Scientists have discovered antibodies that can fight not only different variants of SARS-CoV-2, but also closely related coronaviruses. These findings could help in developing a wide range of treatments and vaccines.
Tyler Starr, a biochemist at the Fred Hutchinson Cancer Research Center in Seattle, Washington, and colleagues describe the problems antibodies face when dealing with COVID-19. Several variants of SARS-CoV-2 have mutated that allow the virus to escape the influence of antibodies.
The researchers examined 12 antibodies isolated from people who had recovered from COVID-19 by Vir Biotechnology, a San Francisco, California-based company involved in the study. Antibodies attach to fragments of viral proteins that bind to receptors on human cells. Many antibody therapies for SARS-CoV-2 infection use the same protein fragment, called the receptor-binding domain.
The researchers compiled a list of thousands of mutations in the binding domain of several SARS-CoV-2 variants. They also cataloged mutations in the binding domain in dozens of coronaviruses such as SARS-CoV-2 that belong to a group called sarbecovirus. Finally, they assessed how all of these mutations affected the ability of 12 antibodies to attach to the binding domain.
One antibody, S2H97, highlighted its ability to adhere to the binding domains of all sarbecoviruses tested by the researchers. S2H97, referred to by the authors as a pan-sarbecovirus antibody, was able to prevent various variants of SARS-CoV-2 and other sarbecoviruses from spreading between cells grown in the laboratory. It is also strong enough to protect hamsters from SARS-CoV-2 infection.
"That's the most powerful antibody we've described," Starr said.
Further examination of the molecular structure of S2H97 shows that it targets areas of previously invisible and hidden binding domains. Starr noted that molecules targeting these binding domain regions could produce protection against many viruses, and could one day be used in pan-sarbecovirus vaccines.
The other 11 antibodies can target a variety of viruses, but the more effective the antibodies block the entry of the earliest known SARS-CoV-2 strain into a cell, the smaller the viral network they can follow. The team also found that antibodies that can activate multiple viruses target parts of the binding domain that tend not to change as the virus progresses.
In any case, it’s good news that the team has identified antibodies that can bind to various sarbecoviruses, said Arinjay Banerjee, a virologist at the University of Saskatchewan in Saskatoon, Canada. "The biggest question left is, what about viruses we don't yet know exist?"
While scientists have not been able to test antibody activity against the unknown virus, Banerjee added, pan-sarbecovirus treatments and vaccines will help prepare the world to fight the next coronavirus that comes from wildlife that jumps to infect humans.
Tags
SCIENCES
