This “super antibody” for COVID fights several coronaviruses

Scientists have discovered an antibody that can fight not only a wide range of SARS-CoV-2 variants, but also closely related coronaviruses¹. The discovery could help develop large-scale treatments and vaccines.

Tyler Starr, a biochemist at the Fred Hutchinson Cancer Research Center in Seattle, Washington, and his coauthors set out to shed light on a problem facing antibody treatments for COVID-19: Certain variants of SARS-CoV-2 have acquired mutations that allow the virus to escape the grip of the antibodies.

The researchers examined 12 antibodies isolated from people who had recovered from COVID-19 by Vir Biotechnology, a company based in San Francisco, Calif., Which participated in the study. These antibodies attach themselves to a fragment of viral protein that binds to receptors in human cells. Many antibody therapies for SARS-CoV-2 infection capture the same fragment of protein, called the receptor binding domain.

Researchers have compiled a list of thousands of mutations in the binding domains of several variants of SARS-CoV-2. They also cataloged mutations in the binding domain on dozens of SARS-CoV-2-like coronaviruses that belong to a group called sarbecoviruses. Finally, they evaluated how all of these mutations affect the ability of the 12 antibodies to adhere to the binding domain.

One antibody, S2H97, stood out for its ability to adhere to the binding domains of all sarbecoviruses tested by the researchers. S2H97, which the authors call a pan-sarbecovirus antibody, was able to prevent a range of variants of SARS-CoV-2 and other sarbecoviruses from spreading among developing cells in the laboratory. It was also potent enough to protect hamsters from infection with SARS-CoV-2. “It’s the coolest antibody we’ve described,” Starr says.

Further examination of the molecular structure of S2H97 revealed that it targets a previously invisible and well-hidden region on the binding domain – a section that is only revealed when the domain appears to bind to a cell’s receptor. . Starr notes that molecules targeting this binding domain region could generate protection against several viruses and could one day be used in pan-sarbecovirus vaccines.

The other 11 antibodies could target a variety of viruses, but the more effectively an antibody blocked the entry of the first known strain of SARS-CoV-2 into a cell, the smaller the range of viruses it could bind. The team also found that antibodies that could deactivate a wide variety of viruses targeted sections of the binding domain that tended not to change as the virus matured.

It’s good news that the team has identified antibodies that can bind to a range of sarbecoviruses, says Arinjay Banerjee, a virologist at the University of Saskatchewan in Saskatoon, Canada. “The biggest question that remains is, what about viruses that we don’t yet know exist? “

Although scientists cannot test the activity of an antibody against an unknown virus, Banerjee adds, pan-sarbecovirus treatments and vaccines would help prepare the world to fight the next coronavirus which passes from wildlife to humans .