T cells need rest and maintenance to perform their guardian duties, according to an article in the May 27 issue of the journal Science. Understanding why this resting state is crucial to the maintenance and survival of T cells may lead to improved immune system function, the authors say.
Researchers from Yale report that the protein CD8α—found in a subset of T cells called CD8 cells—is crucial to keeping the cells in a quiescent state until pathogens are detected. When they deleted this protein in mice, the protective CD8 cells were unable to enter a quiescent state and died, leaving the host vulnerable to infections.
They also identified another protein, PILRα, that provides a biochemical signal to CD8α. When this protein pair was disrupted, the researchers discovered that “memory” CD8 cells—cells that had been exposed to pathogens—and naïve cells all underwent apoptosis because they lacked the ability to stay in a quiescent state.
“We may have to change how we teach T cell biology,” said Dr. Lieping Chen in a press release. Dr. Chen is the United Technologies Corporation Professor in Cancer Research at Yale and professor of immunobiology, dermatology and medicine and the senior author of the study.
The researchers note that as people age, naïve and memory T cells tend to be lost, making older individuals more susceptible to infections. They believe that the inability of some T cells to remain in a quiescent state could be a harbinger of increased susceptibility to infections and cancer.