IL-2 dependent genes of T regulatory and T effector cells

Interleukin-2 receptor (IL-2R) signaling is essential for T regulatory (Treg) cell development and homeostasis. Here we show that expression of IL-2Rbeta chains that lack tyrosine residues important for the association of the adaptor Shc and the transcription factor STAT5 in IL-2Rbeta-deficient mice resulted in production of a normal proportion of natural Treg cells that suppressed severe autoimmunity related with deficiency in IL-2 or IL-2R. These mutant IL-2Rbeta chains supported suboptimal and transient STAT5 activation that upregulate the transcription factor Foxp3 to normal amounts in natural, but not induced, Treg cells. Using cells T cell obtained from normal C57BL/6 mice and mice harboring Treg cells with impaired IL-2R signaling, gene expression profiling revealed many targets in peripheral natural Treg cells that were IL-2-dependent and a substantial overlap between the Treg cell IL-2-dependent gene program and the Treg cell transcriptional signature. Collectively, these findings demonstrate that a critical, and perhaps minor, subset of IL-2-dependent targets in Treg cells is indexed to a low IL-2R signaling threshold and that a substantial proportion of the Treg cell gene program is regulated by IL-2. CD4 T effector cells also showed many IL-2R-dependent gene and these also overlapped in a distintive manner with the IL-2-dependent genes of Treg cells and the Treg gene signature.

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