Targeting the right regulatory T-cell population for tumor immunotherapy

Regulatory T cells (Tregs) that suppress tumor-specific T cell-mediated immune responses are the subject of an intense wave of investigation. We recently reported that a subset of Tregs, namely effector/memory CD25(low) cells, are responsible for suppressing high avidity tumor-specific T cells in mouse mammary tumors. Here, we discuss additional findings that clarify this mechanism of Treg-mediated immunosuppression.