Scientists at the Rosalind Franklin Institute have discovered a unique type of antibody produced by llamas that could have “significant potential” as a treatment for COVID-19.
Their study, published in the journal Nature Communications, shows that nanobodies – small, simple types of antibodies generated by llamas and camels – can effectively target the SARS-CoV-2 virus responsible for COVID-19.
The team identified short chains of the molecules – which can be produced in the laboratory in large quantities – that can significantly reduce signs of COVID-19 when given to infected animals.
Following clinical studies in humans, scientists say the antibodies could be administered via a simple nasal spray.
Public Health England said the findings have “significant potential for both the prevention and treatment of COVID-19”, adding that the nanobodies “are among the most effective SARS-CoV-2 neutralising agents we have ever tested.”
It is hoped the discovery could provide a cheaper and more simple alternative to human antibodies taken from patients who have recovered from he disease.
“Nanobodies have a number of advantages over human antibodies," commented lead author Professor Ray Owens, head of protein production at the Rosalind Franklin Institute. "They are cheaper to produce and can be delivered directly to the airways through a nebuliser or nasal spray, so can be self-administered at home rather than needing an injection.
“This could have benefits in terms of ease of use by patients but it also gets the treatment directly to the site of infection in the respiratory tract,” he said.
In the study, researchers grew the nanobodies by injecting a portion of the SARS-CoV-2 spike protein into a llama called Fifi, who is part of the antibody production facility at the University of Reading.
Fifi did not become sick as a result of the injection, but it did trigger her immune system to fight off the virus protein by generating nanobodies against it. The team were able to purify four nanobodies capable of binding to the COVID-19 virus from a small blood sample.
They then combined the nanobodies together into chains of three to increase their ability to bind to the virus, which is then produced in cells in the laboratory.
One of the chains was administered to hamsters infected with SARS-CoV-2, which showed “a marked reduction in disease” with the animals losing far less weight after seven days than untreated hamsters, and having a lower viral load.
“Because we can see every atom of the nanobody bound to the spike, we understand what makes these agents so special," said Professor James Naismith, director of the Rosalind Franklin Institute, who helped lead the research.
“While vaccines have proven extraordinarily successful, not everyone responds to vaccination and immunity can wane in individuals at different times. Having medications that can treat the virus is still going to be very important, particularly as not all of the world is being vaccinated at the same speed and there remains a risk of new variants capable of bypassing vaccine immunity emerging.”