BTLA信号对T细胞活化的起始和早期阶段的调节作用  

Regulatory role of BTLA signal in the initiation and early phase of T cell activation

作　　者：王月颖[1] 张世杰[1] 邵毅[1] 蒋玉平[1] 顾宗江[1] 

机构地区：[1]苏州大学医学生物技术研究所,苏州215007

出　　处：《中国免疫学杂志》2010年第4期304-308,共5页Chinese Journal of Immunology

摘　　要：目的:观察BTLA分子在T细胞上的表达并探讨其在各个阶段不同时相对T细胞活化的抑制。方法:分离人外周血单个核细胞,经阴性选择磁珠分离纯化获得T淋巴细胞。检测T细胞上BTLA、CTLA-4和PD-1的表达;用CD3抗体刺激T细胞活化,比较BTLA、CTLA-4和PD-1在T细胞活化过程中的动态表达。CD3抗体联合CD28抗体活化T细胞,在不同的活化时间,MTT法检测BTLA单抗8H9对T细胞增殖的影响。GM-CSF和IL-4体外诱导单核细胞分化成未成熟DC,CD40抗体刺激DC成熟,流式检测HVEM在DC上的表达。用DC诱导T细胞活化,加入游离8H9或抗HVEM抗体,阻断HVEM和BTLA结合,MTT法检测T细胞增殖。结果:静止T细胞组成性高表达BTLA,不表达CTLA-4和PD-1分子。T细胞活化后,BTLA分子表达有所降低,然后迅速回升至高水平。CTLA-4、PD-1分子在活化后两天几乎不表达,第三天开始表达并逐渐上升。8H9可以抑制CD3和CD28抗体活化的T细胞增殖。CD3和CD28抗体预先活化T细胞24小时或48小时后,再加入8H9仍然具有抑制效应,但不如在T细胞活化之初加入8H9的抑制效应。单核细胞诱导的不成熟DC上高表达HVEM,当DC成熟后,HVEM表达降低。用游离8H9或HVEM抗体阻断DC表面HVEM与T细胞表面BTLA结合,48小时之内均明显增强了DC诱导的T细胞增殖。结论:BTLA信号可以提高T细胞的活化阈值,在T细胞活化的起始和早期阶段发挥重要的负性调控作用。Objective：To observe the expression of BTLA on T cells during activation and further analyze its inhibitory effects on T cell activation in different phases.Methods：T cells from PBMC were enriched by negative selection using magnetic beads.Expression of BTLA,CTLA-4 and PD-1 on freshly isolated human T cells and kinetics expression of BTLA,CTLA-4 and PD-1 on CD3 mAb stimulated T cells were examined by flow cytometry.T cells were stimulated by anti-CD3 mAb combined with anti-CD28 mAb in the presence of anti-BTLA mAb 8H9,then T cell proliferation was tested by MTT assay in the different culture time.Immature DCs were generated from monocytes cultured in the medium containing GM-CSF and IL-4,and further driven to maturation by anti-CD40 mAb.Expression of HVEM on DCs was measured by flow cytometry.T cells were co-cultured with DCs in the presence of soluble 8H9 or anti-HVEM antibody to block HVEM-BTLA interaction,T cell proliferation was measured by MTT assay.Results：Freshly isolated T cells exhibited high levels of BTLA expression,but not CTLA4 and PD-1.After T cell activation,BTLA expression decreased on first 2 days,with rapidly increasing to high levels.Unlike BTLA,expression of CTLA-4 and PD-1 was gradually increased during T cell activation.8H9 significantly inhibited the proliferation of T cell stimulated by CD3 mAb and CD28 mAb.8H9 could still exhibit inhibitory effect on T cell proliferation after 24 h or 48 h of preactivation by CD3 mAb plus CD28 mAb stimulation.HVEM was highly expressed on immature DCs,and down-regulated on mature DCs.Blockade of BTLA by soluble 8H9 or anti-HVEM antibody enhanced DC-mediated T cell proliferation within 48 h.Conclusion：BTLA signal enhances the threshold of T cell activation and plays importantly negative regulatory role in the initiation and early phase of T cell activation.

关 键 词：BTLA T细胞活化 免疫调节 

分 类 号：R392[医药卫生—免疫学]