Polarization and apoptosis of T cell subsets in idiopathic thrombocytopenic purpura

It is well-known that idiopathic thrombocytopenic purpura （ITP） is an acquired organ-specific autoimmune hemorrhagic disease and dysfunctional cellular immunity is considered important in the pathophysiology of ITP. However, polarization patterns and apoptosis profiles of T lymphocytes remain unclear. In this study, we investigated the polarization of T cell subsets, the expressions of apoptotic proteins Fas/FasL on the subsets and the level of anti-apoptotic gene bcl-2 and bax mRNA. It was demonstrated that the ratios of Thl/Th2 and Tcl/Tc2 in ITP children were increased obviously and that the average percentages were increased clearly for Thl and Th2, but not for Tcl and Tc2. In ITP children, the enhancing expressions were detected for FasL on Thl and Tcl and for Fas on Th2 and Tc2. With increasing level of bcl-2 mRNA and decreasing expression of bax mRNA in ITP children, the ratio of bcl-2/bax mRNA was improved obviously, which was positive correlated with the ratio of Thl/Th2. Taken together, our findings indicate that ITP is a Thl predominant disease. This polarization pattern of T cell subsets might be related to the high ratio of bcl-2/bax mRNA and the abnormal expressions of Fas and FasL on T cell subsets.     

特发性血小板减少性紫癜患儿外周血T细胞PKC活性变化的研究

为了探讨ITP患儿外周血T细胞蛋白激酶C(PKC)的活性变化及其与T细胞活化和血小板减少程度之间的关系,无菌采集35例ITP患儿及30例正常儿童外周血,采用T细胞分离富集柱法分离纯化T细胞,分别用非同位素标记法检测T细胞PKC的活性变化,用流式细胞仪检测T细胞活化标志FasL蛋白的表达,血细胞计数仪计数血小板的减少程度。结果ITP患儿T细胞PKC的总活性与正常儿童相比明显增强[(0.97±0.21)nmol/ml·min和(0.55±0.13)nmol/ml·min,x±s,P<0.05],T细胞活化标志FasL蛋白表达与正常儿童比较显著升高(CD4+TFasL:32.7%±3.4%和14.7%±4.2%;CD8+TFasL:17.3%±9.7%和11.6%±8.5%,x±s,P<0.05),并且T细胞PKC的活性变化与CD4+TFasL、CD8+TFasL的表达均为显著正相关(r1=0.68,r2=0.53,P<0.05),与血小板计数成显著负相关(r=-0.75,P<0.05)。上述研究结果表明ITP患儿PKC活性增强可能引起T细胞的活化,活性T细胞增多可导致患儿血小板大量损伤,提示PKC信号转导在ITP的免疫病理机制中发挥重要作用。     

急性特发性血小板减少性紫癜免疫功能的观察

目的：探讨急性特发性血小板减少性紫（ITP）患儿细胞因子：血清可溶性白介素－2受体（sIL-2R)、白介素－6（IL－6）,免疫球蛋白轻链,心磷脂抗体（ACA）及淋巴细胞亚群的变化。方法：应用化学发光法,速率散射比浊法,ELISA法及AKP－ABC。结果：急性ITP患儿治疗前sIL-2R、IL－6升高,轻链κλ降低与正常对照P＜0．01,3个月后恢复至对照组近似水平（P均＞0．05）。ACA阳性率占70．37％。CD^ 4细胞减少,CD^ 8细胞增多,CD^ 4/CD^ 8比值下降（P均＜0．01）。结论：为临床提供判断疗效及估计预后较血小板（BPC）计数更可靠的依据,也为免疫调节剂治疗提供理论依据。     

Tat acetylation regulates its actions on microtubule dynamics and apoptosis in T lymphocytes

The transactivator protein Tat of human immunodeficiency virus type 1 (HIV‐1) is known to suppress microtubule dynamics and thereby trigger apoptosis in T lymphocytes. These actions of Tat constitute one of the major mechanisms for the massive destruction of T lymphocytes associated with the acquired immunodeficiency syndrome. Herein, we show that Tat acetylation at lysine‐28 (K28) enhances its interaction with microtubules and increases its activity to promote microtubule assembly, by lowering the critical concentration of tubulin for polymerization into microtubules. In addition, K28 acetylation enhances the ability of Tat to stabilize microtubules, leading to increased apoptosis in T lymphocytes. Our data further reveal that Tat acetylation at K28 stimulates its activity to induce the translocation of Bim, a pro‐apoptotic protein of the Bcl‐2 family, from microtubules to mitochondria. These findings provide the first evidence that Tat acetylation regulates its actions on microtubule dynamics and apoptosis, in addition to the regulation of its transactivation activity. Copyright © 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

特发性血小板减少性紫癜患者T细胞及B细胞亚群变化的研究

目的 探讨特发性血小板减少性紫癜(idiopathic thrombocytopenic purpura,ITP)患者T、B淋巴细胞亚群的变化.方法 从大理州人民医院收集ITP患者和健康者的外周血,用Sysmex血液分析仪及流式细胞术分析T细胞及B细胞亚群.结果 与健康人群比较,ITP患者CD3+T细胞百分率无明显变化,CD4+T细胞百分率降低(42.39％±12.12％,P＜0.05),CD8+T细胞百分率升高(46.93％±11.99％,P＜0.05);CD19+B细胞百分率升高(14.11％±10.28％,P＜0.05),T2B细胞百分率(34.51％±9,70％,P＜0.05)、成熟B细胞百分率(30.91％±7.12％,P＜0.05)及记忆性B细胞百分率(23.31％±8.23％,P＜0.05)增多,差异均有统计学意义.ITP患者T1 B细胞、Kappa+B细胞、Lambda+B细胞百分率与健康人差异无统计学意义.结论 ITP患者外周血T细胞亚群和B细胞亚群分布发生了变化,这种变化在ITP发病中的作用尚需进一步研究.     

特发性血小板减少性紫癜淋巴细胞凋亡及凋亡蛋白表达的研究

目的 :探讨淋巴细胞凋亡及凋亡蛋白表达的变化与特发性血小板减少性紫癜 (ITP)的关系。方法 :采用流式细胞仪检测 2 5例ITP患儿治疗前后外周血淋巴细胞凋亡率和Fas、FasL蛋白表达 ;采用酶联免疫夹心法 (ELISA)测定ITP患儿血清sFas、sFasL的水平。结果 :治疗后血小板恢复正常的患儿淋巴细胞凋亡率 (3 35± 1 4 3)、Fas(32 17± 6 5 4 )和FasL(41 14±6 76 )蛋白表达增加 ,与正常对照组 (0 85± 0 15、2 2 0 4± 4 5 4、2 0 83± 3 75 )和治疗前 (0 92± 0 17、2 3 0 3± 5 95、18 88± 4 5 7)相比差异有显著性意义 (P <0 0 0 1) ;治疗前ITP患者血清sFas含量为 15 5 4± 5 2 6 ,sFasL含量为 0 6 8± 0 2 3,均显著高于正常对照 (5 92± 1 78、0 33± 0 11,P <0 0 0 1)和治疗后组 (6 3± 1 92、0 36± 0 12 ,P <0 0 0 1)。结论 :ITP患者治疗后淋巴细胞凋亡增加可能与其治疗转归有关 ,sFas、sFasL的异常可能参与了ITP的免疫病理过程。     

Caspase在T细胞活化与增殖中的作用

半胱氨酸天冬氨酸特异性蛋白酶( caspases)是一类同源蛋白酶,主要参与细胞的凋亡过程.近年来的研究表明,该家族部分成员在T细胞活化与增殖中亦发挥重要作用,主要体现在以下3个方面:T细胞活化过程中检测到多种caspases活性;caspase-8失活后导致了人与鼠T细胞免疫的缺陷;体外实验中,caspase抑制剂能够阻断抗CD3单抗及超抗原引起的T细胞的活化与增殖.目前,部分体内实验已经证实了caspase抑制剂抗免疫反应及抗炎症反应的有效性,这为免疫性及炎症性疾病提供了新的治疗思路,为研制新型抗免疫、抗炎药物提供了依据.     

银杏内酯B对小鼠T淋巴细胞体外活化、增殖与凋亡的影响

目的银杏内酯B(GB)是已知的天然而强效的血小板激活因子(PAF)受体(PAFR)拮抗剂,本文研究GB对小鼠T淋巴细胞活化、增殖及凋亡3大体外行为的影响,初步探讨其潜在的免疫调节作用与机制,从而为临床应用提供可靠的实验依据。方法分离小鼠淋巴细胞,培养前以不同浓度的GB预孵;以刀豆蛋白A(Con A)诱导细胞的活化与增殖,以荧光抗体双色标记(anti-CD3 mAb-PE/anti-CD69 mAb-FITC、anti-CD3 mAb-PE/anti-CD25 mAb-FITC)结合流式细胞术分别检测T淋巴细胞早、中期活化标志--表面抗原CD69与CD25的表达,以活体荧光染料CFDA-SE标记结合流式细胞术检测细胞增殖并用MTT法佐证;以地塞米松(Dex)诱导细胞的凋亡,以荧光染料双色标记[DiOC6(3)/PI]结合流式细胞术区别凋亡、死亡与活细胞群。结果 Con A刺激后6 h和24 h,T细胞早期活化标志CD69和中期活化标志CD25分别大量表达,Con A刺激后48 h活化的T细胞增殖至第4代,而经终浓度为5、10、20μmol/L GB在Con A刺激前对细胞进行4 h预孵处理可以显著下调T细胞表面抗原CD69、CD25的表达并能有效抑制细胞增殖。Dex诱导后12 h细胞凋亡和死亡群显著增大,而经同样的GB预孵处理可以在一定程度上抑制细胞的凋亡进程,对细胞凋亡显示出一定的保护作用。结论 GB能有效抑制小鼠T淋巴细胞的活化与增殖,并且对细胞凋亡起到一定的保护作用,凭借GB对T细胞此3大行为出色的调节作用,理应将其作为天然的免疫抑制剂候选者进行更深入的研究。     

T淋巴细胞凋亡及其调控机制的研究进展

T淋巴细胞凋亡是免疫系统维持稳定的一种重要机制,在多种疾病中起着重要作用.fas/FasL、Trail/trail受体等死亡受体信号传导可介导T淋巴细胞凋亡,线粒体在诱导细胞凋亡中也起着重要作用;而bcl-2家族、v-FLIP等抗细胞凋亡蛋白和转录因子Nur77等对T淋巴细胞凋亡起调控作用.     

Functional properties of lymphocytes in idiopathic thrombocytopenic purpura

Idiopathic or immune thrombocytopenic purpura (ITP) is characterized by antibody-mediated destruction of platelets. The etiology is unknown. We postulated that increased autoantibody production in ITP might be attributable to either increased or prolonged expression of CD40 ligand (CD40L, CD154) in T or B lymphocytes, as has been previously observed in systemic lupus erythematosus (SLE). In addition, we hypothesized that ITP is characterized by increased levels of interleukin 4 (IL-4), a prototypic Th2 cytokine which, along with CD40 ligation, is required for B cell differentiation and production of several IgG subclasses. Cell surface CD154 expression was measured in freshly-isolated and in vitro-activated peripheral blood lymphocytes of sixteen ITP patients and eight healthy volunteers. Plasma levels of IL-4 and the prototypic Th1 cytokine interferon-gamma (IFNγ) were determined. We observed that CD154 expression in unstimulated and in vitro-activated lymphocytes did not differ between ITP patients and healthy controls. Plasma levels of the Th2 cytokine IL-4 were significantly higher in the ITP patients. These studies indicate that overexpression of CD154 in lymphocytes is unlikely to be a primary pathophysiological defect in most patients with ITP. The data support that in addition to cell membrane antigens such as CD154, soluble cytokines such as IL-4 should be considered as potential targets for therapy in this disease.     

组胺对T细胞IL-2产生及增殖活性影响的实验研究

目的:了解组胺对 CD4 和 CD8 T细胞IL-2产生和细胞增殖活性的影响。方法:密度梯度离心及吸附法分离PBMC和PBLC,采用抗CD4 和CD8 抗体分别制备CD8 和CD4 T细胞进行培养,然后采用ELISA法和MTT比色法测上清液IL-2含量及增殖活性。结果:①组胺 CD4 （CD8 ）培养上清液中IL-2水平及MTT增殖指数与T细胞自然培养孔比较明显降低（P<0.05）。②组胺 CD4 （CD8 ） 西咪替丁培养孔上清液中IL-2水平及 MTT增殖指数明显高于未加西咪替丁孔（P<0.05）。③CD4 T细胞自然培养孔上清液中IL-2水平显著高于CD8 T细胞自然培养孔。结论:组胺可抑制T细胞IL-2产生及增殖。西咪替丁可阻断组胺对T细胞的抑制作用。CD8 T细胞也可产生IL-2,但其功能较 CD4 T细胞为低。     

Effect of low-dose ultraviolet-B radiation on the function of human T lymphocytes in vitro.

Purified peripheral blood human T lymphocytes, derived from normal individuals, were assayed for their susceptibility to low doses of ultraviolet B (UVB) in vitro. Exposure of T cells to graded single doses (range 0-8 mJ/cm2) of UVB resulted in a dose-dependent reduction of viability. This phototoxic effect was not immediately apparent, however, but became manifest 48-72 h subsequent to irradiation. A dose as little as 0.5-1 mJ/cm2 was sufficient to cause 50% mortality. Irradiated T cells showed a reduced ability to proliferate, irrespective of the stimulus used, and a reduced ability to produce cytokines IL-2, IL-4, IL-5, interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha). This decreased ability was UVB-dose related and, remarkably, was exactly correlated to phototoxicity. UVB had no effect on CD4 and CD8 expression or their ratio, whereas the expression of IL-2R (CD25) was only slightly reduced. Our data suggest that UVB radiation neither selectively affects Th1 or Th2 nor CD4 or CD8 T cell subsets. The high susceptibility of T cells to UVB might explain, at least in part, the beneficial effect of phototherapy during treatment of certain immunodermatological diseases.     

原核表达、稀释复性的可溶性HLA-G1抑制混合淋巴细胞培养中T细胞增殖

目的：探讨原核表达体外稀释复性的可溶性人类白细胞抗原G1（soluble　HLA-G1，sHLA-G1）对体外混合淋巴细胞反应中T细胞增殖的影响。方法利用原核表达的sHIA-G1的重链、轻链及人工合成的九肽，折叠形成正确构象的sHLA-G1．肽复合物；在混合淋巴细胞培养（MLC）体系中加入折叠所得的sHLA-G1-肽复合物及相同浓度的对照物，流式细胞仪检测T细胞的增殖情况。结果sHLA-G1．肽复合物加入到混合淋巴细胞培养中能够抑制T细胞的增殖，3个个体的抑制率分别为28．5％、32．5％及22．1％（Dunnett t检验，P〈0．05）；这种抑制作用可以被HLA-G特异性McAb（G11E5）所逆转。结论通过原核表达，体外稀释复性的方法可以大量制备正确构象的sHLA-G1-肽复合物，该复合物分子能够抑制混合淋巴细胞培养中T细胞的增殖。     

米诺环素对小鼠T淋巴细胞体外活化和增殖的影响

研究米诺环素(MNC)对刀豆蛋白A(ConA)刺激的小鼠T细胞体外活化和增殖的影响,并对其免疫调节作用进行初步探讨。以ConA刺激小鼠淋巴结来源的淋巴细胞,以不同终浓度的MNC与T细胞共培养,荧光抗体染色结合流式细胞术,检测T细胞早期活化抗原CD69的表达;用羧基荧光素双醋酸盐琥珀酰(CFDA-SE)染色结合流式细胞术,并用ModFit软件分析T细胞增殖相关指数。结果:终浓度为10、25和50μmol/L的MNC显著抑制ConA诱导的T细胞CD69的表达,由ConA组的71.20%±1.08%,分别降低为64.43%±1.39%、53.34%±1.26%和33.65%±1.91%;CFDA-SE染色结果显示,培养48 h和72 h的ConA组T细胞的增殖指数(PI)分别为1.57±0.03和2.06±0.02,各浓度的MNC对ConA刺激的T细胞增殖具有明显的抑制作用,以50μmol/L的MNC抑制作用最明显,48 h和72 h的PI分别为1.01±0.02和1.03±0.01,与相应时间的对照组比较,均有统计学意义(P<0.01)。MNC能有效地抑制小鼠T细胞的体外活化和增殖。具有独立于其抗菌活性的抗炎作用。     

c-Jun氨基末端激酶在小鼠T细胞增殖中的作用

目的研究c-Jun氨基末端激酶(c-Jun N-terminal kinase,JNK)在小鼠T细胞增殖中的作用。方法以活体染料羧基荧光素乙酰乙酸琥珀酰亚胺酯(CFSE)染色,建立了在多克隆刺激剂刀豆蛋白A(Con A)刺激下评价小鼠T细胞增殖的模型,通过流式细胞术分析JNK的一种新的特异性抑制剂SP600125在不同剂量、不同时间对T细胞增殖的影响,并应用CellQuest软件分析增殖细胞各代所占比例和增殖指数(PI)及抑制指数(HI)。采用碘化丙锭染色分析不同剂量SP600125对Con A或佛波醇酯(PDB)加离子霉素(Ion)刺激的小鼠T细胞周期变化的作用。结果随着SP600125浓度从1.0μmol/L逐渐增至16.0μmol/L,Con A对T细胞的促增殖作用逐渐减弱,以8.0～16.0μmol/L的抑制作用最为明显,呈剂最依赖关系(r=0.98,P<0.01);选择最佳剂量8.0μmol/L,SP600125对T细胞增殖的抑制作用随时间从24h递增至96b而逐渐增强;进一步发现SP600125能使PDB加Ion刺激的小鼠T细胞停滞于G_0/G_1期,阻止其进入S期和G_2/M期,且阻止作用随上述浓度的增加而增强,呈明显剂量依赖关系(S期:r=-0.98,P<0.01;G_2/M期:r=-0.88,P<0.05);SP600125也呈剂量依赖性地使Con A诱导的T细胞停滞于G_0/G_1期,阻止其进入S期(r=-0.90,P<0.05)。结论JNK信号通路的活化在小鼠T细胞增殖中可能起着重要作用。     

Anti-CD3-induced changes in protein kinase C isozymes expression in human CD4+ and CD8+ T lymphocytes

In order to determine whether there is a differential expression and activation of PKC isozymes between CD4+ and CD8+ T cells, peripheral blood mononuclear cells were stimulated with anti-CD3 monoclonal antibody (moAb) for various time intervals and the expression of calcium-dependent PKC isozymes (, , ) and calcium-independent PKC isozymes (, , ) was analyzed with dual color flow cytometry, using anti-PKC isozyme antibodies and anti-CD4 or anti-CD8 antibodies. The basal fluorescence intensity of all PKC isozymes was comparable between CD4+ T cells and CD8+ T cells. Following activation with anti-CD3 moAb a marked increase in the fluorescence intensity of all PKC isozymes in both CD4+ and CD8+ T cells, albeit to a different extent and with different kinetics was observed. Among all PKC isozymes studied, the least striking changes were observed in PKC isozyme and the most striking changes were observed in PKC- isozyme. Laser-based confocal microscopic studies confirmed that the increase in fluorescence intensity of PKC isozymes following anti-CD3 moAb stimulation, as measured by flow cytometry was accompanied by the translocation of PKC isozymes from cytosol to the plasma membrane. This study demonstrates a differential effect of anti-CD3 moAb on the expression of PKC isozymes between CD4+ and CD8+ T cells and suggests that flow cytometry can be used to study the translocation of PKC isozymes from cytosol to the plasma membrane.     

间充质干细胞体外对ITP患者T淋巴细胞分泌功能的影响

目的： 体外观察间充质干细胞（MSCs）对特发性血小板减少性紫癜（ITP）患者T淋巴细胞分泌细胞因子功能的影响。方法: 采用Ficoll分离和体外贴壁、传代培养,扩增出骨髓MSCs;通过Ficoll分离法和尼龙棉柱法获取ITP患者外周血T淋巴细胞。以经丝裂霉素（MMC）处理后不同数量（2×103、1×104、5×104 cells/well）的MSCs作为基底层细胞,接种体外分离纯化的异体ITP患者T淋巴细胞,分别于2 d、4 d、6 d后各自收集培养上清,用酶联免疫吸附试验(ELISA)法动态测定T淋巴细胞分泌白细胞介素2(IL-2)、干扰素-γ(IFN-γ)、白细胞介素4(IL-4)、白细胞介素10(IL-10)水平的变化。结果: ITP患者T淋巴细胞分泌细胞因子IL-2、IFN-γ较正常人高(P<0.05),IL-4、IL-10较正常人低(P<0.05)。MSCs可显著抑制ITP患者或正常对照组T淋巴细胞分泌IL-2、IFN-γ(P<0.05),且随MSCs数量的增加,抑制增强(P<0.05),共培养4 d、6 d时作用明显强于2 d时(P<0.05);MSCs可促进ITP患者T淋巴细胞分泌IL-4、IL-10 (P<0.05),且随MSCs量的增加,促进作用增强(P<0.05),对IL-10的作用随时间延长而增强(P<0.05),但对IL-4的作用在培养第2 d、4 d、6 d时无显著差异(P>0.05);在正常对照组,当MSCs数量>1×104可以促进T淋巴细胞分泌IL-4 与IL-10 (P<0.05),且随MSCs数量的增加,作用增强(P<0.05),共培养4 d、6 d时作用明显强于2 d时(P<0.05)。结论: MSCs能够在体外调节ITP患者辅助性T细胞1 (Thl)和辅助性T细胞2 (Th2)反应平衡,可使ITP患者Th1极化状态部分改善。     

异黄酮Genistein对T细胞体外活化CD69表达的影响

目的 :研究异黄酮Genistein对T淋巴细胞活化的影响 ,探讨将其发展为免疫干预药物的可能性。方法 :应用荧光标记的单克隆抗体和流式细胞技术 ,在全血培养体系中于 2h和 6h时间点检测分别经 10 ,5 0或 10 0 μmol L浓度Genistein预培养的 ,PHA或PDB诱导活化的T细胞的CD6 9表达百分率。结果 :培养 2h后 ,Genistein对PHA活化组的抑制作用要强于PDB活化组 ,P <0 0 5 ;培养 6h后 ,Genistein对PHA活化组的抑制作用同样强于PDB活化组 ,P <0 0 5 ,但较之 2h时间点均有所降低 ;无论PHA活化组或PDB活化组 ,Genistein对T细胞CD6 9表达率的抑制效应均随作用浓度的升高而增强。结论 :Genistein对PHA和PDB诱导活化的T细胞的CD6 9表达率均有明显的抑制作用 ,这种抑制作用存在浓度依赖关系。Genistein有潜力发展成一种免疫干预药物。     

电离辐射诱发的Jurkat T淋巴细胞凋亡及其机制

用原位末端标记法，麦格－姬联（ＭＧＧ）染色法和免疫组化技术，观察了经５，１０，２０和３０Ｇｙ不同剂量的γ射线照射后４ｈ－３６ｈ，人Ｊｕｒｋａｔ Ｔ淋巴细胞白血病的凋亡及Ｂａｘ和Ｂｃｌ－２蛋白的表达。结果表明，不同剂量γ射线照射后，Ｔ淋巴细胞数的减少和凋亡率均显示出较好的量效和时效关系，证实细胞凋亡是照射后Ｔ淋巴细胞数减少的主要原因之一；