調節T細胞(regulatory T cell,Treg):是一群具有負調節機體免疫反應的淋巴細胞,通常起着維持自身耐受和避免免疫反應過度損傷機體的重要作用,但也參與腫瘤細胞逃避機體免疫監視和慢性感染。
70年代曾命名為抑制T細胞(suppressor T cell),因缺乏明確的表面標誌,研究長期處於尷尬和停頓的境地;直到90年代研究出現轉機並成為目前研究熱點,但現多稱為調節T細胞(regulatory T cell)。
調節性T細胞最重要的分子標記是一種轉錄因子Foxp3,在所有調節性T細胞中均可發現有多量表現。
亞群
調節T細胞是免疫系統的重要組成成分,可抑制其他免疫細胞的免疫反應。這是免疫系統之中重要的「自檢」組分,可防止產生過激的免疫反應。調節T細胞有多種形式,但被了解的最透徹的是表達CD4、CD25及FOXP3調節T細胞(CD4+CD25+調節T細胞)。調節T細胞與輔助T細胞不同[1]。另一類調節T細胞亞群是Treg17細胞[2]。調節T細胞參與到成功清除入侵生物後關閉免疫反應之中,同時也防止產生自身免疫反應[3]。
CD4+ Foxp3+ CD25(high) regulatory T cells have been called "naturally occurring" regulatory T cells[4] to distinguish them from "suppressor" T cell populations that are generated in vitro. Additional regulatory T cell populations include Tr1, Th3, CD8+CD28-, and Qa-1 restricted T cells. The contribution of these populations to self-tolerance and immune homeostasis is less well defined. Foxp3 can be used as a good marker for mouse CD4+CD25+ T cells, although recent studies have also shown evidence for Foxp3 expression in CD4+CD25- T cells. In humans, Foxp3 is also expressed by recently activated conventional T-cells and thus does not specifically identify human Tregs.[5]
調節/抑制T細胞有很多種,可分為自然存在與誘導產生兩類:
自然存在:
- CD4+ CD25+T細胞:在維持機體對自身抗原的耐受中扮演重要角色,是目前研究最廣泛深入的一種調節/抑制T細胞。
誘導產生:
參見
參考資料
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