Researchers at the Institute for Animal Health have examined a new type of vaccination regime that protects cattle against foot-and-mouth disease (FMD). This regime features the use of a DNA vaccine approach and the experimental results show that such vaccines have the potential, with further development, to protect against this important disease. Such vaccines do not require high containment facilities for production, making them easier to design and cheaper to produce than current vaccines against FMD. The research was published last week inAntiviral Research.
Dr Paul Barnett, who led the research, said “This is the first time this type of DNA vaccination regime has been shown to be effective in protecting cattle. We were confident that this would be possible as we have already shown, in collaboration with European partners, that a DNA based vaccine that includes an additional protein to boost its effectiveness can protect pigs against FMD and even without the additional protein boost can prevent sheep from being infected.
“The next challenge for us will be to remove the reliance on this protein boost in cattle so that we have an alternative vaccine that fully lives up to the potential that the DNA approach can offer.”
Foot-and-mouth disease is caused by one of the most infectious viruses in the world. It poses a significant threat to economic and food security and the UK outbreak in 2001 cost several billion pounds. In the EU, vaccination may be considered in emergency outbreak situations and many member countries have access to strategic FMD vaccine reserves. DNA vaccines are much more stable under storage and consequently have a longer shelf life, making them more amenable to this type of strategy.
Routine vaccination against FMD is vitally important in countries where the virus is always circulating. Whilst this does not include the UK, by controlling the disease elsewhere in the world FMD vaccines protect global food security and reduce the likelihood of the virus entering the UK from elsewhere.
Conventional FMD vaccines involve the use of chemically inactivated virus antigen to initiate an immune response without causing disease. Though these work well they have to be manufactured under expensive high containment facilities, must be kept cool at all times, and may not always be best suited to a specific virus threat, requiring then a need to develop a new vaccine strain which can be a lengthy and sometimes fruitless process.
DNA vaccines, on the other hand, can be easily and quickly manipulated for a specific disease threat and can be expanded to manufacturing scale without the need for facilities with high biosecurity. They work by incorporation of a small piece of synthetic DNA into the cells of the animal you wish to immunise, which is then processed within these cells to make proteins that are almost identical to the chemically inactivated virus antigen. The cells then attach these proteins to their outer surface to signal to the immune system that something foreign has arrived – thus simulating one of the events that happen when an infection occurs, but importantly triggering a wider variety of immune parameters than that by conventional vaccines so the immune system is better primed to respond quickly to the real virus should it arrive.