單元名稱:TH0細胞如何分化成TH1、TH2、TH17和Treg（調節型T細胞）次族群，

Feng Ling Yu

建立於 2023年08月22日

輔助T細胞（TH）的活化是啟動細胞調節性免疫之重要關鍵，請說明TH0細胞如何分化成TH1、TH2、TH17和Treg（調節型T細胞）次族群，並說明這些次族群各如何調節相關之免疫反應。 醫用微生物及免疫學 (6)尤鋒64-66       Following activation by antigen-presenting cells such as dendritic cells (DCs), naive CD4+ T cells can be polarized into different effector T cell subsets — T helper 1 (TH1), TH2, TH17 and regulatory T (TReg) cells — depending on the local cytokine environment. The differentiation of each of these effector T cell subsets is controlled by distinct sets of transcription factors. In the presence of interleukin-6 (IL-6) and transforming growth factor-β (TGFβ), naive T cells can differentiate into TH17 cells, which are characterized by expression of the transcription factors retinoic acid receptor-related orphan receptor-γt (RORγt) and signal transducer and activator of transcription 3 (STAT3). Furthermore, IL-1 and IL-23 can promote and/or stabilize TH17 cell differentiation and expansion. FOXP3, forkhead box P3; GATA3, GATA-binding protein 3; IFNγ, interferon-γ; TCR, T cell receptor. ( Nature Reviews Immunology 10, 248-256 (April 2010))   Thp(T0)的分化 1.當細胞內細菌及病毒感染時，樹突細胞會分泌IL-12，使得Naïve T helper cell分化成TH1 cell 2.當寄生蟲感染時，Natural Kill T cell（NKT cell）會分泌IL-4，使得Naïve T helper cell分化成TH2 cell 3.當細胞外細菌及黴菌感染時，樹突細胞會分泌大量的TGF-β、IL-6、IL-23，使得Naïve T helper cell分化成TH17 cell 4.沒有病原入侵時，樹突細胞會分泌大量的TGF-β，使得Naïve T helper cell分化成Treg cell Th17 cell 可活化並誘導neutrolphil 聚集至發炎區域和宿主防禦反應 與Th1 cell 相互拮抗以調節免疫反應 Th17 cell 功能異常可能導致多發性硬化症、紅斑性狼瘡、autoimmune encephalomyelitis (EAE) 等自體免疫性疾病。 Th17 cell的發育及分化路徑，過程需要 IL-6、TGF-β的刺激下，活化 STAT3、轉錄因子RORγt 進而促使Th17 cells 分化相關基因大量表現。RORγt 是 Th17 細胞誘導中的重要轉錄激素，