T cells, biology textbooks teach us, are the soldiers of the immune system, constantly ready to respond to a variety of threats, from viruses to tumors. However, without rest and maintenance, T cells can die and make their hosts more susceptible to pathogens, Yale scientists report May 27 in the journal Science.
“We may need to change the way we teach T cell biology,” said Lieping Chen, United Technologies Corporation professor of cancer research at Yale and professor of immunobiology, dermatology and medicine and lead author. of the study.
Until pathogens are detected, T cells remain in a quiescent state. However, the molecular mechanisms that keep T cells inactive were previously unknown.
In the new study, the Yale researchers show that a protein known as CD8a – which is found in a subset of T cells called CD8 cells – is crucial in keeping cells in this dormant state. When scientists deleted this protein in mice, the protective CD8 cells were unable to enter a quiescent state and died, leaving the host vulnerable to infection.
In addition, they identified another protein, PILRa, which provides a biochemical signal to CD8a. By disrupting this pair of proteins, CD8 “memory” cells – cells that had been previously exposed to pathogens – and naïve cells died because they lacked the ability to stay in a quiescent state.
Researchers hope that understanding why this resting state is crucial for T cell maintenance and survival may lead to improved immune system function.
Chen noted that as people age, they tend to lose both naïve and memory T cells, making older people more susceptible to infections. It’s possible that the inability of T cells to stay in a quiescent state might make people more susceptible to infections and cancer, the authors suggest.
Source of the story:
Materials provided by Yale University. Original written by Bill Hathaway. Note: Content may be edited for style and length.
