Department of Immunology, Graduate School of Medicine, Chiba University, Chiba, Japan.
Institute for Advanced Academic Research, Chiba University, Chiba, Japan.
Front Immunol. 2022 Aug 9;13:945063. doi: 10.3389/fimmu.2022.945063. eCollection 2022.
Type 2 helper T (Th2) cells, a subset of CD4 T cells, play an important role in the host defense against pathogens and allergens by producing Th2 cytokines, such as interleukin-4 (IL-4), IL-5, and IL-13, to trigger inflammatory responses. Emerging evidence reveals that Th2 cells also contribute to the repair of injured tissues after inflammatory reactions. However, when the tissue repair process becomes chronic, excessive, or uncontrolled, pathological fibrosis is induced, leading to organ failure and death. Thus, proper control of Th2 cells is needed for complete tissue repair without the induction of fibrosis. Recently, the existence of pathogenic Th2 (Tpath2) cells has been revealed. Tpath2 cells produce large amounts of Th2 cytokines and induce type 2 inflammation when activated by antigen exposure or tissue injury. In recent studies, Tpath2 cells are suggested to play a central role in the induction of type 2 inflammation whereas the role of Tpath2 cells in tissue repair and fibrosis has been less reported in comparison to conventional Th2 cells. In this review, we discuss the roles of conventional Th2 cells and pathogenic Th2 cells in the sequence of tissue inflammation, repair, and fibrosis.
2 型辅助性 T（Th2）细胞是 CD4 T 细胞的一个亚群，通过产生 Th2 细胞因子（如白细胞介素-4（IL-4）、IL-5 和 IL-13）来触发炎症反应，从而在宿主防御病原体和过敏原方面发挥重要作用。新出现的证据表明，Th2 细胞也有助于炎症反应后受损组织的修复。然而，当组织修复过程变得慢性、过度或不受控制时，会诱导病理性纤维化，导致器官衰竭和死亡。因此，需要适当控制 Th2 细胞，以在不诱导纤维化的情况下完成组织修复。最近，已经发现了致病性 Th2（Tpath2）细胞的存在。Tpath2 细胞在抗原暴露或组织损伤激活时会大量产生 Th2 细胞因子并诱导 2 型炎症。在最近的研究中，Tpath2 细胞被认为在 2 型炎症的诱导中起核心作用，而与传统 Th2 细胞相比，Tpath2 细胞在组织修复和纤维化中的作用报道较少。在这篇综述中，我们讨论了传统 Th2 细胞和致病性 Th2 细胞在组织炎症、修复和纤维化序列中的作用。
