Growth properties of recombinant equine influenza viruses with different backbones generated by reverse genetics in embryonated chicken eggs.
Abstract: Reverse genetics (RG) technology is useful for quickly updating influenza vaccine strains. A high-yield backbone (i.e., six segments other than hemagglutinin and neuraminidase) derived from A/Puerto Rico/8/1934 (PR8) has been developed to improve the growth of avian and human influenza viruses. However, for equine influenza virus (EIV), an EIV-derived backbone may have better growth properties due to more-natural segment combinations. We compared the growth properties in eggs between the PR8 backbone and an EIV backbone from A/equine/Ibaraki/1/2007, a vaccine strain in Japan. The results showed that the PR8 backbone was propagated more efficiently and is therefore more suitable for EIV vaccine production.
© 2025. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.
Publication Date: 2025-07-12 PubMed ID: 40646296PubMed Central: 6135912DOI: 10.1007/s00705-025-06368-5Google Scholar: Lookup
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Summary
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The study aims to investigate and compare the growth attributes of different recombinant equine influenza viruses in chicken eggs using reverse genetics technology. The researchers found that the PR8 backbone, derived from A/Puerto Rico/8/1934, exhibited better propagation efficiency, making it preferable for equine influenza virus vaccine production.
Reverse Genetics Technology and Influenza Vaccines
- The research is predicated on the concept of reverse genetics (RG), a method that allows for the alteration of the genetic sequence of viruses to study their properties and behavior. This technology is considered advantageous in swiftly updating influenza vaccine strains.
- Prior to this study, a high-yield backbone extracted from A/Puerto Rico/8/1934 (often referred to as PR8) was formulated for improving the growth properties of avian and human strains of influenza viruses. A virus “backbone” refers to the structural proteins that hold the virus together.
Comparing Growth Properties of EIV with PR8 and EIV Backbones
- The researchers speculated that for equine influenza virus (EIV), a backbone derived from the same virus might exhibit improved growth characteristics, likely due to more natural combinations of viral segments.
- To test this hypothesis, the growth properties in eggs of PR8 backbone and an EIV backbone derived from A/equine/Ibaraki/1/2007 (a vaccine strain used in Japan) were compared.
- Eggs are often used as a medium for virus growth in laboratories due to their suitability for virus propagation and ease of use.
Results and Implications
- The study results revealed that the PR8 backbone was more efficiently propagated, demonstrating superior growth properties compared to the EIV backbone.
- These findings imply that the PR8 backbone, rather than an EIV-derived backbone, is more appropriate for developing and producing vaccines for equine influenza virus.
- This research contributes valuable information to the field of veterinary virology and could lead to the formulation of more effective vaccines for equine influenza, ultimately leading to better disease prevention and control strategies in horses.
Cite This Article
APA
Nemoto M, Kawanishi N, Kambayashi Y, Bannai H, Yamanaka T, Garvey M, Cullinane A, Yamayoshi S, Kawaoka Y, Tsujimura K.
(2025).
Growth properties of recombinant equine influenza viruses with different backbones generated by reverse genetics in embryonated chicken eggs.
Arch Virol, 170(8), 181.
https://doi.org/10.1007/s00705-025-06368-5 Publication
Researcher Affiliations
- Equine Research Institute, Japan Racing Association, Tochigi, Japan. nemoto_manabu@equinst.go.jp.
- Equine Research Institute, Japan Racing Association, Tochigi, Japan.
- Equine Research Institute, Japan Racing Association, Tochigi, Japan.
- Equine Research Institute, Japan Racing Association, Tochigi, Japan.
- Equine Research Institute, Japan Racing Association, Tochigi, Japan.
- Virology Unit, Irish Equine Centre, Kildare, Ireland.
- Virology Unit, Irish Equine Centre, Kildare, Ireland.
- Division of Virology, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
- The Research Center for Global Viral Diseases, National Center for Global Health and Medicine Research Institute, Tokyo, Japan.
- The University of Tokyo Pandemic Preparedness, Infection and Advanced Research Center, Tokyo, Japan.
- Division of Virology, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
- The Research Center for Global Viral Diseases, National Center for Global Health and Medicine Research Institute, Tokyo, Japan.
- The University of Tokyo Pandemic Preparedness, Infection and Advanced Research Center, Tokyo, Japan.
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA.
- Equine Research Institute, Japan Racing Association, Tochigi, Japan.
MeSH Terms
- Animals
- Reverse Genetics / methods
- Horses
- Chick Embryo
- Influenza A Virus, H3N8 Subtype / growth & development
- Influenza A Virus, H3N8 Subtype / genetics
- Influenza Vaccines / genetics
Conflict of Interest Statement
Declarations. Ethical approval: This study was approved by the Japan Racing Association Research Planning Committee (approval no. 2021-2827-02). Conflict of interest: The authors declare no conflicts of interest.
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