T cells are an elite fighting force of the immune system, seeking out and destroying diseased cells. But in a prolonged campaign against a chronic condition — like a viral infection, or cancer — the body needs a steady supply of these killer troops. Where and how these killer troops are generated has been a mystery.
That led a team of scientists from Weill Cornell Medicine and Memorial Sloan Kettering Cancer Center (MSK) to dig deeper. They found that a small subset of T cells, called stem T cells, are responsible for making new T cells and for continuously replenishing them in chronic disease. Importantly, these rare stem T cells express a protein called LEF1.
The team’s findings in laboratory models, published July 1 in Cell, showed that focusing on this population of LEF1-positive T cells is key. Boosting LEF1-positive cells overcame T cell “exhaustion” in the case of chronic infection. And removing them was successful in reining in overactive immune cells in the case of type 1 diabetes, an autoimmune disease.
