Researchers have discovered antibodies in the blood of recovered COVID-19 patients that may provide powerful protection against SARS-CoV-2, which is the coronavirus that causes COVID-19, when tested in human cell and animal cultures. The research offers a paradigm of swift reaction of the emergent and deadly pandemic and sets the stage for clinical trials and additional tests of the antibodies.
These antibodies are now being produced as potential preventatives and treatments for the virus. This discovery represents an extremely rapid response to this totally new pathogen.
Injections of such antibodies, in principle, could be given to people in the early states of COVID-19 to help reduce the level of the virus and also protect against severe disease. These antibodies may also be used to provide temporary, vaccine-like protection against SARS-CoV-2 infection of elderly people, healthcare workers, and others who respond poorly to traditional vaccines or may have had recent exposure to the virus.
The research project was led by groups at Scripps Research; IAVI which is a nonprofit scientific research organization dedicated to addressing urgent and unmet global health challenges; and the University of California San Diego School of Medicine.
The research has been a tremendous collaborative effort, and the team is now focused on making large quantities of these promising antibodies for clinical trials. Currently the treatment or a vaccine for the virus is the world’s top public health priority. The daily toll of new infections is still rising which makes the efforts even more pressing.
One approach to new viral threats is to identify antibodies in the blood of recovering patients that neutralize the virus’s ability to infect cells. These antibodies can then be mass produced through biotech methods and potentially used as a treatment that would block severe disease and also as a vaccine-like preventative that circulates in the blood for several weeks to protect against infection. This particular approach has been successfully demonstrated against the Ebola virus and RSV which is the pneumonia causing respiratory syncytial virus.
For the project, part of the team took blood samples from patients who were recovered from mild to severe COVID-19. Another team developed test cells that express ACE2 which is the receptor that SARS-CoV-2 uses to get into human cells. In a set of the initial experiments, the team tested whether the antibody containing blood from the recovered patients could bind to the virus and then strongly block it from infecting the test cells.
The team was able to isolate more than 1,000 distinct antibody producing immune cells which are known as B cells, each of which produced a distinct anti-SARS-CoV-2 antibody. They obtained the antibody gene sequences from these cells so they could produce the antibodies in the lab. Through screening these antibodies individually, they identified several that even in tiny quantities, could block the virus in test cells and additionally one that could also protect hamsters against heavy viral exposure.
All of the work including the development of the cell and animal infection models and studies to discover where the antibodies they were interested in bind to the virus, was completed in less than seven weeks. The team’s leveraged their institution’s decades of expertise in antibody isolation and then quickly pivoted their focus to SARS-CoV-2 to identify these highly potent antibodies.
If additional safe tests in clinical trials and animals go well, then the antibodies could conceivably be used in clinical settings as early as January 2021. The team intends to make them available to those who need them the most including low and middle income countries.
During the course of the researcher’s attempts to isolate anti-SARS-CoV-2 antibodies from the COVID-19 recovered patients, they found one that can also neutralize SARS-CoV which is the related coronavirus that led to the 2002 to 2004 outbreak of SARS (Severe Acute Respiratory Syndrome) in Asia. This discovery gave the team hope that they will eventually find broadly neutralizing antibodies that will provide at least partial protection against all or most SARS coronaviruses which should be helpful if another virus jumps to humans.
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