Biochemists at the Fred Hutchinson Cancer Research Center in Seattle have made the discovery by studying the challenges faced in treating covid with antibodies. The fact is that some variants of SARS-CoV-2 have acquired mutations that allow the virus to avoid capture by antibodies.
The researchers looked at 12 antibodies from people who were infected with either SARS-CoV-2 or its close relative SARS-CoV, Nature reports. These antibodies attach to a fragment of a viral protein that binds to receptors on human cells. When treating covid with antibodies, the same protein fragment, called the receptor binding domain, is often captured.
Researchers have compiled a list of thousands of mutations in the binding domains of several SARS-CoV-2 variants. They also cataloged mutations in the binding domain of dozens of SARS-CoV-2-like coronaviruses, all of which belong to the sarbecovirus group. Finally, they evaluated how all of these mutations affect the ability of 12 antibodies to "adhere" to the binding domain.
One antibody, S2H97, stood out for its ability to adhere to the binding domains of all the sarbecoviruses the researchers tested. S2H97, which the authors call "anti-pansarbekovirus antibody," was able to prevent the spread of a number of variants of SARS-CoV-2 and other sarbecoviruses among cells growing in the laboratory. It was also potent enough to protect hamsters from SARS-CoV-2 infection.
The study of the molecular structure of S2H97 has shown that it targets a previously undetected, well-hidden region of the binding domain - a region that is only found when the domain appears to bind to a cell receptor. According to the authors of the discovery, molecules targeting this region of the binding domain can provide protection against several viruses and be used in vaccines.
After examining the remaining 11 antibodies, the scientists found that they could target different viruses, but the more effectively the antibody blocks the entry of the earliest known strain of SARS-CoV-2 into the cell, the smaller the range of viruses that it can bind. Antibodies, which could turn off a wide variety of viruses, target regions of the binding domain that generally have not changed as the virus evolved.
This discovery will help scientists prepare for the fight against the next coronavirus, which will leap from wild animals to humans.