体外抗原诱导T细胞对NK细胞功能的抑制作用及其影响因素  

Mechanism of NK cell activity inhibition induced by allo-antigen loaded T cell

作　　者：袁军[1,2] 王庆红[1] 王小娟[1] 解志杰[1] 郑峻松[1] 王锡华[1] 罗高兴[1] 吴军[1] 

机构地区：[1]第三军医大学创伤,烧伤,复合伤国家重点实验室,重庆西南医院烧伤研究所,重庆市疾病蛋白质组学重点实验室,重庆市器官移植基础研究所,重庆400038 [2]贵州省人民医院检验科,贵阳550002

出　　处：《免疫学杂志》2007年第6期614-618,共5页Immunological Journal

基　　金：国家自然科学基金面上项目(30200261);贵州省优秀科技教育人才省长资金项目(黔省专合字:2005144);贵州省科技计划课题(黔科合NY字20063055)资助项目

摘　　要：目的研究①体外抗原诱导后,T细胞对NK细胞功能的抑制及其机制。②APC及不同T细胞亚群对这一过程的影响。方法①分离小鼠APC及T细胞,按1∶3混合后分组进行诱导,48h加入NK细胞通过51Cr标准4h释放实验观察NK细胞功能状况;激光共聚焦显微镜观察T细胞对NK细胞功能的抑制作用;RT-PCR法检测抗原诱导后小鼠T细胞bc1、bc2的表达。②标准51Cr释放试验检测NK细胞功能以观察CD4+CD25+T细胞,抗原诱导的CD4+及CD4-T细胞对NK的抑制以及APC对体系中T-NK细胞间相互作用的影响。结果①51Cr释放率分别为:Anti-CD80诱导组21%,抗原激活组24.4%,细胞对照组34%,无T细胞对照组32%,前3组上清液与NK细胞作用后靶细胞51Cr释放率分别为34%、31.6%、33.1%。1、2两组51Cr释放率显著低于其余各组(P<0.01),两组间无显著性差异。无T细胞对照组及各组上清液中51Cr释放率无显著性差异。共聚焦显微镜下可观察到T细胞与NK细胞的直接接触。经抗原诱导48h的细胞培养物可检出bc1、bc2的表达。②祛除或未祛除APC两组51Cr的释放率均显著低于各对照组,且两组间无显著性差异(P>0.05)。CD4+CD25+T细胞组与CD4+T细胞组,51Cr释放显著低于其他各组(P<0.01),且前者显著低于后者(P<0.05);CD4-T组与两对照组间无显著性差异。结论①抗原诱导T细胞对NK细胞的抑制作用可通过直接接触的方式,与共刺激因子CD80无关。T细胞上bc1、bc2表达是T细胞抑制NK细胞的可能分子机制之一;②抗原诱导的APC单独或通过T细胞均不能抑制NK细胞功能,提示T细胞对NK细胞的抑制是APC非依赖性的。抗原诱导后CD4+T细胞群体对NK细胞功能有显著抑制,而CD4-群体则无此特性。CD4+CD25+T细胞在无抗原参与情况下对NK细胞有显著性抑制作用。Objective To investigate the possible mechanism of NK cell activity inhibition induced by antigen-loaded T cell and the influence of APC and different T cell subtypes on NK activity in vitro. Methods The T ceil and APC were isolated and mixed at the ratio of 3 ： 1, and then divided into four different groups. Groups 1 and 2 were stimulated by ailo-antigen, and at the same time anti-CD80 antibody were added in the group 1. Groups 3 and 4 were control groups. NK ceil was added in each group at 48 h and then standard 4 h ^51Cr release experiment was applied to detect the activity of NK ceil. Meanwhile, RT-PCR was used to detect the bcl and bc-2 mRNA ofT ceil. After T ceil had been stimulated by antigen, APC was deleted with L-leucine-methylester （terminal concentration： 10 mmol/L）. The effects of APC, CD4^＋ CD25^＋ , CD4^＋ CD25^- , and CD4^- T ceil on function of NK cell were assayed, respectively. Results The release rate of ^51Cr was remarkable difference between the antigen encounter system and the antigen absence system （ P 〈 0.01 ） （the rates were 21%, 24.4%, 34%, and 32% in groups 1, 2, 3, and 4, respectively）, but there was no significant difference among the antigen absence systems and the supemate of each system （the release rates groups 1, 2, and 3 were 34%, 31.6%, and 33.1%, respectively）. The antigen-stimulated T ceil with or without APC presence did not have remarkable different effects on NK cell function （P 〈 0.05）. Both CD4^＋ CD25^＋ T ceil and CD4^＋ CD25^- T ceil showed the inhibitory effects on NK ceil when compared with the control groups （ P 〈 0.01 ）. Moreover, the value of ^51 Cr release in CD4^＋ CD25^＋ T ceil group was significantly lower than that in CD4^＋ CD25^- T ceil group （ P 〈 0.05 ）. Conclusion These results suggest that the ailo-antigen-activated T ceil might induce the inhibition of NK with a direct way and seemed that CD28/B7 signal was not necessary in the inhibition mechanism. The expressions of bc-1 and bc-2 of murine T cell i

关 键 词：T细胞 NK细胞 抗原 共刺激阻断 非经典MHC—I类抗原 

分 类 号：R392[医药卫生—免疫学]