Cell-surface IL-7 receptor expression facilitates the purification of FOXP3+ regulatory T cells

FOXP3(+) regulatory T (Treg) cells have crucial roles in maintaining self-tolerance and modulating adaptive immune responses. Functional studies of Treg cells have been hampered by a lack of suitable cell-surface markers that specifically enable their purification without contamination by non-regulatory CD25(+) effector T cells. Two recent studies have demonstrated that downregulation of the interleukin-7 receptor (CD127) distinguishes Treg cells from activated T cells, facilitating both Treg-cell purification and their functional characterization in human diseases. CD127 uniquely enables the purification of FOXP3(+) Treg cells and, potentially, also 'adaptive' regulatory T-cell subsets from the CD4(+)CD25(-) T-cell population.