Super-Potent Human Antibodies Protect Against COVID-19 in Animal Tests

A team of scientists at Scripps Research (La Jolla, CA, USA) have isolated powerful coronavirus-neutralizing antibodies from COVID-19 patients and successfully tested them in animals, all in less than seven weeks.

The scientists discovered antibodies in the blood of recovered COVID-19 patients that provide powerful protection against SARS-CoV-2 when tested in animals and human cell cultures. For their project, the scientists took blood samples from patients who had recovered from mild-to-severe COVID-19. Simultaneously, the team developed test cells that express ACE2, the receptor that SARS-CoV-2 uses to get into human cells. In a set of initial experiments, the team tested whether antibody-containing blood from the patients could bind to the virus and strongly block it from infecting the test cells.

The scientists were able to isolate more than 1,000 distinct antibody-producing immune cells, called B cells, each of which produced a distinct anti-SARS-CoV-2 antibody. The team obtained the antibody gene sequences from these B cells so that they could produce the antibodies in the laboratory. By screening these antibodies individually, the team identified several that, even in tiny quantities, could block the virus in test cells, and one that could also protect hamsters against heavy viral exposure. All of this work—including the development of the cell and animal infection models, and studies to discover where the antibodies of interest bind the virus—was completed in less than seven weeks. If further safety tests in animals and clinical trials in people go well, then conceivably the antibodies could be used in clinical settings as early as next January, the researchers say.

“The discovery of these very potent antibodies represents an extremely rapid response to a totally new pathogen,” said study co-senior author Dennis Burton, PhD, the James and Jessie Minor Chair in Immunology in the Department of Immunology & Microbiology at Scripps Research.

In the course of their attempts to isolate anti-SARS-CoV-2 antibodies from the COVID-19 patients, the researchers found one that can also neutralize SARS-CoV, the related coronavirus that caused the 2002-2004 outbreak of severe acute respiratory syndrome (SARS) in Asia.

“That discovery gives us hope that we will eventually find broadly neutralizing antibodies that provide at least partial protection against all or most SARS coronaviruses, which should be useful if another one jumps to humans,” added Burton.

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