T-cell-refreshing molecule could be key to preventing immune exhaustion during chronic infection and cancer

Good news! Potentially, a breakthrough, but it is still early stage research!

"... The new study may lead to new ways to prevent or reverse this immune exhaustion. The researchers have previously identified a subset of T cells, named Tpex cells, which are able to keep up the fight long after other T cells have burnt out. Now the team has identified a subset of this subset, as well as the specific molecule that gives them their powers.

This group of Tpex cells were found to have an ability to renew themselves, in a fashion similar to stem cells. As such, the researchers have opted to name them “stem-cell-like exhausted T cells.” ...
On closer inspection, the researchers singled out a specific transcription factor called Myb, which controls the development and function of these stem-cell-like exhausted T cells. ..."

"Researchers ... have discovered a new population of immune cells which are critical in maintaining the immune response against chronic infections and cancer.

This new population of cells also mediates the response to immunotherapy using checkpoint inhibitors, which has revolutionised cancer therapy in recent years.

The discovery may explain why immunotherapy fails in some people and could lead to the development of more effective new therapies for cancer or severe viral infections. ...
 identified a novel cell population that is critical in overcoming exhaustion and maintaining long-term T cell responses during chronic viral infection."

From the abstract:

"CD8+ T cells that respond to chronic viral infections or cancer are characterized by the expression of inhibitory receptors such as programmed cell death protein 1 (PD-1) and by the impaired production of cytokines. This state of restrained functionality—which is referred to as T cell exhaustion—is maintained by precursors of exhausted T (TPEX) cells that express the transcription factor T cell factor 1 (TCF1), self-renew and give rise to TCF1− exhausted effector T cells. Here we show that the long-term proliferative potential, multipotency and repopulation capacity of exhausted T cells during chronic infection are selectively preserved in a small population of transcriptionally distinct CD62L+ TPEX cells. The transcription factor MYB is not only essential for the development of CD62L+ TPEX cells and maintenance of the antiviral CD8+ T cell response, but also induces functional exhaustion and thereby prevents lethal immunopathology. Furthermore, the proliferative burst in response to PD-1 checkpoint inhibition originates exclusively from CD62L+ TPEX cells and depends on MYB. Our findings identify CD62L+ TPEX cells as a stem-like population that is central to the maintenance of long-term antiviral immunity and responsiveness to immunotherapy. Moreover, they show that MYB is a transcriptional orchestrator of two fundamental aspects of exhausted T cell responses: the downregulation of effector function and the long-term preservation of self-renewal capacity."

T-cell-refreshing molecule could be key to preventing immune exhaustion

Researchers uncover the key to maintaining immunity against chronic infection and cancer

MYB orchestrates T cell exhaustion and response to checkpoint inhibition (open access)

Fig. 1: CD62L marks transcriptionally distinct and functionally superior TPEX cells during chronic infection.

Stem-like T cell taken under microscope.