A new study published in the journal Nature has identified a type of antibodies that could neutralize Omicron and other coronavirus variants. These antibodies target areas of the viral spike protein that remain largely unchanged as the virus mutates. These findings could offer the possibility to design better vaccines and treatments against not only current but also possible future variants.
The Omicron variant has an unusually high number of mutations (37) in the spike protein, which it uses to latch onto and invade cells. These mutations explain the variant’s high transmissibility and capacity to cause reinfections and breakthrough infections.
“The main question we were trying to answer was: how has this constellation of mutations in the spike protein of the Omicron variant affected its ability to bind to cells and to evade the immune system’s antibody responses?” said study lead author David Veesler, an investigator at the Howard Hughes Medical Institute and associate professor of Biochemistry at the University of Washington School of Medicine in Seattle.
To assess the effects of these mutations, Professor Veesler and his colleagues designed a pseudovirus that mimics Omicron, and exposed it to different types of antibodies collected from patients who had been infected with previous variants, vaccinated, or both infected and vaccinated.
The scientists found that people previously infected or vaccinated had reduced ability to block infection, while people who were both infected and vaccinated, or got a booster dose of vaccine showed less reduction in neutralizing capacity, thus being more able to ward off Omicron infection.
From the three antibodies currently authorized to be used as a treatment, only one seemed to be able to offer some degree of protection. However, when researchers tested a larger panel of antibodies generated against earlier versions of the virus, they managed to identify four classes of antibodies that retained their ability to neutralize Omicron. These antibodies target one of four specific areas of the spike protein that is conserved not only in different SARS-CoV-2 variants, but also in other coronaviruses called sarbecoviruses.
The findings that antibodies targeting conserved areas present in a large array of coronaviruses suggests that designing vaccines and antibody treatments that target these particular areas could prove effective against a broad spectrum of present as well as future variants that may emerge through mutations.