The key to a cure for Covid-19 could be standing in a field in southern England, grazing on green pastures.
A herd of llamas in the town of Reading could hold the key to treating patients who are severely ill with the disease, new research suggests.
Immune systems produce antibodies when they are attacked by infections.
The woolly animals naturally produce tiny antibodies called nanobodies that can latch on to the deadly "spikes" of SarsCov-2, the virus that causes Covid-19.
Camels and alpacas can also produce nanobodies, which have a simpler structure than human antibodies.
Scientists from Rosalind Franklin Institute at the University of Oxford, Diamond Light Source – the UK's national synchrotron – and Public Health England have engineered llama antibodies to create an immune-boosting therapy.
Synchrotrons accelerate electrons to produce bright light that scientists use to study viruses and vaccines.
The therapy in the study, published in Nature Structural and Molecular Biology, could undergo clinical trials within months.
"With the llama's antibodies we have keys that don't quite fit," said study author Prof James Naismith, of Oxford.
"They'll go into the lock but won't turn all the way round.
"So we take that key and use molecular biology to polish bits of it until we've cut a key that fits."
"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."
Researchers are now screening antibodies from Fifi, a llama at the University of Reading, after she was immunised with harmless purified virus proteins.
The team is examining whether the animal’s immune system has produced different antibodies from those already identified, which will enable new nanobodies to be tested against the coronavirus.
A similar study where llamas were immunised with SarsCov-2 took place in Buenos Aires, Argentina, last month.
Scientists in the Argentinian capital also believe that the Covid-19 can be neutralised using nano-antibodies grown in llamas.