Analyze Diet
Equine veterinary journal2009; 41(1); 87-92; doi: 10.2746/042516408x371937

Influenza A viruses with truncated NS1 as modified live virus vaccines: pilot studies of safety and efficacy in horses.

Abstract: Three previously described NS1 mutant equine influenza viruses encoding carboxy-terminally truncated NS1 proteins are impaired in their ability to inhibit type I IFN production in vitro and are replication attenuated, and thus are candidates for use as a modified live influenza virus vaccine in the horse. Objective: One or more of these mutant viruses is safe when administered to horses, and recipient horses when challenged with wild-type influenza have reduced physiological and virological correlates of disease. Methods: Vaccination and challenge studies were done in horses, with measurement of pyrexia, clinical signs, virus shedding and systemic proinflammatory cytokines. Results: Aerosol or intranasal inoculation of horses with the viruses produced no adverse effects. Seronegative horses inoculated with the NS1-73 and NS1-126 viruses, but not the NS1-99 virus, shed detectable virus and generated significant levels of antibodies. Following challenge with wild-type influenza, horses vaccinated with NS1-126 virus did not develop fever (>38.5 degrees C), had significantly fewer clinical signs of illness and significantly reduced quantities of virus excreted for a shorter duration post challenge compared to unvaccinated controls. Mean levels of proinflammatory cytokines IL-1beta and IL-6 were significantly higher in control animals, and were positively correlated with peak viral shedding and pyrexia on Day +2 post challenge. Conclusions: These data suggest that the recombinant NS1 viruses are safe and effective as modified live virus vaccines against equine influenza. This type of reverse genetics-based vaccine can be easily updated by exchanging viral surface antigens to combat the problem of antigenic drift in influenza viruses.
Publication Date: 2009-03-24 PubMed ID: 19301588PubMed Central: PMC2878972DOI: 10.2746/042516408x371937Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
  • Journal Article
  • Research Support
  • N.I.H.
  • Extramural
  • Research Support
  • Non-U.S. Gov't
  • Research Support
  • U.S. Gov't
  • Non-P.H.S.

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research study explores the safety and effectiveness of using NS1 mutant equine influenza viruses with truncated NS1 proteins as a live influenza virus vaccine for horses. The results suggest that these viruses are safe for use and can help to reduce the physiological and virological signs of disease.

Objective

The main objective of this study was to investigate the safety and efficacy of NS1 mutant equine influenza viruses as a modified live virus vaccine for horses. The hypothesis was that these NS1 mutant viruses would not trigger any adverse effects in the horses, and that the horses would demonstrate reduced signs of illness and decreased virus shedding when challenged with wild-type influenza.

Methods

  • The study was undertaken using vaccination and challenge protocols in horses.
  • The team recorded observations pertaining to fever, signs of illness, virus shedding, and systemic proinflammatory cytokines.
  • The horses were initially exposed to the NS1-73, NS1-99, and NS1-126 viruses and any resulting virus shedding and the generation of antibodies were observed and assessed.
  • Following this, the horses were challenged with wild-type influenza to evaluate how the NS1 mutant viruses would respond.

Results

  • The application of the NS1 mutant viruses through aerosol or intranasal methods did not lead to any adverse effects in the horses.
  • It was seen that horses exposed to the NS1-73 and NS1-126 viruses, but not the NS1-99, shed detectable virus and produced significant levels of antibodies.
  • Horses vaccinated with the NS1-126 virus did not develop a fever, showed significantly fewer signs of illness, and had drastically reduced quantities of virus over a shorter period post wild-type influenza challenge as compared to the control or unvaccinated animals.
  • Proinflammatory cytokines IL-1beta and IL-6 were found to be significantly higher in the control group, and were linked with peak viral shedding and fever development.

Conclusions

The conclusions drawn from this study were that the NS1 mutant equine influenza viruses are safe and potent as a live virus vaccine against equine influenza. The recombinant NS1 viruses also present a potential solution to the issue of antigenic drift in influenza viruses, as this method-based vaccine can be easily updated by changing the viral surface antigens.

Cite This Article

APA
Chambers TM, Quinlivan M, Sturgill T, Cullinane A, Horohov DW, Zamarin D, Arkins S, García-Sastre A, Palese P. (2009). Influenza A viruses with truncated NS1 as modified live virus vaccines: pilot studies of safety and efficacy in horses. Equine Vet J, 41(1), 87-92. https://doi.org/10.2746/042516408x371937

Publication

ISSN: 0425-1644
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 41
Issue: 1
Pages: 87-92

Researcher Affiliations

Chambers, T M
  • Department of Veterinary Science, University of Kentucky, Lexington, Kentucky, USA.
Quinlivan, M
    Sturgill, T
      Cullinane, A
        Horohov, D W
          Zamarin, D
            Arkins, S
              García-Sastre, A
                Palese, P

                  MeSH Terms

                  • Administration, Intranasal
                  • Animals
                  • Antibodies, Viral / blood
                  • Cytokines / biosynthesis
                  • Horse Diseases / immunology
                  • Horse Diseases / prevention & control
                  • Horse Diseases / virology
                  • Horses
                  • Influenza A Virus, H3N8 Subtype / immunology
                  • Influenza Vaccines / adverse effects
                  • Influenza Vaccines / genetics
                  • Influenza Vaccines / immunology
                  • Nebulizers and Vaporizers / veterinary
                  • Orthomyxoviridae Infections / immunology
                  • Orthomyxoviridae Infections / prevention & control
                  • Orthomyxoviridae Infections / veterinary
                  • Orthomyxoviridae Infections / virology
                  • Pilot Projects
                  • Recombination, Genetic
                  • Safety
                  • Time Factors
                  • Treatment Outcome
                  • Vaccination / veterinary
                  • Vaccines, Attenuated / adverse effects
                  • Vaccines, Attenuated / immunology
                  • Viral Nonstructural Proteins / genetics
                  • Viral Nonstructural Proteins / immunology
                  • Virus Shedding

                  Grant Funding

                  • T32 AI007647 / NIAID NIH HHS
                  • U01 AI070469 / NIAID NIH HHS
                  • U19 AI062623-050003 / NIAID NIH HHS
                  • AI007647 / NIAID NIH HHS
                  • U01 AI070469-03 / NIAID NIH HHS
                  • U01AI070469 / NIAID NIH HHS
                  • T32 AI007647-10 / NIAID NIH HHS
                  • U54 AI057158 / NIAID NIH HHS
                  • HHSN2662000700010C / AHRQ HHS
                  • U19 AI062623 / NIAID NIH HHS
                  • U54 AI057158-04 / NIAID NIH HHS
                  • HHNSN266200700010C / PHS HHS
                  • HHSN266200700010C / NIAID NIH HHS
                  • U54 AI057158-05S10003 / NIAID NIH HHS

                  References

                  This article includes 40 references
                  1. Baskin CR, Bielefeldt-Ohmann H, García-Sastre A, Tumpey TM, Van Hoeven N, Carter VS, Thomas MJ, Proll S, Solórzano A, Billharz R, Fornek JL, Thomas S, Chen CH, Clark EA, Murali-Krishna K, Katze MG. Functional genomic and serological analysis of the protective immune response resulting from vaccination of macaques with an NS1-truncated influenza virus.. J Virol 2007 Nov;81(21):11817-27.
                    pmc: PMC2168783pubmed: 17715226doi: 10.1128/jvi.00590-07google scholar: lookup
                  2. Chambers TM, Holland RE, Tudor LR, Townsend HG, Cook A, Bogdan J, Lunn DP, Hussey S, Whitaker-Dowling P, Youngner JS, Sebring RW, Penner SJ, Stiegler GL. A new modified live equine influenza virus vaccine: phenotypic stability, restricted spread and efficacy against heterologous virus challenge.. Equine Vet J 2001 Nov;33(7):630-6.
                    pubmed: 11770982doi: 10.2746/042516401776249291google scholar: lookup
                  3. Daly JM, Yates PJ, Newton JR, Park A, Henley W, Wood JL, Davis-Poynter N, Mumford JA. Evidence supporting the inclusion of strains from each of the two co-circulating lineages of H3N8 equine influenza virus in vaccines.. Vaccine 2004 Sep 28;22(29-30):4101-9.
                    pubmed: 15364463doi: 10.1016/j.vaccine.2004.02.048google scholar: lookup
                  4. Donelan NR, Basler CF, García-Sastre A. A recombinant influenza A virus expressing an RNA-binding-defective NS1 protein induces high levels of beta interferon and is attenuated in mice.. J Virol 2003 Dec;77(24):13257-66.
                  5. Edwards KM, Dupont WD, Westrich MK, Plummer WD Jr, Palmer PS, Wright PF. A randomized controlled trial of cold-adapted and inactivated vaccines for the prevention of influenza A disease.. J Infect Dis 1994 Jan;169(1):68-76.
                    pubmed: 8277200doi: 10.1093/infdis/169.1.68google scholar: lookup
                  6. Egorov A, Brandt S, Sereinig S, Romanova J, Ferko B, Katinger D, Grassauer A, Alexandrova G, Katinger H, Muster T. Transfectant influenza A viruses with long deletions in the NS1 protein grow efficiently in Vero cells.. J Virol 1998 Aug;72(8):6437-41.
                  7. Ferko B, Kittel C, Romanova J, Sereinig S, Katinger H, Egorov A. Live attenuated influenza virus expressing human interleukin-2 reveals increased immunogenic potential in young and aged hosts.. J Virol 2006 Dec;80(23):11621-7.
                    pmc: PMC1642586pubmed: 16971432doi: 10.1128/jvi.01645-06google scholar: lookup
                  8. Fodor E, Devenish L, Engelhardt OG, Palese P, Brownlee GG, García-Sastre A. Rescue of influenza A virus from recombinant DNA.. J Virol 1999 Nov;73(11):9679-82.
                  9. García-Sastre A, Egorov A, Matassov D, Brandt S, Levy DE, Durbin JE, Palese P, Muster T. Influenza A virus lacking the NS1 gene replicates in interferon-deficient systems.. Virology 1998 Dec 20;252(2):324-30.
                    pubmed: 9878611doi: 10.1006/viro.1998.9508google scholar: lookup
                  10. Gorse GJ, Campbell MJ, Otto EE, Powers DC, Chambers GW, Newman FK. Increased anti-influenza A virus cytotoxic T cell activity following vaccination of the chronically ill elderly with live attenuated or inactivated influenza virus vaccine.. J Infect Dis 1995 Jul;172(1):1-10.
                    pubmed: 7797897doi: 10.1093/infdis/172.1.1google scholar: lookup
                  11. Hannant D, Mumford JA. Cell mediated immune responses in ponies following infection with equine influenza virus (H3N8): the influence of induction culture conditions on the properties of cytotoxic effector cells.. Vet Immunol Immunopathol 1989 Jul;21(3-4):327-37.
                    pubmed: 2552651doi: 10.1016/0165-2427(89)90040-8google scholar: lookup
                  12. Hannant D, Mumford JA, Jessett DM. Duration of circulating antibody and immunity following infection with equine influenza virus.. Vet Rec 1988 Feb 6;122(6):125-8.
                    pubmed: 2835850doi: 10.1136/vr.122.6.125google scholar: lookup
                  13. Hayden FG, Fritz R, Lobo MC, Alvord W, Strober W, Straus SE. Local and systemic cytokine responses during experimental human influenza A virus infection. Relation to symptom formation and host defense.. J Clin Invest 1998 Feb 1;101(3):643-9.
                    pmc: PMC508608pubmed: 9449698doi: 10.1172/jci1355google scholar: lookup
                  14. Kochs G, García-Sastre A, Martínez-Sobrido L. Multiple anti-interferon actions of the influenza A virus NS1 protein.. J Virol 2007 Jul;81(13):7011-21.
                    pmc: PMC1933316pubmed: 17442719doi: 10.1128/jvi.02581-06google scholar: lookup
                  15. Lunn DP, Soboll G, Schram BR, Quass J, McGregor MW, Drape RJ, Macklin MD, McCabe DE, Swain WF, Olsen CW. Antibody responses to DNA vaccination of horses using the influenza virus hemagglutinin gene.. Vaccine 1999 May 4;17(18):2245-58.
                    pubmed: 10403592doi: 10.1016/s0264-410x(98)00496-4google scholar: lookup
                  16. Morley PS, Hanson LK, Bogdan JR, Townsend HG, Appleton JA, Haines DM. The relationship between single radial hemolysis, hemagglutination inhibition, and virus neutralization assays used to detect antibodies specific for equine influenza viruses.. Vet Microbiol 1995 Jun;45(1):81-92.
                    pubmed: 7653031doi: 10.1016/0378-1135(94)00105-6google scholar: lookup
                  17. Mumford EL, Traub-Dargatz JL, Salman MD, Collins JK, Getzy DM, Carman J. Monitoring and detection of acute viral respiratory tract disease in horses.. J Am Vet Med Assoc 1998 Aug 1;213(3):385-90.
                    pubmed: 9702229
                  18. Mumford JA, Hannant D, Jessett DM. Experimental infection of ponies with equine influenza (H3N8) viruses by intranasal inoculation or exposure to aerosols.. Equine Vet J 1990 Mar;22(2):93-8.
                  19. Neumann G, Watanabe T, Ito H, Watanabe S, Goto H, Gao P, Hughes M, Perez DR, Donis R, Hoffmann E, Hobom G, Kawaoka Y. Generation of influenza A viruses entirely from cloned cDNAs.. Proc Natl Acad Sci U S A 1999 Aug 3;96(16):9345-50.
                    pmc: PMC17785pubmed: 10430945doi: 10.1073/pnas.96.16.9345google scholar: lookup
                  20. Newton JR, Townsend HG, Wood JL, Sinclair R, Hannant D, Mumford JA. Immunity to equine influenza: relationship of vaccine-induced antibody in young Thoroughbred racehorses to protection against field infection with influenza A/equine-2 viruses (H3N8).. Equine Vet J 2000 Jan;32(1):65-74.
                    pubmed: 10661388doi: 10.2746/042516400777612116google scholar: lookup
                  21. Paillot R, Grimmett H, Elton D, Daly JM. Protection, systemic IFNgamma, and antibody responses induced by an ISCOM-based vaccine against a recent equine influenza virus in its natural host.. Vet Res 2008 May-Jun;39(3):21.
                    pubmed: 18252187doi: 10.1051/vetres:2007062google scholar: lookup
                  22. Paillot R, Hannant D, Kydd JH, Daly JM. Vaccination against equine influenza: quid novi?. Vaccine 2006 May 8;24(19):4047-61.
                    pubmed: 16545507doi: 10.1016/j.vaccine.2006.02.030google scholar: lookup
                  23. Paillot R, Kydd JH, Sindle T, Hannant D, Edlund Toulemonde C, Audonnet JC, Minke JM, Daly JM. Antibody and IFN-gamma responses induced by a recombinant canarypox vaccine and challenge infection with equine influenza virus.. Vet Immunol Immunopathol 2006 Aug 15;112(3-4):225-33.
                    pubmed: 16621023doi: 10.1016/j.vetimm.2006.02.007google scholar: lookup
                  24. Palese P, García-Sastre A. Influenza vaccines: present and future.. J Clin Invest 2002 Jul;110(1):9-13.
                    pmc: PMC151037pubmed: 12093881doi: 10.1172/jci15999google scholar: lookup
                  25. Palese P, Shaw ML. Orthomyxoviridae: the viruses and their replication. Fields' Virology 5th edn. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins; 2007. pp. 1647–1690.
                  26. Park AW, Wood JL, Newton JR, Daly J, Mumford JA, Grenfell BT. Optimising vaccination strategies in equine influenza.. Vaccine 2003 Jun 20;21(21-22):2862-70.
                    pubmed: 12798628doi: 10.1016/s0264-410x(03)00156-7google scholar: lookup
                  27. Quinlivan M, Nelly M, Prendergast M, Breathnach C, Horohov D, Arkins S, Chiang YW, Chu HJ, Ng T, Cullinane A. Pro-inflammatory and antiviral cytokine expression in vaccinated and unvaccinated horses exposed to equine influenza virus.. Vaccine 2007 Oct 10;25(41):7056-64.
                    pubmed: 17825959doi: 10.1016/j.vaccine.2007.07.059google scholar: lookup
                  28. Quinlivan M, Zamarin D, García-Sastre A, Cullinane A, Chambers T, Palese P. Attenuation of equine influenza viruses through truncations of the NS1 protein.. J Virol 2005 Jul;79(13):8431-9.
                  29. Renegar KB, Small PA Jr. Passive transfer of local immunity to influenza virus infection by IgA antibody.. J Immunol 1991 Mar 15;146(6):1972-8.
                    pubmed: 2005388
                  30. Richt JA, Lekcharoensuk P, Lager KM, Vincent AL, Loiacono CM, Janke BH, Wu WH, Yoon KJ, Webby RJ, Solórzano A, García-Sastre A. Vaccination of pigs against swine influenza viruses by using an NS1-truncated modified live-virus vaccine.. J Virol 2006 Nov;80(22):11009-18.
                    pmc: PMC1642165pubmed: 16943300doi: 10.1128/jvi.00787-06google scholar: lookup
                  31. Soboll G, Horohov DW, Aldridge BM, Olsen CW, McGregor MW, Drape RJ, Macklin MD, Swain WF, Lunn DP. Regional antibody and cellular immune responses to equine influenza virus infection, and particle mediated DNA vaccination.. Vet Immunol Immunopathol 2003 Jul 15;94(1-2):47-62.
                    pubmed: 12842611doi: 10.1016/s0165-2427(03)00060-6google scholar: lookup
                  32. Soboll G, Nelson KM, Leuthner ES, Clark RJ, Drape R, Macklin MD, Swain WF, Olsen CW, Lunn DP. Mucosal co-administration of cholera toxin and influenza virus hemagglutinin-DNA in ponies generates a local IgA response.. Vaccine 2003 Jun 20;21(21-22):3081-92.
                    pubmed: 12798652doi: 10.1016/s0264-410x(03)00161-0google scholar: lookup
                  33. Solórzano A, Webby RJ, Lager KM, Janke BH, García-Sastre A, Richt JA. Mutations in the NS1 protein of swine influenza virus impair anti-interferon activity and confer attenuation in pigs.. J Virol 2005 Jun;79(12):7535-43.
                  34. Talon J, Salvatore M, O'Neill RE, Nakaya Y, Zheng H, Muster T, García-Sastre A, Palese P. Influenza A and B viruses expressing altered NS1 proteins: A vaccine approach.. Proc Natl Acad Sci U S A 2000 Apr 11;97(8):4309-14.
                    pmc: PMC18238pubmed: 10725408doi: 10.1073/pnas.070525997google scholar: lookup
                  35. Tamura S, Funato H, Hirabayashi Y, Kikuta K, Suzuki Y, Nagamine T, Aizawa C, Nakagawa M, Kurata T. Functional role of respiratory tract haemagglutinin-specific IgA antibodies in protection against influenza.. Vaccine 1990 Oct;8(5):479-85.
                    pubmed: 2251874doi: 10.1016/0264-410x(90)90250-pgoogle scholar: lookup
                  36. Edlund Toulemonde C, Daly J, Sindle T, Guigal PM, Audonnet JC, Minke JM. Efficacy of a recombinant equine influenza vaccine against challenge with an American lineage H3N8 influenza virus responsible for the 2003 outbreak in the United Kingdom.. Vet Rec 2005 Mar 19;156(12):367-71.
                    pubmed: 15816180doi: 10.1136/vr.156.12.367google scholar: lookup
                  37. Townsend HG, Penner SJ, Watts TC, Cook A, Bogdan J, Haines DM, Griffin S, Chambers T, Holland RE, Whitaker-Dowling P, Youngner JS, Sebring RW. Efficacy of a cold-adapted, intranasal, equine influenza vaccine: challenge trials.. Equine Vet J 2001 Nov;33(7):637-43.
                    pubmed: 11770983doi: 10.2746/042516401776249354google scholar: lookup
                  38. Van Reeth K, Nauwynck H, Pensaert M. Bronchoalveolar interferon-alpha, tumor necrosis factor-alpha, interleukin-1, and inflammation during acute influenza in pigs: a possible model for humans?. J Infect Dis 1998 Apr;177(4):1076-9.
                    pmc: PMC7109807pubmed: 9534986doi: 10.1086/517398google scholar: lookup
                  39. Wattrang E, Jessett DM, Yates P, Fuxler L, Hannant D. Experimental infection of ponies with equine influenza A2 (H3N8) virus strains of different pathogenicity elicits varying interferon and interleukin-6 responses.. Viral Immunol 2003;16(1):57-67.
                    pubmed: 12725689doi: 10.1089/088282403763635456google scholar: lookup
                  40. Wilson WD, Mihalyi JE, Hussey S, Lunn DP. Passive transfer of maternal immunoglobulin isotype antibodies against tetanus and influenza and their effect on the response of foals to vaccination.. Equine Vet J 2001 Nov;33(7):644-50.
                    pubmed: 11770984doi: 10.2746/042516401776249435google scholar: lookup

                  Citations

                  This article has been cited 27 times.
                  1. Su CM, Du Y, Rowland RRR, Wang Q, Yoo D. Reprogramming viral immune evasion for a rational design of next-generation vaccines for RNA viruses.. Front Immunol 2023;14:1172000.
                    doi: 10.3389/fimmu.2023.1172000pubmed: 37138878google scholar: lookup
                  2. Nogales A, DeDiego ML, Martínez-Sobrido L. Live attenuated influenza A virus vaccines with modified NS1 proteins for veterinary use.. Front Cell Infect Microbiol 2022;12:954811.
                    doi: 10.3389/fcimb.2022.954811pubmed: 35937688google scholar: lookup
                  3. Vandoorn E, Stadejek W, Parys A, Chepkwony S, Chiers K, Van Reeth K. Pathobiology of an NS1-Truncated H3N2 Swine Influenza Virus Strain in Pigs.. J Virol 2022 Jun 8;96(11):e0051922.
                    doi: 10.1128/jvi.00519-22pubmed: 35546120google scholar: lookup
                  4. Oladunni FS, Oseni SO, Martinez-Sobrido L, Chambers TM. Equine Influenza Virus and Vaccines.. Viruses 2021 Aug 20;13(8).
                    doi: 10.3390/v13081657pubmed: 34452521google scholar: lookup
                  5. Ghorbani A, Abundo MC, Ji H, Taylor KJM, Ngunjiri JM, Lee CW. Viral Subpopulation Screening Guides in Designing a High Interferon-Inducing Live Attenuated Influenza Vaccine by Targeting Rare Mutations in NS1 and PB2 Proteins.. J Virol 2020 Dec 22;95(2).
                    doi: 10.1128/JVI.01722-20pubmed: 33115873google scholar: lookup
                  6. Nogales A, Martinez-Sobrido L, Topham DJ, DeDiego ML. Modulation of Innate Immune Responses by the Influenza A NS1 and PA-X Proteins.. Viruses 2018 Dec 12;10(12).
                    doi: 10.3390/v10120708pubmed: 30545063google scholar: lookup
                  7. Singh RK, Dhama K, Karthik K, Khandia R, Munjal A, Khurana SK, Chakraborty S, Malik YS, Virmani N, Singh R, Tripathi BN, Munir M, van der Kolk JH. A Comprehensive Review on Equine Influenza Virus: Etiology, Epidemiology, Pathobiology, Advances in Developing Diagnostics, Vaccines, and Control Strategies.. Front Microbiol 2018;9:1941.
                    doi: 10.3389/fmicb.2018.01941pubmed: 30237788google scholar: lookup
                  8. Chen C, Fan W, Li J, Zheng W, Zhang S, Yang L, Liu D, Liu W, Sun L. A Promising IFN-Deficient System to Manufacture IFN-Sensitive Influenza Vaccine Virus.. Front Cell Infect Microbiol 2018;8:127.
                    doi: 10.3389/fcimb.2018.00127pubmed: 29765910google scholar: lookup
                  9. Rodriguez L, Reedy S, Nogales A, Murcia PR, Chambers TM, Martinez-Sobrido L. Development of a novel equine influenza virus live-attenuated vaccine.. Virology 2018 Mar;516:76-85.
                    doi: 10.1016/j.virol.2018.01.005pubmed: 29331866google scholar: lookup
                  10. Gahan J, Garvey M, Gildea S, Gür E, Kagankaya A, Cullinane A. Whole-genome sequencing and antigenic analysis of the first equine influenza virus identified in Turkey.. Influenza Other Respir Viruses 2018 May;12(3):374-382.
                    doi: 10.1111/irv.12485pubmed: 28940727google scholar: lookup
                  11. Na W, Lyoo KS, Yoon SW, Yeom M, Kang B, Moon H, Kim HK, Jeong DG, Kim JK, Song D. Attenuation of the virulence of a recombinant influenza virus expressing the naturally truncated NS gene from an H3N8 equine influenza virus in mice.. Vet Res 2016 Nov 15;47(1):115.
                    doi: 10.1186/s13567-016-0400-7pubmed: 27846859google scholar: lookup
                  12. Barba M, Daly JM. The Influenza NS1 Protein: What Do We Know in Equine Influenza Virus Pathogenesis?. Pathogens 2016 Aug 31;5(3).
                    doi: 10.3390/pathogens5030057pubmed: 27589809google scholar: lookup
                  13. Jindra C, Huber B, Shafti-Keramat S, Wolschek M, Ferko B, Muster T, Brandt S, Kirnbauer R. Attenuated Recombinant Influenza A Virus Expressing HPV16 E6 and E7 as a Novel Therapeutic Vaccine Approach.. PLoS One 2015;10(9):e0138722.
                    doi: 10.1371/journal.pone.0138722pubmed: 26381401google scholar: lookup
                  14. Paillot R. A Systematic Review of Recent Advances in Equine Influenza Vaccination.. Vaccines (Basel) 2014 Nov 14;2(4):797-831.
                    doi: 10.3390/vaccines2040797pubmed: 26344892google scholar: lookup
                  15. Margine I, Krammer F. Animal models for influenza viruses: implications for universal vaccine development.. Pathogens 2014 Oct 21;3(4):845-74.
                    doi: 10.3390/pathogens3040845pubmed: 25436508google scholar: lookup
                  16. Alymova IV, York IA, McCullers JA. Non-avian animal reservoirs present a source of influenza A PB1-F2 proteins with novel virulence-enhancing markers.. PLoS One 2014;9(11):e111603.
                    doi: 10.1371/journal.pone.0111603pubmed: 25368997google scholar: lookup
                  17. Atasheva S, Kim DY, Frolova EI, Frolov I. Venezuelan equine encephalitis virus variants lacking transcription inhibitory functions demonstrate highly attenuated phenotype.. J Virol 2015 Jan;89(1):71-82.
                    doi: 10.1128/JVI.02252-14pubmed: 25320296google scholar: lookup
                  18. Muranaka M, Yamanaka T, Katayama Y, Niwa H, Oku K, Matsumura T, Oyamada T. Time-related Pathological Changes in Horses Experimentally Inoculated with Equine Influenza A Virus.. J Equine Sci 2012;23(2):17-26.
                    doi: 10.1294/jes.23.17pubmed: 24833992google scholar: lookup
                  19. Chambers TM, Balasuriya UB, Reedy SE, Tiwari A. Replication of avian influenza viruses in equine tracheal epithelium but not in horses.. Influenza Other Respir Viruses 2013 Dec;7 Suppl 4(Suppl 4):90-3.
                    doi: 10.1111/irv.12188pubmed: 24224824google scholar: lookup
                  20. Abdelwhab EM, Veits J, Mettenleiter TC. Avian influenza virus NS1: A small protein with diverse and versatile functions.. Virulence 2013 Oct 1;4(7):583-8.
                    doi: 10.4161/viru.26360pubmed: 24051601google scholar: lookup
                  21. Ault A, Zajac AM, Kong WP, Gorres JP, Royals M, Wei CJ, Bao S, Yang ZY, Reedy SE, Sturgill TL, Page AE, Donofrio-Newman J, Adams AA, Balasuriya UB, Horohov DW, Chambers TM, Nabel GJ, Rao SS. Immunogenicity and clinical protection against equine influenza by DNA vaccination of ponies.. Vaccine 2012 Jun 6;30(26):3965-74.
                    doi: 10.1016/j.vaccine.2012.03.026pubmed: 22449425google scholar: lookup
                  22. Cullinane A, Elton D, Mumford J. Equine influenza - surveillance and control.. Influenza Other Respir Viruses 2010 Nov;4(6):339-44.
                  23. Zhou B, Li Y, Belser JA, Pearce MB, Schmolke M, Subba AX, Shi Z, Zaki SR, Blau DM, García-Sastre A, Tumpey TM, Wentworth DE. NS-based live attenuated H1N1 pandemic vaccines protect mice and ferrets.. Vaccine 2010 Nov 23;28(50):8015-25.
                    doi: 10.1016/j.vaccine.2010.08.106pubmed: 20934458google scholar: lookup
                  24. Walkiewicz MP, Basu D, Jablonski JJ, Geysen HM, Engel DA. Novel inhibitor of influenza non-structural protein 1 blocks multi-cycle replication in an RNase L-dependent manner.. J Gen Virol 2011 Jan;92(Pt 1):60-70.
                    doi: 10.1099/vir.0.025015-0pubmed: 20881091google scholar: lookup
                  25. Chan TC, Hsiao CK, Lee CC, Chiang PH, Kao CL, Liu CM, King CC. The impact of matching vaccine strains and post-SARS public health efforts on reducing influenza-associated mortality among the elderly.. PLoS One 2010 Jun 25;5(6):e11317.
                    doi: 10.1371/journal.pone.0011317pubmed: 20592764google scholar: lookup
                  26. Hale BG, Albrecht RA, García-Sastre A. Innate immune evasion strategies of influenza viruses.. Future Microbiol 2010 Jan;5(1):23-41.
                    doi: 10.2217/fmb.09.108pubmed: 20020828google scholar: lookup
                  27. Lowen AC, Steel J, Mubareka S, Carnero E, García-Sastre A, Palese P. Blocking interhost transmission of influenza virus by vaccination in the guinea pig model.. J Virol 2009 Apr;83(7):2803-18.
                    doi: 10.1128/JVI.02424-08pubmed: 19153237google scholar: lookup