title: Rapid adaptation of avian H7N9 virus in pigs.
abstract: How the H7N9 avian influenza virus gained the distinct ability to infect humans is unclear. Pigs are an important host in influenza virus ecology because they are susceptible to infection with both avian and human influenza viruses and are often involved in interspecies transmission. Here, we passaged one avian isolate and one human isolate in pigs to examine the mammalian host adaptation of the H7N9 virus. The avian virus replicated to a high titer after one passage, whereas the human isolate replicated poorly after three passages in pig lungs. Sequence analysis found nine substitutions in the HA, NA, M and NS segments of the avian isolate, which enhanced the binding affinity for human-type receptors. These results indicate that avian H7N9 influenza viruses can be easily adapted to pigs and that pigs may act as an important intermediate host for the reassortment and transmission of such novel viruses.
authors.affiliation: Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS) & Comparative Medicine Center, Peking Union Medical Collage (PUMC), Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Pan Jia Yuan Nan Li No. 5, Chao Yang District, Beijing, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Xu
authors.affiliation: Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS) & Comparative Medicine Center, Peking Union Medical Collage (PUMC), Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Pan Jia Yuan Nan Li No. 5, Chao Yang District, Beijing, China.
authors.forename: Linlin
authors.initials: L
authors.lastname: Bao
authors.affiliation: Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS) & Comparative Medicine Center, Peking Union Medical Collage (PUMC), Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Pan Jia Yuan Nan Li No. 5, Chao Yang District, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Deng
authors.affiliation: Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS) & Comparative Medicine Center, Peking Union Medical Collage (PUMC), Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Pan Jia Yuan Nan Li No. 5, Chao Yang District, Beijing, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhu
authors.affiliation: Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS) & Comparative Medicine Center, Peking Union Medical Collage (PUMC), Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Pan Jia Yuan Nan Li No. 5, Chao Yang District, Beijing, China.
authors.forename: Fengdi
authors.initials: F
authors.lastname: Li
authors.affiliation: Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS) & Comparative Medicine Center, Peking Union Medical Collage (PUMC), Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Pan Jia Yuan Nan Li No. 5, Chao Yang District, Beijing, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Chen
authors.affiliation: Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS) & Comparative Medicine Center, Peking Union Medical Collage (PUMC), Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Pan Jia Yuan Nan Li No. 5, Chao Yang District, Beijing, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Lv
authors.affiliation: Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS) & Comparative Medicine Center, Peking Union Medical Collage (PUMC), Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Pan Jia Yuan Nan Li No. 5, Chao Yang District, Beijing, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Yuan
authors.affiliation: Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS) & Comparative Medicine Center, Peking Union Medical Collage (PUMC), Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Pan Jia Yuan Nan Li No. 5, Chao Yang District, Beijing, China.
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS) & Comparative Medicine Center, Peking Union Medical Collage (PUMC), Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Pan Jia Yuan Nan Li No. 5, Chao Yang District, Beijing, China.
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Li
authors.affiliation: Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS) & Comparative Medicine Center, Peking Union Medical Collage (PUMC), Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Pan Jia Yuan Nan Li No. 5, Chao Yang District, Beijing, China.
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Yao
authors.affiliation: Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS) & Comparative Medicine Center, Peking Union Medical Collage (PUMC), Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Pan Jia Yuan Nan Li No. 5, Chao Yang District, Beijing, China.
authors.forename: Songzhi
authors.initials: S
authors.lastname: Gu
authors.affiliation: Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS) & Comparative Medicine Center, Peking Union Medical Collage (PUMC), Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Pan Jia Yuan Nan Li No. 5, Chao Yang District, Beijing, China.
authors.forename: Pin
authors.initials: P
authors.lastname: Yu
authors.affiliation: State Key Laboratory for Emerging Infectious Diseases, Department of Microbiology and the Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Honglin
authors.initials: H
authors.lastname: Chen
authors.affiliation: Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS) & Comparative Medicine Center, Peking Union Medical Collage (PUMC), Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Pan Jia Yuan Nan Li No. 5, Chao Yang District, Beijing, China. Electronic address: qinchuan@pumc.edu.cn.
authors.forename: Chuan
authors.initials: C
authors.lastname: Qin
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001717:Birds; D006801:Humans; D064766:Influenza A Virus, H7N9 Subtype / Q000235:genetics / Q000502:physiology*; D005585:Influenza in Birds / Q000821:virology*; D007251:Influenza, Human / Q000821:virology*; D009976:Orthomyxoviridae Infections / Q000662:veterinary* / Q000821:virology; D034421:Sus scrofa; D013552:Swine; D013553:Swine Diseases / Q000821:virology*
keywords: Adaptation; H7N9 influenza virus; Mutation; Pig; Receptor binding