title: S1 gene sequence heterogeneity of a pathogenic infectious bronchitis virus strain and its embryo-passaged, attenuated derivatives.
abstract: Infectious bronchitis virus CK/CH/LDL/97I was attenuated by serial passage in chicken embryos. Virus of passage 115 was attenuated as determined by clinical response to inoculation to 15-day-old specific pathogen free chickens. The vaccination-challenge test showed that the attenuated passage 115 virus could afford protection against the homologous pathogenic virus, passage 5, by the clinical response. Based on the sequence analysis and comparison of the S1 gene, both the pathogenic and attenuated CK/CH/LDL/97I viruses were populations that each included at least two subpopulations. Also, from analysis of the amino acid and nucleotide sequences of S1 gene, we speculate that recombination between the minor and dominant subpopulations plus accumulation of mutations in the S1 region of pathogenic passage 5 might lead to the formation of the embryo-passaged, attenuated passage 115.
authors.affiliation: Division of Avian Infectious Diseases, National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China. swliu@hvri.ac.cn
authors.forename: Shengwang
authors.initials: S
authors.lastname: Liu
authors.forename: Zongxi
authors.initials: Z
authors.lastname: Han
authors.forename: Jianfei
authors.initials: J
authors.lastname: Chen
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.forename: Yuhao
authors.initials: Y
authors.lastname: Shao
authors.forename: Xiangang
authors.initials: X
authors.lastname: Kong
authors.forename: Guangzhi
authors.initials: G
authors.lastname: Tong
authors.forename: Jungong
authors.initials: J
authors.lastname: Rong
mesh_terms: D000818:Animals; D002642:Chick Embryo; D005814:Genes, Viral / Q000235:genetics*; D014644:Genetic Variation; D001351:Infectious bronchitis virus / Q000145:classification / Q000235:genetics* / Q000472:pathogenicity*; D008969:Molecular Sequence Data; D012692:Serial Passage; D014613:Vaccines, Attenuated / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D014765:Viral Vaccines / Q000737:chemistry / Q000235:genetics / Q000276:immunology
chemical_list: D014613:Vaccines, Attenuated; D014765:Viral Vaccines