Potential vaccine for foot-and-mouth

British scientists have developed an experimental vaccine for foot-and-mouth disease.

The vaccine, which is wholly synthetic, has been developed by scientists from Oxford and Reading Universities, the Pirbright Institute, and the UKs national synchrotron facility, the Diamond Light Source near Oxford.

According to researchers, the way the vaccine has been produced takes away the need to use live and potentially infectious viruses. The usual way of producing a vaccine requires manufacturers to work in strict and controlled environments, so hazardous pathogens do not escape.

Writing in the journal PLOS Pathogens, scientists explained the vaccine did not use a live virus, making it more stable and potentially cheaper to produce than traditional live vaccines. The increase in stability could mean the vaccine can be left out of the fridge for longer than a standard vaccine, which could be the key to administering vaccines in the developing world.

Synthetic vaccine

In order to be produced, current inactivated vaccines require containment facilities, including cold storage technology. Since, at present, vaccines rely on inactivated viruses, which are produced in large bio-reactors, this a combination that makes them expensive to produce. And, along with it being an expensive set up, there is limited scope for global production; storage and supply time; and the way the vaccine works makes it difficult to determine which animal has been infected or vaccinated.

"We have addressed these major drawbacks," scientists said. "Firstly we have developed methods to efficiently express recombinant empty capsids. Expression constructs were used, aimed at lowering the levels and activity of the viral protease required for the cleavage of the capsid protein precursor."

Scientists have also enhanced capsid stability by incorporating a "rationally designed mutation", which is shown by X-ray crystallography. This stabilises the wild-type empty capsids, which have, essentially, the same structure as an intact virus.

"Attempts to produce alternative vaccines have shown that intact virus particles stimulate the best immune response," scientists added. "However, the synthetic virus replicates the protein structure of a standard vaccine made with a live virus, since the capsid proteins spontaneously assemble to produce empty virus-like-particles."