SARS neutralizing antibody suggests COVID-19 therapy

Our bodies create antibodies to recognize, neutralize and clear specific pathogens. That's why scientists are looking at neutralizing anbodies as models for therapies against the new coronavirus, SARS-CoV-2. David Veesler, assistant professor of biochemistry at the University of Washington School of Medicine, and his team have found a promising antibody. They identified it in a patient who recovered from  Severe Acure Respiratory Syndrome during the 2003 outbreak, which was caused by a different SARS coronavirus.

The projections, or spikes, on the coronavirus give it the appearance of being crowned.  These projections contain spike glycoproteins, which are the building blocks for the machinery that allows the virus to gain entry into target cells. This mechanism is also the main target of the neutralizing antibodies that try to fend off a coronavirus infection.  

Veesler and his team conducted atomic level studies, using cryo-electromicroscopy,  to observe and describe interactions between the spike glycoprotein and the antibody.  This research enabled his lab to understand why this antibody can neutralize multiple strains of the SARS coronavirus that causes Severe Acute Respiratory Syndrome, as well as the new coronavirus that causes COVID-19.

"We have already shown this antibody neutralizes, to some extent, bat-related virus because the region recognized by the antibody is conserved across this subfamily of viruses," Veesler said. The findings suggest the possibility that this antibody from the 2003 SARS infection could become a therapeutic tool in case a related coronavirus emerged in the future.  That coronavirus pandemic prediction is now an actuality. 

Vir Biotechnology, a company Veesler's lab has been working with, is on an accelerated path to developing this neutralizing antibody, called S309, alone or in a mixture, for clinical trials.  The hope is that it might prove useful in preventing COVID-19 in people who are at high risk of exposure or as a post-exposure therapy to limit the infection or reduce diease severity.