The findings – published by experts at the Rosalind Franklin Institute in the Nature Communication journal – show that the tiny antibodies bind tightly to the virus, neutralising it, and could provide a cheaper and easier alternative to human antibodies taken from recovered Covid patients.
Nanobodies produced by llamas and camels can effectively target the Sars-CoV-2 virus that causes Covid-19, new research suggests, leading scientists to believe they could develop an effective new treatment.
It was also discovered that when the molecules were produced in the laboratory, and combined together into chains, they were capable of offsetting both the original variants of Covid, as well as the Alpha and Beta variants.
A new nasal spray is now in talks to be produced, with its ingredients to include the nanobodies.
Prof Miles Carroll, deputy director of Public Health England (PHE)’s National Infection Service, said that the single domain antibodies “are among the most effective Sars-CoV-2 neutralising agents we have ever tested”.
“Although this research is still at an early stage, it opens up significant possibilities for the use of effective nanobody treatments for Covid-19,” he added.
“We believe the unique structure and strength of the nanobodies contribute to their significant potential for both the prevention and treatment of Covid-19 and look forward to working collaboratively to progress this work into clinical studies.”
Short chains of the molecules, which can be produced in large quantities in the laboratory, also significantly reduced signs of the virus when given to infected animal models, according to the study.
Human antibodies have been used for serious cases during the pandemic but usually need to be administered by infusion through a needle in hospital, making it a more time-consuming procedure.
Professor Ray Owens, head of protein production at the Rosalind Franklin Institute and lead author of the research, said: “Nanobodies have a number of advantages over human antibodies: 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.”
He added: “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.”
Researchers were able to generate the nanobodies by injecting a portion of the spike protein into a llama called Fifi, who is part of the antibody production facility at the University of Reading. The spike protein is found on the outside of the virus and is responsible for binding to human cells so it can infect them.
While the injections did not make Fifi sick, they triggered her immune system to fight off the virus protein by generating nanobodies against it, scientists said.
A small blood sample was taken from the llama and the researchers were able to purify four nanobodies, which were then combined together into chains of three to increase their ability to bind to the infection. These were then produced in cells in the laboratory.
When one of the nanobody chains were given to hamsters infected with the virus, the animals showed a marked reduction in disease.
Researchers say the results are the first step towards developing a new type of treatment against Covid-19, which could prove invaluable as the pandemic continues.
Professor James Naismith, director of the Rosalind Franklin Institute, who helped lead the research, said: “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.”
The research team, which included scientists at the University of Liverpool, University of Oxford and PHE, now hope to obtain funding to prepare for clinical studies in humans.