UK scientists have developed a new vaccine against foot and mouth disease that is cheaper and safer to manufacture thanks to the fact it doesn’t rely on inactivating live infectious virus but uses a synthetic virus shell to provoke an immune response. The new vaccine is also more stable and easier to store than current ones.
The scientists who developed the new vaccine report their work in the 27 March online issue of PLoS Pathogens.
The team was jointly led by David Stuart, professor of structural biology at the University of Oxford and life science director at Diamond Light Source, and Bryan Charleston of The Pirbright Institute.
Foot and mouth is a major disease of livestock and outbreaks can cause economic catastrophe.
The outbreak that hit Britain in 2001 was devastating and billions of pounds were spent controlling it and compensating those affected.
An ensuing Royal Society report recommended new approaches be developed to control the virus.
An improved vaccine against foot and mouth disease would also be of great benefit to countries where the disease is endemic, many of which are in the developing world.
A key disadvantage of the current vaccine is that it uses inactivated virus and has to be made and stored in expensive high containment facilities.
The researchers say their new vaccine addresses both these drawbacks. It doesn’t have to be made in an expensive biosecure facility and doesn’t require refrigeration.
The product is made of manmade empty protein shells created by recombining virus-like particles, and is devoid of viral genome, so it can’t reproduce.
Researchers have tried to achieve something like this before, but have struggled to make a stable empty shell.
In this study, the team notes how it enhanced the stability of the shells or capsids by “incorporating a rationally designed mutation”, and using X- ray crystallography showed that “stabilised and wild-type empty capsids have essentially the same structure as intact virus”.
The work on the structure of the virus shell and identifying mutations that improve it was done using Diamond Light Source, the UK’s national synchrotron facility.
The researchers incorporated the mutations into the empty virus shells and showed they provoked immunity in the cattle to protect them against foot and mouth virus.
They say these early clinical trials in cattle suggest the new vaccine is as effective as current ones. However, larger trials are now needed, and and the team doesn’t see the product being ready for market for several years.
Another problem with the current foot and mouth vaccines is that it is difficult to tell which animals have been immunized and which have not.
But the new vaccine overcomes this, as Charleston explains:
“The complete absence of some viral proteins from this new vaccine will also allow companion diagnostic tests to be further refined to demonstrate the absence of infection in vaccinated animals with greater confidence.”
Foot and mouth disease is caused by a small RNA virus belonging to a group known as picornaviruses.
The researchers believe their new approach to producing a vaccine and making it stable could work with other picornaviruses, such as the human polio virus and hand foot and mouth disease, a human virus which is currently endemic in south-east Asia.
Funds from the Department for Environment, Food and Rural Affairs (Defra) and the Wellcome Trust financed the study.
Written by Catharine Paddock PhD