The now famous T cells are one of the body’s key defenses against COVID-19 and are still effective in generating an immune response against omicron, although this is the variant that presents the most changes with respect to the original SARS COV-2. This is the positive conclusion of a new investigation carried out by scientists from the Hong Kong University of Science and Technology (HKUST) and the University of Melbourne, in Australia, after analyzing more than 1,500 proteins contained in the omicon strain.
T cells are generated after having passed an infectious disease or with the administration of a vaccine and are essential to reduce the most serious cases, because they are able to eliminate cells infected by the virus and help with other functions of the immune system.
Therefore, although omicron escapes, to a large extent, the antibodies generated by current vaccines, the same does not happen with T cells. To be able to prove it, this team of Chinese and Australian scientists has analyzed more than 1,500 protein fragments SARS-CoV-2 viruses, called epitopes, which have been found to be recognized by T cells in recovered COVID-19 patients or after vaccination.
The team’s findings suggest that omicron is unlikely to be able to evade T cells, adding to a growing body of evidence from research groups around the world that are also investigating T cell responses to COVID-19.
“Despite being a preliminary study, we think this is positive news. Even if Omicron, or some other variant for that matter, can potentially escape antibodies, a robust T-cell response can still be expected to offer protection and help prevent major diseases, “said Professor Matthew MCKAY of the University of Melbourne, who co-led this research.
The most concerning aspect of omicron is the abundance of mutations in its spike protein, which is the main target of COVID-19 vaccines. The spike allows the virus to adhere to and enter the cells of humans. Current vaccines induce neutralizing antibodies designed to block this process; however, these antibodies have been reported to be less effective against omicron compared to earlier variants such as delta.
By analyzing spike protein virus epitopes that are targeted by T cells in vaccinated or previously infected individuals, the study found that only 20 percent showed omicron-associated mutations. Even then, these mutations do not necessarily mean that the virus will be able to evade the body’s T cells.
“Among these T-cell epitopes that have omicron mutations, our subsequent analysis revealed that more than half are expected to remain visible to T cells. This further reduces the chance that omicron may escape the cell’s defenses. T “, has assured the other co-leader of the study, Professor Ahmed Abdul QUADEER, professor in the Department of Electronic and Computer Engineering at HKUST.
While the study focused on the spike protein of the virus, when the team expanded their analysis to other proteins in the virus, they found that an overwhelming majority (more than 97%) of non-spike T cell epitopes do not encompass mutations associated with Omicron.
“These results would generally suggest that extensive T-cell escape is highly unlikely,” concludes Professor McKay. He adds: “Based on our data, we anticipate that T-cell responses elicited by vaccines and boosters, for example, will continue to help protect against omicron, as seen for other variants.”