A temperature-sensitive recombinant IB vaccine
According to a recent research publication, Pirbright researchers have a candidate vaccine that could protect chickens from severe disease with a single dose. A recombinant IBV (rIBV) known as M41-R, based on a pathogenic strain M41-CK was attenuated in vivo by two amino acid changes, Nsp10-Pro85Leu and Nsp14-Val393Leu.
Attenuation of IBV was caused by changes located in non-structural proteins, and that two specific amino acids were responsible for this. The research showed that these amino acid changes resulted in the virus being less able to cause disease in poultry.
The researchers then investigated how changes in these amino acids weakened the virus. The two amino acids were found to be associated with temperature-sensitive replication of IBV, meaning that the attenuated virus is less able to replicate at higher temperatures, a characteristic that can be advantageous for vaccine development.
Vaccination of specific-pathogen-free chickens with M41-R induced 100% protection against clinical disease, tracheal ciliary damage, and challenge virus replication following homologous challenge with virulent M41-CK.
