A small protein derived from llama antibodies neutralizes the coronavirus


British researchers at Rosalind Franklin Institute, University of Oxford, Diamond Light Source and Public Health England, announced they have discovered antibodies from llamas that can neutralize coronavirus SARS-CoV-2 in laboratory tests . They are now hoping that these antibodies – called nanobodies, due to their small size – can eventually be used to develop treatment for patients with severe forms of COVID-19 disease. The results have been peer reviewed and have been published in Nature Structural & Molecular Biology.

You should know that llamas, camels and alpacas naturally produce quantities of small antibodies with a simpler structure, which can be transformed into nanobodies. The team of scientists designed new nanobodies using a collection of antibodies taken from llama blood cells. They then demonstrated that these nanobodies bind tightly to the advanced protein of the SARS-CoV-2 virus, preventing it from entering human cells, and thus stopping infection.

This is by using advanced X-ray imaging and electrons at Diamond Light Source and Oxford University that the team also identified that nanobodies bind to the advanced protein in a new and different way from other antibodies already discovered to date.

Nanobodies to neutralize advanced coronavirus protein

We remind you: at present, there is no cure or vaccine for COVID-19. However, it has been shown that transfusion of critically ill patients with serum of recovering individuals (which contains human antibodies to the virus) significantly improves clinical outcomes. This process, known asimmunisation passive, has been used for over 100 years, but it is not easy to identify the right people with the right antibodies and donate such a blood product safely.

Indeed, you should know that passive immunization consists of directly injecting antibodies against the pathogen or against a toxin of the pathogen in the body. The organism is therefore immediately protected, without having to wait for the antibodies to develop. It is an emergency procedure and the effect lasts only a few weeks, since the defense cells of the immune system have not been sufficiently in contact with the real antigen. Therefore, a laboratory product that can be made on demand would have considerable benefits and could be used earlier in the course of the illness, where it is also likely to be more effective.

« These nanobodies have the potential to be used in a similar way to convalescent serum, effectively stopping the progression of the virus in sick patients. We were able to combine one of the nanobodies with a human antibody and show that the combination was even more powerful than the two separately. These combinations are particularly useful, because the virus has to change several things at the same time to escape it, and it is very difficult for it to do so. Nanobodies also have powerful diagnostic potential Said Professor James Naismith, director of the Rosalind Franklin Institute and professor of structural biology at the University of Oxford.

« This research is a great example of teamwork in science, as we created, analyzed and tested nanobodies in 12 weeks. The team carried out experiments in a few days which would generally take months to complete. We hope to continue this breakthrough with preclinical trials Said Professor Ray Owens of the University of Oxford, who heads the Nanobody program at the Rosalind Franklin Institute.

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« Electron microscopy structures have shown us that the three nanobodies can bind to the virus’s advanced protein, essentially covering the parts that the virus uses to enter human cells. »added Professor David Stuart of Diamond Light Source and the University of Oxford.

Testing mixtures of antibodies to the coronavirus

The research team began their study using a llama antibody database in the laboratory. Now researchers are screening for antibodies to Fifi, one of the lamas de Franklin based at the University of Reading, collected after the llama was immunized with purified and harmless viral proteins. In addition, the team is studying preliminary results which show that Fifi’s immune system has produced antibodies different from those already identified, which will make it possible to test mixtures of nanobodies against the virus.

You should know that the Rosalind Franklin Institute is a research institute which directs the work of the United Kingdom in the innovative field of nanobodies, whose small size and specificity make them perfect tools for scientific research, generally used to stabilize proteins for imaging. This institute is named after researcher Rosalind Franklin, born 100 years ago this year. Although famous for his contribution to the discovery of DNA, Franklin’s latest research turned to imaging viral structures, including polio. ” 2020 marks the centenary of the birth of Franklin. As an institute named after a pioneer in biological imaging, we are proud to follow in its footsteps and continue its work on viruses, applied here to an unprecedented global pandemic. Franklin’s work has transformed biology, and our projects aspire to the same transformational effect Said Naismith.

Source : Nature Structural & Molecular Biology

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