Award details

Molecular characterisation of the avian coronavirus infectious bronchitis virus to identify regions of the genome involved in virulence

Reference	BBS/E/I/00001145
Principal Investigator / Supervisor	Professor Paul Britton
Co-Investigators / Co-Supervisors
Institution	The Pirbright Institute
Department	The Pirbright Institute Department
Funding type	Research
Value (£)	266,389
Status	Completed
Type	Institute Project
Start date	01/04/2003
End date	30/06/2009
Duration	75 months

Abstract

This project involves the use of an in house reverse genetics system for modifying the genome of the avian coronavirus infectious bronchitis virus (IBV) to identify IBV proteins that determine pathogenicity/attenuation and will allow for the rational attenuation of pathogenicity in a non-reversible manner. In addition, we are using the system for maintaining or enhancing the immunogenicity of potential IBV vaccines by swapping of spike proteins, for the induction of immunity to new serotypes, in rationally attenuated viruses. We are using several full-length cDNA copies of the IBV genome integrated into the vaccinia virus genome for further modification by homologous recombination using transient dominant selection. Recombinant IBVs are subsequently rescued from the DNA isolated from recombinant vaccinia viruses. The backbone genome we are using for the basis of our reverse genetics system is from the Beaudette strain of IBV; a virus that is avirulent in chickens but virulent for 11-day-old embryos. Viruses that have been recovered appear to be substantially less virulent in 18-day-old embryos and are potential candidates for in ovo vaccination. We have modified genomes in which the Beaudette S gene, responsible for producing the IBV receptor binding protein, has been replaced with the S gene from virulent IBVs and deleted accessory protein genes. We also have a chimaeric IBV genome that consists of the replicase gene from Beaudette but the structural and accessory genes are from the virulent M41 strain of IBV. Recombinant IBVs with this chimaeric genome are avirulent in chickens but have the growth characteristics of M41, indicating that the replicase gene of Beaudette is responsible for the loss of pathogenicity. This project is supporting several projects involved in the gradual swap of Beaudette encoding replicase sequences with those form M41 to identify the region(s) involved in pathogenicity.

Summary

unavailable

Committee	Closed Committee - Animal Sciences (AS)
Research Topics	Animal Health, Immunology, Microbiology
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

I accept the terms and conditions of use (opens in new window)

export PDF file

back to list new search