title: Antigenic evolution of H9N2 chicken influenza viruses isolated in China during 2009-2013 and selection of a candidate vaccine strain with broad cross-reactivity.
abstract: We previously demonstrated that H9N2 subtype avian influenza viruses (AIVs) isolated from 1994 to 2008 evolved into distinct antigenic groups (C, D, and E) and then underwent antigenic drift from commercial vaccines, causing a country-wide outbreak during 2010-2013. In this study, H9N2 AIVs isolated from chickens during 2009-2013 were antigenically analyzed by performing hemagglutination inhibition and neutralization assays using a panel of polyclonal antibodies. Our findings confirmed the antigenic drift of recent H9N2 viruses from the commercial vaccine and showed that most of these antigenic variants form a novel HI antigenic group, F, with a few belonging to groups D and E. Slight antigenic variation was observed in group F viruses. Genetic analysis of amino acid sequences deduced from hemagglutinin (HA) gene sequences indicated that 9 of 15 mutations predominant in the 2009-2013 viruses can be mapped to known antigenic sites, which might be responsible for the novel antigenicity of group F. These antigenic changes make it necessary to modify the influenza vaccine to ensure efficient protection. A vaccine candidate, Ck/HeB/YT/10, was selected and provided significant protection against viruses from different antigenic groups in terms of reduction in virus shedding, suggesting broad cross-reactivity. Taken together, our results indicate that the H9N2 chicken influenza viruses in China have evolved from distinct antigenic groups into a novel group F that became dominant during the country-wide outbreak and now seems to be undergoing new antigenic divergence. Systematic surveillance and timely updating of vaccine strains are important for viral prevention and control in the future.
authors.affiliation: Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, College of Veterinary Medicine, 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, China Agricultural University, Beijing, 100193, China.
authors.forename: Guanlong
authors.initials: G
authors.lastname: Xu
authors.affiliation: Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.
authors.forename: Guozhong
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.
authors.forename: Chu
authors.initials: C
authors.lastname: Wen
authors.affiliation: Animal Health Supervision Institute of Xinjiang Uygur Autonomous Region, Urumqi, 830023, China.
authors.forename: Furkat
authors.initials: F
authors.lastname: Anwar
authors.affiliation: Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN 38105-3678, USA.
authors.forename: Shuoguo
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN 38105-3678, USA; Eccles Institute of Human Genetics, Salt Lake City, UT 84112, USA.
authors.forename: Gordon
authors.initials: G
authors.lastname: Lemmon
authors.affiliation: Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.
authors.forename: Jinliang
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN 38105-3678, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Carter
authors.affiliation: Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.
authors.forename: Min
authors.initials: M
authors.lastname: Wang
authors.affiliation: Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, College of Veterinary Medicine, 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, 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, China Agricultural University, Beijing, 100193, China.
authors.forename: Jixun
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN 38105-3678, USA.
authors.forename: Gang
authors.initials: G
authors.lastname: Wu
authors.affiliation: Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105-3678, USA.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Webster
authors.affiliation: Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.
authors.forename: Jinhua
authors.initials: J
authors.lastname: Liu
authors.affiliation: Key Laboratory of Animal Epidemiology and Zoonosis, Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China. Electronic address: pujuan@cau.edu.cn.
authors.forename: Juan
authors.initials: J
authors.lastname: Pu
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D000956:Antigens, Viral / Q000235:genetics*; D002645:Chickens; D002681:China / Q000453:epidemiology; D019143:Evolution, Molecular; D053127:Influenza A Virus, H9N2 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000276:immunology*; D005585:Influenza in Birds / Q000097:blood / Q000453:epidemiology / Q000517:prevention & control / Q000821:virology*; D008958:Models, Molecular; D010802:Phylogeny; D011487:Protein Conformation; D013047:Specific Pathogen-Free Organisms; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; D007252:Influenza Vaccines; D014764:Viral Proteins
keywords: Antigenic evolution; Chicken influenza virus; H9N2; Vaccine