Antibody That Inhibits The New Coronavirus Discovered In Patient Who Had SARS 17 Years Ago

August 7, 2020

A person who suffered from severe acute respiratory syndrome (SARS) 17 years ago could help scientists find a therapy against the new coronavirus SARS-CoV-2, according to a new study by a biotechnology company.

Researchers found that the blood sample from this 2003 SARS patient contained an antibody that also appeared to inhibit SARS-CoV-2.

Antibodies form part of the body’s immune response to the pathogen. According to a statement from the Washington University School of Medicine, which was involved in the study, this particular antibody, which the researchers call S309, shows the ability to bind to and disable the “spike protein” on SARS-CoV-2, which allows the virus to enter cells. Several of the study’s authors work for Vir Biosciences, which is developing a treatment based on the findings.

Because the study was conducted in a laboratory petri dish, more research is needed to prove whether the antibody is effective against SARS-CoV-2 in humans, but Vir Biotech has fast-tracked the development and testing of the antibody and hopes to begin clinical trials in humans, the statement said.

The authors write in a paper published today (May 18) in the journal Nature that the findings “pave the way” for the use of S309 on its own or as part of an “antibody cocktail” to prevent or treat COVID-19, a disease caused by a novel coronavirus.

Currently, many labs are looking for so-called “neutralizing antibodies” – which prevent the pathogen from infecting cells – as a way to treat COVID-19. But unlike most previous studies, which looked for these antibodies in people who had COVID-19, the new study looked for them in people who had been infected with SARS back in 2003. The researchers began studying this person in 2004 and had previously found neutralizing antibodies against SARS.” This is the reason we were able to move so quickly compared to other groups,” said study co-lead author David Veesler, an assistant professor of biochemistry at Washington University School of Medicine.

Of the 25 antibodies studied, the authors identified several that could bind to SARS-CoV-2, and one in particular, S309, was a “potent” neutralizing antibody.

Further research revealed that S309 binds to a site on the SARS-CoV-2 spiking protein that is conserved in many coronaviruses, which may explain why the antibody appears to show activity against a variety of coronaviruses.

This “antibody cocktail” was further enhanced when the researchers combined S309 with other antibodies that were less active against SARS-CoV-2, the authors said. The cocktail may be used as a prophylactic treatment for people at high risk of exposure to COVID-19, such as health care workers, or as a treatment for severe disease, they said.

Clinical trials of the two drug candidates, which are genetically engineered versions of S309, in collaboration with GlaxoSmithKline, are expected to begin this summer, according to a statement from Vir Biotech.