A function for interleukin 2 in Foxp3-expressing regulatory T cell (Nat Immunol, 2005, 6:1142-1151)

報告日期: 2006/04/18
報告時間: 16:00/16:50
報告學生: 李一平
講評老師: 林以行


A function for interleukin 2 in Foxp3-expressing regulatory T cells

Nature Immunology, Vol. 6, 1142-1151 (2005)


Time: Apr. 18. 2006,

Place: Room 602

Speaker: 李一平

Commentator: 林以行 老師



       Naturally occurring regulatory T cells (Treg cells) expressing the forkhead family transcription factor Foxp3 are key in controlling autoimmune and inflammatory responses. Most Treg cells constitutively express the high-affinity interleukin 2 (IL-2) receptor a-chain (CD25); however, the precise function of IL-2 in Treg cell biology has remained controversial. In this study, the authors analyzed transgenic mice expressing Foxp3-green fluorescent protein (Foxp3gfp) genetically deficient in either IL-2 (Il2-/-) or CD25 (Il2ra-/-) to establish the effect of IL-2 signaling on Treg cell development and function. The results demonstrated that Foxp3 was induced in a subset of developing thymocytes in the absence of IL-2 signaling and Treg cells were present in substantial numbers. Notably, Il2-/- and Il2ra-/- Treg cells were functionally competent suppressors with a suppressive function equal to that of wild-type Treg cells. In contrast, no Treg cells were detectable in the thymus or periphery of IL-2 receptor g-deficient mice, indicating that common g-chain signals are absolutely required for Treg cell development. Furthermore, gene expression analysis showed that IL-2 signaling was required for maintenance of the expression of genes involved in the regulation of cell growth and metabolism. Thus, whereas IL-2 is not directly required for Treg cell development and function, it is required for sustaining the Treg cell population at a size necessary to maintain immune homeostasis and tolerance to self.



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2.     Maloy, K.J. & Powrie, F. Fueling regulation: IL-2 keeps CD4+ Treg cells fit. Nat. Immunol. 6, 1071-1072 (2005).