抗原特异性初始CD4+T细胞的体内分化及特性

为了探讨抗原特异性CD4+T细胞在体内的分裂、表型、Th1细胞因子的产生和组织器官的分布。将CFSE标记的抗原特异性初始CD4+T细胞静脉被动输给小鼠后,进行免疫,3d后处死小鼠取其脾脏、淋巴结和肺组织,分离单个核细胞,利用流式细胞计数仪在单个细胞水平上,观察细胞的分裂、表型、Th1细胞因子的产生和组织分布。结果显示在没有抗原刺激的情况下,未见初始CD4+T细胞分裂,其主要分布于淋巴结和脾脏。当受到抗原刺激后,CD4+T细胞分裂1～5次,主要分布于脾脏和肺组织,CD25的表达增加,CD62L的表达随着细胞分裂次数的增加而减少。IL-12促进CD25的表达和细胞的分裂。促进Th1细胞的分化和IFN-γ的表达。研究的结果提示,在体内,当CD4+T细胞活化后,主要分布于脾和非淋巴组织发挥其免疫效应。

Differentiation and characteristics of the antigen-specific naive CD4+ T cells in vivo

The division, phenotypes, production of the Th1 type cytokines and tissue distribution of the antigen-specific nave CD4+ T cells were to be investigated in the present study, in which the antigen-specific CD4+T cells were isolated from OVA-TCR transgenic mouse(TCR-Tg), labeled with CFSE and adoptively transferred into normal BALB/c mice. After immunization with OVA, the mononuclear cells were prepared from spleens, lymph nodes and lungs, and the division, phenotypes, production of the Th1-type cytokines and tissue distribution were determined by FACS. It was demonstrated that the antigen-specific nave CD4+ T cells were primarily located in lymph nodes and spleens without any antigenic stimulation, whereas, after in vivo stimulation with antigen, the cells divided 1～5 times, and were located mainly in spleens and lungs. With the increasing in times of cell divisions the expressions of CD25 and CD62L molecules were enhanced or reduced respectively. IL-12 could enhance cell divisions, expression of CD25, differentiation of the Th1 cells and the expression of IFN-γ. It is evident that the antigen specific nave and effector CD4+ T cells express different cell surface molecules and produce different cytokines.