title: Generation and protective efficacy of a cold-adapted attenuated avian H9N2 influenza vaccine.
abstract: To prevent H9N2 avian influenza virus infection in chickens, a long-term vaccination program using inactivated vaccines has been implemented in China. However, the protective efficacy of inactivated vaccines against antigenic drift variants is limited, and H9N2 influenza virus continues to circulate in vaccinated chicken flocks in China. Therefore, developing a cross-reactive vaccine to control the impact of H9N2 influenza in the poultry industry remains a high priority. In the present study, we developed a live cold-adapted H9N2 influenza vaccine candidate (SD/01/10-ca) by serial passages in embryonated eggs at successively lower temperatures. A total of 13 amino acid mutations occurred during the cold-adaptation of this H9N2 virus. The candidate was safe in chickens and induced robust hemagglutination-inhibition antibody responses and influenza virus-specific CD4(+) and CD8(+) T cell immune responses in chickens immunized intranasally. Importantly, the candidate could confer protection of chickens from homologous and heterogenous H9N2 viruses. These results demonstrated that the cold-adapted attenuated H9N2 virus would be selected as a vaccine to control the infection of prevalent H9N2 influenza viruses in chickens.
authors.affiliation: Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, College of Veterinary Medicine, and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, 100193, China.
authors.forename: Yandi
authors.initials: Y
authors.lastname: Wei
authors.affiliation: Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, College of Veterinary Medicine, and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, 100193, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Qi
authors.affiliation: Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, College of Veterinary Medicine, and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, 100193, China.
authors.forename: Huijie
authors.initials: H
authors.lastname: Gao
authors.affiliation: Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, College of Veterinary Medicine, and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, 100193, China.
authors.forename: Honglei
authors.initials: H
authors.lastname: Sun
authors.affiliation: Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, College of Veterinary Medicine, and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, 100193, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Pu
authors.affiliation: Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, College of Veterinary Medicine, and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, 100193, China.
authors.forename: Yipeng
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, College of Veterinary Medicine, and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, 100193, China.
authors.forename: Jinhua
authors.initials: J
authors.lastname: Liu
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002645:Chickens; D003080:Cold Temperature; D004285:Dogs; D053127:Influenza A Virus, H9N2 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000276:immunology* / Q000592:standards; D005585:Influenza in Birds / Q000276:immunology*; D061985:Madin Darby Canine Kidney Cells; D014611:Vaccination / Q000662:veterinary; D014613:Vaccines, Attenuated / Q000276:immunology* / Q000592:standards
chemical_list: D007252:Influenza Vaccines; D014613:Vaccines, Attenuated