Continuous requirement for the T cell receptor for regulatory T cell function

Foxp3+ regulatory T cells (Treg cells) maintain immunological tolerance and their deficiency results in fatal multi-organ autoimmunity. Although heightened T cell receptor (TCR) signaling is critical for the differentiation of Treg cells, the role of TCR signaling in Treg cell function remains largely unknown. Here we demonstrate inducible ablation of the TCR results in Treg cell dysfunction which cannot be attributed to impaired Foxp3 expression, decreased expression of Treg cell signature genes or altered ability to sense and consume interleukin 2. Rather, TCR signaling was required for maintaining the expression of a limited subset of genes comprising 25% of the activated Treg cell transcriptional signature. Our results reveal a critical role for the TCR in Treg cell suppressor capacity. Array expression of Foxp3-CreERT2 CalphaFL/WT mice