Thymus dialogs

Medullary thymic epithelial cells (mTECs) that express the autoimmune regulator Aire are specialized cells that regulate thymocyte selection and are essential for establishing tolerance to self. In Immunity, Anderson and colleagues show that progenitors of V_γ5⁺ dendritic epidermal T cells (DETCs) are involved in the maturation of Aire⁺ mTECs in embryonic thymus. V_γ5⁺ DETC progenitors express the ligand for the cytokine receptor RANK and control the maturation of Aire⁺ mTECs in a RANK-dependent way. In turn, Aire⁺ mTECs foster the maturation of V_γ5⁺ DETC progenitors dependent on the selection molecule Skint-1 but independent of Aire. These results suggest that before the emergence of positively selected αβ thymocytes, which are a source of RANK ligand and contribute to the maintenance of Aire⁺ mTECs in the adult thymus, the first embryonic waves of γδ T cell progenitors establish similar reciprocal links with the thymic epithelium. IV

Immunity 36, 427–437 (2012)