As the Omicron coronavirus variant sweeps the world, concerns about the efficacy of existing vaccines against the mutated virus are spreading.
While most available COVID-19 vaccines target the virus' spike protein in order to activate the immune response, variants including Delta and Omicron have mutations that affect this protein, making them more difficult for antibodies to detect.
A method that could be used to develop vaccines that are effective against these variants and other ones in the future is augmenting vaccines with a piece of another viral protein that is less susceptible to mutations than the spike protein.
Experts from the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at the University of California, Los Angeles (UCLA), found that a part of a protein present in SARS-CoV-2, viral polymerase, may fit the bill.
The researchers, including graduate student and lead study author Pavlo Nesterenko and co-author Dr. Owen Witte, president of developmental immunology at the UCLA Department of Microbiology, Immunology and Molecular Genetics and founding director emeritus of the Broad Stem Cell Research Center, found rare immune cells that can target this part of the protein when it is added to COVID vaccines, increasing the duration of the immune response, as well as resistance to novel variants. They published their findings in the peer-reviewed journal Cell Reports on Thursday.
Viral polymerases, which appear in some coronaviruses, are used in viral replication. Whereas the spike protein may be affected by mutations as the virus spreads and subsequently evolves, viral polymerases are not likely to mutate.
To find whether or not humans have immune cell receptors that can detect viral polymerase, the UCLA team took blood samples from donors and introduced the polymerase antigen. They found that some receptors were able to detect the substance, so they sequenced these receptors and then augmented immune cells with them in order to observe how they could detect and destroy the virus.
These findings could have a significant impact in the global war against COVID-19, potentially enhancing immune protection against new variants. The researchers are continuing to study the use of viral polymerases in future vaccines, according to a UCLA statement.