While Fifi the llama bites on the grass in a pasture in Reading, his immune system has provided the blueprint for a breakthrough in the treatment of coronaviruses.
Scientists at the Rosalind Franklin Institute in the UK used Fifi’s specially developed antibodies to perform immunostimulatory therapy.
The llama-based “antibody cocktail” specific to Covid could enter clinical trials in a matter of months.
The development is published in Nature Structural and Molecular Biology.
These are “engineering” of llama antibodies, which are relatively small and much more simply structured than the antibodies in our own blood. This size and structure means that they can be “redesigned” in the laboratory.
Unlocking the Coronavirus
Professor James Naismith, director of the Rosalind Franklin Institute – and principal investigator – described the technique as akin to cutting a key that corresponds to the coronavirus lock.
“With the llama’s antibodies, we have keys that don’t quite match – they’ll go into the lock but won’t turn completely,” he said.
“So we take this key and use molecular biology to fine-tune it, until we have cut a suitable key.” ”
Antibodies are part of what is called the adaptive immune system; these are molecules that essentially transform in response to a virus or invasive bacteria.
“Then if you get re-infected,” said Professor Naismith, “your body is looking [virus particles] with antibodies stuck around them and destroys them. “
This type of immune therapy essentially strengthens the immune system of a sick person with antibodies that have already adapted to the virus.
There is already evidence that antibody-rich blood from people recently cured of the coronavirus could be used for treatment. But the main trick of this llama-derived antibody therapy is that scientists can produce specific coronavirus antibodies on command.
The small, reworked part of the llama antibody is also known as a nanobody, said Professor Naismith.
“In the laboratory, we can make nanobodies that kill the living virus extremely well – better than almost anything we’ve seen,” he added. “They are incredibly good at killing the virus in culture. ”
Nanobodies do this by binding – or locking on – what is known as “peak protein” outside the viral capsule; disabling this tip prevents it from accessing human cells.
“Basically, we do in the laboratory what all the immune systems in the body do,” said Professor Naismith.
“And we can do it very quickly, so if the virus suddenly changes, or if we get a new virus, we can design new nanobodies in the laboratory. ”
The team aims to test its prospective therapy in animal trials this summer, with a view to starting clinical trials later this year.
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