If you had SARS, does that make you immune to COVID-19?

Scientists are only just now starting to discover clues as to how the body’s immune system responds to COVID-19 and if that translates into herd immunity or an effective vaccine. However, one group of researchers learned of a possible breakthrough by studying a person who had been infected during the original SARS outbreak (severe acute respiratory syndrome) 17 years ago.

The study, which was conducted by Vir Biotechnology along with researchers from the University of Washington School of Medicine, found that blood samples from the 2003 SARS patient contained an antibody that also appears to inhibit the new coronavirus, SARS-CoV-2. 

Antibodies called “Memory B” cells—which form following a period of infectious illness—can typically remember an exact or similar pathogen that the body has previously fought off and then later launch a defense against reinfection. Memory B cells can sometimes last throughout a person’s lifetime.

The Memory B cells found in the study, called the S309 antibody, have been found particularly effective at targeting and disabling the spike protein structure that helps the coronavirus infect healthy cells. This structure is critical for the virus to recognize a cell’s receptor, fuse to it, and then inject its genetic material into the cell. 

The S309 antibody is now on a fast-track development and testing path at Vir Biotechnology in the next step toward possible clinical trials. These trials will likely involve an “antibody cocktail” combined with other antibodies that had weaker performances against the virus but could help neutralize SARS-CoV-2 when used together.

Should the clinical trials be successful, the antibody cocktail would have the potential to be used as a preventative treatment for people with a high risk of exposure, such as health care workers, or as a treatment in severe cases. But it’s worth noting that the research so far has been solely conducted in lab dishes, which is why the trials will be extremely important.

“We still need to show that this antibody is protective in living systems, which has not yet been done,” said David Veesler, assistant professor of biochemistry at the University of Washington School of Medicine and one of the senior authors on the study.

“Right now there are no approved tools or licensed therapeutics proven to fight against the coronavirus that causes COVID-19,” added Veesler. “If the antibody is shown to work against the novel coronavirus in people, it could become part of the pandemic armamentarium.”

As an existing antibody, the S309 allowed the research team to move faster than other groups. Clinical trials of two possible drug candidates are expected to begin in collaboration with pharmaceutical company GlaxoSmithKline this summer.

Sources: LiveScience, University of Washington Medicine, Genetic Engineering & Biotechnology News

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