA), an activation mechanism that is essential for the infectivity of influenza viruses, including the recently emerged H7N9. They also address the potential of host proteases as targets for developing new influenza drugs. This review will be of considerable interest to virologists, microbiologists and pharmaceutical companies alike.
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21
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Zhang Y, Zhu J, Li Y, Bradley KC, Cao J, Chen H, Jin M, Zhou H. Glycosylation on hemagglutinin affects the virulence and pathogenicity of pandemic H1N1/2009 influenza A virus in mice. PLoS One 2013; 8:e61397. [PMID: 23637827 PMCID: PMC3634815 DOI: 10.1371/journal.pone.0061397] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 03/08/2013] [Indexed: 11/30/2022] Open
Abstract
The two glycosylation sites (Asn142 and Asn177) were observed in the HA of most human seasonal influenza A/H1N1 viruses, while none in pandemic H1N1/2009 influenza A (pH1N1) viruses. We investigated the effect of the two glycosylation sites on viral virulence and pathogenicity in mice using recombinant pH1N1. The H1N1/144 and H1N1/177 mutants which gained potential glycosylation sites Asn142 and Asn177 on HA respectively were generated from A/Mexico/4486/2009(H1N1) by site-directed mutagenesis and reverse genetics, the same as the H1N1/144+177 gained both glycosylation sites Asn142 and Asn177. The biological characteristics and antigenicity of the mutants were compared with wild-type pH1N1. The virulence and pathogenicity of recombinants were also detected in mice. Our results showed that HA antigenicity and viral affinity for receptor may change with introduction of the glycosylation sites. Compared with wild-type pH1N1, the mutant H1N1/177 displayed an equivalent virus titer in chicken embryos and mice, and increased virulence and pathogenicity in mice. The H1N1/144 displayed the highest virus titer in mice lung. However, the H1N1/144+177 displayed the most serious alveolar inflammation and pathogenicity in infected mice. The introduction of the glycosylation sites Asn144 and Asn177 resulted in the enhancement on virulence and pathogenicity of pH1N1 in mice, and was also associated with the change of HA antigenicity and the viral affinity for receptor.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/immunology
- Antibodies, Viral/immunology
- Chick Embryo
- Cytokines/immunology
- Cytokines/metabolism
- Erythrocytes/virology
- Female
- Glycosylation
- Hemagglutinin Glycoproteins, Influenza Virus/chemistry
- Hemagglutinin Glycoproteins, Influenza Virus/genetics
- Hemagglutinin Glycoproteins, Influenza Virus/immunology
- Hemagglutinin Glycoproteins, Influenza Virus/metabolism
- Humans
- Inflammation Mediators/immunology
- Inflammation Mediators/metabolism
- Influenza A Virus, H1N1 Subtype/genetics
- Influenza A Virus, H1N1 Subtype/immunology
- Influenza A Virus, H1N1 Subtype/metabolism
- Influenza A Virus, H1N1 Subtype/pathogenicity
- Lung/immunology
- Lung/metabolism
- Lung/pathology
- Lung/virology
- Mice
- Models, Molecular
- Molecular Sequence Data
- Mutation
- Orthomyxoviridae Infections/immunology
- Orthomyxoviridae Infections/metabolism
- Orthomyxoviridae Infections/virology
- Swine
- Virulence/genetics
- Virus Replication
- Weight Loss
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Affiliation(s)
- Yan Zhang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Jiping Zhu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Yongtao Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Konrad C. Bradley
- Department of Microbiology and Immunology, Emory University School of Medicine, O. Wayne Rollins Research Center, Atlanta, Georgia, United States of America
| | - Jiyue Cao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Huanchun Chen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Meilin Jin
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, People's Republic of China
| | - Hongbo Zhou
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, People's Republic of China
- * E-mail:
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22
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Experimental transmission in guinea pigs of H9N2 avian influenza viruses from indoor air of chicken houses. Virus Res 2012; 170:102-8. [DOI: 10.1016/j.virusres.2012.09.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 09/11/2012] [Accepted: 09/12/2012] [Indexed: 11/23/2022]
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23
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New DIVA vaccine for the protection of poultry against H5 highly pathogenic avian influenza viruses irrespective of the N-subtype. Vaccine 2012; 30:7078-83. [DOI: 10.1016/j.vaccine.2012.09.050] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 09/06/2012] [Accepted: 09/20/2012] [Indexed: 11/18/2022]
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24
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Sun S, Wang Q, Zhao F, Chen W, Li Z. Prediction of biological functions on glycosylation site migrations in human influenza H1N1 viruses. PLoS One 2012; 7:e32119. [PMID: 22355413 PMCID: PMC3280219 DOI: 10.1371/journal.pone.0032119] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Accepted: 01/19/2012] [Indexed: 12/28/2022] Open
Abstract
Protein glycosylation alteration is typically employed by various viruses for escaping immune pressures from their hosts. Our previous work had shown that not only the increase of glycosylation sites (glycosites) numbers, but also glycosite migration might be involved in the evolution of human seasonal influenza H1N1 viruses. More importantly, glycosite migration was likely a more effectively alteration way for the host adaption of human influenza H1N1 viruses. In this study, we provided more bioinformatics and statistic evidences for further predicting the significant biological functions of glycosite migration in the host adaptation of human influenza H1N1 viruses, by employing homology modeling and in silico protein glycosylation of representative HA and NA proteins as well as amino acid variability analysis at antigenic sites of HA and NA. The results showed that glycosite migrations in human influenza viruses have at least five possible functions: to more effectively mask the antigenic sites, to more effectively protect the enzymatic cleavage sites of neuraminidase (NA), to stabilize the polymeric structures, to regulate the receptor binding and catalytic activities and to balance the binding activity of hemagglutinin (HA) with the release activity of NA. The information here can provide some constructive suggestions for the function research related to protein glycosylation of influenza viruses, although these predictions still need to be supported by experimental data.
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Affiliation(s)
- Shisheng Sun
- Laboratory of Functional Glycomics, College of Life Sciences, Northwest University, Xi'an, People's Republic of China
| | - Qinzhe Wang
- Laboratory of Functional Glycomics, College of Life Sciences, Northwest University, Xi'an, People's Republic of China
| | - Fei Zhao
- Laboratory of Functional Glycomics, College of Life Sciences, Northwest University, Xi'an, People's Republic of China
| | - Wentian Chen
- Laboratory of Functional Glycomics, College of Life Sciences, Northwest University, Xi'an, People's Republic of China
| | - Zheng Li
- Laboratory of Functional Glycomics, College of Life Sciences, Northwest University, Xi'an, People's Republic of China
- * E-mail:
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25
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Chen JR, Ma C, Wong CH. Vaccine design of hemagglutinin glycoprotein against influenza. Trends Biotechnol 2011; 29:426-34. [PMID: 21640418 DOI: 10.1016/j.tibtech.2011.04.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 04/19/2011] [Accepted: 04/20/2011] [Indexed: 11/29/2022]
Abstract
Influenza viruses continue to cause annual epidemics and pose the threat of a deadly global pandemic. Vaccination has remained the best approach for prevention and control of influenza infection. However, current influenza vaccines are only effective against closely-matched circulating strains, and therefore must be updated and administered every year. In this review, we discuss recent developments in the search for better influenza vaccines, especially using the major virus surface glycoprotein hemagglutinins (HAs). Understanding how glycans on HAs affect the immune response and knowledge of how broadly neutralizing antibodies are induced will pave the way for a cross-protective influenza vaccine that does not require frequent updates or annual immunizations.
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Affiliation(s)
- Juine-Ruey Chen
- Genomics Research Center, Academia Sinica, 128 Academia Road Section 2, Taipei 115, Taiwan
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26
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Tombari W, Nsiri J, Larbi I, Guerin JL, Ghram A. Genetic evolution of low pathogenecity H9N2 avian influenza viruses in Tunisia: acquisition of new mutations. Virol J 2011; 8:467. [PMID: 21992186 PMCID: PMC3223530 DOI: 10.1186/1743-422x-8-467] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 10/12/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Since the end of 2009, H9N2 has emerged in Tunisia causing several epidemics in poultry industry resulting in major economic losses. To monitor variations of Influenza viruses during the outbreaks, Tunisian H9N2 virus isolates were identified and genetically characterized. METHODS The genomic RNA segments of Tunisian H9N2 strains were subjected to RT-PCR amplifications followed by sequencing analysis. RESULTS Phylogenetic analysis demonstrated that A/Ck/TUN/12/10 and A/Migratory Bird/TUN/51/10 viruses represent multiple reassortant lineages, with genes coming from Middle East strains, and share the common ancestor Qa/HK/G1/97 isolate which has contributed internal genes of H5N1 virus circulating in Asia. Some of the internal genes seemed to have undergone broad reassortments with other influenza subtypes. Deduced amino acid sequences of the hemagglutinin (HA) gene showed the presence of additional glycosylation site and Leu at position 234 indicating to binding preference to α (2, 6) sialic acid receptors, indicating their potential to directly infect humans. The Hemagglutinin cleavage site motif sequence is 333 PARSSR*GLF341 which indicates the low pathogenicity nature of the Tunisian H9N2 strains and the potential to acquire the basic amino acids required for the highly pathogenic strains. Their neuraminidase protein (NA) carried substitutions in the hemadsorption (HB) site, similar to those of other avian H9N2 viruses from Asia, Middle Eastern and human pandemic H2N2 and H3N2 that bind to α -2, 6 -linked receptors. Two avian virus-like aa at positions 661 (A) and 702 (K), similar to H5N1 strains, were identified in the polymerase (PB2) protein. Likewise, matrix (M) protein carried some substitutions which are linked with increasing replication in mammals. In addition, H9N2 strain recently circulating carried new polymorphism, "GSEV" PDZ ligand (PL) C-terminal motif in its non structural (NS) protein.Two new aa substitutions (I) and (V), that haven't been previously reported, were identified in the polymerase and matrix proteins, respectively. Nucleoprotein and non-structural protein carried some substitutions similar to H5N1 strains. CONCLUSION Considering these new mutations, the molecular basis of tropism, host responses and enhanced virulence will be defined and studied. Otherwise, Continuous monitoring of viral genetic changes throughout the year is warranted to monitor variations of Influenza viruses in the field.
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Affiliation(s)
- Wafa Tombari
- Veterinary Microbiology laboratory, Pasteur Institute of Tunis, 1002 Tunis-Belvédère, Tunisia
| | - Jihene Nsiri
- Veterinary Microbiology laboratory, Pasteur Institute of Tunis, 1002 Tunis-Belvédère, Tunisia
| | - Imen Larbi
- Veterinary Microbiology laboratory, Pasteur Institute of Tunis, 1002 Tunis-Belvédère, Tunisia
| | - Jean Luc Guerin
- INRA, UMR 1225, Ecole nationale vétérinaire de Toulouse, F-31076 Toulouse, France
| | - Abdeljelil Ghram
- Veterinary Microbiology laboratory, Pasteur Institute of Tunis, 1002 Tunis-Belvédère, Tunisia
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Sun S, Wang Q, Zhao F, Chen W, Li Z. Glycosylation site alteration in the evolution of influenza A (H1N1) viruses. PLoS One 2011; 6:e22844. [PMID: 21829533 PMCID: PMC3145772 DOI: 10.1371/journal.pone.0022844] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 07/01/2011] [Indexed: 12/24/2022] Open
Abstract
Influenza virus typically alters protein glycosylation in order to escape immune pressure from hosts and hence to facilitate survival in different host environments. In this study, the patterns and conservation of glycosylation sites on HA and NA of influenza A/H1N1 viruses isolated from various hosts at different time periods were systematically analyzed, by employing a new strategy combining genome-based glycosylation site prediction and 3D modeling of glycoprotein structures, for elucidation of the modes and laws of glycosylation site alteration in the evolution of influenza A/H1N1 viruses. The results showed that influenza H1N1 viruses underwent different alterations of protein glycosylation in different hosts. Two alternative modes of glycosylation site alteration were involved in the evolution of human influenza virus: One was an increase in glycosylation site numbers, which mainly occurred with high frequency in the early stages of evolution. The other was a change in the positional conversion of the glycosylation sites, which was the dominating mode with relatively low frequency in the later evolutionary stages. The mechanisms and possibly biological functions of glycosylation site alteration for the evolution of influenza A/H1N1 viruses were also discussed. Importantly, the significant role of positional alteration of glycosylation sites in the host adaptation of influenza virus was elucidated. Although the results still need to be supported by experimental data, the information here may provide some constructive suggestions for research into the glycosylation of influenza viruses as well as even the design of surveillance and the production of viral vaccines.
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Affiliation(s)
- Shisheng Sun
- Laboratory of Functional Glycomics, College of Life Sciences, National Engineering Research Center for Miniaturized Detection System, Northwest University, Xi'an, People's Republic of China
| | - Qinzhe Wang
- Laboratory of Functional Glycomics, College of Life Sciences, National Engineering Research Center for Miniaturized Detection System, Northwest University, Xi'an, People's Republic of China
| | - Fei Zhao
- Laboratory of Functional Glycomics, College of Life Sciences, National Engineering Research Center for Miniaturized Detection System, Northwest University, Xi'an, People's Republic of China
| | - Wentian Chen
- Laboratory of Functional Glycomics, College of Life Sciences, National Engineering Research Center for Miniaturized Detection System, Northwest University, Xi'an, People's Republic of China
| | - Zheng Li
- Laboratory of Functional Glycomics, College of Life Sciences, National Engineering Research Center for Miniaturized Detection System, Northwest University, Xi'an, People's Republic of China
- * E-mail:
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Zhirnov OP, Klenk HD, Wright PF. Aprotinin and similar protease inhibitors as drugs against influenza. Antiviral Res 2011; 92:27-36. [PMID: 21802447 DOI: 10.1016/j.antiviral.2011.07.014] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 06/24/2011] [Accepted: 07/18/2011] [Indexed: 02/06/2023]
Abstract
Efforts to develop new antiviral chemotherapeutic approaches are focusing on compounds that target either influenza virus replication itself or host factor(s) that are critical to influenza replication. Host protease mediated influenza hemagglutinin (HA) cleavage is critical for activation of virus infectivity and as such is a chemotherapeutic target. Influenza pathogenesis involves a "vicious cycle" in which host proteases activate progeny virus which in turn amplifies replication and stimulates further protease activities which may be detrimental to the infected host. Aprotinin, a 58 amino acid polypeptide purified from bovine lung that is one of a family of host-targeted antivirals that inhibit serine proteases responsible for influenza virus activation. This drug and similar agents, such as leupeptin and camostat, suppress virus HA cleavage and limit reproduction of human and avian influenza viruses with a single arginine in the HA cleavage site. Site-directed structural modifications of aprotinin are possible to increase its intracellular targeting of cleavage of highly virulent H5 and H7 hemagglutinins possessing multi-arginine/lysine cleavage site. An additional mechanism of action for serine protease inhibitors is to target a number of host mediators of inflammation and down regulate their levels in virus-infected hosts. Aprotinin is a generic drug approved for intravenous use in humans to treat pancreatitis and limit post-operative bleeding. As an antiinfluenzal compound, aprotinin might be delivered by two routes: (i) a small-particle aerosol has been approved in Russia for local respiratory application in mild-to-moderate influenza and (ii) a proposed intravenous administration for severe influenza to provide both an antiviral effect and a decrease in systemic pathology and inflammation.
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Affiliation(s)
- O P Zhirnov
- D.I. Ivanovsky Institute of Virology, Moscow 123098, Russia.
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29
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Passage of low-pathogenic avian influenza (LPAI) viruses mediates rapid genetic adaptation of a wild-bird isolate in poultry. Arch Virol 2011; 156:565-76. [DOI: 10.1007/s00705-010-0891-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Accepted: 12/10/2010] [Indexed: 10/18/2022]
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Bertram S, Glowacka I, Steffen I, Kühl A, Pöhlmann S. Novel insights into proteolytic cleavage of influenza virus hemagglutinin. Rev Med Virol 2010; 20:298-310. [PMID: 20629046 PMCID: PMC7169116 DOI: 10.1002/rmv.657] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The influenza virus hemagglutinin (HA) mediates the first essential step in the viral life cycle, virus entry into target cells. Influenza virus HA is synthesised as a precursor protein in infected cells and requires cleavage by host cell proteases to transit into an active form. Cleavage is essential for influenza virus infectivity and the HA‐processing proteases are attractive targets for therapeutic intervention. It is well established that cleavage by ubiquitously expressed subtilisin‐like proteases is a hallmark of highly pathogenic avian influenza viruses (HPAIV). In contrast, the nature of the proteases responsible for cleavage of HA of human influenza viruses and low pathogenic avian influenza viruses (LPAIV) is not well understood. Recent studies suggest that cleavage of HA of human influenza viruses might be a cell‐associated event and might be facilitated by the type II transmembrane serine proteases (TTSPs) TMPRSS2, TMPRSS4 and human airway trypsin‐like protease (HAT). Here, we will introduce the different concepts established for proteolytic activation of influenza virus HA, with a particular focus on the role of TTSPs, and we will discuss their implications for viral tropism, pathogenicity and antiviral intervention. Copyright © 2010 John Wiley & Sons, Ltd.
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Affiliation(s)
- Stephanie Bertram
- Institute of Virology, Hannover Medical School, 30625 Hannover, Germany
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31
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Cross-reactive neutralizing antibodies directed against pandemic H1N1 2009 virus are protective in a highly sensitive DBA/2 mouse influenza model. J Virol 2010; 84:7662-7. [PMID: 20484500 DOI: 10.1128/jvi.02444-09] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Our ability to rapidly respond to an emerging influenza pandemic is hampered somewhat by the lack of a susceptible small-animal model. To develop a more sensitive model, we pathotyped 18 low-pathogenic non-mouse-adapted influenza A viruses of human and avian origin in DBA/2 and C57BL/6 mice. The majority of the isolates (13/18) induced severe morbidity and mortality in DBA/2 mice upon intranasal challenge with 1 million infectious doses. Also, at a 100-fold-lower dose, more than 50% of the viruses induced severe weight loss, and mice succumbed to the infection. In contrast, only two virus strains were pathogenic for C57BL/6 mice upon high-dose inoculation. Therefore, DBA/2 mice are a suitable model to validate influenza A virus vaccines and antiviral therapies without the need for extensive viral adaptation. Correspondingly, we used the DBA/2 model to assess the level of protection afforded by preexisting pandemic H1N1 2009 virus (H1N1pdm) cross-reactive human antibodies detected by a hemagglutination inhibition assay. Passive transfer of these antibodies prior to infection protected mice from H1N1pdm-induced pathogenicity, demonstrating the effectiveness of these cross-reactive neutralizing antibodies in vivo.
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32
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Novel type II transmembrane serine proteases, MSPL and TMPRSS13, Proteolytically activate membrane fusion activity of the hemagglutinin of highly pathogenic avian influenza viruses and induce their multicycle replication. J Virol 2010; 84:5089-96. [PMID: 20219906 DOI: 10.1128/jvi.02605-09] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Host cellular proteases induce influenza virus entry into cells by cleaving the viral surface envelope glycoprotein hemagglutinin (HA). However, details on the cellular proteases involved in this event are not fully available. We report here that ubiquitous type II transmembrane serine proteases, MSPL and its splice variant TMPRSS13, are novel candidates for proteases processing HA proteins of highly pathogenic avian influenza (HPAI) viruses, apart from the previously identified furin and proprotein convertases 5 and 6. HAs from all HPAI virus H5 and H7 strains have one of two cleavage site motifs, the R-X-K/R-R motif with R at position P4 and the K-K/R-K/T-R motif with K at position P4. In studies of synthetic 14-residue HPAI virus HA peptides with these cleavage site motifs, furin preferentially cleaved only HA peptides with the R-K-K-R motif in the presence of calcium and not peptides with the other motif, whereas MSPL and TMPRSS13 cleaved both types of HA peptides (those with the R/K-K-K-R motif) efficiently in the absence of calcium. Full-length recombinant HPAI virus HA with the K-K-K-R cleavage motif exhibited poor susceptibility to cleavage in the absence of MSPL or TMPRSS13 and the presence of furin in infected cells, but it was converted to mature HA subunits in transfected cells expressing MSPL or TMPRSS13, with membrane-fused giant-cell formation. This conversion and membrane fusion were suppressed by inhibitors of MSPL and TMPRSS13. Furthermore, infection with and multiplication of genetically modified live HPAI virus A/Crow/Kyoto/53/2004 (H5N1) with the K-K-K-R cleavage site motif were detected only in MSPL- and TMPRSS13-expressing cells.
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Ji K, Jiang WM, Liu S, Chen JM, Chen J, Hou GY, Li JP, Huang BX. Characterization of the hemagglutinin gene of subtype H9 avian influenza viruses isolated in 2007-2009 in China. J Virol Methods 2009; 163:186-9. [PMID: 19781574 DOI: 10.1016/j.jviromet.2009.09.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2009] [Revised: 09/08/2009] [Accepted: 09/14/2009] [Indexed: 11/25/2022]
Abstract
Subtype H9 avian influenza viruses (AIVs) circulating in China have aroused concerns for their impact on poultry and risk to public health. In this report, three surveys of the viruses were reported, and the hemagglutinin gene of 55 strains of the viruses isolated in China in 2007-2009 was sequenced and analyzed. The results indicated that the prevalence of the viruses was rising in China, and most of the H9 AIVs circulating in the past decade in China belonged to sublineage h9.4.2. The viruses isolated in China in 2007-2009 were a little different from previous strains (genetic distances >7.1%). Meanwhile, a presumably predominant clade of the viruses circulating in China in 2007-2009 was identified. Mutation analysis suggested that the viruses have become of greater risk to public health in recent years.
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Affiliation(s)
- Kang Ji
- China Animal Health & Epidemiology Center, Qingdao 266032, China
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34
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Wang SF, Lee YM, Chan YJ, Liu HF, Yen YF, Liu WT, Huang JC, Chen YMA. Influenza A virus in Taiwan, 1980-2006: Phylogenetic and antigenic characteristics of the hemagglutinin gene. J Med Virol 2009; 81:1457-70. [PMID: 19551820 PMCID: PMC7166446 DOI: 10.1002/jmv.21531] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Limited amount of information is available in Taiwan on the genetic or antigenic characteristics of influenza A virus prior to the establishment of a Taiwan surveillance network in 2000. Isolates of H1N1 and H3N2 viruses in Taiwan between 1980 and 2006 were studied, and part of the hemagglutinin gene was analyzed due to its importance in terms of viral infection and antibody neutralization. Results from a phylogenetic analysis indicate continuous evolutionary topology in H3N2 isolates, and two distinct H1N1 lineages. Many genetic relationships between vaccine strains and epidemic isolates appearing in Taiwan before other global locations were also observed and recorded in addition to a gradual increase in the number of N‐linked glycosylation sites on partial HA1 proteins since 1980. The results from pairwise comparisons of HA1 nucleotide and deduced amino acid sequences indicate shared identities within groups organized according to their bootstrap and P‐values of approximately 95.5–100% and 95.7–100% in H1N1 and 94.5–100% and 93.2–100% in H3N2 viruses, respectively. Comparisons of amino acid substitutions in the five antigenic regions reveal highly non‐synonymous changes occurring in the Sb region of H1N1 and in the B region of H3N2. The results of an antigenic analysis using a hemagglutinin inhibition (HI) test indicate the presence of some epidemic strains 1–2 years earlier in Taiwan than in other parts of the world, as well as higher vaccine mismatch rates. This information supports the need for continuous surveillance of emerging influenza viruses in Taiwan, which will be useful for making global vaccine decisions. J. Med. Virol. 81:1457–1470, 2009. © 2009 Wiley‐Liss, Inc.
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Affiliation(s)
- Sheng-Fan Wang
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan
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35
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Nipah virus fusion protein: influence of cleavage site mutations on the cleavability by cathepsin L, trypsin and furin. Virus Res 2009; 145:300-6. [PMID: 19665506 PMCID: PMC7126315 DOI: 10.1016/j.virusres.2009.07.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Revised: 07/28/2009] [Accepted: 07/29/2009] [Indexed: 11/22/2022]
Abstract
Nipah virus (NiV), a highly pathogenic member of the Paramyxoviridae which originated from bats, encodes for a fusion (F) protein which is proteolytically processed within endosomes by cathepsin L. We show here that sequence requirements for NiV F activation differ markedly from other para- or orthomyxoviral fusion proteins. In contrast to other viral fusion proteins with monobasic cleavage sites, processing of NiV F proteins with one single basic amino acid in the cleavage peptide by exogenous trypsin is very inefficient, and introduction of a consensus sequence for furin does not result in cleavage by this ubiquitous protease. In contrast, a multibasic cleavage peptide in the NiV F protein completely impairs proteolytic processing and the generation of biological activity.
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36
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37
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Blake TA, Williams TL, Pirkle JL, Barr JR. Targeted N-linked glycosylation analysis of H5N1 influenza hemagglutinin by selective sample preparation and liquid chromatography/tandem mass spectrometry. Anal Chem 2009; 81:3109-18. [PMID: 19290601 DOI: 10.1021/ac900095h] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Using liquid chromatography/tandem mass spectrometry (LC/MS/MS) analysis of deglycosylated and intact glycopeptides from tryptic digests of whole influenza virus, we determined that the six predicted N-linked glycosylation sites within the N-terminal ectodomain of hemagglutinin (HA) from three selected H5N1 strains are occupied. The use of selective sample preparation strategies, including solid-phase extraction (SPE) of glycopeptides via hydrazide capture chemistry as well as hydrophilic interaction liquid chromatography (HILIC), sufficiently reduced sample complexity to allow determination of occupied glycosylation sites. The specific amino acid sequence of the tryptic glycopeptides for the identified sites varied slightly among strains, but the overall locations of the occupied glycosylation sites were conserved in the protein sequence. We used this knowledge of glycosylation site occupation to examine the glycans attached to these occupied sites on HA for a reassortant H5N1 strain grown in embryonated chicken eggs. By applying mass spectrometry-based methodologies for examining glycosylation to the study of influenza virus proteins, we can better understand the effect that this post-translational modification has upon the virulence and antigenicity of emerging strains.
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Affiliation(s)
- Thomas A Blake
- Biological Mass Spectrometry Laboratory, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Highway, MS F-50, Atlanta, Georgia 30341, USA
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38
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Secondary structural analysis of the mRNA regions encoding the hemagglutinin cleavage site basic amino acids of the avian influenza virus H5N1 subtype samples. CHINESE SCIENCE BULLETIN-CHINESE 2008. [DOI: 10.1007/s11434-008-0119-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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39
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Londt BZ, Banks J, Alexander DJ. Highly pathogenic avian influenza viruses with low virulence for chickens in in vivo tests. Avian Pathol 2007; 36:347-50. [PMID: 17899457 DOI: 10.1080/03079450701589134] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Four avian influenza viruses have been recognized that have genetic coding for highly pathogenic avian influenza viruses, but do not show virulence for chickens. The two different mechanisms that prevent this potential being expressed have been determined for A/chicken/Pennsylvania/1/83 (H5N2) and A/goose/Guandong/2/96 (H5N1), but neither of these applies to A/turkey/England/87-92BFC/91 (H5N1) or A/chicken/Texas/298313/04 (H5N2).
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Affiliation(s)
- Brandon Z Londt
- Virology Department, Veterinary Laboratories Agency Weybridge, New Haw, Addlestone, Surrey, UK
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40
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Lee CW, Lee YJ, Swayne D, Senne D, Linares DJ, Suarez D. Assessing potential pathogenicity of avian influenza virus: current and experimental system. Avian Dis 2007; 51:260-3. [PMID: 17494562 DOI: 10.1637/7572-033106r.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
An avian influenza (AI) isolate can be classified as a high pathogenicity avian influenza (HPAI) virus based upon the results of the standard intravenous pathogenicity index test; molecular classification, which is derived by sequencing the hemagglutinin gene across the site coding for the cleavage site; or a combination. However, discordant results between the molecular classification and virulence for experimentally infected chickens have been observed with several H5 and H7 subtype AI viruses. Because the declaration of HPAI virus results in severe effects on trade for the entire country, the gap between the genetic and phenotypic markers is an important issue, and it requires us to reexamine what should be considered an HPAI virus by the Office International des Epizooties standards. To better understand and assess the true virulence of the virus, potential pathogenicity of H5 and H7 subtype AI virus isolates has been assessed by examining the plaquing efficiency of the virus in chicken embryo fibroblast cells, conducting 14-day-old embryo passage and selection system, and applying in vitro mutagenesis coupled with reverse genetics. The potential value of these complimentary methods in assessing potential pathogenicity of the AI virus is discussed.
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Affiliation(s)
- C W Lee
- The Ohio State University, Food Animal Health Research Program, Wooster, OH 44691, USA
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41
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Developments in Avian Influenza Virus Vaccines. J Poult Sci 2007. [DOI: 10.2141/jpsa.44.238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Pourmand N, Diamond L, Garten R, Erickson JP, Kumm J, Donis RO, Davis RW. Rapid and highly informative diagnostic assay for H5N1 influenza viruses. PLoS One 2006; 1:e95. [PMID: 17183727 PMCID: PMC1762361 DOI: 10.1371/journal.pone.0000095] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2006] [Accepted: 11/20/2006] [Indexed: 11/19/2022] Open
Abstract
A highly discriminative and information-rich diagnostic assay for H5N1 avian influenza would meet immediate patient care needs and provide valuable information for public health interventions, e.g., tracking of new and more dangerous variants by geographic area as well as avian-to-human or human-to-human transmission. In the present study, we have designed a rapid assay based on multilocus nucleic acid sequencing that focuses on the biologically significant regions of the H5N1 hemagglutinin gene. This allows the prediction of viral strain, clade, receptor binding properties, low- or high-pathogenicity cleavage site and glycosylation status. H5 HA genes were selected from nine known high-pathogenicity avian influenza subtype H5N1 viruses, based on their diversity in biologically significant regions of hemagglutinin and/or their ability to cause infection in humans. We devised a consensus pre-programmed pyrosequencing strategy, which may be used as a faster, more accurate alternative to de novo sequencing. The available data suggest that the assay described here is a reliable, rapid, information-rich and cost-effective approach for definitive diagnosis of H5N1 avian influenza. Knowledge of the predicted functional sequences of the HA will enhance H5N1 avian influenza surveillance efforts.
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MESH Headings
- Animals
- Base Sequence
- Birds
- DNA Primers/genetics
- DNA, Viral/genetics
- Genes, Viral
- Hemagglutinin Glycoproteins, Influenza Virus/genetics
- Humans
- Influenza A Virus, H5N1 Subtype/genetics
- Influenza A Virus, H5N1 Subtype/isolation & purification
- Influenza A Virus, H5N1 Subtype/pathogenicity
- Influenza in Birds/virology
- Influenza, Human/diagnosis
- Influenza, Human/transmission
- Influenza, Human/virology
- Molecular Sequence Data
- Phylogeny
- Polymerase Chain Reaction/methods
- Sequence Analysis, RNA/methods
- Virology/methods
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Affiliation(s)
- Nader Pourmand
- Stanford Genome Technology Center, Stanford University, Palo Alto, California, United States of America.
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Bragstad K, Jørgensen PH, Handberg KJ, Fomsgaard A. Genome characterisation of the newly discovered avian influenza A H5N7 virus subtype combination. Arch Virol 2006; 152:585-93. [PMID: 17115305 DOI: 10.1007/s00705-006-0860-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Accepted: 08/18/2006] [Indexed: 11/27/2022]
Abstract
In Denmark, in 2003, a previously unknown subtype combination of avian influenza A virus, H5N7 (A/Mallard/Denmark/64650/03), was isolated from a flock of 12,000 mallards. The H5N7 subtype combination might be a reassortant between recent European avian influenza A H5, H7, and a third subtype, possibly an H6. The haemagglutinin and the acidic polymerase genes of the virus were closely related to a low-pathogenic Danish H5N2 virus A/Duck/Denmark/65041/04 (H5N2). The neuraminidase gene and the non-structural gene were most similar to the highly pathogenic A/Chicken/Netherlands/1/03 (H7N7) and the human-fatal A/Netherlands/219/03 (H7N7), respectively. The basic polymerase 1 and 2 genes were phylogenetically equidistant to both A/Duck/Denmark/65047/04 (H5N2) and A/Chicken/Netherlands/1/03 (H7N7). The nucleoprotein and matrix gene had highest nucleotide sequence similarity to the H6 subtypes A/Duck/Hong Kong/3096/99 (H6N2) and A/WDk/ST/1737/2000 (H6N8), respectively. All genes of the H5N7 strain were of avian origin, and no further evidence of pathogenicity to humans has been found.
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Affiliation(s)
- K Bragstad
- Department of Virology, Statens Serum Institut, Copenhagen, Denmark
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Lee CW, Lee YJ, Senne DA, Suarez DL. Pathogenic potential of North American H7N2 avian influenza virus: a mutagenesis study using reverse genetics. Virology 2006; 353:388-95. [PMID: 16828833 DOI: 10.1016/j.virol.2006.06.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Revised: 05/16/2006] [Accepted: 06/02/2006] [Indexed: 11/27/2022]
Abstract
An H7N2 subtype avian influenza virus (AIV) first appeared in the live bird marketing system (LBMS) in the Northeastern United States in 1994. Since then this lineage of virus has become the predominant subtype of AIV isolated from the LBMS and has been linked to several costly commercial poultry outbreaks. Concern for this low pathogenicity isolate mutating to the highly pathogenic form has remained high because of the increasing number of basic amino acids at the hemagglutinin (HA) cleavage site, which is known to be associated with increased pathogenicity of AIV. To address the risk of low pathogenic LBMS-lineage H7N2 virus mutating to the highly pathogenic form of the virus, we generated a series of mutant viruses that have changes in the sequence at the HA cleavage site by using plasmid-based reverse genetics. We confirmed that a conserved proline at -5 position from the HA cleavage site could be changed to a basic amino acid, producing a virus with five basic amino acids in a row at the cleavage site, but with no increase in virulence. Increased virulence was only observed when additional basic amino acids were inserted. We also observed that the virus preferred the arginine instead of lysine at the -4 position from the cleavage site to manifest increased virulence both in vitro and in vivo. Using helper virus-based reverse genetics, where only one transcription plasmid expressing a mutated HA vRNA is used, we identified specific HA cleavage site sequences that were preferentially incorporated into the low pathogenic wild-type virus. The resultant reassortant viruses were highly pathogenic in chickens. This study provides additional evidence that H7 avian influenza viruses require an insertional event to become highly pathogenic, as compared to H5 viruses that can become highly pathogenic strictly by mutation or by insertions.
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Affiliation(s)
- Chang-Won Lee
- Southeast Poultry Research Laboratory, USDA-ARS, 934 College Station Road, Athens, GA 30605, USA
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Lee CW, Swayne DE, Linares JA, Senne DA, Suarez DL. H5N2 avian influenza outbreak in Texas in 2004: the first highly pathogenic strain in the United States in 20 years? J Virol 2005; 79:11412-21. [PMID: 16103192 PMCID: PMC1193578 DOI: 10.1128/jvi.79.17.11412-11421.2005] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In early 2004, an H5N2 avian influenza virus (AIV) that met the molecular criteria for classification as a highly pathogenic AIV was isolated from chickens in the state of Texas in the United States. However, clinical manifestations in the affected flock were consistent with avian influenza caused by a low-pathogenicity AIV and the representative virus (A/chicken/Texas/298313/04 [TX/04]) was not virulent for experimentally inoculated chickens. The hemagglutinin (HA) gene of the TX/04 isolate was similar in sequence to A/chicken/Texas/167280-4/02 (TX/02), a low-pathogenicity AIV isolate recovered from chickens in Texas in 2002. However, the TX/04 isolate had one additional basic amino acid at the HA cleavage site, which could be attributed to a single point mutation. The TX/04 isolate was similar in sequence to TX/02 isolate in several internal genes (NP, M, and NS), but some genes (PA, PB1, and PB2) had sequence of a clearly different origin. The TX/04 isolate also had a stalk deletion in the NA gene, characteristic of a chicken-adapted AIV. By analyzing viruses constructed by in vitro mutagenesis followed by reverse genetics, we found that the pathogenicity of the TX/04 virus could be increased in vitro and in vivo by the insertion of an additional basic amino acid at the HA cleavage site and not by the loss of a glycosylation site near the cleavage site. Our study provides the genetic and biologic characteristics of the TX/04 isolate, which highlight the complexity of the polygenic nature of the virulence of influenza viruses.
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Affiliation(s)
- Chang-Won Lee
- Southeast Poultry Research Laboratory, USDA-ARS, Athens, GA 30605, USA
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Bragstad K, Jørgensen PH, Handberg KJ, Mellergaard S, Corbet S, Fomsgaard A. New avian influenza A virus subtype combination H5N7 identified in Danish mallard ducks. Virus Res 2005; 109:181-90. [PMID: 15763149 DOI: 10.1016/j.virusres.2004.12.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2004] [Revised: 12/13/2004] [Accepted: 12/13/2004] [Indexed: 12/09/2022]
Abstract
During the past years increasing incidences of influenza A zoonosis have made it of uppermost importance to possess methods for rapid and precise identification and characterisation of influenza A viruses. We present here a convenient one-step RT-PCR method that will amplify full-length haemagglutinin (HA) and neuraminidase (NA) directly from clinical samples and from all known subtypes of influenza A. We applied the method on samples collected in September 2003 from a Danish flock of mallards with general health problems and by this a previously undescribed influenza A subtype combination, H5N7, was identified. The HA gene showed great sequence similarity to the highly pathogenic avian influenza A virus (HPAIV) A/Chicken/Italy/312/97 (H5N2); however, the cleavage site sequence between HA1 and HA2 had a motif typical for low pathogenic avian influenza viruses (LPAIV). The full-length NA sequence was most closely related to the HPAIV A/Chicken/Netherlands/01/03 (H7N7) that infected chickens and humans in the Netherlands in 2003. Ten persons with direct or indirect contact with the Danish mallard ducks showed signs of influenza-like illness 2-3 days following the killing of the ducks, but no evidence of influence infections was detected. To our knowledge this is the first report of an H5N7 influenza A virus.
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Affiliation(s)
- K Bragstad
- Department of Virology, Statens Serum Institut, 5 Artillerivej, DK-2300 Copenhagen S, Denmark
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Al-Natour MQ, Abo-Shehada MN. Sero-prevalence of avian influenza among broiler-breeder flocks in Jordan. Prev Vet Med 2005; 70:45-50. [PMID: 15967241 DOI: 10.1016/j.prevetmed.2005.02.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2004] [Revised: 11/30/2004] [Accepted: 02/22/2005] [Indexed: 11/29/2022]
Abstract
Thirty blood samples were collected randomly from each of the 38 breeder-broiler farms in Jordan. Serum samples were examined using indirect ELISA for specific antibodies to avian influenza virus. The overall true flock-level sero-prevalence of avian influenza was 71% (95% CI: 55,83). Positive flocks had 2-30 sero-positive chickens and half of flocks had >20 sero-positive birds. The number of sero-positive flocks varied in the studied localities with more sero-positives in farms located within the migratory route of migratory wild fowl. The examined broiler-breeder flocks had no clinical signs, or noticeable decrease in egg production; mortalities were within the normal range (0.1-1%). The number of positive sera/flock correlated with flock size. There were a no significant (Pearsons r=0.21, p=0.21) correlation between positive flocks and age. A non-pathogenic AI virus infects broiler-breeder farms in Jordan. Wild local and migrating birds might promote the further spread of this virus in Jordan and other countries.
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Affiliation(s)
- Mohammad Q Al-Natour
- Department of Pathology and Animal Health, Faculty of Veterinary Medicine, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110, Jordan
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Xu C, Fan W, Wei R, Zhao H. Isolation and identification of swine influenza recombinant A/Swine/Shandong/1/2003(H9N2) virus. Microbes Infect 2004; 6:919-25. [PMID: 15310468 DOI: 10.1016/j.micinf.2004.04.015] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2004] [Accepted: 04/20/2004] [Indexed: 10/26/2022]
Abstract
Ten influenza virus isolates were obtained from infected pigs from different places in Shandong province showing clinical symptoms from October 2002 to January 2003. All 10 isolates were identified in China's National Influenza Research Center as influenza A virus of H9N2 subtype. The complete genome of one isolate, designated A/Swine/Shandong/1/2003(H9N2), was sequenced and compared with sequences available in GenBank. The results of analyses indicated that the sequence of A/Swine/Shandong/1/2003(H9N2) was similar to those of several chicken influenza viruses and duck influenza viruses recently prevalent in South China. According to phylogenetic analysis of the complete gene sequences, A/Swine/Shandong/1/2003(H9N2) possibly originated from the reassortment of chicken influenza viruses and duck influenza viruses. It was found that the amino acid sequence at the HA cleavage site in Sw/SD/1/2003 is R-S-L-R-G, differing clearly from that of other H9N2 subtype isolates of swine influenza and avian influenza, which is R-S-S-R-G.
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Affiliation(s)
- Chuantian Xu
- College of Animal Science, Shandong Agriculture University, Shandong Province, Taian City 271018, People's Republic of China.
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Baigent SJ, McCauley JW. Influenza type A in humans, mammals and birds: determinants of virus virulence, host-range and interspecies transmission. Bioessays 2003; 25:657-71. [PMID: 12815721 DOI: 10.1002/bies.10303] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The virulence of a virus is determined by its ability to adversely affect the host cell, host organism or population of host organisms. Influenza A viruses have been responsible for four pandemics of severe human respiratory disease this century. Avian species harbour a large reservoir of influenza virus strains, which can contribute genes to potential new pandemic human strains. The fundamental importance of understanding the role of each of these genes in determining virulence in birds and humans was dramatically emphasised by the recent direct transmission of avian influenza A viruses to humans, causing fatal infection but not community spread. An understanding of the factors involved in transmission between avian and mammalian species should assist in the development of better surveillance strategies for early recognition of influenza A virus strains having human pandemic potential, and possibly in the design of anti-viral strategies.
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Affiliation(s)
- Susan J Baigent
- Division of Molecular Biology, Institute for Animal Health, Newbury, UK.
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Tsuchiya E, Sugawara K, Hongo S, Matsuzaki Y, Muraki Y, Nakamura K. Role of overlapping glycosylation sequons in antigenic properties, intracellular transport and biological activities of influenza A/H2N2 virus haemagglutinin. J Gen Virol 2002; 83:3067-3074. [PMID: 12466483 DOI: 10.1099/0022-1317-83-12-3067] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The haemagglutinin (HA) protein of influenza A/H2N2 virus possesses five oligosaccharide attachment sites, two of which have overlapping glycosylation sequons at positions 20-23 (NNST) and 169-172 (NNTS). Here, the role of these two oligosaccharide attachment sites is investigated with regard to antigenic property, intracellular transport and biological activity of the HA protein. Glycosylation-site HA mutants with mutation(s) in their overlapping glycosylated sequons, each of which had one or two oligosaccharide attachment sites removed, were constructed. Comparison of electrophoretic mobility between the wt and mutant HA proteins showed that both Asn residues 20 and 21 and Asn residues 169 and 170 could be used for glycosylation. Analysis of reactivity of the mutants with anti-HA monoclonal antibodies suggested that amino acid changes at these two positions result in a conformational change of the HA molecule. Even if oligosaccharide chains linked to Asn 20 or 21 and Asn 169 or 170 are eliminated, the antigenic properties, intracellular transport and biological activities are not influenced strongly. Thus it is reasonable to conclude that the two overlapping glycosylation sequons at positions 20-23 and 169-172 are conserved among all of the HAs of influenza A/H2N2 viruses because conservation of the amino acid sequence itself rather than that of N-glycosylation is essential for the formation of the proper conformation, intracellular transport and biological activities of the H2 subtype HA.
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Affiliation(s)
- Emi Tsuchiya
- Department of Bacteriology, Yamagata University School of Medicine, Iida-Nishi, Yamagata 990-9585, Japan1
| | - Kanetsu Sugawara
- Department of Bacteriology, Yamagata University School of Medicine, Iida-Nishi, Yamagata 990-9585, Japan1
| | - Seiji Hongo
- Department of Bacteriology, Yamagata University School of Medicine, Iida-Nishi, Yamagata 990-9585, Japan1
| | - Yoko Matsuzaki
- Department of Bacteriology, Yamagata University School of Medicine, Iida-Nishi, Yamagata 990-9585, Japan1
| | - Yasushi Muraki
- Department of Bacteriology, Yamagata University School of Medicine, Iida-Nishi, Yamagata 990-9585, Japan1
| | - Kiyoto Nakamura
- Department of Bacteriology, Yamagata University School of Medicine, Iida-Nishi, Yamagata 990-9585, Japan1
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