title: A novel B-cell epitope of avian infectious bronchitis virus N protein.
abstract: This report describes the identification of a novel linear B-cell epitope at the N-terminus of the avian infectious bronchitis virus (IBV) nucleocapsid (N) protein. A monoclonal antibody designated 2D2 was prepared against the IBV N protein, and a series of 23 partially overlapping, tagged fragments of the IBV N gene were expressed. These peptides and five heterogeneous IBV strains were used to identify the epitope recognized by 2D2 using enzyme-linked immunosorbent assay (ELISA) and Western blotting analysis. The linear motif (11)DSPAPIIKLGG(21), located at the N-terminus of the N protein, was identified as the epitope bound by 2D2. ELISA and Western blotting also showed that this epitope was recognized by IBV-positive chicken serum. We propose that this motif is a linear B-cell epitope of N protein, and is the core sequence for reactivity, as demonstrated by binding of 2D2 to the truncated peptides and different IBV strains. Alignment and comparison of the 2D2-defined epitope with other coronavirus sequences showed that the epitope is conserved among avian coronaviruses. The identified epitope might be useful for clinical applications and as a tool for further study of the structure and function of the IBV N protein.
authors.affiliation: Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China.
authors.forename: Dan
authors.initials: D
authors.lastname: Yu
authors.forename: Zongxi
authors.initials: Z
authors.lastname: Han
authors.forename: Jia
authors.initials: J
authors.lastname: Xu
authors.forename: Yuhao
authors.initials: Y
authors.lastname: Shao
authors.forename: Huixin
authors.initials: H
authors.lastname: Li
authors.forename: Xiangang
authors.initials: X
authors.lastname: Kong
authors.forename: Shengwang
authors.initials: S
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology; D000918:Antibody Specificity; D002681:China; D003001:Cloning, Molecular; D018604:Epitope Mapping; D018985:Epitopes, B-Lymphocyte / Q000235:genetics / Q000276:immunology*; D005260:Female; D001351:Infectious bronchitis virus / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D019590:Nucleocapsid Proteins / Q000235:genetics / Q000276:immunology*; D016415:Sequence Alignment
chemical_list: D000914:Antibodies, Viral; D018985:Epitopes, B-Lymphocyte; D019590:Nucleocapsid Proteins