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Llama antibodies could be harnessed in the shape of a nasal spray to treat coronavirus, a study suggests.
Scientists at the Rosalind Franklin Institute injected a llama with the Covid spike protein from which it generated coronavirus-busting nanobodies.
The researchers have found that the nanobodies - a smaller, simple form of antibody generated by llamas and camels - can effectively target the Sars-CoV-2 virus that causes Covid-19.
Short chains of the molecules, which can be produced in large quantities in the laboratory, significantly reduced signs of Covid-19 when given to infected animal models, according to the study.
The nanobodies bind tightly to the virus, neutralising it in the laboratory, and could provide a cheaper and easier alternative to human antibodies taken from recovered Covid-19 patients.
Human antibodies have been used for serious cases during the pandemic but usually need to be administered by infusion through a needle in hospital.
“Although this research is still at an early stage, it opens up significant possibilities for the use of effective nanobody treatments for Covid-19,” said Professor Miles Carroll, deputy director of the National Infection Service, Public Health England (PHE).
“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 easier to produce and administer than human antibodies
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.
“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, at the University of Reading's antibody production facility.
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.
A small blood sample was taken from the llama and the researchers were able to purify four nanobodies capable of binding to the virus.
The nanobodies were then combined together into chains of three to increase their ability to bind to the virus. These were then produced in cells in the laboratory.
Nanobodies effective against Covid variants
The study found that three nanobody chains were able to neutralise both the original variants of the Covid-19 virus and the alpha variant.
A fourth nanobody chain was able to neutralise the beta variant.
When one of the nanobody chains was given to hamsters infected with the virus, the animals showed a marked reduction in disease.
Hamsters that received the nanobody treatment also had a lower viral load in their lungs and airways after seven days than untreated animals.
Scientists appear increasingly drawn to the natural world in the pursuit of treatments for coronavirus. This study comes just weeks after a Brazilian team suggested a molecule contained within snake venom held similar promise.