CD4 T细胞最初被描述为促进细胞免疫应答（Th1细胞）或体液免疫应答（Th2细胞）的辅助细胞。自那时以来，已经描述了大量具有不同功能的辅助和调节CD4 T细胞亚群。具有细胞毒性功能的CD4 T细胞最初在病毒感染和自身免疫疾病中被描述，并且最近在癌症和肠道菌群失调中也有所描述。调节性CD4 T细胞亚群，如调节性T细胞（Tregs）和调节型1型（Tr1）细胞，也显示出具有细胞毒性能力。确实，Tr1细胞被证明对于骨髓和肠道干细胞间质的维持至关重要。本综述将概述细胞毒性CD4 T细胞的发育，并讨论炎症和类似Tr1的细胞毒性CD4 T细胞在维持肠道干细胞和抗癌免疫应答中的作用。版权所有 © 2023 Venkatesh, Tracy and Farrar.

CD4 T cells were initially described as helper cells that promote either the cellular immune response (Th1 cells) or the humoral immune response (Th2 cells). Since then, a plethora of functionally distinct helper and regulatory CD4 T cell subsets have been described. CD4 T cells with cytotoxic function were first described in the setting of viral infections and autoimmunity, and more recently in cancer and gut dysbiosis. Regulatory CD4 T cell subsets such as Tregs and T-regulatory type 1 (Tr1) cells have also been shown to have cytotoxic potential. Indeed, Tr1 cells have been shown to be important for maintenance of stem cell niches in the bone marrow and the gut. This review will provide an overview of cytotoxic CD4 T cell development, and discuss the role of inflammatory and Tr1-like cytotoxic CD4 T cells in maintenance of intestinal stem cells and in anti-cancer immune responses.Copyright © 2023 Venkatesh, Tracy and Farrar.