The Pirbright Institute is joining in the global battle to help control COVID-19 by using its unique expertise and facilities to support the development of vaccines to protect against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of the current pandemic.
Working in collaboration with researchers at the University of Oxford and Public Health England, a team of scientists at Pirbright will begin testing new vaccines for their ability to induce protective antibodies against SARS-CoV-2. The vaccines will include the chimpanzee adenovirus vaccine vector (ChAdOx1) which is soon to enter human phase I clinical trials and has been used to create vaccines for diseases like Ebola, Middle Eastern respiratory syndrome (MERS) and flu.
The vaccine candidates developed at Oxford will contain the spike protein from SARS-CoV-2, the protein against which protective antibodies are generated in infected patients. Pirbright scientists will measure the level of antibodies produced after vaccination of pigs and assess whether the antibodies can block SARS-CoV-2 from infecting cells, thereby preventing infection. Importantly, the pig immune system shares significant similarities to that of humans, so a good response to a vaccine in pigs will help to predict the success of vaccines for human use. Researchers will also test the safety of the new vaccines and monitor whether any adverse effects are observed in the pigs.
This work will inform the development of vaccines that are both effective and safe for humans. If successful, the next step would be to begin human trials, although a useable vaccine is still many months away.
Pirbright is one of few facilities in the world that has the expertise in animal immunology and the state-of-the-art virology facilities required to undertake this type of work. Pigs have previously been used as a large animal model in research on influenza viruses because pigs have a very similar respiratory system to humans, are naturally infected by influenza viruses and produce antibodies with similar characteristics as humans. Pigs are therefore an appropriate model to use in this urgent coronavirus research.
Professor Bryan Charleston, Director of The Pirbright Institute, said: “The ChAdOx1 vector vaccine developed by Oxford will be used in this SARS-CoV-2 vaccine research as it can generate a strong immune response with just a single dose. The vaccine vector is non-replicating which means it cannot cause ongoing infection in an individual, making it safer to use for those with underlying health conditions like diabetes. This approach has been used in other vaccines and we are hopeful that this research will enable this vaccine to move into the next stage of human testing.”
“This work is a fantastic collaboration between world-leading medical and veterinary scientists in immunology, virology and molecular biology. It will provide an evaluation of new SARS-CoV-2 vaccines in a relevant model and will also generate a panel of antibody-based tools which will help us understand virus structure and how it stimulates the immune response. These antibodies could also be developed as additional novel therapeutics to treat COVID-19”, said Dr Toby Tuthill, Head of the Virus Programme at Pirbright.
These animal studies are funded by The Pirbright Institute from BBSRC UK Research and Innovation (UKRI) Institute Strategic Programme Grants. The vaccine is being developed by a team led by Professor Sarah Gilbert at the University of Oxford, who have received £2.2 million to support them through pre-clinical and clinical trials to determine if the vaccine is safe and effective, as part of the £20 million rapid research response funded by UKRI, and by the Department of Health and Social Care through the National Institute for Health Research.
SARS-CoV-2 is thought to have emerged from an animal reservoir (such as bats) and jumped into the human population, first appearing in China in December 2019 before going on to cause the current pandemic. This type of virus is described as zoonotic. Scientists around the world are racing to find a vaccine and understand more about the mechanisms the virus uses to invade the body and replicate, and why it causes more severe disease in some individuals.
Pirbright has a long history of research on livestock coronaviruses including porcine coronaviruses, which affect pigs, and infectious bronchitis virus (IBV) that affects poultry. The Institute was granted a patent in 2018 for a new approach to vaccine development in order to make improved IBV vaccines for poultry. Previously Pirbright has not carried out research on human coronaviruses but we are now working closely with many other science and health organisations to collectively devise ways to control and prevent COVID-19 in order to protect human health, thus fulfilling our mission to protect the UK from both livestock diseases and those that spread from animals to humans.
Image: This scanning electron microscope image shows SARS-CoV-2 (orange) isolated from a patient in the U.S., emerging from the surface of cells (brown) cultured in the lab. Credit: NIAID-RML