Fig. 1: Role of T cells in ALI.
From: Regulatory T cell and macrophage crosstalk in acute lung injury: future perspectives
Under the effects of various cytokines, CD4 + T cells differentiate into different cell types. IL-2 initiates the transcription of STAT5 and Foxp3 to induce Treg conversion, while IL-6 is necessary for the activation of Th17 cell-specific transcription factors. In addition, PKB/Akt acts intracellularly to prevent Treg differentiation. Tregs secrete TGF-β, inducing neutrophil death or preventing neutrophil extravasation. Tregs also stimulate the proliferation and differentiation of type II alveolar cells (AECII) to achieve direct repair of the alveolar epithelium. In contrast, Th17 cells produce IL-17 and exacerbate inflammation by inducing neutrophil infiltration and monocyte maturation. The role of monocytes in ALI is also inhibited by Tregs. IL interleukin, TGF tissue growth factor, STAT signal transducer and activator of transcription, RORγt retinoid-related orphan nuclear receptor γt, Foxp3 forkhead box protein 3.
