多房棘球蚴感染宿主CD4^+T淋巴细胞缺失机制的探讨  

Study on CD4^+ Cells Deletion Mechanism in Experimental Alveolar Echinococcosis

作　　者：李富荣 石佑恩[2] 史大中[3] DA Vuitton PS Craig 

机构地区：[1]深圳市人民医院暨南大学医学院第二附属医院临床医学研究中心,深圳518020 [2]华中科技大学同济医学院寄生虫学教研室,武汉430030 [3]兰州医学院寄生虫学教研室,兰州730000 [4]法国贝藏松大学中心医院 [5]英国苏尔沃德大学生命科学院

出　　处：《中国寄生虫学与寄生虫病杂志》2003年第4期197-202,共6页Chinese Journal of Parasitology and Parasitic Diseases

基　　金：欧共体基金(STD-2)

摘　　要：目的 探讨多房棘球蚴感染宿主CD4^+T淋巴细胞缺失的机制,多房棘球蚴感染与宿主T淋巴细胞亚群凋亡相互关系。方法 利用尼龙柱和补体法从多房棘球蚴感染12wk,25wk和正常对照组BALB/c 小鼠脾脏分离出纯CD4^+、CDS8^+T细胞,在体外分别经多房棘球蚴抗原(EmAg)、抗CD3抗原(anti-CD3)、白细胞介素-2(IL-2)、肿瘤坏死因子α(TNFα)及商陆丝裂原(PWM)刺激培养16h,用DNA凝胶电泳分析;透射电镜观察形态学变化;原位末端标记法(Tunel)和碘化丙锭(PI)双染后,流式细胞仪(FCM)分析凋亡细胞数和凋亡发生的细胞周期。结果 感染25wk小鼠,CD4^+T细胞DNA电泳图均出现典型“梯形”条带,透射电镜见染色质浓染、胞质出泡、凋亡小体形成;CD8^+T细胞DNA电泳国无梯形带,透射电镜见染色质浓染,电子密度增强。FCM分析,感染12wk小鼠,CD4^+、CD8^+T细胞凋亡数与正常对照组差异无显著性意义(P>0.05);感染25wk小鼠,CD4^+T细胞凋亡数较正常对照组显著增高(P<0.01),也显著高于同组CD8^+T细胞(P<0.01)。凋亡主要发生在细胞周期S期。结论 多房棘球蚴寄生宿主后期,可诱导宿主成熟CD4^+T细胞发生活化诱导性死亡(AICD),使宿主处于免疫抑制状态。Objective To study the possible mechanism of CD4^+ T cells deletion in mice with alveolar echinococco- sis, particularly on the relationship between Echinococcus multilocularis infection and apoptosis of T lymphocyte subsets. Methods BALB/c mice were infected with E. multilocularis and uninfected mice were used as control group. CD4^+ T cell and CD8^+ T cells were separated 12 weeks and 25 weeks after infection. Purified CD4^+ and CD8^+ T cell subsets were cul- tured in complete medium and stimulated with EmAg, anti-CD3 mAb, rIL-2, mouse rTNFα and PWM respectively. After 16 h of incubation, cells were collected and assessed by electron microscopy. DNA fragmentation was observed by eletrophoresis, stained by TUNEL assays and PI, analyzed by flow cytometry. Results CD4^+ and CD8^+ T cells in 25 weeks experiment group presented chromatin condensation, lost nuclear membrane integrity, and formed exocytoplasmic vacuolization. DNA ladder was observed by agarose gel eletrophoresis, and the appearance of DNA fragments was equiva- lent to approximately 200 bp. None of these appearances were observed in control group in 12 weeks post infection and CD8^+ T cell in mice of 25 weeks post infection group. The apoptosis level of CD4^+ and CD8^+ T cells in 12 weeks post infec- tion group was not significantly different from the control group. While the apoptosis level of CD4^+ and CD8^+ T cells in- creased significantly in 25 weeks post infection group as compared with the control (P<0. 01). Higher apoptosis in CD4^+ T cells was observed than that of CD8^+ T cells. Apoptosis mainly appeared during S phase of cell cycle. Conclusion Apoptosis is a prominent causation of activation-induced CD4^+ T cell death in later period of E. multilocularis infection. In- crease of the death-promoter signals and decrease of the death suppresser signals may have been responsible, in part, for the

关 键 词：多房棘球蚴感染 宿主 CD4^+T淋巴细胞缺失机制 白细胞介素-2 肿瘤坏死因子Α 

分 类 号：R532.32[医药卫生—内科学] R383.33[医药卫生—临床医学]