While Fifi, the llama chews grass in a grass in Reading, her immune system has provided the template for a breakthrough in coronavirus treatment.
Scientists at the Rosalind Franklin Institute in the UK have used Fifi’s specially developed antibodies to make immune-boosting therapy.
The resulting flame-based Covid-specific “antibody cocktail” could enter clinical trials in a few months.
The development is published in Nature Structural and Molecular Biology.
It involves “engineered” flame antibodies, which are relatively small and much more simply structured than the antibodies in our own blood. That size and structure means that they can be “redesigned” in the laboratory.
Coronavirus Unlock
Professor James Naismith, director of the Rosalind Franklin Institute, and the principal investigator, described the technique as if it were about cutting a key to fit the coronavirus lock.
“With the antibodies in the flame, we have keys that don’t quite fit: they will go into the lock but they won’t turn around,” he said.
“So we take that key and use molecular biology to polish it, until we’ve cut a key that fits.”
Antibodies are part of what is known as the adaptive immune system; they are molecules that transform essentially in response to an invading virus or bacteria.
“So if you get infected again,” Professor Naismith explained, “your body looks for any [virus particles] with antibodies stuck around it and destroys them. “
This type of immune therapy essentially boosts a sick person’s immune system with antibodies that have already adapted to the virus.
There is already evidence that antibody-rich blood, taken from people who have recently recovered from the coronavirus, could be used as a treatment. But the key trick with this flame-derived antibody therapy is that scientists can produce coronavirus-specific antibodies on request.
The small redesigned part of the flame antibody is also known as a nanobody, Professor Naismith said.
“In the laboratory, 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 culture.”
Nanobodies do this by binding to, or blocking, what is known as the “spike protein” on the outside of the virus capsule; disabling that spike prevents it from having access to human cells.
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“Basically, we are doing in the laboratory what all the immune systems do in the body,” explained Professor Naismith.
“And we can do this 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 their prospective therapy in animal trials this summer, in order to start clinical trials later in the year.
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