Antibodies that can neutralize Omicron identified
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A team of scientists have identified antibodies they believe can neutralize Omicron and other variants of COVID-19.
According to a new study, a group of international researchers have found that certain antibodies can target areas of the virus spike protein that do not undergo significant changes when the virus mutates.
The results were published on December 23 in the scientific journal Nature.
The research project was led by David Veelser, a researcher at Howard Hughes Medical Institute, and Davide Corti of Humabs Biomed, a subsidiary of Vir Biotechnology in Switzerland.
Veesler, who is also an associate professor of biochemistry at the University of Washington School of Medicine in Seattle, said that by identifying the targets of the “largely neutralizing” antibodies on the spike protein, it might be possible to design vaccines and antibody treatments that will be effective against Omicron, or other variations that may emerge.
“This discovery tells us that by focusing on the antibodies that target these highly conserved sites on the spike protein, there is a way to overcome the continued evolution of the virus,” Veesler said in a press release.
AN UNUSUAL VARIANT
The Omicron variant is considered “unusual” due to a large number of mutations in two key areas of the virus spike protein.
Speaking at a press conference last month, Canada’s Chief Public Health Officer Dr Theresa Tam said an area of mutations is found in the peak receptor binding domain virus.
“Where the virus attaches itself and invades our cells,” she explained.
The other area of mutation is in the antigenic supersite, Tam said, “because it’s a target for our body’s defensive or neutralizing antibodies.”
Thirty-seven mutations were detected in the spike protein in the Omicron variant.
Researchers believe this is part of why the variant was able to spread so quickly and can infect people who are fully vaccinated, as well as those who have previously had a COVID-19 infection.
According to Veesler, the main question he and his colleagues sought to answer was how the “constellation of mutations in the spike protein of the Omicron variant affected its ability to bind to cells and escape the system’s antibody responses. immune”.
CREATE A PSEUDOVIRUS
In order to conduct the study, the researchers created a pseudovirus – a disabled, non-replicating virus – that produces advanced proteins like a coronavirus.
Then they created pseudoviruses that had spike proteins similar to those of the Omicron variant, and other earlier strains of SARS-CoV-2, the virus that causes COVID-19.
The researchers did this in order to see how well different versions of the spike protein were able to bind to the protein on the surface of cells, which is how the virus attaches itself and enters the cell.
“The protein is known as the angiotensin-2 converting enzyme (ACE2) receptor,” according to the study.
The researchers found that the Omicron variant could bind 2.4 times better than the spike protein from the viral strain detected at the start of the pandemic.
Scientists also found that the Omicron variant could quickly bind to ACE2 receptors in mice.
The researchers said this suggests that Omicron “may be able to ‘ping pong’ between humans and other mammals.”
Scientists also used antibodies from patients who had previously been infected with earlier versions of the COVID-19 virus, those who had been vaccinated against earlier strains, and those who had both previously been infected and vaccinated.
They looked at how well antibodies from vaccines and previous infections protected against the Omicron variant.
The researchers found that people who had been infected with previous strains and those who had received one of the “six most used vaccines” all had a reduced ability to block an infection with Omicron.
Those who had previously been infected and those who had received the Johnson & Johnson, Sputnik V, or Sinopharm vaccines had little or no ability to prevent the Omicron variant from invading their cells.
However, those who had received two doses of a series of mRNA vaccines from Moderna or Pfizer-BioNTech, or the AstraZeneca vaccine, had some neutralizing activity.
Despite this, the press release notes that the ability to neutralize the variant has been reduced between 20 and 40 times.
The study found that antibodies from people who had previously been infected, recovered, and then received two doses of the vaccine were also found to have some neutralizing ability.
The researchers tested a large panel of antibodies generated against earlier versions of the virus and identified four classes of antibodies that retained their ability to neutralize the Omicron variant.
“Members of each of these classes target one of four specific areas of the spike protein found not only in SARS-CoV-2 variants, but also in a group of related coronaviruses, called sarbecoviruses,” the statement said. Press. “These sites on the protein can persist because they play an essential function that the protein would lose if mutated. Such areas are called “conserved”.
Veesler said the finding that antibodies are able to neutralize the virus by recognizing areas conserved in various variants suggests that vaccines and antibody treatments that target these areas may be effective against a number of strains that could arise due to a mutation.
Each of the biggest vaccine makers has said they plan to make a vaccine specific to Omicron amid the most recent surge in COVID-19 cases.
In Canada, authorities are urging members of the public to get a third dose of a COVID-19 vaccine as soon as it becomes available, and provinces and territories have opened up eligibility for recalls to larger sections of the population with the aim of increasing protection and stemming the spread of the virus.
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