Cytokines control the immune system by regulating the proliferation, differentiation and function of immune cells. They activate their target cells through binding to specific receptors, which either are transmembrane proteins or attached to the cell-surface via a GPI-anchor. Different tissues and individual cell types have unique expression profiles of cytokine receptors, and consequently this expression pattern dictates to which cytokines a given cell can respond. Furthermore, soluble variants of several cytokine receptors exist, which are generated by different molecular mechanisms, namely differential mRNA splicing, proteolytic cleavage of the membrane-tethered precursors, and release on extracellular vesicles. These soluble receptors shape the function of cytokines in different ways: they can serve as antagonistic decoy receptors which compete with their membrane-bound counterparts for the ligand, or they can form functional receptor/cytokine complexes which act as agonists and can even activate cells that would usually not respond to the ligand alone. In this review, we focus on the IL-2 and IL-6 families of cytokines and the so-called Th2 cytokines. We summarize for each cytokine which soluble receptors exist, were they originate from, how they are generated, and what their biological functions are. Furthermore, we give an outlook on how these soluble receptors can be exploited for therapeutic purposes.

细胞因子通过调节免疫细胞的增殖、分化和功能来控制免疫系统。它们通过与特定受体结合来激活靶细胞，这些受体要么是跨膜蛋白，要么通过 GPI 锚附着到细胞表面。不同的组织和单个细胞类型具有独特的细胞因子受体表达谱，因此这种表达模式决定了给定细胞可以对哪些细胞因子作出反应。此外，存在几种细胞因子受体的可溶性变体，它们由不同的分子机制产生，即差异 mRNA 剪接、膜系留前体的蛋白水解切割和细胞外囊泡上的释放。这些可溶性受体以不同方式塑造细胞因子的功能：它们可以作为拮抗诱饵受体，与其膜结合的对应物竞争配体，或者它们可以形成功能性受体/细胞因子复合物，作为激动剂，甚至可以激活通常不会单独对配体作出反应的细胞。在这篇综述中，我们关注 IL-2 和 IL-6 细胞因子家族以及所谓的 Th2 细胞因子。我们总结了可溶性受体存在的每种细胞因子，它们来自哪里，它们是如何产生的，以及它们的生物学功能是什么。此外，我们展望了如何将这些可溶性受体用于治疗目的。在这篇综述中，我们关注 IL-2 和 IL-6 细胞因子家族以及所谓的 Th2 细胞因子。我们总结了可溶性受体存在的每种细胞因子，它们来自哪里，它们是如何产生的，以及它们的生物学功能是什么。此外，我们展望了如何将这些可溶性受体用于治疗目的。在这篇综述中，我们关注 IL-2 和 IL-6 细胞因子家族以及所谓的 Th2 细胞因子。我们总结了可溶性受体存在的每种细胞因子，它们来自哪里，它们是如何产生的，以及它们的生物学功能是什么。此外，我们展望了如何将这些可溶性受体用于治疗目的。