An international team of researchers has identified antibodies that neutralize Omicron and other variants of SARS-CoV-2. These antibodies target areas of the protein spike of the coronavirus that remain essentially unchanged as the viruses mutate.
By identifying the targets of the "strongly neutralizing" antibodies in the protein spikeit may be possible to design vaccines and antibody treatments that will be effective not only against the Omicron variant, but also against other variants that may emerge in the future, said David Veesler, a Howard Hughes Medical Institute researcher and associate professor of biochemistry, quoted in a study published in the scientific journal Nature.
"The finding tells us that by focusing on antibodies that target these highly conserved sites on the protein spikeThere is a way to overcome the continuous evolution of the virus," added the researcher.
The Omicron variant has 37 mutations in the spike protein, which it uses to cling to and invade cells. This is an exceptionally high number of mutations, which the researchers think partly explains why the variant has been able to spread so quickly, infecting vaccinated people and reinfecting those who were previously infected.
"The main questions we were trying to answer were: how does this constellation of mutations in the protein spike of the Omicron variant affected its ability to bind to cells and evade the immune system's antibody responses," said David Veesler.
The team of researchers, coordinated by David Veesler, speculates that the large number of Omicron mutations may have accumulated during a prolonged infection in someone with a weakened immune system or by passing the virus from humans to an animal species and vice versa.
To evaluate the effect of these mutations, the researchers developed a deactivated, non-replicating virus, called a pseudovirus, to produce proteins spike on the surface, as coronaviruses do. They created pseudoviruses that had proteins spike with the Omicron mutations and those found in the first variants identified in the pandemic.
The researchers first looked at how the different versions of the protein spike were able to bind to the protein on the surface of the cells, which the virus uses to attach itself and enter the cell. This protein is called the angiotensin II-converting enzyme receptor (ACE2).
The researchers found that the protein spike in the Omicron variant was able to bind 2.4 times better than the spike protein found in the virus isolated at the start of the pandemic. "It's not a huge increase," David Veesler noted, "but in the SARS outbreak in 2002-2003, mutations in the protein spike that increased affinity were associated with greater transmissibility and infectivity. In the study, already published in the journal "Nature" the researchers also found that the Omicron variant was able to bind to mouse ACE2 receptors efficiently, suggesting that Omicron may be able to "ping-pong" between humans and other mammals.