Selection of regulatory T cells in the thymus

How are regulatory T (TReg) cells selected in the thymus? What is the role of T cell receptor specificity in the generation of self antigen-specific TReg cells? What is the involvement of thymic antigen-presenting cells in TReg cell differentiation and how is FOXP3 expression induced in developing thymocytes? Here, the authors summarize the latest findings in the field of TReg cells to provide answers to these long-standing questions.