title: Adaptation of H9N2 AIV in guinea pigs enables efficient transmission by direct contact and inefficient transmission by respiratory droplets.
abstract: H9N2 avian influenza viruses circulate worldwide in poultry and have sporadically infected humans, raising concern whether H9N2 viruses have pandemic potential. Here, we use a guinea pig model to examine whether serial passage results in adaptive viral changes that confer a transmissible phenotype to a wild-type H9N2 virus. After nine serial passages of an H9N2 virus through guinea pigs, productive transmission by direct contact occurred in 2/3 guinea pig pairs. The efficiency of transmission by direct contact increased following the fifteenth passage and occurred in 3/3 guinea pig pairs. In contrast, airborne transmission of the passaged virus was less efficient and occurred in 1/6 guinea pig pairs and 0/6 ferret pairs after the fifteenth passage. Three amino acid substitutions, HA1-Q227P, HA2-D46E, and NP-E434K, were sufficient for contact transmission in guinea pigs (2/3 pairs). The two HA amino acid substitutions enhanced receptor binding to α2,3-linked sialic acid receptors. Additionally, the HA2-D46E substitution increased virus thermostability whereas the NP-E434K mutation enhanced viral RNA polymerase activity in vitro. Our findings suggest that adaptive changes that enhance viral receptor binding, thermostability, and replicative capacity in mammalian cells can collectively enhance the transmissibility of H9N2 AIVs by direct contact in the guinea pig model.
authors.affiliation: Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China.|Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Research Institute, Academy of Military Medical Sciences, Changchun, 130122, China.|College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, 110866, China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Sang
authors.affiliation: Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Research Institute, Academy of Military Medical Sciences, Changchun, 130122, China.|College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an, 271000, China.
authors.forename: Airong
authors.initials: A
authors.lastname: Wang
authors.affiliation: Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Research Institute, Academy of Military Medical Sciences, Changchun, 130122, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Ding
authors.affiliation: Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China.
authors.forename: Huihui
authors.initials: H
authors.lastname: Kong
authors.affiliation: Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China.|Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Research Institute, Academy of Military Medical Sciences, Changchun, 130122, China.
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Gao
authors.affiliation: Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Research Institute, Academy of Military Medical Sciences, Changchun, 130122, China.|College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130000, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Li
authors.affiliation: College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an, 271000, China.
authors.forename: Tongjie
authors.initials: T
authors.lastname: Chai
authors.affiliation: Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Research Institute, Academy of Military Medical Sciences, Changchun, 130122, China.
authors.forename: Yuanguo
authors.initials: Y
authors.lastname: Li
authors.affiliation: Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Research Institute, Academy of Military Medical Sciences, Changchun, 130122, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Research Institute, Academy of Military Medical Sciences, Changchun, 130122, China.
authors.forename: Chengyu
authors.initials: C
authors.lastname: Wang
authors.affiliation: Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Research Institute, Academy of Military Medical Sciences, Changchun, 130122, China.
authors.forename: Zhonghai
authors.initials: Z
authors.lastname: Wan
authors.affiliation: Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Research Institute, Academy of Military Medical Sciences, Changchun, 130122, China.
authors.forename: Geng
authors.initials: G
authors.lastname: Huang
authors.affiliation: Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Research Institute, Academy of Military Medical Sciences, Changchun, 130122, China.
authors.forename: Tiecheng
authors.initials: T
authors.lastname: Wang
authors.affiliation: Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Research Institute, Academy of Military Medical Sciences, Changchun, 130122, China.|College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130000, China.
authors.forename: Na
authors.initials: N
authors.lastname: Feng
authors.affiliation: Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Research Institute, Academy of Military Medical Sciences, Changchun, 130122, China.
authors.forename: Xuexing
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Research Institute, Academy of Military Medical Sciences, Changchun, 130122, China.
authors.forename: Hualei
authors.initials: H
authors.lastname: Wang
authors.affiliation: Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Research Institute, Academy of Military Medical Sciences, Changchun, 130122, China.
authors.forename: Yongkun
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Research Institute, Academy of Military Medical Sciences, Changchun, 130122, China.
authors.forename: Songtao
authors.initials: S
authors.lastname: Yang
authors.affiliation: Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Research Institute, Academy of Military Medical Sciences, Changchun, 130122, China.|College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an, 271000, China.|Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, 130122, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Qian
authors.affiliation: College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130000, China.
authors.forename: Guixue
authors.initials: G
authors.lastname: Hu
authors.affiliation: Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Research Institute, Academy of Military Medical Sciences, Changchun, 130122, China.|College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an, 271000, China.|Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, 130122, China.|Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225000, China.
authors.forename: Yuwei
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China.|Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Research Institute, Academy of Military Medical Sciences, Changchun, 130122, China.|College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an, 271000, China.|Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, 130122, China.|Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225000, China.
authors.forename: Xianzhu
authors.initials: X
authors.lastname: Xia
mesh_terms: D000818:Animals; D001717:Birds; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D005260:Female; D005289:Ferrets; D006168:Guinea Pigs; D057809:HEK293 Cells; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics / Q000378:metabolism; D006801:Humans; D053127:Influenza A Virus, H9N2 Subtype / Q000502:physiology*; D005585:Influenza in Birds / Q000635:transmission* / Q000821:virology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D023421:Models, Animal; D016297:Mutagenesis, Site-Directed; D009698:Nucleoproteins / Q000235:genetics / Q000378:metabolism; D009976:Orthomyxoviridae Infections / Q000635:transmission / Q000821:virology; D011485:Protein Binding; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D013696:Temperature; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism; D014774:Virulence
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus; D009698:Nucleoproteins; D011994:Recombinant Proteins; D014764:Viral Proteins; C493831:hemagglutinin HA1, influenza B virus; D012321:DNA-Directed RNA Polymerases