Much data support an essential role for interleukin (IL)-2 in immune tolerance. This idea is much different from the early paradigm in which IL-2 is central for protective immune responses. This change in thinking occurred when a T regulatory cell defect was shown to be responsible for the lethal autoimmunity associated with IL-2/IL-2R deficiency. This realization allowed investigators to explore immune responses in IL-2-nonresponsive mice rendered autoimmune-free. Such studies established that IL-2 sometimes contributes to optimal primary immune responses, but it is not mandatory. Emerging findings, however, suggest an essential role for IL-2 in immune memory. Here, the current understanding of the dual role of IL-2 in maintaining tolerance and contributing to immunity in vivo is reviewed with some emphasis on T regulatory cell production and homeostasis. Also discussed are implications of this new appreciation concerning the immunobiology of IL-2 with respect to targeting IL-2 or its receptor in immunotherapy.

中文翻译：

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白介素2的生物学。

许多数据支持白介素（IL）-2在免疫耐受中的重要作用。这个想法与IL-2在保护性免疫反应中起关键作用的早期范例大不相同。当T调节细胞缺陷被证明与IL-2 / IL-2R缺乏相关的致死性自身免疫负责时，就会发生这种思想上的改变。这一认识使研究者能够在无自身免疫的IL-2无反应小鼠中探索免疫反应。此类研究表明，IL-2有时有助于最佳的初次免疫反应，但这不是强制性的。然而，新发现提示IL-2在免疫记忆中起重要作用。这里，综述了目前对IL-2在体内维持耐受性和促进免疫力的双重作用的理解，并着重于T调节细胞的产生和体内平衡。还讨论了关于在免疫疗法中针对IL-2或其受体的针对IL-2的免疫生物学的这种新认识的含义。