Induction, control, and plasticity of Treg cells: the immune regulatory network revised?

Treg cells expressing the Foxp3 transcription factor play a key role in several aspects of immunological tolerance and in the establishment of immune homeostasis. Here, we discuss the mechanisms, including new evidence on the signals required by Tconv cells to convert into Treg cells described by Yao and colleagues [Eur. J. Immunol. 2013. 43: 458467] in this issue of European Journal of Immunology, by which Treg-cell dynamics, plasticity and diversification correlate with diverse functions (induction, suppression, contra-suppression) in a variety of settings, such as inflammation, chronic infections, cancer, and autoimmunity.