Award details

Development of an IBV reverse genetics system based on the pathogenic M41 strain for the identification of regions of the genome involved in virulence

Reference	BBS/E/I/00001424
Principal Investigator / Supervisor	Professor Paul Britton
Co-Investigators / Co-Supervisors
Institution	The Pirbright Institute
Department	The Pirbright Institute Department
Funding type	Research
Value (£)	157,324
Status	Completed
Type	Institute Project
Start date	01/07/2009
End date	31/03/2012
Duration	33 months

Abstract

This project will be involved in the generation of an IBV reverse genetics system based on the virulent M41 strain of IBV. We will use our in house method to modifying the M41 genome to identify regions of the genome involved in pathogenicity/attenuation for the rational attenuation of pathogenicity in a non-reversible manner. We have previously used an IBV reverse genetics system based on the avirulent Beaudette strain to show that introduction of a Spike gene from a virulent isolate modified tropism, did not increase pathogenicity but did induce a protective immune response for protection of chickens challenged with the virulent strain that was used as donor for the S protein. We will replace in the M41 S protein in the M41-based infectious clone with the corresponding S gene from Beaudette. Recombinant IBVs will be assessed for pathogenicity and used in a challenge study to determine whether the Beaudette-derived S gene can be used for protection when used in a different genomic background. Recombinant IBVs that have been recovered from our Beaudette-based infectious clone system were found to be substantially less virulent in 18-day-old embryos; they did not cause a substantial drop in hatchability when compared to IBV vaccine strains and were potential candidates for in ovo vaccination. An amino acid substitution within the replicase Nsp16 protein was identified as a potential change that may be involved in the loss of hatchability associated with IBV vaccines. We will back mutate the mutation in Nsp16 and in collaboration with Intervet determine whether this affects hatchability.

Summary

unavailable

Committee	Not funded via Committee
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

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