Back in 2003, a patient who recovered from the Severe Acute Respiratory Syndrome (SARS) virus had an antibody (S309) that was found to inhibit related coronaviruses, including the novel coronavirus. Now, researchers from the University of Washington School of Medicine and Humabs Biomed SA are studying S309 on the fast-track development and testing path, with the next step being clinical trials. Their findings are reported in the May 18 edition of the journal, Nature.
Senior paper author, David Veesler, assistant professor of biochemistry at the University of Washington School of Medicine says, “We still need to show that this antibody is protective in living systems, which has not yet been done. Right now, there are no approved tools or licensed therapeutics proven to fight against the coronavirus that causes COVID-19.”
While many labs are looking for neutralizing antibodies to treat COVID-19 disease, Vessler’s lab is different because its search took place in someone who was infected with SARS, rather than COVID-19. "This is what allowed us to move so fast compared to other groups," Veesler said.
After infection occurs, memory B cells form, and they can last for life. Memory B cells can usually remember a pathogen or a similar one and defend the body against any re-infection. The S309 antibody is good at targeting and disabling the spike protein that allows the coronavirus to enter healthy cells. The scientists found that S309 binds to a site that is used by multiple coronaviruses, which may explain its ability to work against SARS-related coronaviruses.
When the researchers combined the S309 antibody with weaker antibodies that were also found in the recovered SARS patient, they found that the combination enhanced the neutralization of the novel coronavirus. By using multiple antibodies, it could be possible to limit the ability of the coronavirus to form mutant strains.