The avian coronavirus infectious bronchitis virus (IBV) is the most economically important disease of chickens in the UK, causing significant losses as a result of poor weight gain and reduced egg quality in infected birds. IBV expresses a large spike (S) glycoprotein on the surface of the virion which is responsible for attachment to host cells and is the main antigenic target for neutralising antibodies during infection. Previous work has also demonstrated that the S protein determines cell tropism in vitro. In order to investigate the involvement of the S gene in IBV pathogenesis and explore the potential for vaccine propagation in cell culture, recombinant viruses were generated using vaccinia virus based reverse genetics. Two isolates of the pathogenic M41 strain were mutated to include the S gene from a non-pathogenic lab strain with extended tropism (Beau-R) or a heterologous pathogenic field strain with restricted tropism (4/91), resulting in two recombinant IBVs termed M41K-BeauR(S) and M41K-4/91(S), respectively. These viruses were characterised in vitro and in vivo to determine the involvement of the S gene in IBV replication and pathogenicity. M41K-BeauR(S) was attenuated in vivo but exhibited the extended host tropism of the S donor strain. M41K-4/91(S) remained pathogenic and also adopted the restricted in vitro tropism of 4/91. This indicates that the S gene not only determines the cellular tropism of the virus but also plays a key role during in vivo infections, and that replacing the ectodomain of IBV S can significantly alter the pathogenicity of the resulting virus.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error