Neutralize COVID-19
Chinese scientists have found neutralizing antibodies to coronavirus
Chinese scientists have published two articles in the journal Nature (1, 2) devoted to the production of monoclonal antibodies that neutralize the SARS-CoV-2 coronavirus. The authors report successful preclinical trials on primates.
Neutralizing human antibodies are one of the most promising therapeutic approaches to the treatment of COVID-19. They can also be used as a "temporary vaccine" to protect healthy people from infection.
From the plasma of a person who has had COVID-19, scientists were able to isolate two monoclonal antibodies – CA1 and CB6 – and describe their characteristics. Both antibodies have proven effective against SARS-CoV-2 in laboratory conditions, and CB6 has been successfully tested on rhesus monkeys.
Antibodies are proteins synthesized by the body's immune cells in response to infection. They bind to the pathogen protein – the antigen – and neutralize the virus. Antibodies tuned to interact with a specific antigen are called monoclonal.
If the characteristics of antibodies are known, they can be produced in the laboratory and on an industrial scale for diagnostic tests and antiviral drugs.
The SARS-CoV-2 coronavirus has spiny appendages folded with S-protein. With the help of them, it connects to the receptors of angiotensin converting enzyme 2 (ACE2) on the surface of healthy cells and penetrates through it.
One of the ways to neutralize the virus is to prevent the binding of spike proteins to the ACE2 receptor. Structural studies of CB6 have shown that this monoclonal antibody recognizes SARS-CoV-2 antigens well by binding to them and prevents the virus S-protein from connecting to the ACE2 receptor.
The research was conducted by the biopharmaceutical company Junshi Biosciences together with scientists from the Institute of Microbiology of the Chinese Academy of Sciences.
"We have successfully used our many years of experience and an integrated technology platform for antibody research and development," Hui Feng, one of the authors of the study, said in a company press release. – We have conducted many parallel developments of candidate antibodies, which were subsequently tested on an in vivo infection model. One of these candidates has demonstrated strong neutralizing activity against COVID-19."
In total, the scientists obtained 206 specific monoclonal antibodies from the plasma of eight patients who had been ill with COVID-19. Two of them had a sufficiently powerful neutralizing activity against SARS-CoV-2.
What was unexpected for the researchers was that these antibodies did not work against other coronaviruses – SARS-CoV and MERS-CoV.
Scientists plan to conduct clinical trials of a new monoclonal antibody in the second quarter. The fact that CB6 effectively protected rhesus monkeys from infection gives reason for optimism, according to the authors of the study.
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