title: Application of purified recombinant antigenic spike fragments to the diagnosis of avian infectious bronchitis virus infection.
abstract: The spike (S) protein, containing two subunits, S1 and S2, is the major immunity-eliciting antigen of avian infectious bronchitis virus (IBV), a highly contagious disease of chickens. Several immunogenic regions, mainly located within the S1 subunit, have been identified. Nonetheless, these immune-dominant regions were defined using selected monoclonal antibodies or using a short peptide approach that involves only certain limited regions of the S protein. In addition, some immune-dominant regions are located in hypervariable regions (HVRs) which are not present in all serotypes. Hence, the aim of this study was to determine a broader range of antigenic regions that have strong antibody eliciting ability; these could then be applied for development of an IBV-diagnostic tool. Initially, the S1 and part of the S2 subunit protein (24-567 amino acids) were expressed as five fragments in prokaryotic system. The antigenicity was confirmed using IBV immunized sera. Performance of the S subfragments was evaluated by ELISA using a panel of field chicken sera with known IBV titres determined by a commercial kit. This indicated that, among the five antigenic recombinant proteins, the region S-E showed the highest specificity and sensitivity, namely 95.38 % and 96.29 %, respectively. The κ value for the in-house ELISA using the S-E fragment compared to a commercial kit was 0.9172, indicating a high agreement between these two methods. As region S-E harbors strong immunogenicity within the spike protein, it has the potential to be exploited as an antigen when developing a cost-effective ELISA-based diagnosis tool.
authors.affiliation: Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan.
authors.forename: Kuan-Hsun
authors.initials: KH
authors.lastname: Lin
authors.forename: Chuen-Fu
authors.initials: CF
authors.lastname: Lin
authors.forename: Shyan-Song
authors.initials: SS
authors.lastname: Chiou
authors.forename: Ai-Ping
authors.initials: AP
authors.lastname: Hsu
authors.forename: Min-Shiuh
authors.initials: MS
authors.lastname: Lee
authors.forename: Chao-Chin
authors.initials: CC
authors.lastname: Chang
authors.forename: Tien-Jye
authors.initials: TJ
authors.lastname: Chang
authors.forename: Jui-Hung
authors.initials: JH
authors.lastname: Shien
authors.forename: Wei-Li
authors.initials: WL
authors.lastname: Hsu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D000956:Antigens, Viral / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism; D002645:Chickens; D018352:Coronavirus Infections / Q000175:diagnosis / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D004797:Enzyme-Linked Immunosorbent Assay; D001351:Infectious bronchitis virus / Q000235:genetics / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism; D008969:Molecular Sequence Data; D011201:Poultry Diseases / Q000175:diagnosis* / Q000276:immunology / Q000821:virology; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; D008562:Membrane Glycoproteins; D011994:Recombinant Proteins; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins; C578557:spike glycoprotein, SARS-CoV; C578553:spike protein, mouse hepatitis virus