title: Duration of the protective immune response after prime and booster vaccination of yearlings with a live modified cold-adapted viral vaccine against equine influenza.
abstract: We previously created a live vaccine against equine influenza based the new reassortant cold-adapted (Ca) strain A/HK/Otar/6:2/2010. The live vaccine contains surface proteins (HA, NA) from the wild-type virus A/equine/Otar/764/2007 (Н3N8; American Lineage Florida Clade 2), and internal proteins (PB2, PB1, PA, NP, M, NS) from the attenuated Ca donor virus A/Hong Kong/1/68/162/35CA (H3N2). To determine the safety and duration of the protective immune responses, 90 yearlings were intranasally vaccinated in single mode, double mode at an interval of 42 days (10(7.0) EID50/animal for both vaccinations), or with PBS (control group). Ten animals from each group were challenged with the homologous wild-type virus A/equine/Otar/764/07 (Н3N8) at 1, 2, 3, 4, 5, 6, 9 and 12 months after vaccination. Similarly, 10 animals from each group were challenged with the heterologous wild-type virus A/equine/Sydney/2888-8/07 (Н3N8; American Lineage Florida Clade 1) 12 months after vaccination. The vaccine was completely safe, and single intranasal vaccination of yearlings was capable of inducing statistically significant (from P=0.03 to P<0.0001) clinical and virological protection against the homologous virus; however, only double mode vaccination generated significant (from P=0.02 to P<0.0001) protection against the heterologous virus at 12 months (observation period). Interestingly, this vaccine enables the differentiation of infected and vaccinated animals. On this basis of this study, we recommend double intranasal administration of this vaccine at an interval of 42 days in veterinary practice.
authors.affiliation: Research Institute for Biological Safety Problems (RIBSP), Science Committee, Ministry of Education and Science of the Republic of Kazakhstan, Kazakhstan. Electronic address: tabynov_81@mail.ru.
authors.forename: K
authors.initials: K
authors.lastname: Tabynov
authors.affiliation: Research Institute for Biological Safety Problems (RIBSP), Science Committee, Ministry of Education and Science of the Republic of Kazakhstan, Kazakhstan.
authors.forename: Zh
authors.initials: Zh
authors.lastname: Kydyrbayev
authors.affiliation: Research Institute for Biological Safety Problems (RIBSP), Science Committee, Ministry of Education and Science of the Republic of Kazakhstan, Kazakhstan.
authors.forename: Sh
authors.initials: Sh
authors.lastname: Ryskeldinova
authors.affiliation: Research Institute for Biological Safety Problems (RIBSP), Science Committee, Ministry of Education and Science of the Republic of Kazakhstan, Kazakhstan.
authors.forename: N
authors.initials: N
authors.lastname: Assanzhanova
authors.affiliation: Research Institute for Biological Safety Problems (RIBSP), Science Committee, Ministry of Education and Science of the Republic of Kazakhstan, Kazakhstan.
authors.forename: A
authors.initials: A
authors.lastname: Sansyzbay
mesh_terms: D000281:Administration, Intranasal; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D005260:Female; D006734:Horse Diseases / Q000517:prevention & control*; D006736:Horses / Q000276:immunology*; D007111:Immunity, Cellular; D007117:Immunization, Secondary / Q000662:veterinary*; D007071:Immunoglobulin A, Secretory / Q000276:immunology; D053122:Influenza A Virus, H3N2 Subtype; D053123:Influenza A Virus, H3N8 Subtype; D007252:Influenza Vaccines / Q000276:immunology*; D008297:Male; D009976:Orthomyxoviridae Infections / Q000517:prevention & control* / Q000662:veterinary; D014611:Vaccination / Q000662:veterinary*; D014613:Vaccines, Attenuated / Q000276:immunology; D017201:Virus Shedding
chemical_list: D000914:Antibodies, Viral; D007071:Immunoglobulin A, Secretory; D007252:Influenza Vaccines; D014613:Vaccines, Attenuated
keywords: Cold-adapted vaccine; Duration of the protective immune response; Equine influenza virus; Safety; Yearlings