The importance of interleukin (IL)‐33 in promoting effective antiviral immune responses is evident, yet the critical cellular sources of IL‐33 in homeostasis and infection are largely unknown. In this issue of the European Journal of Immunology, Aparicio‐Domingo et al. [Eur. J. Immunol. 2021. 51: 76–90] explore the main source of IL‐33 expression in lymph nodes (LNs) and dissect its role in LN homeostasis and antiviral adaptive immune response. The authors reveal that fibroblastic reticular cells and lymphatic endothelial cells are both producing IL‐33 in steady‐state LNs. Remarkably, however, by using cell‐type specific deletion approaches, the authors demonstrate that exclusively fibroblastic reticular cells, and not lymphatic endothelial cells, are the critical cellular source for promoting antiviral CD8⁺ T‐cell responses upon infection. These findings provide an important insight into the role of specific LN stromal cell subsets as potent modulators of antiviral immunity.

中文翻译：

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IL-33 在体内平衡和感染中的奇特案例

白细胞介素 (IL)-33 在促进有效抗病毒免疫反应中的重要性是显而易见的，但 IL-33 在体内平衡和感染中的关键细胞来源在很大程度上是未知的。在本期《欧洲免疫学杂志》中，Aparicio-Domingo 等人。[欧元。J.免疫。2021. 51: 76-90] 探索淋巴结 (LNs) 中 IL-33 表达的主要来源，并剖析其在 LN 稳态和抗病毒适应性免疫反应中的作用。作者揭示，成纤维细胞网状细胞和淋巴管内皮细胞都在稳态 LN 中产生 IL-33。然而，值得注意的是，通过使用细胞类型特异性缺失方法，作者证明了仅成纤维细胞网状细胞，而不是淋巴管内皮细胞，是促进抗病毒 CD8 的关键细胞来源⁺感染后的 T 细胞反应。这些发现为了解特定 LN 基质细胞亚群作为抗病毒免疫的有效调节剂的作用提供了重要的见解。