A new, phenotypically distinct subpopulation of Regulatory Killer T ex-Th17 cells expressing CD4lowCD25hiCD49hiFoxp3hiRORlowIL-17low

Th17 and regulatory T (Treg) cells are integral in maintaining immune homeostasis and Th17- Treg imbalance is associated with inflammatory immunosuppression in cancer. Here it is shown that in addition to ROR+Foxp3+ cells eTreg cells are a source of ex-Th17 CD4lowCD25hiCD49hiFoxp3hi (Regulatory Killer T - RKT) cells while the latest are much more suppressive. Moreover, we have identified a set of key cytokines that favor the generation and expansion ex-Th17 Foxp3low cells. These findings should accelerate efforts to define the function of this new subset of Treg cells in the immune response to cancer.