title: A recombinant avian infectious bronchitis virus expressing a heterologous spike gene belonging to the 4/91 serotype.
abstract: We have shown previously that replacement of the spike (S) gene of the apathogenic IBV strain Beau-R with that from the pathogenic strain of the same serotype, M41, resulted in an apathogenic virus, BeauR-M41(S), that conferred protection against challenge with M41. We have constructed a recombinant IBV, BeauR-4/91(S), with the genetic backbone of Beau-R but expressing the spike protein of the pathogenic IBV strain 4/91(UK), which belongs to a different serogroup as Beaudette or M41. Similar to our previous findings with BeauR-M41(S), clinical signs observations showed that the S gene of the pathogenic 4/91 virus did not confer pathogenicity to the rIBV BeauR-4/91(S). Furthermore, protection studies showed there was homologous protection; BeauR-4/91(S) conferred protection against challenge with wild type 4/91 virus as shown by the absence of clinical signs, IBV RNA assessed by qRT-PCR and the fact that no virus was isolated from tracheas removed from birds primarily infected with BeauR-4/91(S) and challenged with IBV 4/91(UK). A degree of heterologous protection against M41 challenge was observed, albeit at a lower level.Our results confirm and extend our previous findings and conclusions that swapping of the ectodomain of the S protein is a precise and effective way of generating genetically defined candidate IBV vaccines.
authors.affiliation: Avian Viral Diseases, Institute for Animal Health, Compton Laboratory, Compton, Newbury, Berkshire, United Kingdom.
authors.forename: Maria
authors.initials: M
authors.lastname: Armesto
authors.forename: Sharon
authors.initials: S
authors.lastname: Evans
authors.forename: David
authors.initials: D
authors.lastname: Cavanagh
authors.forename: Abu-Bakr
authors.initials: AB
authors.lastname: Abu-Median
authors.forename: Sarah
authors.initials: S
authors.lastname: Keep
authors.forename: Paul
authors.initials: P
authors.lastname: Britton
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002642:Chick Embryo; D004274:DNA, Recombinant / Q000235:genetics*; D015870:Gene Expression; D016679:Genome, Viral / Q000235:genetics; D006023:Glycoproteins / Q000737:chemistry / Q000235:genetics*; D001351:Infectious bronchitis virus / Q000235:genetics* / Q000472:pathogenicity; D008969:Molecular Sequence Data; D015202:Protein Engineering / Q000379:methods*; D014132:Trachea / Q000821:virology; D014616:Vaccinia virus / Q000235:genetics; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics*
chemical_list: D004274:DNA, Recombinant; D006023:Glycoproteins; D014764:Viral Proteins