It turned out that antibodies derived from llamas neutralize the SARS-CoV-2 virus in laboratory tests, British researchers announced today. An international team of researchers hopes that antibodies – known as nanobodies because of their small size – can ultimately be developed to treat patients with severe COVID-19. The results of the study are published in the journal Nature Structural & Molecular Biology.
Llamas, camels, and alpacas produce small amounts of antibodies with a simpler structure that can be turned into nanobodies. The team developed their own new nanobodies using a set of antibodies taken from llama blood cells. They showed that nanobodies tightly bind to the pointed protein of the SARS-CoV-2 virus, blocking its penetration into human cells and stopping the infection.
Using advanced X-ray and electron imaging at the Diamond Light Source (accelerator complex, third-generation synchrotron radiation source) at Oxford University, the team also determined that nanobodies bind to a pointed protein in a completely new way. The difference was obvious when compared with other previously detected antibodies.
There is currently no cure or vaccine for COVID-19. However, it has been shown that transfusion of critically ill patients with serum from recovered people who contain human antibodies against the virus significantly improves the clinical outcome of the disease. This process, known as passive immunization, has been used for over 100 years, but it’s not easy to identify the right people with the right antibodies and to safely put such a “product” into the bloodstream. A laboratory product that can be manufactured on demand will have significant benefits and can destroy the coronavirus.
New nanobodies have a potential that can be used similarly to convalescent serum, effectively stopping the progression of the virus in sick patients. Scientists were able to combine one of the nanobodies with human antibodies. The experiment showed that such a combination was even more powerful than any of the individual components.
Scientists noted that three nanobodies can bind to peaks of the virus, essentially covering the parts that it uses to enter human cells.
The team is studying preliminary results, which show that the laboratory llama’s immune system produces antibodies that are different from those already identified, which will test the cocktails from nanobodies for viruses.