When the Fifi llamas whine on grass in a pasture in Reading, her immune system has provided the template for a breakthrough of coronavirus treatment.
Researchers from the UK’s Rosalind Franklin Institute have used Fiifi’s specially developed antibodies to make an immunosuppressive therapy.
The resulting lamella-based, Covid-specific “antibody cocktail” could participate in clinical trials within months.
The development is published in Nature Structural and Molecular Biology.
It involves “engineering” llama antibodies, which are relatively small and much more easily structured than the antibodies in our own blood. That size and structure means they can be “redesigned” in the lab.
Professor James Naismith, head of the Rosalind Franklin Institute – and leading researchers – described the technology as related to cutting a key that fits the coronavirus lock.
“With llama’s antibodies, we have keys that don’t quite fit – they come into the lock but won’t turn all the way,” he said.
“So we take that key and use molecular biology to polish bits of it until we’ve cut a key that fits.”
Antibodies are part of what is called the adaptive immune system. they are molecules that change substantially in response to an invading virus or bacteria.
“If you get infected again,” explained Prof Naismith, “your body looks for something [virus particles] with antibodies stuck around them and destroy them. ”
This type of immunotherapy essentially boosts a sick person’s immune system with antibodies that have already been adapted to the virus.
There is already evidence that antibody-rich blood, taken from people who have recently recovered from coronavirus, can be used as a treatment. But the most important trick with this llama-derived antibody therapy is that scientists can produce coronavirus-specific antibodies to order.
The small reconstructed part of the llama antibody is also known as a nanobody, says Prof Naismith.
“In the lab, we can make nanobodies that kill the live virus extremely well – better than almost anything we’ve seen,” he added. “They are incredibly good at killing the virus in the culture.”
The nanobodies do so by binding – or locking – what is known as the “spike protein” on the outside of the viral capsule; disabling the nail prevents it from accessing human cells.
“Essentially, we do in the lab what all immune systems do in the body,” explained Prof Naismith.
“And we can do this very quickly, so if the virus suddenly changes, or if we get a new virus, we can construct new nanobodies in the lab.”
The team aims to test their future therapy in animal testing this summer with the aim of starting clinical trials later this year.
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