, a journal from the American Society for Microbiology.
“We found in a January 2021 study that in people previously infected with the original COVID strain, specific epitopes [portions of a protein that elicit an immune response] from the virus are recognized by immune system cells known as CD8+ T lymphocytes or killer T cells and that this recognition enables a cell-mediated attack on COVID,” says study lead author Andrew Redd, Ph.D., assistant professor of medicine at the Johns Hopkins University School of Medicine and staff scientist at NIAID.
Other research groups in the United States and South Africa have demonstrated very similar results for people previously infected by or vaccinated against the original COVID-19 strain.
Immune cells are known for their ability to eliminate foreign invaders such as bacteria and viruses from the body. The T cells used in the latest study were from blood samples collected in 2020 from 30 patients who had recovered from mild to moderate cases of COVID-19.
The convalescent plasma donors had six human leukocyte antigens (cell-surface proteins that regulate the immune system and are part of each person’s genetic profile), which are representative of greater than 73% of the U.S. population.
During that assessment, donor samples were sent to ImmunoScape for the difficult task of identifying which T cells had responded to SARS-CoV-2.
More specifically, the company’s deep immune cell profiling method showed which virus proteins elicited a T cell-directed response data that could provide valuable insight into the T cells’ functional properties.
In the original analysis, researchers found that T cells from the convalescent donors recognized 52 of the 408 epitopes.
In the latest study, researchers examined the 52 epitopes previously identified in the convalescent blood samples to determine if they had been altered by genetic changes that would enable the virus to avoid being susceptible to cell-mediated immunity.
They found one low-prevalence epitope from the omicron spike protein that had a minor change from its predecessor in the original virus.
Overall, the omicron variant is known to have some 50-plus mutational differences between it and the original SARS-CoV-2 strain, but it seems the virus has not evolved the ability to avoid T cell recognition.
While significant cell-mediated immunity appears to have been maintained from the original SARS-CoV-2 through its subsequent variants, more research is needed to fully define why people who have this protection may still get sick from omicron.
Source: Medindia
