Australian infectious bronchitis viruses: identification of nine subtypes by a neutralisation test

Wadey, C.N.; Faragher, J. T.

doi:10.1016/s0034-5288(18)32611-0

Cited by 44 publications

(16 citation statements)

References 14 publications

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“…The GenBank accession numbers for these genome sequences are the same as those in Fig. 1. maximum value defining serotype relatedness, respectively (Wadey and Faragher, 1981). The low antigenic relatedness between the I1101/16 isolate and the ck/CH/LJL/140901 strain was not due to differences in their B cell epitopes because the sequences of the B cell antigenic epitopes located in the spike protein were nearly identical in both viruses, although it has been reported that only a few amino acid changes in the S1 subunit of the spike protein can result in serologically distinct viruses (Cavanagh et al, 1992a,b).…”

Section: Discussionmentioning

confidence: 99%

Characterization of the complete genome, antigenicity, pathogenicity, tissue tropism, and shedding of a recombinant avian infectious bronchitis virus with a ck/CH/LJL/140901-like backbone and an S2 fragment from a 4/91-like virus

et al. 2018

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In this study, we isolated an infectious bronchitis virus, designated I1101/16, from broiler breeders in China. Analysis of the S1 gene showed that isolate I1101/16 was genetically close to strain ck/CH/LJL/140901, which belongs to the TW I genotype (also known as lineage GI-7 based on the recent IBV classification), however the S2 gene showed genetic diversity comparing to that of S1 gene. Comparison of the genomic sequences showed that the genome of isolate I1101/16 was similar to that of strain ck/CH/LJL/140901 from the 5' end of the genome to the 5' end of the S2 gene and from the 5' end of the 3a gene to the end of the genome, whereas the remaining parts of the genome sequences were more closely related to those of strain 4/91 than those of ck/CH/LJL/140901, thereby suggesting that recombination might have occurred during the origin of the virus. SimPlot and Bootscan analysis of the complete genomic sequence confirmed this hypothesis, where it showed that isolate I1101/16 arose through recombination events between ck/CH/LJL/140901- and 4/91-like viruses. Isolate I1101/16 and strain ck/CH/LJL/140901 shared identical amino acids in almost all five of their B cell epitopes, but the two viruses had a serotype relatedness value of 65, which is well below 80, i.e., the lower cutoff value for viruses of the same serotype. In addition, pathogenicity tests demonstrated that isolate I1101/16 was more pathogenic to 1-day-old specific-pathogen-free chickens than strain ck/CH/LJL/140901, according to analysis of the clinical signs, whereas strain ck/CH/LJL/140901 exhibited prolonged replication and shedding after challenge compared with isolate I1101/16. This study did not provide evidence that recombination can directly alter the antigenicity, virulence, replication, shedding, and tissue tropism of a virus, but it did show that recombination events are likely to be major determinants of viral evolution.

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Section: Discussionmentioning

confidence: 99%

Characterization of the complete genome, antigenicity, pathogenicity, tissue tropism, and shedding of a recombinant avian infectious bronchitis virus with a ck/CH/LJL/140901-like backbone and an S2 fragment from a 4/91-like virus

et al. 2018

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“…The end-point titer for each serum sample was calculated using the Reed-Muench method. Antigenic relatedness values were calculated (Archetti and Horsfall et al, 1950;Wadey and Faragher, 1981).…”

Section: Cross-virus Neutralization Assaymentioning

confidence: 99%

Effects of hypervariable regions in spike protein on pathogenicity, tropism, and serotypes of infectious bronchitis virus

et al. 2018

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To study the roles of hypervariable regions (HVRs) in receptor-binding subunit S1 of the spike protein, we manipulated the genome of the IBV Beaudette strain using a reverse genetics system to construct seven recombinant strains by separately or simultaneously replacing the three HVRs of the Beaudette strain with the corresponding fragments from a QX-like nephropathogenic isolate ck/CH/LDL/091022 from China. We characterized the growth properties of these recombinant IBVs in Vero cells and embryonated eggs, and their pathogenicity, tropism, and serotypes in specific pathogen-free (SPF) chickens. All seven recombinant IBVs proliferated in Vero cells, but the heterogenous HVRs could reduce their capacity for adsorption during in vitro infection. The recombinant IBVs did not significantly increase the pathogenicity compared with the Beaudette strain in SPF chickens, and they still shared the same serotype as the Beaudette strain, but the antigenic relatedness values between the recombinant strain and Beaudette strain generally decreased with the increase in the number of the HVRs exchanged. The results of this study demonstrate the functions of HVRs and they may help to develop a vaccine candidate, as well as providing insights into the prevention and control of IBV.

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“…Other farms from which isolates were obtained usually house between 2.5 and 7.5 X 10 4 broilers at any one time. Broilers, regardless of location, were vaccinated at one day of age with either Vic S, Inghams or Steggles strains of IB vaccine, which are antigenically identical (Ignjatovic & McWaters, 1991;Wadey & Faragher, 1981). Strains listed in Table 1 are representative of several antigenically identical strains isolated from the same location.…”

Section: Origin Of Samples and Strain Designationmentioning

confidence: 99%

“…Only two strains isolated before the introduction of vaccination, Nl/62 ('T') and N3/62, have been characterized to date (Ignjatovic & McWaters, 1991;Wadey & Faragher, 1981). Seven additional IBV strains, Ql/61, Ql/63, Ql/64, Ql/65, Q2/66, Ql/67 and Ql/69 isolated between 1961 and 1969, were therefore used in this study to obtain more comprehensive information on the antigenic diversity of strains predominating on commercial sites before the introduction of vaccination.…”

Section: Ibv Strains Isolated Before the Introduction Of Vaccinationmentioning

confidence: 99%

A long‐term study of Australian infectious bronchitis viruses indicates a major antigenic change in recently isolated strains

1997

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The antigenic relationship among 36 IBV strains isolated between 1961 and 1994 from vaccinated and non-vaccinated chicken flocks was determined. Based on the reaction with nine monoclonal antibodies (MAbs) in ELISA and polyclonal chicken sera in western blotting, IBV strains clearly fell into two distinct antigenic groups. Nineteen IBV strains isolated between 1961 and 1994 from various locations were antigenically related, having common cross-reactive epitopes on the peplomer S, the nucleocapsid N and the membrane M proteins. IBV strains within this classical group could be antigenically differentiated further by serotyping and by their reaction with MAbs. Seventeen IBV strains isolated between 1988 and 1994, shared only a minor degree of antigenic similarity with strains in the classical group. Strains in this novel group were antigenically related to each other and shared cross-reactive epitopes particularly on the N and M proteins. The novel IBV strains were not detected before 1988 and their origin is unknown. They appeared suddenly and almost simultaneously at two distant commercial sites, Redland Bay and Appin, and were also isolated at a third location in Victoria 3 years later. The Appin strains persisted on the site for 3 years without changes in antigenicity, including the serotype; however, following introduction of vaccination with novel strains a variant of new serotype was isolated. Variants isolated in Victoria on the other hand showed greater antigenic diversity and tendency for change. Novel strains have not displaced classical strains which continued to be isolated frequently.

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Australian infectious bronchitis viruses: identification of nine subtypes by a neutralisation test

Cited by 44 publications

References 14 publications

Characterization of the complete genome, antigenicity, pathogenicity, tissue tropism, and shedding of a recombinant avian infectious bronchitis virus with a ck/CH/LJL/140901-like backbone and an S2 fragment from a 4/91-like virus

Characterization of the complete genome, antigenicity, pathogenicity, tissue tropism, and shedding of a recombinant avian infectious bronchitis virus with a ck/CH/LJL/140901-like backbone and an S2 fragment from a 4/91-like virus

Effects of hypervariable regions in spike protein on pathogenicity, tropism, and serotypes of infectious bronchitis virus

A long‐term study of Australian infectious bronchitis viruses indicates a major antigenic change in recently isolated strains

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