Microarray analysis of FoxP3-expressing or non-expressing subsets of human CD4+ T cells

Gene expression profiles of subsets of CD4+ T cells according to their expression of FoxP3 and CD45RA were compared. Abstract: FoxP3 is a key transcription factor for the development and function of natural CD4+ regulatory T cells (Tregs). Here we show that human FoxP3+CD4+ T cells are composed of three phenotypically and functionally distinct subpopulations: CD45RA+FoxP3low resting Tregs (rTregs) and CD45RA-FoxP3high activated Tregs (aTregs), both of which are suppressive in vitro, and cytokine-secreting CD45RA-FoxP3low non-suppressive T cells. The proportion of the three subpopulations characteristically altered in cord blood, aged individuals, and patients with immunological diseases. Terminally differentiated aTregs rapidly die while rTregs proliferate and convert into aTregs in vitro and in vivo as shown by the transfer of rTregs into NOD-scid-common gamma-chain-knockout mice and by TCR sequence-based T cell clonotype tracing in peripheral blood of normal individuals. Taken together, the dissection of FoxP3+ cells into subsets enables one to analyze Treg differentiation dynamics and interactions in normal and disease states, and to control immune responses through manipulating particular FoxP3+ subpopulations. RNA was extracted from freshly obtained peripheral blood lymphocytes from a healthy donor that were separated according to their expression of CD25, CD127 and CD45RA after surface staining.