Health

T cell response directed to the SARS-CoV-2 binding domain enhances protection

Researchers say the results of the analysis may help inform future COVID-19 vaccine development.

The T cell response to the receptor-binding domain of the SARS-CoV-2 spike protein was associated with protection from infection in vaccinated individuals with and without cancer, but lower in individuals with hematological malignancies. A T cell response was observed.According to the research results published in Cancer detection..

Researchers have found that approximately 20% to 25% of the population, including both healthy individuals and cancer patients, have an existing SARS-CoV-2 -specific T cell response.

In addition, they found that the types of cytokines released by memory T cells are associated with protection against SARS-CoV-2 infection, whereas the IL-2 and IL-5 cytokine imbalances are associated with higher susceptibility. I observed what I was doing.

For example, if the IL-2 / IL-5 ratio is less than 1, infection can be predicted regardless of the cancer status. This suggests that relative levels of cytokines released by T cells may be predictors of susceptibility to infection.

In addition, the researchers analyzed T cells in individuals who had a primary infection, a breakthrough infection after vaccination, or a reinfection with SARS-CoV-2. They found that even though there was an immune response to other regions of the viral genome, those individuals did not respond to the receptor-binding domain of the peplomer.

The lack of responsiveness to the spike receptor binding domain may have made these individuals more susceptible to infection, the researchers said.

In addition, the responsiveness of T cells to the receptor-binding domain promotes the evolution of peplomers and may even contribute to the emergence of new viral variants, the researchers said.

The researchers also examined the T cell response after vaccination in healthy individuals as well as patients with blood or solid tumors.

T cell responses differed between this population, but patients with hematological cancer showed significantly lower responses than those with solid tumors and those without cancer.

About 10% of patients with hematological cancer had T cells that responded to the receptor-binding domain, compared with 49% and 34% of those without cancer and those with solid tumors, respectively.

In addition, researchers found that vaccine-induced T cell responses to the original wild-type sequence of spike receptor binding domains were inadequately cross-reactive to those of alpha, beta, and delta mutants. discovered.

“This may explain why the omicron variant of SARS-CoV-2 is now widespread among vaccinated people,” said Laurence Zitvogel, MD, PhD, a professor at the Gustave Roussy Institute in Villejuif, France. Said in a statement. “Available vaccines have been developed for the original sequences of the receptor binding domain, not for the mutant sequences found in the mutants.”

This study collects blood samples prior to infection with SARS-CoV-2 and evaluates how polarity and repertoire of T cell responses correlate with susceptibility to subsequent wave infections of the COVID-19 pandemic. We have done various in vitro experiments for this purpose. ..

In addition, T cell polarity was assessed by identifying the types of cytokines released by each individual T cell when exposed to viral antigens. Researchers examined the composition of each individual’s T cell pool to determine the proportion of different T cells.

reference

T cell responses may help predict protection against SARS-CoV-2 infection, with or without cancer. Eurek Alert. news release. February 18, 2022. Accessed on February 18, 2022. https: //www.eurekalert.org/news-releases/943715

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T cell response directed to the SARS-CoV-2 binding domain enhances protection