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Sives S, Keep S, Bickerton E, Vervelde L. Revealing Novel-Strain-Specific and Shared Epitopes of Infectious Bronchitis Virus Spike Glycoprotein Using Chemical Linkage of Peptides onto Scaffolds Precision Epitope Mapping. Viruses 2023; 15:2279. [PMID: 38005955 PMCID: PMC10675791 DOI: 10.3390/v15112279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 11/16/2023] [Accepted: 11/17/2023] [Indexed: 11/26/2023] Open
Abstract
The avian coronavirus, infectious bronchitis virus (IBV), is an economically important infectious disease affecting chickens, with a diverse range of serotypes found globally. The major surface protein, spike (S), has high diversity between serotypes, and amino acid differences in the S1 sub-unit are thought to be responsible for poor cross-protection afforded by vaccination. Here, we attempt to address this, by using epitope mapping technology to identify shared and serotype-specific immunogenic epitopes of the S glycoprotein of three major circulating strains of IBV, M41, QX, and 4/91, via CLIPS peptide arrays based on peptides from the S1 sub-units. The arrays were screened with sera from chickens immunised with recombinant IBV, based on Beau-R backbone expressing heterologous S, generated in two independent vaccination/challenge trials. The screening of sera from rIBV vaccination experiments led to the identification of 52 immunogenic epitopes on the S1 of M41, QX, and 4/91. The epitopes were assigned into six overlapping epitope binding regions. Based on accessibility and location in the hypervariable regions of S, three sequences, 25YVYYYQSAFRPPNGWHLQGGAYAVVNSTN54, 67TVGVIKDVYNQSVASI82, and 83AMTVPPAGMSWSVS96, were selected for further investigation, and synthetic peptide mimics were recognised by polyclonal sera. These epitopes may have the potential to contribute towards a broader cross-protective IBV vaccine.
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Affiliation(s)
- Samantha Sives
- Division of Immunology, The Roslin Institute & R(D)SVS, University of Edinburgh, Easter Bush, Edinburgh EH25 9RG, UK;
| | - Sarah Keep
- The Pirbright Institute, Ash Road, Woking GU24 0NF, UK (E.B.)
| | - Erica Bickerton
- The Pirbright Institute, Ash Road, Woking GU24 0NF, UK (E.B.)
| | - Lonneke Vervelde
- Division of Immunology, The Roslin Institute & R(D)SVS, University of Edinburgh, Easter Bush, Edinburgh EH25 9RG, UK;
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2
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Wang Q, Sun Z, Li J, Qin T, Ma H, Chen S, Peng D, Liu X. Identification of a universal antigen epitope of influenza A virus using peptide microarray. BMC Vet Res 2021; 17:22. [PMID: 33413356 PMCID: PMC7792037 DOI: 10.1186/s12917-020-02725-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 12/15/2020] [Indexed: 02/08/2023] Open
Abstract
Background Hemagglutinin is a major surface protein in influenza A virus (IAV), and HA2 is relative conserved among different IAVs. It will be meaningful to identify broad-spectrum epitopes based on the HA2 protein. Results Overlapping peptides of the HA2 protein of the H5N1 IAV A/Mallard/Huadong/S/2005 were synthesized and loaded on modified silica gel film to form a microarray, and antisera against different subtypes of IAVs were used to screen universal epitopes. The selected epitope was further confirmed by western blotting using anti-peptide immune serum and viruses rescued with amino acid substitution. The results showed that 485-FYHKCDNECME-495 of the H5 14th peptide in HA2 had broad-spectrum binding activity with antisera against H1, H3, H4, H5, H6, H7, H8, H9, and H10 subtype IAV. Substitution of amino acids (K or D) in rescued viruses resulted in decreased serum binding, indicating that they were critical residues for serum binding activity. In Immune Epitope Database, some epitopes containing 14–4 peptide were confirmed as MHC-II-restricted CD4 T cell epitope and had effects on releasing IL-2 or IFN. Conclusion The identified epitope should be a novel universal target for detection and vaccine design and its ability to generate immune protection needs further exploration. Supplementary Information The online version contains supplementary material available at 10.1186/s12917-020-02725-5.
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Affiliation(s)
- Qiuxia Wang
- College of Veterinary Medicine, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, People's Republic of China.,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, 225009, Jiangsu, People's Republic of China.,Jiangsu Research Centre of Engineering and Technology for Prevention and Control of Poultry Disease, Yangzhou, 225009, Jiangsu, People's Republic of China
| | - Zhihao Sun
- College of Veterinary Medicine, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, People's Republic of China.,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, 225009, Jiangsu, People's Republic of China.,Jiangsu Research Centre of Engineering and Technology for Prevention and Control of Poultry Disease, Yangzhou, 225009, Jiangsu, People's Republic of China
| | - Jingzhi Li
- Division of Nanobiomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215000, People's Republic of China
| | - Tao Qin
- College of Veterinary Medicine, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, People's Republic of China.,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, 225009, Jiangsu, People's Republic of China.,Jiangsu Research Centre of Engineering and Technology for Prevention and Control of Poultry Disease, Yangzhou, 225009, Jiangsu, People's Republic of China
| | - Hongwei Ma
- Division of Nanobiomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215000, People's Republic of China
| | - Sujuan Chen
- College of Veterinary Medicine, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, People's Republic of China. .,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, 225009, Jiangsu, People's Republic of China. .,Jiangsu Research Centre of Engineering and Technology for Prevention and Control of Poultry Disease, Yangzhou, 225009, Jiangsu, People's Republic of China. .,Joint Laboratory Safety of International Cooperation of Agriculture & Agricultural-Products, Yangzhou, Jiangsu, 225009, People's Republic of China.
| | - Daxin Peng
- College of Veterinary Medicine, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, People's Republic of China. .,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, 225009, Jiangsu, People's Republic of China. .,Jiangsu Research Centre of Engineering and Technology for Prevention and Control of Poultry Disease, Yangzhou, 225009, Jiangsu, People's Republic of China. .,Joint Laboratory Safety of International Cooperation of Agriculture & Agricultural-Products, Yangzhou, Jiangsu, 225009, People's Republic of China.
| | - Xiufan Liu
- College of Veterinary Medicine, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, 225009, People's Republic of China.,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, Yangzhou, 225009, Jiangsu, People's Republic of China.,Joint Laboratory Safety of International Cooperation of Agriculture & Agricultural-Products, Yangzhou, Jiangsu, 225009, People's Republic of China
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3
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Human Monoclonal Antibody Derived from Transchromosomic Cattle Neutralizes Multiple H1 Clades of Influenza A Virus by Recognizing a Novel Conformational Epitope in the Hemagglutinin Head Domain. J Virol 2020; 94:JVI.00945-20. [PMID: 32847862 DOI: 10.1128/jvi.00945-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 08/03/2020] [Indexed: 11/20/2022] Open
Abstract
Influenza remains a global health risk and challenge. Currently, neuraminidase (NA) inhibitors are extensively used to treat influenza, but their efficacy is compromised by the emergence of drug-resistant variants. Neutralizing antibodies targeting influenza A virus surface glycoproteins are critical components of influenza therapeutic agents and may provide alternative strategies to the existing countermeasures. However, the major hurdle for the extensive application of antibody therapies lies in the difficulty of generating nonimmunogenic antibodies in large quantities rapidly. Here, we report that one human monoclonal antibody (MAb), 53C10, isolated from transchromosomic (Tc) cattle exhibits potent neutralization and hemagglutination inhibition titers against different clades of H1N1 subtype influenza A viruses. In vitro selection of antibody escape mutants revealed that 53C10 recognizes a novel noncontinuous epitope in the hemagglutinin (HA) head domain involving three amino acid residues, glycine (G), serine (S), and glutamic acid (E) at positions 172, 207, and 212, respectively. The results of our experiments supported a critical role for substitution of arginine at position 207 (S207R) in mediating resistance to 53C10, while substitutions at either G172E or E212A did not alter antibody recognition and neutralization. The E212A mutation may provide structural stability for the epitope, while the substitution G172E probably compensates for loss of fitness introduced by S207R. Our results offer novel insights into the mechanism of action of MAb 53C10 and indicate its potential role in therapeutic treatment of H1 influenza virus infection in humans.IMPORTANCE Respiratory diseases caused by influenza viruses still pose a serious concern to global health, and neutralizing antibodies constitute a promising area of antiviral therapeutics. However, the potential application of antibodies is often hampered by the challenge in generating nonimmunogenic antibodies in large scale. In the present study, transchromosomic (Tc) cattle were used for the generation of nonimmunogenic monoclonal antibodies (MAbs), and characterization of such MAbs revealed one monoclonal antibody, 53C10, exhibiting a potent neutralization activity against H1N1 influenza viruses. Further characterization of the neutralization escape mutant generated using this MAb showed that three amino acid substitutions in the HA head domain contributed to the resistance. These findings emphasize the importance of Tc cattle in the production of nonimmunogenic MAbs and highlight the potential of MAb 53C10 in the therapeutic application against H1 influenza virus infection in humans.
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Bhatta TR, Ryt-Hansen P, Nielsen JP, Larsen LE, Larsen I, Chamings A, Goecke NB, Alexandersen S. Infection Dynamics of Swine Influenza Virus in a Danish Pig Herd Reveals Recurrent Infections with Different Variants of the H1N2 Swine Influenza A Virus Subtype. Viruses 2020; 12:v12091013. [PMID: 32927910 PMCID: PMC7551734 DOI: 10.3390/v12091013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/06/2020] [Accepted: 09/08/2020] [Indexed: 12/15/2022] Open
Abstract
Influenza A virus (IAV) in swine, so-called swine influenza A virus (swIAV), causes respiratory illness in pigs around the globe. In Danish pig herds, a H1N2 subtype named H1N2dk is one of the main circulating swIAV. In this cohort study, the infection dynamic of swIAV was evaluated in a Danish pig herd by sampling and PCR testing of pigs from two weeks of age until slaughter at 22 weeks of age. In addition, next generation sequencing (NGS) was used to identify and characterize the complete genome of swIAV circulating in the herd, and to examine the antigenic variability in the antigenic sites of the virus hemagglutinin (HA) and neuraminidase (NA) proteins. Overall, 76.6% of the pigs became PCR positive for swIAV during the study, with the highest prevalence at four weeks of age. Detailed analysis of the virus sequences obtained showed that the majority of mutations occurred at antigenic sites in the HA and NA proteins of the virus. At least two different H1N2 variants were found to be circulating in the herd; one H1N2 variant was circulating at the sow and nursery sites, while another H1N2 variant was circulating at the finisher site. Furthermore, it was demonstrated that individual pigs had recurrent swIAV infections with the two different H1N2 variants, but re-infection with the same H1N2 variant was also observed. Better understandings of the epidemiology, genetic and antigenic diversity of swIAV may help to design better health interventions for the prevention and control of swIAV infections in the herds.
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Affiliation(s)
- Tarka Raj Bhatta
- Geelong Centre for Emerging Infectious Diseases, Geelong, VIC 3220, Australia;
- School of Medicine, Deakin University, Geelong, VIC 3220, Australia
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg C, Denmark; (P.R.-H.); (J.P.N.); (L.E.L.); (I.L.); (N.B.G.)
- Correspondence: (T.R.B.); (S.A.); Tel.: +61-0-452199095 (T.R.B.); +61-0-342159635 (S.A.)
| | - Pia Ryt-Hansen
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg C, Denmark; (P.R.-H.); (J.P.N.); (L.E.L.); (I.L.); (N.B.G.)
| | - Jens Peter Nielsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg C, Denmark; (P.R.-H.); (J.P.N.); (L.E.L.); (I.L.); (N.B.G.)
| | - Lars Erik Larsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg C, Denmark; (P.R.-H.); (J.P.N.); (L.E.L.); (I.L.); (N.B.G.)
| | - Inge Larsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg C, Denmark; (P.R.-H.); (J.P.N.); (L.E.L.); (I.L.); (N.B.G.)
| | - Anthony Chamings
- Geelong Centre for Emerging Infectious Diseases, Geelong, VIC 3220, Australia;
- School of Medicine, Deakin University, Geelong, VIC 3220, Australia
| | - Nicole B. Goecke
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg C, Denmark; (P.R.-H.); (J.P.N.); (L.E.L.); (I.L.); (N.B.G.)
- Division for Diagnostics & Scientific Advice, National Veterinary Institute, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Soren Alexandersen
- Geelong Centre for Emerging Infectious Diseases, Geelong, VIC 3220, Australia;
- School of Medicine, Deakin University, Geelong, VIC 3220, Australia
- Barwon Health, University Hospital Geelong, Geelong, VIC 3220, Australia
- Correspondence: (T.R.B.); (S.A.); Tel.: +61-0-452199095 (T.R.B.); +61-0-342159635 (S.A.)
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5
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Sato-Kaneko F, Yao S, Lao FS, Shpigelman J, Messer K, Pu M, Shukla NM, Cottam HB, Chan M, Chu PJ, Burkhart D, Schoener R, Matsutani T, Carson DA, Corr M, Hayashi T. A Novel Synthetic Dual Agonistic Liposomal TLR4/7 Adjuvant Promotes Broad Immune Responses in an Influenza Vaccine With Minimal Reactogenicity. Front Immunol 2020; 11:1207. [PMID: 32636840 PMCID: PMC7318308 DOI: 10.3389/fimmu.2020.01207] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 05/14/2020] [Indexed: 12/19/2022] Open
Abstract
The limited efficacy of seasonal influenza vaccines is usually attributed to ongoing variation in the major antigenic targets for protective antibody responses including hemagglutinin (HA) and neuraminidase (NA). Hence, vaccine development has largely focused on broadening antigenic epitopes to generate cross-reactive protection. However, the vaccine adjuvant components which can accelerate, enhance and prolong antigenic immune responses, can also increase the breadth of these responses. We previously demonstrated that the combination of synthetic small-molecule Toll-like receptor 4 (TLR4) and TLR7 ligands is a potent adjuvant for recombinant influenza virus HA, inducing rapid, and sustained antibody responses that are protective against influenza viruses in homologous and heterologous murine challenge models. To further enhance adjuvant efficacy, we performed a structure-activity relationship study for the TLR4 ligand, N-cyclohexyl-2-((5-methyl-4-oxo-3-phenyl-4,5-dihydro-3H-pyrimido[5,4-b]indol-2-yl)thio)acetamide (C25H26N4O2S; 1Z105), and identified the 8-(furan-2-yl) substituted pyrimido[5,4-b]indole analog (C29H28N4O3S; 2B182C) as a derivative with higher potency in activating both human and mouse TLR4-NF-κB reporter cells and primary cells. In a prime-boost immunization model using inactivated influenza A virus [IIAV; A/California/04/2009 (H1N1)pdm09], 2B182C used as adjuvant induced higher serum anti-HA and anti-NA IgG1 levels compared to 1Z105, and also increased the anti-NA IgG2a responses. In combination with a TLR7 ligand, 1V270, 2B182C induced equivalent levels of anti-NA and anti-HA IgG1 to 1V270+1Z105. However, the combination of 1V270+2B182C induced 10-fold higher anti-HA and anti-NA IgG2a levels compared to 1V270+1Z105. A stable liposomal formulation of 1V270+2B182C was developed, which synergistically enhanced anti-HA and anti-NA IgG1 and IgG2a responses without demonstrable reactogenicity after intramuscular injection. Notably, vaccination with IIAV plus the liposomal formulation of 1V270+2B182C protected mice against lethal homologous influenza virus (H1N1)pdm09 challenge and reduced lung viral titers and cytokine levels. The combination adjuvant induced a greater diversity in B cell clonotypes of immunoglobulin heavy chain (IGH) genes in the draining lymph nodes and antibodies against a broad spectrum of HA epitopes encompassing HA head and stalk domains and with cross-reactivity against different subtypes of HA and NA. This novel combination liposomal adjuvant contributes to a more broadly protective vaccine while demonstrating an attractive safety profile.
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Affiliation(s)
- Fumi Sato-Kaneko
- Moores Cancer Center, University of California, San Diego, La Jolla, CA, United States
| | - Shiyin Yao
- Moores Cancer Center, University of California, San Diego, La Jolla, CA, United States
| | - Fitzgerald S. Lao
- Moores Cancer Center, University of California, San Diego, La Jolla, CA, United States
| | - Jonathan Shpigelman
- Moores Cancer Center, University of California, San Diego, La Jolla, CA, United States
| | - Karen Messer
- Division of Biostatistics, University of California, San Diego, La Jolla, CA, United States
| | - Minya Pu
- Division of Biostatistics, University of California, San Diego, La Jolla, CA, United States
| | - Nikunj M. Shukla
- Moores Cancer Center, University of California, San Diego, La Jolla, CA, United States
| | - Howard B. Cottam
- Moores Cancer Center, University of California, San Diego, La Jolla, CA, United States
| | - Michael Chan
- Moores Cancer Center, University of California, San Diego, La Jolla, CA, United States
| | - Paul J. Chu
- Moores Cancer Center, University of California, San Diego, La Jolla, CA, United States
| | | | | | | | - Dennis A. Carson
- Moores Cancer Center, University of California, San Diego, La Jolla, CA, United States
| | - Maripat Corr
- Department of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Tomoko Hayashi
- Moores Cancer Center, University of California, San Diego, La Jolla, CA, United States
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Zhao K, Rong G, Teng Q, Li X, Lan H, Yu L, Yu S, Jin Z, Chen G, Li Z. Dendrigraft poly-L-lysines delivery of DNA vaccine effectively enhances the immunogenic responses against H9N2 avian influenza virus infection in chickens. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2020; 27:102209. [PMID: 32305593 DOI: 10.1016/j.nano.2020.102209] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 02/03/2020] [Accepted: 03/27/2020] [Indexed: 11/28/2022]
Abstract
Biodegradable nanomaterials can protect antigens from degradation, promote cellular absorption, and enhance immune responses. We constructed a eukaryotic plasmid [pCAGGS-opti441-hemagglutinin (HA)] by inserting the optimized HA gene fragment of H9N2 AIV into the pCAGGS vector. The pCAGGS-opti441-HA/DGL was developed through packaging the pCAGGS-opti441-HA with dendrigraft poly-l-lysines (DGLs). DGL not only protected the pCAGGS-opti441-HA from degradation, but also exhibited high transfection efficiency. Strong cellular immune responses were induced in chickens immunized with the pCAGGS-opti441-HA/DGL. The levels of IFN-γ and IL-2, and lymphocyte transformation rate of the vaccinated chickens increased at the third week post the immunization. For the vaccinated chickens, T lymphocytes were activated and proliferated, the numbers of CD3+CD4+ and CD4+/CD8+ increased, and the chickens were protected completely against H9N2 AIV challenge. This study provides a method for the development of novel AIV vaccines, and a theoretical basis for the development of safe and efficient gene delivery carriers.
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Affiliation(s)
- Kai Zhao
- Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Heilongjiang University, Harbin, China; Key Laboratory of Microbiology, College of Heilongjiang Province, School of Life Science, Heilongjiang University, Harbin, China.
| | - Guangyu Rong
- Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Heilongjiang University, Harbin, China; Key Laboratory of Microbiology, College of Heilongjiang Province, School of Life Science, Heilongjiang University, Harbin, China; Department of Avian Infectious Disease, and Innovation Team for Pathogenic Ecology Research on Animal Influenza, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, China
| | - Qiaoyang Teng
- Department of Avian Infectious Disease, and Innovation Team for Pathogenic Ecology Research on Animal Influenza, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, China
| | - Xuesong Li
- Department of Avian Infectious Disease, and Innovation Team for Pathogenic Ecology Research on Animal Influenza, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, China
| | - Hailing Lan
- Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Heilongjiang University, Harbin, China; Key Laboratory of Microbiology, College of Heilongjiang Province, School of Life Science, Heilongjiang University, Harbin, China; Department of Avian Infectious Disease, and Innovation Team for Pathogenic Ecology Research on Animal Influenza, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, China
| | - Lu Yu
- Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Heilongjiang University, Harbin, China; Key Laboratory of Microbiology, College of Heilongjiang Province, School of Life Science, Heilongjiang University, Harbin, China
| | - Shuang Yu
- Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Heilongjiang University, Harbin, China; Key Laboratory of Microbiology, College of Heilongjiang Province, School of Life Science, Heilongjiang University, Harbin, China
| | - Zheng Jin
- Key Laboratory of Chemical Engineering Process and Technology for High-efficiency Conversion, College of Chemistry and Material Sciences, Heilongjiang University, Harbin, China
| | - Guangping Chen
- Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK, USA.
| | - Zejun Li
- Department of Avian Infectious Disease, and Innovation Team for Pathogenic Ecology Research on Animal Influenza, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai, China.
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7
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Ryt-Hansen P, Pedersen AG, Larsen I, Kristensen CS, Krog JS, Wacheck S, Larsen LE. Substantial Antigenic Drift in the Hemagglutinin Protein of Swine Influenza A Viruses. Viruses 2020; 12:E248. [PMID: 32102230 PMCID: PMC7077184 DOI: 10.3390/v12020248] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 02/18/2020] [Accepted: 02/20/2020] [Indexed: 12/16/2022] Open
Abstract
The degree of antigenic drift in swine influenza A viruses (swIAV) has historically been regarded as minimal compared to that of human influenza A virus strains. However, as surveillance activities on swIAV have increased, more isolates have been characterized, revealing a high level of genetic and antigenic differences even within the same swIAV lineage. The objective of this study was to investigate the level of genetic drift in one enzootically infected swine herd over one year. Nasal swabs were collected monthly from sows (n = 4) and piglets (n = 40) in the farrowing unit, and from weaners (n = 20) in the nursery. Virus from 1-4 animals were sequenced per month. Analyses of the sequences revealed that the hemagglutinin (HA) gene was the main target for genetic drift with a substitution rate of 7.6 × 10-3 substitutions/site/year and evidence of positive selection. The majority of the mutations occurred in the globular head of the HA protein and in antigenic sites. The phylogenetic tree of the HA sequences displayed a pectinate typology, where only a single lineage persists and forms the ancestor for subsequent lineages. This was most likely caused by repeated selection of a single immune-escape variant, which subsequently became the founder of the next wave of infections.
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Affiliation(s)
- Pia Ryt-Hansen
- National Veterinary Institute, Technical University of Denmark, Kemitorvet Building 204, DK-2800 Kongens Lyngby, Denmark
- Dpt. of Veterinary and Animal Sciences, University of Copenhagen, Grønnegårdsvej 2, DK-1870 Frederiksberg C, Denmark; (I.L.); (L.E.L.)
| | - Anders Gorm Pedersen
- Department of Health Technology, Section for Bioinformatics, Technical University of Denmark, Kemitorvet Building 208, DK-2800 Kongens Lyngby, Denmark;
| | - Inge Larsen
- Dpt. of Veterinary and Animal Sciences, University of Copenhagen, Grønnegårdsvej 2, DK-1870 Frederiksberg C, Denmark; (I.L.); (L.E.L.)
| | | | - Jesper Schak Krog
- Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark;
| | - Silke Wacheck
- Ceva Santé Animale 10 Avenue de la Ballastière, 33500 Libourne, France;
| | - Lars Erik Larsen
- Dpt. of Veterinary and Animal Sciences, University of Copenhagen, Grønnegårdsvej 2, DK-1870 Frederiksberg C, Denmark; (I.L.); (L.E.L.)
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