scorecardresearch
Follow Us:
Monday, January 24, 2022

Explained: What scientists have found about a class of antibodies that can neutralise the Omicron variant

The antibodies identified by the scientists target areas of the virus spike protein that remain unchanged as it mutates.

By: Explained Desk |
December 30, 2021 7:58:53 pm
The Omicron variant of the virus, first detected in South Africa is now responsible for surges that many nations, especially in the west, are seeing with some countries registering a record number of daily cases.

An international team of scientists has identified those antibodies that neutralise the Omicron variant of SARS-CoV-2. The results of their study were published in the journal Nature on December 23.

The antibodies identified by the scientists target areas of the virus spike protein that remain unchanged as it mutates.

David Veesler, who is one of the co-authors of the study and is an associate professor of biochemistry at the University of Washington School of Medicine in Seattle, was referred to as saying in a press release issued by the university that by identifying the targets of these “broadly neutralizing” antibodies on the spike protein, it could be possible to design vaccines and antibody treatments that will be effective against not only the Omicron variant but other variants that will possibly emerge in the future.

The Omicron variant

The Omicron variant of the virus, first detected in South Africa is now responsible for surges that many nations, especially in the west, are seeing with some countries registering a record number of daily cases.

The variant is thought to be more transmissible than previous variants and, therefore, scientists say that it is likely that more breakthrough infections will be recorded. It has also cast some doubt on the efficacy of vaccines and reignited conversation on the requirement of booster doses.

Even so, even with high transmissibility, it is thought to cause less severe disease and fewer hospitalisations and deaths. But worries remain since in a scenario with a large number of cases, even if a small percentage require hospitalisation, the health system is at the risk of becoming overwhelmed.

In the study, authors note that the variant has 37 mutations in the spike protein, which it uses to latch onto and invade cells. These number of mutations are ‘unusually high’ and could explain why this variant has been able to spread rapidly across the world, with the capability of not only causing breakthrough infections but infecting those who have been previously infected.

Newsletter | Click to get the day’s best explainers in your inbox

How did these mutations develop?

Veesler and his colleagues speculate that Omicron’s large number of mutations could have accumulated during a prolonged infection in someone with a weakened immune system or in a scenario when the virus jumped from humans to an animal species and back again, the press release notes.

How should the Omicron mutations be interpreted?

When they compared the different versions of spike proteins between the earliest variants of the virus and the Omicron variant, they noticed that the spike proteins on the latter were able to bind 2.4 times better than those found on the earliest variant. “That’s not a huge increase,” Veesler was quoted as saying in the release, “but in the SARS outbreak in 2002-2003, mutations in the spike protein that increased affinity were associated with higher transmissibility and infectivity.”

Significantly, scientists also found that the Omicron variant was able to bind to mouse ACE2 receptors (this receptor also found in human cells is what the spike protein latches itself to before invading the cell) efficiently, suggesting omicron might be able to “ping-pong” between humans and other mammals.

Are vaccines effective against preventing infection from the Omicron variant?

After this, the scientists used antibodies generated in patients who were infected with earlier variants of the virus and were vaccinated, or had been infected and then vaccinated. They found that antibodies from people who had been previously infected and from those who had received six of the most commonly used vaccines against Covid-19 had reduced ability to block infection.

Antibodies from people who had previously been infected and those who received either the Sputnik V or Sinopharm vaccines or the J&J single-dose vaccine had “little or no ability” to block the omicron variant from infecting the individual. Those who had taken two doses of Moderna, Pfizer-BioNTech or AstraZeneca retained some neutralising antibodies.

Also, antibodies from people who had been infected, recovered, and subsequently took two doses of vaccines also had reduced neutralising activity, but the reduction was less, which signals the utility of getting vaccinated even after previous infection.

The authors also analysed antibodies from a group of renal dialysis patients, who had received both doses plus a booster dose of an mRNA vaccine. These patients showed only a four-fold decrease in neutralising activity, which means that booster doses can be helpful in dealing with this variant.

Scientists also identified four classes of antibodies that retained their ability to neutralise this variant. The members of each of these classes of antibodies target one of four specific areas of the spike protein that is present in the SARS-CoV-2 virus and also a group of related coronaviruses called sarbecoviruses. These sites possibly didn’t change because they play an important role which the protein would lose if these were to mutate.

“The finding that antibodies are able to neutralize via recognition of conserved areas in so many different variants of the virus suggests that designing vaccines and antibody treatments that target these regions could be effective against a broad spectrum of variants that emerge through mutation, Veesler said,” the release noted.

📣 The Indian Express is now on Telegram. Click here to join our channel (@indianexpress) and stay updated with the latest headlines

For all the latest Explained News, download Indian Express App.

  • Newsguard
  • The Indian Express website has been rated GREEN for its credibility and trustworthiness by Newsguard, a global service that rates news sources for their journalistic standards.
  • Newsguard
0 Comment(s) *
* The moderation of comments is automated and not cleared manually by indianexpress.com.
Advertisement
Advertisement
Advertisement
Advertisement