Development of an H9N2 vaccine strain with enhanced neuraminidase immunogenicity via dual hemagglutinin and neuraminidase modification.

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Název: Development of an H9N2 vaccine strain with enhanced neuraminidase immunogenicity via dual hemagglutinin and neuraminidase modification.
Autoři: Jin-Ha Song1, Seung-Eun Son1, Howon Kim1, Seung-Ji Kim1, Se-Hee An2, Chung-Young Lee3, Kang-Seuk Choi1,4, Hyuk-Joon Kwon5,6 kwonhj01@snu.ac.kr
Zdroj: Journal of Veterinary Science. Nov2025, Vol. 26 Issue 6, p1-15. 15p.
Druh dokumentu: Article
Témata: Neuraminidase, Hemagglutinin, Vaccines, Antibody formation, Genetic engineering, Avian influenza A virus, Vaccine development, Immune response
Geografický termín: Korea
Author-Supplied Keywords: cross protection
H9N2 subtype
inactivated
Influenza A virus
neuraminidase
vaccines
virus replication
Abstrakt: Importance: The Y439 lineage 01310 E20 H9N2 vaccine strain currently used in South Korea has undergone extensive egg adaptation, resulting in substantial changes, including an 18-amino acid neuraminidase (NA) stalk deletion. Additionally, both early and late 01310 passages inherently harbor an N-glycan at hemagglutinin (HA) residue 158-160 (HA158) that may interfere with virus-specific antibodies. Objective: We aimed to develop a high-yield vaccine strain without egg passaging and to overcome the limitations of the conventional vaccine strain that may compromise immunogenicity. Methods: We introduced a genetically modified 01310 PB2 gene (310-MVV: I66M, I109V, I133V) to increase replication in embryonated eggs and removed the N-glycan at HA158 and restored the NA stalk to improve immunogenicity. The resulting strain was assessed for egg replication and immunogenicity in chickens. Results: The resulting vaccine strain (310-SNS-193D-MVV) grew efficiently in embryonated eggs without repeated passaging. As restoring the NA stalk alone was insufficient to enhance NA-specific immunity, simultaneously removing the N-glycan at HA158 markedly increased NA-specific antibody responses and neutralizing antibody titers across multiple H9N2 lineages. Additionally, incorporating 310-SNS-193D-MVV into a bivalent formulation with a Y280 lineage strain conferred broader coverage without evidence of immune interference. Conclusions and Relevance: These findings underscore how PB2, HA, and NA targeted genetic modifications can improve H9N2 vaccine productivity and immunogenicity. These strategies are not limited to our H9N2 strain and can be applied to other low propagating or NA stalk-deleted virus strains. [ABSTRACT FROM AUTHOR]
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Author Affiliations: 1Laboratory of Avian Diseases, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
2Avian Influenza Research & Diagnostic Division, Animal and Plant Quarantine Agency, Gimcheon 39660, Korea
3Department of Microbiology, College of Medicine, Kyungpook National University, Daegu 41944, Korea
4Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
5Laboratory of Poultry Medicine, Department of Farm Animal Medicine, College of Veterinary Medicine and BK21 PLUS for Veterinary Science, Seoul National University, Seoul 08826, Korea
6GeNiner, Seoul 08826, Korea
ISSN: 1229-845X
DOI: 10.4142/jvs.25069
Přístupové číslo: 189873716
Databáze: Veterinary Source
Popis
Abstrakt:Importance: The Y439 lineage 01310 E20 H9N2 vaccine strain currently used in South Korea has undergone extensive egg adaptation, resulting in substantial changes, including an 18-amino acid neuraminidase (NA) stalk deletion. Additionally, both early and late 01310 passages inherently harbor an N-glycan at hemagglutinin (HA) residue 158-160 (HA158) that may interfere with virus-specific antibodies. Objective: We aimed to develop a high-yield vaccine strain without egg passaging and to overcome the limitations of the conventional vaccine strain that may compromise immunogenicity. Methods: We introduced a genetically modified 01310 PB2 gene (310-MVV: I66M, I109V, I133V) to increase replication in embryonated eggs and removed the N-glycan at HA158 and restored the NA stalk to improve immunogenicity. The resulting strain was assessed for egg replication and immunogenicity in chickens. Results: The resulting vaccine strain (310-SNS-193D-MVV) grew efficiently in embryonated eggs without repeated passaging. As restoring the NA stalk alone was insufficient to enhance NA-specific immunity, simultaneously removing the N-glycan at HA158 markedly increased NA-specific antibody responses and neutralizing antibody titers across multiple H9N2 lineages. Additionally, incorporating 310-SNS-193D-MVV into a bivalent formulation with a Y280 lineage strain conferred broader coverage without evidence of immune interference. Conclusions and Relevance: These findings underscore how PB2, HA, and NA targeted genetic modifications can improve H9N2 vaccine productivity and immunogenicity. These strategies are not limited to our H9N2 strain and can be applied to other low propagating or NA stalk-deleted virus strains. [ABSTRACT FROM AUTHOR]
ISSN:1229845X
DOI:10.4142/jvs.25069