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Llama blood could help save lives of seriously ill coronavirus patients

Bonnie the Llama grazes in front of a sign supporting the NHS. Scientists say llama antibodies could help in the fight against Covid-19 - Jane Barlow/PA Wire
Bonnie the Llama grazes in front of a sign supporting the NHS. Scientists say llama antibodies could help in the fight against Covid-19 - Jane Barlow/PA Wire
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Coronavirus Article Bar with counter

Llama blood could hold the key to saving the lives of patients who are seriously ill with coronavirus, a new study suggests.

Researchers led by Oxford University have used repurposed antibodies taken from the South American camelids to fight the virus in laboratory trials.

Doctors are already using antibodies derived from humans who have survived coronavirus, but the new findings herald the prospect of a more potent and easily available treatment.

Llamas, camels and alpacas naturally produce quantities of small antibodies with a simple structure, meaning they can be turned into nanobodies.

The team from the Rosalind Franklin Institute at Oxford University, Diamond Light Source – the UK's national synchrotron, which harnesses the power of electrons to produce bright light that scientists use to study viruses and vaccines – and Public Health England found the nanobodies bind tightly to the spike protein of the Sars-CoV-2 virus, blocking it from entering human cells and stopping infection.

In the study, published in Nature Structural and Molecular Biology, the team also identified that the nanobodies bind to the spike protein in a new and different way to other antibodies already discovered.

James Naismith, the director of the Rosalind Franklin Institute and a professor of structural biology at Oxford University, said: "These nanobodies have the potential to be used in a similar way to convalescent serum, effectively stopping progression of the virus in patients who are ill.

"We were able to combine one of the nanobodies with a human antibody and show the combination was even more powerful than either alone.

"Combinations are particularly useful, since the virus has to change multiple things at the same time to escape – this is very hard for the virus to do. The nanobodies also have potential as a powerful diagnostic."

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Professor Ray Owens, of Oxford University,who leads the nanobodies programme at the Franklin, said the researchers hope they can push the breakthrough on into pre-clinical trials.

Professor David Stuart, of Diamond Light Source and Oxford University, said: "The electron microscopy structures showed us that the three nanobodies can bind to the virus spike, essentially covering up the portions that the virus uses to enter human cells."

Researchers started from a lab-based library of llama antibodies and are now screening antibodies from Fifi, one of the "Franklin llamas"based at the University of Reading, taken after she was immunised with harmless purified virus proteins.

The team is looking at preliminary results which show that Fifi's immune system has produced different antibodies from those already identified, which will enable cocktails of nanobodies to be tested against the virus.

In a separate study, published in Nature Medicine, scientists say they have uncovered how a crucial component of the immune system responds to the spike protein of Sars-CoV-2.

Coronavirus particles have a corona (crown) of proteins that resemble spikes, which enable the virus to attach and enter cells in humans. The spike protein is crucial in inducing neutralising antibodies to protect from reinfection. Neutralising antibodies not only bind to the viral spike protein, but prevent it from being able to attach to and enter human cells.

Researchers from the Peter Doherty Institute for Infection and Immunity in Australia investigated how the immune system, particularly B and T-cells, responds to the spike.

B-cells are responsible for producing the antibodies that recognise Sars-CoV-2, while T-cells play an important role in supporting the development of the B-cell response.

Dr Jennifer Juno, of the University of Melbourne and a postdoctoral researcher at the Doherty Institute, said researchers looked at people who had recovered from Covid-19 and had mostly experienced mild or no symptoms.

She said: "We found that those who showed strong neutralising antibody activity had a robust B-cell response, but most surprisingly, we also found that a particular subset of T-cells, called T-follicular helper cells, was a great predictor of an effective immune response.

"Now we know how the immune system responds to the spike protein, and we have these biomarkers, or predictors of what elicits a good or poor immune response to Covid-19, we can look at the vaccine candidates and see what will offer the best protection."