Intrathymic IL-7: The where, when, and why of IL-7 signaling during T cell development
- 作者：Changwan Hong ; Megan A. Luckey ; Jung-Hyun Park ; parkhy@mail.nih.gov
- 关键词：Thymus ; IL-7 receptor ; Thymocytes ; SOCS ; Positive selection
- 刊名：Seminars in Immunology
- 出版年：2012
- 期刊代码：105_10445323
- 类别：imm
- 出版时间：June, 2012
- 卷：24
- 期：3
- 页码：151-158
- 文件大小：452 K
摘要
The thymus is the birthplace of all T lineage cells. But the thymus is also a cradle as it provides the environment for further maturation and differentiation of immature thymocytes. While many factors contribute to make the thymus a unique place for T cell development, here we review the essential role of intrathymic interleukin-7 (IL-7). In the absence of IL-7 signaling, survival, proliferation and differentiation of immature thymocytes are all severely impaired. Consequently, IL-7 is critical to nurture and guide T precursor cells through the diverse steps of thymic maturation. Interestingly, even as IL-7 signaling is such a critical factor, IL-7 signaling must be also actively suppressed during specific stages of T cell differentiation. These contradictory observations are puzzling but can be satisfactorily explained when understanding the developmental context of IL-7 signaling. In this regard, here we will discuss the spatiotemporal expression of intrathymic IL-7 and address the stage-specific effects of IL-7 signaling in developing thymocytes. Specifically, we will review other facets of intrathymic IL-7 beyond its role as a pro-survival factor and so clarify and reaffirm the unique role of IL-7 as a prime factor in T cell development and differentiation.