CD4+Foxp3+调节性T细胞表达升高提示免疫应答而非移植耐受

目的 探讨诱导CD4+Foxp3+调节性T细胞(regulatory T cells,Tregs)表达的机制及其在移植耐受中可能的作用.方法 构建新生移植耐受小鼠动物模型,分析移植耐受与同种异体反应性T细胞、Tregs表达及嵌合体的关系;运用过继转移实验、EGFP转基因小鼠,研究移植排斥过程中Tregs表达及抗原特异性.结果 新生耐受小鼠形成嵌合体,同种异体反应性T细胞被克隆清除,但Tregs表达与初始小鼠相同;同种异体反应性T细胞识别抗原诱导免疫反应,Tregs在移植排斥反应中表达升高,且不仅同种异体反应性Tregs表达升高,非同种异体反应性Tregs表达也升高.结论 Tregs在移植排斥中非特异性诱导产生,可能为一种负反馈免疫调控机制.

Increased CD4 +Foxp3 + T cells reflect immune response but not transplant tolerance

Objective To investigate the mechanism underlying the development of CD4 + Foxp3 + reg-ulatory T cells(Tregs)in transplantation and their potential role in immune system. Methods Transplant toler-ant mice were established by neonatal infusion with donor cells. Chimerism,alloreactive T cells,and Tregs of the mice were examined. Adoptive transfer experiments were used to analyze the development of Tregs in alloimmune response. Results The frequency of Tregs was the same in naive as in neonatal tolerant mice,while alloreactive T cells were selectively depleted in the latter. When lymphocytes from naive mice were adoptively transferred in-to syngenic tolerant mice,transferred alloreactive T cells destroyed chimerism and sustained skin grafts in recipi-ents and induced an increase of Tregs in both transferred alloreactive T cells and host derived non - alloreactive T cells. Conclusion Tregs,which were induced in immune response in an antigen - independent manner,may regulate immune response as a negative feedback.