Adaptive amino acid substitutions enable transmission of an H9N2 avian influenza virus in guinea pigs

• Published in: Scientific reports Vol. 9; no. 1; pp. 19734 - 8
• Main Authors: Lina, Liu, Saijuan, Chen, Chengyu, Wang, Yuefeng, Lu, Shishan, Dong, Ligong, Chen, Kangkang, Guo, Zhendong, Guo, Jiakai, Li, Jianhui, Zhang, Qingping, Luo, Wenting, Zhang, Yu, Shang, Honglin, Wang, Tengfei, Zhang, Guoyuan, Wen, Jiping, Zhu, Chunmao, Zhang, Meilin, Jin, Yuwei, Gao, Huabin, Shao, Zongzheng, Zhao
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 24.12.2019; Nature Publishing Group
• Subjects: 13/106; 38/77; 42/70; 631/326/596/1578; 631/326/596/2554; 631/326/596/2555; 64/60; Amino Acid Substitution; Amino acids; Animals; Avian flu; Dogs; Female; Genomes; Guinea Pigs; Humanities and Social Sciences; Influenza; Influenza A Virus, H9N2 Subtype - genetics; Influenza A Virus, H9N2 Subtype - metabolism; Madin Darby Canine Kidney Cells; Mice; Mice, Inbred BALB C; multidisciplinary; Mutation; Mutation, Missense; Orthomyxoviridae Infections - genetics; Orthomyxoviridae Infections - metabolism; Orthomyxoviridae Infections - transmission; Pandemics; Pathogenicity; Phenotypes; Poultry; Science; Science (multidisciplinary); Viruses; Hong Kong
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-019-56122-6

H9N2 is the most prevalent low pathogenic avian influenza virus (LPAIV) in domestic poultry in the world. Two distinct H9N2 poultry lineages, G1-like (A/quail/Hong Kong/G1/97) and Y280-like (A/Duck/Hong Kong/Y280/1997) viruses, are usually associated with binding affinity for both α 2,3 and α 2,6 sialic acid receptors (avian and human receptors), raising concern whether these viruses possess pandemic potential. To explore the impact of mouse adaptation on the transmissibility of a Y280-like virus A/Chicken/Hubei/214/2017(H9N2) (abbreviated as WT), we performed serial lung-to-lung passages of the WT virus in mice. The mouse-adapted variant (MA) exhibited enhanced pathogenicity and advantaged transmissibility after passaging in mice. Sequence analysis of the complete genomes of the MA virus revealed a total of 16 amino acid substitutions. These mutations distributed across 7 segments including PB2, PB1, PA, NP, HA, NA and NS1 genes. Furthermore, we generated a panel of recombinant or mutant H9N2 viruses using reverse genetics technology and confirmed that the PB2 gene governing the increased pathogenicity and transmissibility. The combinations of 340 K and 588 V in PB2 were important in determining the altered features. Our findings elucidate the specific mutations in PB2 contribute to the phenotype differences and emphasize the importance of monitoring the identified amino acid substitutions due to their potential threat to human health.