Although IL-2 was first recognized as growth factor for T cells, it is now also appreciated to be a key regulator of T cells through its effects on regulatory T cells (Treg). The IL-2 receptor (IL-2R) subunits' different (i) ligand affinities, (ii) dimerization or trimerization relationships with other cytokine subunits, (iii) expression across multiple cell types, and (iv) downstream signaling effects, largely dictate cellular tolerance and antimicrobial processes. Defects in IL-2Rγ result in profound and almost universally fatal immune deficiency, unless treated with hematopoietic stem cell transplantation (HSCT). Defects in IL-2Rα and IL-2Rβ result in more limited infection susceptibility, particularly to herpesviruses. However, the most prominent clinical symptomatology for IL-2Rα and IL-2Rβ defects include multi-organ autoimmunity and inflammation, consistent with the critical role of IL-2 in establishing and maintaining immune tolerance. Here, we review how we have arrived at our current understanding of the complex roles of IL-2/2R in host defense and tolerance focusing on the insights gained from human clinical immunology.

中文翻译：

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通道 2 清理：IL-2 受体在宿主防御和耐受中的作用。

虽然 IL-2 最初被认为是 T 细胞的生长因子，但现在通过其对调节性 T 细胞 (Treg) 的影响，它也被认为是 T 细胞的关键调节剂。IL-2 受体 (IL-2R) 亚基的不同 (i) 配体亲和力，(ii) 与其他细胞因子亚基的二聚或三聚关系，(iii) 跨多种细胞类型的表达，以及 (iv) 下游信号传导效应，在很大程度上决定了细胞耐受性和抗菌过程。除非用造血干细胞移植 (HSCT) 治疗，否则 IL-2Rγ 的缺陷会导致严重且几乎普遍致命的免疫缺陷。IL-2Rα 和 IL-2Rβ 的缺陷导致更有限的感染易感性，特别是对疱疹病毒。然而，IL-2Rα 和 IL-2Rβ 缺陷最突出的临床症状包括多器官自身免疫和炎症，这与 IL-2 在建立和维持免疫耐受中的关键作用一致。在这里，我们回顾了我们目前对 IL-2/2R 在宿主防御和耐受中的复杂作用的理解，重点关注从人类临床免疫学中获得的见解。