Research aims to lower the cost of IBV vaccine production
Infectious bronchitis virus (IBV) vaccines are currently produced in hen’s eggs – a cumbersome and expensive process – because most IBV strains do not grow in cell cultures. In a step towards making vaccine production more efficient and reducing costs, a team led by Dr Erica Bickerton at The Pirbright Institute identified the exact genetic code which enables a non-virulent lab strain of IBV to grow in cell cultures rather than eggs. They then transferred this code into a vaccine strain, which allowed it to also be grown in cells.
Dr Bickerton, leader of the Coronaviruses group at Pirbright, said: “To find the genetic code that made the lab strain able to replicate in cell cultures, we scanned the gene that produces the spike protein – the protein which enables the virus to attach to and enter cells – and found a genetic sequence which was unique to that virus. We were able cut this sequence out of the lab strain and replace it in the vaccine strain to see if this allowed the vaccine strain to replicate in cell cultures too.
“The most interesting part of the study was discovering that the sequence which allows lab growth of IBV strains results in the change of only three amino acids in the spike protein. We can now apply this modification to other IBV vaccine strains, which will help improve the speed and efficiency of IBV studies and can eventually be applied to vaccine production.”
The team has recently been awarded funding by the Biotechnology and Biological Sciences Research Council (BBSRC) to further develop this research, which was published in the Journal of Virology, and license the method to a commercial partner. The technique will allow the rapid production of many IBV vaccine viruses in large volumes, thereby lowering production costs and allowing greater flexibility for protecting against the ever changing circulation of IBV strains.
Read article: The S2 subunit of infectious bronchitis virus Beaudette is a determinant of cellular tropism by Erica Bickerton, Helena J. Maier, Phoebe Stevenson-Leggett, Maria Armesto and Paul Britton published in Journal of Virology, accepted manuscript posted online 18 July 2018, doi: 10.1128/JVI.01044-18
[SOURCE: The Pirbright Institute]