肝移植自发免疫耐受大鼠CD8^+CD28^- T抑制细胞的生物学特性  

The biological features of CD8^+CD28^- T suppressor cells in spontaneous tolerance of rats liver transplantation

作　　者：肖文斌[1] 刘玉兰[1] 陈国栋[1] 尤鹏[1] 孙君泓[2] 

机构地区：[1]北京大学人民医院消化科 [2]澳大利亚悉尼大学国家肝移植中心

出　　处：《中华微生物学和免疫学杂志》2004年第8期639-643,共5页Chinese Journal of Microbiology and Immunology

基　　金：国家自然科学基金资助项目 (No .3 0 2 40 0 5 1)

摘　　要：目的　研究近交系大鼠原位肝移植自发免疫耐受模型中CD8+ CD2 8- T抑制细胞的生物学特点。方法　建立大鼠原位肝移植模型 ,流式细胞技术检测自发免疫耐受模型中CD8+ CD2 8- T抑制细胞含量变化 ;通过体外混合淋巴细胞反应和体内输注验证CD8+ CD2 8- T细胞的抑制功能 ,并检测其增殖、细胞因子mRNA的表达和诱导靶细胞发生凋亡的情况 ,并与急性排异组相比较。结果　自发免疫耐受模型大鼠脾脏CD8+ CD2 8- T细胞含量 (31.5 %± 2 .6 % )显著高于正常大鼠 (5 .4 %±1.5 % )和急性排异组大鼠 (6 .0 %± 1.3% )。自发免疫耐受组CD8+ CD2 8- T细胞明显抑制体外混合淋巴细胞反应的增殖 ,体内输注显著延长皮肤移植物的存活时间 (MST :10± 0 .8dvs 15± 1.8d ,P <0 .0 5 ) ,但急性排异组大鼠脾脏CD8+ CD2 8- T细胞无抑制功能。外源性IL 2 4 0U ml可逆转CD8+CD2 8- T细胞的抑制功能。CD8+ CD2 8- T细胞不会增加靶细胞凋亡的发生 ,其IFN γmRNA为高表达 ,而急性排异组无表达。PHA 5 0 μg ml和IL 2 4 0U ml、PMA ion 5 0 2 5 0ng ml和IL 2 4 0U ml联合应用可有效刺激CD8+ CD2 8- T细胞增殖。结论　自发耐受组大鼠脾脏CD8+ CD2 8- T细胞是一种T抑制细胞 ,在自发免疫耐受的形成过程中具有重要作用 。ObjectiveTo explore the biological features of spleen CD8 +CD28 - T cells from spontaneous tolerance models of rats with orthotopic liver transplantation. MethodsThe proportion of spleen CD8 +CD28 - T cells from spontaneous tolerance model and acute rejection model was determined by flow cytometry. The suppressor activities of spleen CD8 +CD28 - T cells were tested by mixed lymphocyte reaction in vitro and infusion in vivo. The cytokines mRNA was detected by RT-PCR and apoptosis was estimated by annexin Ⅴ-FITC. ResultsThe percentage of spleen CD8 +CD28 - T cells in spontaneous tolerance models was increased to 31.5%±2.6%,which was higher than that in normal controls(5.4%±1.5%) and that in acute rejection model(6.0%± 1.3%). Spleen CD8 +CD28 - T cells isolated from spontaneous tolerance models inhibited the proliferation of mixed lymphocyte reaction and the inhibition was reversed by exogenous IL-2 40U/ml. They strongly expressed IFN-γ mRNA,and prolonged median survival time (15±1.8 days vs 10±0.8 days,P<0.05) of skin allograft by infusion. No increased apoptosis was induced by CD8 +CD28 - T cells. The same function was not found in spleen CD8 +CD28 - T cells isolated from acute rejection model. The combination of IL-2 and mitogen proliferated CD8 +CD28 - T cells effectively. ConclusionSpleen CD8 +CD28 - T cells isolated from spontaneous tolerance model is a unique kind of suppressor T cells. The mechanism probably involves IFN-γ and anergy of alloreactive T cells.

关 键 词：肝移植 免疫耐受 大鼠 CD8^+ CD28^- T抑制细胞 生物学特性 细胞凋亡 

分 类 号：R392[医药卫生—免疫学]