Researchers have described an antibody fragment that can neutralize major variants of Covid. (representative)
Toronto:
A team led by an Indian-origin researcher has discovered a key vulnerability in all major variants of SARS-CoV-2, the virus that causes COVID-19, including the recently emerged BA.1 and BA.2 Omicron sub-variants.
The weakness could be targeted by neutralizing antibodies, potentially paving the way for treatments that would be universally effective across all variants, the researchers said.
The study, published Thursday in the journal Nature Communications, used cryo-electron microscopy (cryo-EM) to reveal the atomic-level structure of the vulnerable spot on the virus’ spike protein, known as an epitope — or part to which an antibody attaches.
The spike protein is used by the SARS-CoV-2 virus to enter and infect human cells. The researchers also described an antibody fragment called VH Ab6 that can attach to this site and neutralize any major variant.
“This is a highly adaptive virus that has evolved to evade most existing antibody treatments, as well as much of the immunity provided by vaccines and natural infection,” said Sriram Subramaniam, a professor at the University of British Columbia and senior author of the study. .
“This study reveals a weak site that is largely unchanged across variants and can be neutralized by an antibody fragment. It paves the way for the design of pan-variant treatments that could potentially help many vulnerable people,” said Mr Subramaniam. Antibodies are produced naturally by our bodies to fight infection, but they can also be made in a laboratory and given to patients as a treatment.
Although several antibody treatments have been developed for COVID-19, their effectiveness has diminished in the face of highly mutated variants such as Omicron.
“Antibodies attach to a virus in a very specific way, like a key going into a lock. But when the virus mutates, the key no longer fits,” Mr Subramaniam said.
“We were looking for major keys—antibodies that continue to neutralize the virus even after extensive mutations,” he added.
The “master key” identified by the researchers is the VH Ab6 antibody fragment, which has been shown to be effective against the Alpha, Beta, Gamma, Delta, Kappa, Epsilon and Omicron variants.
The fragment neutralizes SARS-CoV-2 by attaching to the spike protein epitope and blocking the entry of the virus into human cells.
By mapping the molecular structure of each spike protein, the team looked for areas of vulnerability that could inform new treatments.
“The epitope we describe in this paper is mostly removed from the mutation hotspots, so its capabilities are preserved across all variants,” said Mr. Subramaniam.
“Now that we have described the structure of this site in detail, it opens up a whole new area of treatment possibilities,” he said.
Mr Subramaniam said this key vulnerability could now be exploited by drug makers, and because the site was relatively free of mutations, the resulting treatments could be effective against existing and even future variants.
(Except for the headline, this story was not edited by NDTV staff and was published by a syndicated channel.)
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