title: Identification of an infectious bronchitis coronavirus strain exhibiting a classical genotype but altered antigenicity, pathogenicity, and innate immunity profile.
abstract: Avian coronavirus infectious bronchitis virus (IBV) poses economic threat to the poultry industry worldwide. Pathogenic IBV 3575/08 was isolated from broilers vaccinated with the attenuated viral vaccine derived from a Taiwan strain 2575/98. In this study, extensive investigations were conducted on the genome sequences, antigenicity, pathogenicity, and host immune responses of several IBV strains in specific-pathogen-free chickens. Sequence analyses revealed that 3575/08 and 2575/98 shared high homology in their structural genes, but not in non-structural accessory proteins such as 3a, 3b and 5b. Despite a high degree of homology in their spike protein genes, cross neutralization test showed low cross protection between 3575/08 and 2575/98, suggesting distinct antigenicity for the two strains. Animal challenge experiments exhibited strong respiratory and renal pathogenicity for 3575/08. In addition, early and prolonged viral shedding and rapid viral dissemination were observed. Immune gene expression profiling by PCR array showed chickens infected with 3575/08 had delayed expression of a subset of early innate immune genes, whereas chickens infected with the wild-type or attenuated-type 2575/08 revealed quick gene induction and efficient virus control. In summary, this study reveals a new IBV strain, which harbors a known local genotype but displays remarkably altered antigenicity, pathogenicity and host defenses.
authors.affiliation: Department of Veterinary Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Shu-Yi
authors.initials: SY
authors.lastname: Lin
authors.affiliation: Department of Veterinary Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Yao-Tsun
authors.initials: YT
authors.lastname: Li
authors.affiliation: Department of Veterinary Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: You-Ting
authors.initials: YT
authors.lastname: Chen
authors.affiliation: Department of Veterinary Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Ting-Chih
authors.initials: TC
authors.lastname: Chen
authors.affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.|Research Center for Nanotechnology and Infectious Diseases, Taipei, Taiwan.
authors.forename: Che-Ming J
authors.initials: CJ
authors.lastname: Hu
authors.affiliation: Department of Veterinary Medicine, National Taiwan University, Taipei, Taiwan.|Research Center for Nanotechnology and Infectious Diseases, Taipei, Taiwan.
authors.forename: Hui-Wen
authors.initials: HW
authors.lastname: Chen
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology; D000956:Antigens, Viral / Q000276:immunology*; D002645:Chickens / Q000821:virology; D018352:Coronavirus Infections / Q000235:genetics / Q000276:immunology / Q000821:virology; D005814:Genes, Viral; D005838:Genotype; D007113:Immunity, Innate / Q000235:genetics; D001351:Infectious bronchitis virus / Q000235:genetics* / Q000472:pathogenicity*; D009500:Neutralization Tests; D009928:Organ Specificity; D010802:Phylogeny; D012689:Sequence Homology, Nucleic Acid; D012703:Serotyping
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral