Scientists at The Pirbright Institute have identified African swine fever virus (ASFV) proteins that can trigger an immune response in pigs. The team hopes to develop a vaccine using these proteins that is capable of protecting against the deadly pig disease.
Published in Frontiers in Immunology, the study shows that when some pigs were challenged with a virulent strain of ASF after receiving a vaccine that included the identified proteins, the level of virus in the blood was reduced. This demonstrates that this method of vaccination could provide effective protection to pigs, though further work is needed.
Dr Chris Netherton, Head of the ASF Vaccinology Group at Pirbright said: “ASFV has more than 150 proteins; understanding which of these triggers an immune response is difficult but crucial for creating this kind of vaccine. Now we have identified proteins that activate pig immune cells, we can work on optimising the vaccine components to ensure pigs are protected against virulent ASF strains”.
To determine which ASF proteins should be used in the vaccine, the team screened proteins to find those that activated immune cells in pigs, which had previously been infected by a weakened form of ASFV. The 18 proteins that generated the strongest immune cell response were then transferred into viral vectors; viruses which deliver the ASF proteins to pig cells, but are not harmful to pigs.
The development of a safe and effective vaccine is vital for preventing the transmission of ASF. The rapid spread of this fatal pig disease through Europe and China has already decimated pig populations, resulting in the culling of over 1.1m pigs in China and nearly 2.5m pigs in Vietnam alone. Culling, quarantine and strict biosecurity measures are currently the only defences farmers can use to prevent its spread.
Various types of vaccine are being developed, but relatively little is known about the virus and how the immune system responds to it, which hampers progression. Vaccines made with inactivated viruses have not offered protection to domestic pigs, and although live attenuated vaccines (which contain weakened versions of a live virus) show promise for protection, more testing is needed to ensure their safety. Pirbright researchers therefore hope that these vector vaccines will provide an alternative, which could help to control the spread of this devastating pig disease.
The UK Chief Veterinary Officer, Christine Middlemiss, said: “I welcome this research by The Pirbright Institute which demonstrates the UK’s world-leading role in developing the science and tools needed to tackle devastating animal diseases such as African swine fever. While this is encouraging progress, we continue to work closely with the UK pig sector to raise awareness of the risks and advise on maintaining high biosecurity standards, including minimising the risk of the virus infecting commercial pigs.”
Notes to editors:
ASF is caused by the highly infectious ASF virus which can cause fever, loss of appetite, vomiting and bloody diarrhoea in all pigs and wild boar. The disease is often deadly, with some strains approaching case fatality rates of 100%. The virus does not cause disease in humans, but it does pose a significant threat to food security and has a substantial impact on the economy, especially on trade and farming. For more information about the virus, visit the Pirbright ASF page or watch the Pirbright ASF animation video on YouTube.
Pirbright scientists are at the forefront of ASF research. Current areas of work include understanding how the virus functions, how it interacts with pig immune systems and vaccine development. In addition, Pirbright ASF experts offer advice to the UK government and have recently helped to provide a resource which helps with diagnosis of the disease. Pirbright is also home to the National and World Organisation for Animal Health (OIE) ASF reference laboratories, where samples from suspected cases are tested.
About The Pirbright Institute
The Pirbright Institute is a world leading centre of excellence in research and surveillance of virus diseases of farm animals and viruses that spread from animals to humans. Based in the UK and receiving strategic funding from the Biotechnology and Biological Sciences Research Council (BBSRC UKRI), the Institute works to enhance capability to contain, control and eliminate these economically and medically important diseases through highly innovative fundamental and applied bioscience.
With an annual income of nearly £32.1 million from grants and commercial activity, and a total of £14.3 million strategic investment from BBSRC during 2017-2018, the Institute contributes to global food security and health, improving quality of life for animals and people.
For more information about The Pirbright Institute see: www.pirbright.ac.uk
The Biotechnology and Biological Sciences Research Council (BBSRC) is part of UK Research and Innovation, a non-departmental public body funded by a grant-in-aid from the UK government.
BBSRC invests in world-class bioscience research and training on behalf of the UK public. Our aim is to further scientific knowledge, to promote economic growth, wealth and job creation and to improve quality of life in the UK and beyond.
Funded by government, BBSRC invested £498 million in world-class bioscience in 2017-18. We support research and training in universities and strategically funded institutes. BBSRC research and the people we fund are helping society to meet major challenges, including food security, green energy and healthier, longer lives. Our investments underpin important UK economic sectors, such as farming, food, industrial biotechnology and pharmaceuticals.
More information about BBSRC, our science and our impact: www.bbsrc.ukri.org
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