A Covid treatment made from llama antibodies has been hailed by experts at Public Health England as one of the most effective ever tested.
Researchers at the Rosalind Franklin Institute based in Oxfordshire have been investigating using llama antibodies to treat Covid since the pandemic first took hold in the UK in 2020.
The theory revolves around a quirk of the immune system of camelids, a group of animals that includes camels and llamas, which sees them produce tiny antibodies called nanobodies.
They work in the same way as human antibodies and surround an invading pathogen, but they are much smaller in size and this allows them to better neutralise any threat.
To make Covid-specific nanobodies, the researchers injected a llama called Fifi at the University of Reading with the coronavirus spike protein, the part of the virus that attaches to and unlocks human cells.
Fifi did not get sick, but its immune system went to work producing nanobodies against the spike protein.
Researchers extracted these via blood samples and combined them into chains of three to increase their virus-binding ability and then produced them en masse in a laboratory.
Lab tests by Public Health England, the University of Oxford and the Rosalind Franklin Institute found that the llama nanobody treatment dramatically reduced disease severity in the animals.
Using three conjoined nanobodies was found to be effective against the original and alpha variants of Covid.
Adding a fourth nanobody saw the treatment work successfully against the beta variant, which scientists had feared may be able to avoid antibodies made via vaccination.
Professor Miles Carroll, deputy director of the National Infection Service at Public Health England, said: “Although this research is still at an early stage, it opens up significant possibilities for the use of effective nanobody treatments for Covid-19. These are among the most effective Sars-CoV-2 neutralising agents we have ever tested at PHE.
“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.”
‘Nanobodies have advantages over human antibodies’
Professor Ray Owens, the 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.
“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.”
Professor James Naismith, the 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 findings are published in the journal Nature Communications.