慢性乙肝患者树突状细胞对Th1/Th2分化的影响

探讨慢性乙肝患者树突状细胞(dendritic cells,DC)对CD4+Th细胞亚群分化的影响。分离慢性乙肝患者外周血单个核细胞(PBMC),以rhIL-4(50 ng/ml)、rhGM-CSF(10 ng/ml)和rhTNF-α(100 u/ml)诱导培养DC。以流式细胞仪检测DC表面CD1a、CD83、CD80、CD86、HLA-DR分子表达情况。MTT法检测DC刺激同种异体淋巴细胞增殖能力。免疫磁珠分离外周血CD4+T细胞亚群,PMA+Ionomycin刺激后胞内荧光染色,流式细胞仪检测辅助性T细胞(helper T cell,Th)内特征性细胞因子IFN-γ/IL-4以判断Th1/Th2分化。ELISA法检测DC或Th细胞培养上清中IL-6、IL-12、IFN-γ和IL-4的含量。结果:慢性乙肝患者的DC表达CD1a、CD83、CD80、CD86、HLA-DR分子水平明显低于正常人(P<0.01);培养至第7天,慢性乙肝患者DC分泌的IL-12水平低于正常人(P<0.01),而分泌的IL-6水平增高(P<0.05)。与正常人相比,慢性乙肝患者外周血中Th1细胞占CD4+T细胞的百分比较低(P<0.01),其Th细胞培养上清中IFN-γ的量也较低(P<0.01)。患者DC与同种异体的健康人Th细胞共培养,刺激Th1型细胞因子IFN-γ产生的能力低于正常人(P<0.01)。慢性乙肝患者体内DC功能的异常可能导致了外周血Th1细胞分化不足。     

HCV-NS3重组腺病毒转染树突状细胞体内诱导抗原特异性Th1应答的研究

目的:探讨表达丙型肝炎病毒(HCV)非结构蛋白(NS3)基因的重组腺病毒转染树突状细胞体内诱导特异性Th1细胞免疫应答。方法:分离培养小鼠骨髓树突状细胞,制备表达HCV-NS3蛋白的重组腺病毒转染树突状细胞(DC-AdNS3)疫苗,采用流式细胞术和免疫印迹法分析鉴定细胞及抗原蛋白表达。采用腹腔注射途径免疫接种BALB/c小鼠两次,每次间隔10天,3×105细胞/次。末次接种10天后,采用ELISPOT法和ELISA法分别测定脾NS3特异性分泌IFN-γ的T细胞反应以及细胞因子水平。结果:重组腺病毒转染DC可刺激DC成熟,同时可在DC内成功表达NS3蛋白。小鼠两次接种DC-AdNS3产生明显升高的分泌IFN-γ的T细胞反应(P<0·01),脾T细胞悬液内可测得高水平的IL-2和IFN-γ(P<0·01)以及显著降低的IL-10(P<0·05)。结论:DC-AdNS3疫苗可在BALB/c小鼠体内激发产生抗原特异性的Th1细胞免疫应答,为抗HCV感染的疫苗研究提供参考依据。     

膜表达的HLA-G1对同种反应性PBMC分泌Th1/Th2型细胞因子的影响

目的研究人脐静脉内皮细胞系(ECV304)表达的HLA-G1对同种异体外周血单个核细胞(PBMC)Th1/Th2型细胞因子分泌的影响。方法采用脂质体介导的基因转染技术将pcDNA3-HLA-G1转入ECV304,以间接免疫荧光技术在蛋白质水平上检测HLA-G1分子在ECV304上的表达;以表达HLA-G1的ECV304作为刺激细胞,灭活后,与健康人PBMC共同培养,用ELISA检测上清液中Th1/Th2型细胞因子的浓度,观察HLA-G1对同种异体抗原激活的PBMC分泌Th1/Th2型细胞因子的影响。结果与转染pcDNA3空质粒的对照组相比,HLA-G1能使PBMC的IL-10分泌增加(P<0.05),而IL-2,IFN-γI、L-4分泌无明显影响。结论HLA-G1能引起由同种异体抗原激活的PBMC分泌IL-10增加,提示HLA-G1有可能使Th1/Th2型细胞因子向Th2型偏移。     

负载滋养层细胞抗原对小鼠树突状细胞表型及功能的影响

目的 研究负载滋养层细胞抗原对小鼠髓源性树突状细胞(DC)分化成熟过程的影响,获得致耐受性DC.方法 体外使用粒细胞巨细胞集落刺激因子(GM-CSF)诱导小鼠骨髓细胞定向分化、经LPS刺激获得成熟DC;通过外胎盘锥组织块培养法获得滋养层细胞,制备可溶性抗原,加入DC培养体系.流式细胞术检测DC表面共刺激分子及MHC-Ⅱ的表达,ELISA法检测DC分泌IL-10和IL-12的浓度,混合淋巴细胞培养评估 DC刺激同种T细胞增殖、活化的功能.结果 成熟DC表型为CD40high CD80highCD86highMHC-Ⅱhigh,分泌大量的IL-12和极少量的IL-10 ,体外能有效刺激T细胞的增殖;负载滋养层细胞抗原的DC表型为CD40midCD80lo wCD86lowMHC-Ⅱlow,在分泌大量IL-12的同时IL-10也明显升高,不能有效刺激T细胞增殖,并使T细胞分泌细胞因子呈现明显Th2偏倚.结论 负载滋养层细胞抗原后的DC表面共刺激分子及MHC-Ⅱ表达降低,刺激T细胞增殖能力下降;其自分泌和促使T细胞旁分泌的细胞因子呈现Th2偏倚,是一种耐受性DC.     

子痫前期患者外周血树突状细胞对Th1/Th17细胞分化的影响

目的 观察正常妊娠妇女和子痫前期患者外周血单个核细胞(PBMC)来源的树突状细胞(DC)对Th1、Th17细胞分化的影响.方法 实验组为子痫前期疾病患者32例;对照组为正常妊娠妇女20例.分离正常妊娠组和子痫前期组PBMC,经贴壁获得单核细胞,加GM-CSF,IL-4和LPS培养诱导为成熟DC,流式细胞术检测表面分子标志CD14,CD80,CD83,CD86的表达,ELISA检测培养上清液中IL-23的含量.磁珠分选出CD4+T淋巴细胞,与正常妊娠孕妇外周血单核细胞来源的树突状细胞(N-DC)共同培养,同时添加细胞因子IL-2,或与子痫前期患者外周血单核细胞来源的树突状细胞(P-DC)、IL-2共同培养;或与N-DC共同培养,同时添加细胞因子IL-1p、IL-6;或与P-DC共同培养,并添加细胞因子IL-1β、IL-6.以上各组培养到第6天用流式细胞术检测CD4+ IFN-γ+ Th1、CD4+ IL-17+ Th17细胞比例.结果 P-DC中CD83、CD80、CD86的表达高于N-DC,差异有统计学意义(P＜0.05).P-DC与不同的细胞因子共同作用,促使CD4+T细胞分化为Th1、Th17细胞的能力高于N-DC,差异有统计学意义(P＜0.01).结论 子痫前期患者外周血DC表型和功能的改变可能与患者免疫失衡有一定关系.     

CTLA4Ig诱导对氧化修饰低密度脂蛋白免疫耐受的机制研究

目的： 动脉粥样硬化（AS）是一种炎症过程，获得性免疫应答参与AS发生和发展。氧化修饰的低密度脂蛋白（ox-LDL）是目前认为最重要的AS相关自身抗原。本研究拟应用融合蛋白CTLA4Ig，在体外建立对ox-LDL的免疫耐受模型，从而有可能预防免疫应答导致的炎症损伤在AS发病中的作用，为防治AS提供新的策略。方法: 分离人外周血单个核细胞诱导树突状细胞（DC）。分别加入LPS、LDL、 ox-LDL刺激48 h，与同种异体淋巴细胞行混合淋巴细胞反应（MLR）。ox-LDL组的MLR中，分别加入不同浓度的CTLA4Ig。以MTT法检测T细胞的增殖。流式细胞仪检测MLR中T细胞活化和T细胞凋亡。ELISpot检测MLR中T细胞分泌IL-2、IFN-γ和IL-4的情况。结果: ox-LDL组MTT中的刺激指数（SI）明显高于LDL组（P<0.05）；应用CTLA4Ig后，SI较未应用时明显降低（P<0.05，P<0.01）；CTLA4Ig可明显减少T细胞CD25的表达（P<0.05，P<0.01），增加T细胞的凋亡（P<0.05，P<0.01）。CTLA4Ig可减少T细胞分泌IL-2和IFN-γ的ELISpot计数(P<0.01），增加IL-4的ELISpot计数（P<0.05）。结论: CTLA4Ig可在体外诱导对ox-LDL的免疫耐受；CTLA4Ig通过抑制T细胞活化、诱导T细胞凋亡和促进Th1/Th2免疫偏移等机制，诱导免疫耐受。     

IL-10基因修饰的大鼠树突状细胞表型分析及生物学特性的研究

目的研究IL-10基因修饰后的大鼠树突状细胞(DC)的表型及其生物学特性。方法以含IL-10基因的重组腺病毒载体体外转染大鼠骨髓来源的DC,Western blot测定转染后各组DC中IL-10蛋白的表达,流式细胞仪检测各组DC表面抗原CD83、CD86分子的表达情况,混合淋巴细胞反应法测定各组DC刺激同种异体T细胞增殖的能力。结果 IL-10基因修饰组DC可检测到IL-10高表达,表面抗原CD83、CD86低表达,其刺激T淋巴细胞增殖水平较其他各组低。结论 IL-10基因修饰的DC可有效的表达有功能的IL-10,为研究IL-10修饰的DC诱导同种异体移植免疫耐受奠定了基础。     

腺病毒介导MOMP基因转染对树突状细胞免疫功能的影响

目的 探讨腺病毒(Ad)介导E型沙眼衣原体(Ct)主要外膜蛋白(MOMP)基因转染对树突状细胞(DC)的表型及体内免疫功能的影响.方法 用小鼠重组粒细胞一巨噬细胞集落刺激因子(GM-CSF)及白细胞介素4(IL-4)从小鼠骨髓干细胞中诱导培养DC,并用大肠杆菌脂多糖(LPS)促进DC的成熟,流式细胞仪检测DC表型.用不同感染滴度(MOI)的含增强绿色荧光蛋白(EGFP)基因的重组Ad转染DC,荧光显微镜下观察EGFP的表达细胞百分率,选择最佳MOI;用最佳MOI的含MOMP基因的重组腺病毒(Ad-MOMP)转染DC,流式细胞术检测转染前后DC表型变化,并用活细胞计数试剂盒8(CCK-8)检测转染前后DC刺激同种淋巴细胞增殖的能力;ELISA检测转染前后DC分泌细胞因子及DC、T细胞共同培养上清中细胞因子的水平.Ad-MOMP转染DC经尾静脉免疫小鼠,ELISA检测其脾脏淋巴细胞分泌的细胞因子.结果 诱导的DC形态典型,表面高表达CD11c、MHCⅡ类分子,中度表达CD80分子.MOI=1000为重组Ad转染DC最佳滴度,此时90%以上的DC表达荧光,Ad-MOMP转染DC后能检测到MOMP的表达.Ad-MOMP转染对DC表面的特征性表型CD11c无影响,而CD80及MHCⅡ表达上调;转染后的DC分泌大量IL-12,具有较强的刺激同种异体淋巴细胞增殖的能力,并刺激T细胞分泌大量IFN-γ.Ad-MOMP转染DC后尾静脉免疫小鼠,其脾细胞产生高水平的IFN-γ.结论 Ad载体能介导外源MOMP基因在DC中的表达,Ad-MOMP转染DC后MOMP基因的表达能增强DC抗原提呈功能,促进DC活化,转染后的DC与T细胞共孵育能诱导T细胞向TH1细胞分化,体内实验表明Ad-MOMP转染DC能诱导衣原体特异性TH1反应.这为Ad-MOMP转染的DC疫苗用于免疫治疗提供了理论依据和技术基础.     

HIV-1 C亚型密码子优化gp120负载人DC疫苗的构建及体外功能

目的构建HIV-1C亚型gp120负载人树突状细胞(dentriti ccell,DC)疫苗,并对其体外功能进行初步检测。方法利用Amaxa细胞核转染技术将pcDNA3.1-gp120质粒转染至人成熟DC,以Western blot检测gp120的表达。通过流式细胞仪检测DC表面共刺激分子的变化、混合淋巴细胞反应、CD8+T细胞表面活化分子CD25的表达及其分泌IFN-γ的变化。结果通过Western blot检测,gp120在DC中得到了正确表达。经流式细胞仪检测,DC表面分子CD80表达率由刺激前的33.34%上升至43.20%,CD86表达率由刺激前的60.08%上升至90.34%;负载gp120DC刺激淋巴细胞增殖率为86.72%;CD8+T细胞表面分子CD25表达率由刺激前的5.27%上升至74.21%,IFN-γ的表达率达37%。结论负载了HIV-1gp120的人树突状细胞能够显著刺激淋巴细胞的增殖、增强CD8+T细胞表面活化分子CD25表达以及促进CD8+T细胞分泌IFN-γ,为下一步DC治疗性疫苗的体内研究奠定基础。     

负载CTLA4Ig重组腺病毒的未成熟树突状细胞对大鼠Th细胞增殖的影响

目的 探讨负载CTLA4Ig重组腺病毒的未成熟树突状细胞对大鼠Th细胞增殖的影响.方法 将CTLA4Ig重组腺病毒与Wistar大鼠未成熟树突状细胞于37C共孵育6h后,经尾静脉注射该大鼠作实验组,另外分别设立Wistar大鼠未成熟树突状细胞、CTLA4Ig重组腺病毒、生理盐水经尾静脉注射为对照.1周后,用0.3%戊巴比妥麻醉各组大鼠后抽血检测CTLA4Ig.取脾脏,经流式细胞术分选出Th1、Th2细胞及CD4+T细胞,行混合淋巴细胞培养检测Th细胞的增殖.用免疫组织化学法检测Th1、Th2细胞的比例.结果 实验组血清CTLA4Ig水平(0.654±0.13)显著高于CTLA4Ig重组腺病毒组(0.392±0.10,P＜0.01),树突状细胞组及生理盐水组未检出.实验组Th1细胞的增殖指数(742±161)、Th1/Th2(0.16±0.05)均显著低于各对照组(分别与未成熟树突状细胞组、CTLA4Ig重组腺病毒组、生理盐水组相比,P均＜0.01);而Th2细胞的增殖指数(9162 ±598)显著高于各对照组(P均＜0.01).结论 负载CTLA4Ig重组腺病毒的未成熟树突状细胞可显著抑制大鼠Th1细胞增殖,促进Th2细胞增殖,使Th细胞由Th1向Th2显著偏移,诱导有效的免疫耐受.     

Cytotoxic T lymphocyte antigen 4 immunoglobulin modified dendritic cells attenuate allergic airway inflammation and hyperresponsiveness by regulating the development of T helper type 1 (Th1)/Th2 and Th2/regulatory T cell subsets in a murine model of asthma

T helper type 2 (Th2) and regulatory T cells (T(reg) ) have been postulated to have critical roles in the pathogenesis of allergic asthma. Cytotoxic T lymphocyte antigen 4 immunoglobulin (CTLA4Ig) gene-modified dendritic cells (DC-CTLA4Ig) have the potential to reduce Th2 cells and induce T(reg) cells. In the present study, we evaluated the therapeutic effects and potential mechanisms of the adoptive transfer of DC-CTLA4Ig into mice in an experimental model of asthma. BALB/c mice were sensitized with ovalbumin (OVA) and challenged with aerosolized OVA for 7 days. Just prior to the first challenge, DC-CTLA4Ig, DCs or DCs infected with DC-green fluorescent protein (GFP) were injected intravenously into mice. The administration of DC-CTLA4Ig reduced airway hyperresponsiveness, relieved asthmatic airway inflammation and decreased the numbers of esosinophils in the BALF in OVA-sensitized/challenged mice. In addition, DC-CTLA4Ig altered the balance of Th1/Th2 cytokine production in the lungs with increased interferon (IFN)-γ levels and decreased interleukin (IL)-4 levels, decreased the percentage of Th2 and increased both the percentage of Th1 and T(reg) cells in the lungs of OVA-sensitized/challenged mice. This research demonstrates that DC-CTL4Ig reduces airway hyperresponsiveness effectively and prevents airway inflammation in OVA-sensitized/challenged mice, which is due most probably to attenuated secretion of Th2 cytokines and increased secretion of Th1 cytokines in the local airway, and the correction of the pulmonary imbalance between Th1/Th2 cells and Th2/T(reg) cells.     

Human TSLP and TLR3 ligands promote differentiation of Th17 cells with a central memory phenotype under Th2-polarizing conditions

Background Human thymic stromal lymphopoietin (TSLP) is expressed in the human asthmatic lung and activates dendritic cells (DCs) to strongly induce proallergic T‐helper type 2 (Th2) cell responses, suggesting that TSLP plays a critical role in the pathophysiology of human asthma. Th2 cells are predominantly involved in mild asthma, whereas a mixture of Th1 and Th2 cells with neutrophilic inflammation, probably induced by Th17, affects more severe asthmatic disease. Exacerbation of asthmatic inflammation is often triggered by airway‐targeting RNA viral infection; virus‐derived double‐stranded RNA, Toll‐like receptor (TLR)3 ligand, activates bronchial epithelial cells to produce pro‐inflammatory mediators, including TSLP. Objective Because TSLPR‐expressing DCs express TLR3, we examined how the relationship between TSLP and TLR3 ligand stimulation influences DC activation. Methods CD11c⁺DCs purified from adult peripheral blood were cultured in TLR ligands containing media with or without TSLP and then co‐cultured with allogeneic naïve CD4⁺T cells. Results CD11c⁺ DCs responded to a combination of TSLP and TLR3 ligand, poly(I : C), to up‐regulate expression of the functional TSLP receptor and TLR3. Although TSLP alone did not induce IL‐23 production by DCs, poly(I : C) alone primed DCs for the production of IL‐23, and a combination of TSLP and poly(I : C) primed DCs for further production of IL‐23. The addition of poly(I : C) did not inhibit TSLP‐activated DCs to prime naïve CD4⁺ T cells to differentiate into inflammatory Th2 cells. Furthermore, DCs activated by a combination of TSLP and poly(I : C) primed more naïve CD4⁺ T cells to differentiate into Th17‐cytokine–producing cells with a central memory T cell phenotype compared with DCs activated by poly(I : C) alone. Conclusions These results suggest that through DC activation, human TSLP and TLR3 ligands promote differentiation of Th17 cells with the central memory T cell phenotype under Th2‐polarizing conditions.     

核小体Th表位和CTLA4Ig双基因共表达真核表达载体的构建

目的将核小体Th表位与CTLA4Ig融合基因融合，研究CTLA4Ig作为真核表达载体的可行性。方法用touchdown PCR法扩增CTLA4Ig基因，同时引入核小体Th表位（H2B14-28）。将PCR产物连接真核表达载体pcDNA3．1（＋），构建pcDNA3．1（＋）-CTLA4Ig—H2B。将表达质粒转染COS-7细胞，Western blot检测转染细胞裂解上清中融合蛋白的表达。将构建表达CTLA4Ig—H2B的减毒鼠伤寒沙门氏菌SL7207喂饲BALB／c小鼠，取脾脏进行免疫组化鉴定重组蛋白在动物体内的表达。结果酶切鉴定和基因序列测定显示重组质粒构建成功。在pcDNA3．1（＋）-CTLA4Ig—H2B质粒转染后48h细胞裂解上清中，检测到CTLA4Ig融合蛋白的表达，该蛋白能与抗人CTLA-4单抗特异结合。重组蛋白在BALB／c小鼠脾脏免疫细胞胞浆中有阳性表达。结论成功构建了能稳定表达核小体Th表位和CTLA4Ig融合基因的真核表达载体。     

Leptin deficiency impairs maturation of dendritic cells and enhances induction of regulatory T and Th17 cells

Leptin is an adipose‐secreted hormone that plays an important role in both metabolism and immunity. Leptin has been shown to induce Th1‐cell polarization and inhibit Th2‐cell responses. Additionally, leptin induces Th17‐cell responses, inhibits regulatory T (Treg) cells and modulates autoimmune diseases. Here, we investigated whether leptin mediates its activity on T cells by influencing dendritic cells (DCs) to promote Th17 and Treg‐cell immune responses in mice. We observed that leptin deficiency (i) reduced the expression of DC maturation markers, (ii) decreased DC production of IL‐12, TNF‐α, and IL‐6, (iii) increased DC production of TGF‐β, and (iv) limited the capacity of DCs to induce syngeneic CD4⁺ T‐cell proliferation. As a consequence of this unique phenotype, DCs generated under leptin‐free conditions induced Treg or T_H17 cells more efficiently than DCs generated in the presence of leptin. These data indicate important roles for leptin in DC homeostasis and the initiation and maintenance of inflammatory and regulatory immune responses by DCs.     

CTLA4Ig诱导T细胞对氧化修饰低密度脂蛋白无能的体外研究

目的 在体外诱导T细胞对氧化修饰低密度脂蛋白(ox-LDL)的免疫无能,以期预防免疫损伤在动脉粥样硬化(AS)发病中的作用,为防治AS提供新的思路.方法 分离外周血单个核细胞诱导树突状细胞(DC).分别加入LPS、LDL、ox-LDL等刺激48 h,与同种异体淋巴细胞行混合淋巴细胞反应(MLR).ox-LDL组的MLR中,分别加入不同浓度的CTLA4Ig,以MTY法检测T细胞的增殖.流式细胞仪检测MLR中T细胞活化和T细胞凋亡.ELISPOT检测MLR中T细胞分泌IL-2、IFN-γ和IL-4的情况.结果 ox-LDL组MTT中的刺激指数(SI)明显高于LDL组(DC:T-1:5,1.6717±0.3152 vs 1.4250±0.2874,P<0.05;DC:T=1:10,1.5458±0.2748 vs 1.3352士0.2991,P<0.05);应用CTLA4Ig后,SI较未应用时明显降低(CTLA4Ig 1.25 Ixg/ml,0.96±0.30 vs 1.64±0.33,P<0.01;CTLA4Ig0.62μg/ml,1.12±0.33 vs 1.64±0.33,P<0.05;CTLA4Ig 0.31μg/ml,1.29±0.28vs 1.64±0.33,P<0.05);CTLA4Ig可明显减少T细胞CD25的表达(CTLA4Ig 1.25μg/ml,11.26士0.58 vs 14.25±1.02,P<0.05;CTLA4Ig 10μg/ml,8.42±0.45,P<0.01),增加T细胞的凋亡(CTLA4Ig 1.25μg/ml,12.54±3.69 vs 6.09±2.24,P<0.05;CTLA4Ig 10μg/ml,26.87±5.06 vs 6.09±2.24,P<0.01).ELISPOT表明,CTLA4Ig可减少IL-2(CTLA4Ig 1.25μg/ml,386±42 vs 534±54,P<0.05;CTLA4Ig 10μg/ml,230±27 vs 534±54,P<0.01)和IFN-γ(CTLA4Ig 1.25μg/ml,445±48 v8672±46,P<0.05;CTLA4Ig 10μg/ml,193±39 vs 672±46,P<0.01)的ELISPOT计数,增加IL-4的ELISPOT计数(CTLA4Ig 1.25μg/ml,401±32 vs 332±41,P<0.05;CTLA4Ig 10μg/ml,453±57 vs332±41,P<0.05).结论 CTLA4Ig可在体外诱导T细胞对ox-LDL的免疫无能;CTLA4Ig通过抑制T细胞活化、诱导T细胞凋亡和促进TH1/TH2免疫偏移等机制,诱导T细胞免疫无能.     

CTLA4 Silencing with siRNA Promotes Deviation of Th1/Th2 in Chronic Hepatitis B Patients

To determine whether RNA interference （RNAi） could block cytotoxic T-lymphocyte antigen 4 （CTLA4） in human lymphocytes in vitro and promote IFN-T and IL-2 secretions, three small interfering RNAs （siRNAs） were selected based on target specificity sequences of human CTLA4 and transfected into human lymphocytes of chronic HBV patients. As a result, the expression of human CTLA4 mRNA was efficiently suppressed by all the three siRNAs. Compared with negative control （siRNA-co）, siRNA-1 inhibited the expression of CTLA4 most efficiently and was used in the further study. The expressions of IFN-γ and IL-2 were upregulated and the level of IL-4 was almost unchanged in lymphocytes transfected with siRNA-1 compared with the blank control. These results indicated that siRNA-1 led to IFN-γ and IL-2 secretions, which is a main response of Th1/Th2. In a conclusion, RNAi significantly suppressed the expression of human CTLA4 mRNA in human lymphocytes in vitro, and could induce Th1/Th2 response. It could be a new therapeutic strategy for chronic HBV infection.     

CTLA4Ig修饰的树突状细胞在体外对淋巴细胞增殖及胞毒效应的影响

目的:探讨CTLA4Ig修饰的树突状细胞(DC)对T细胞增殖和细胞毒性T细胞(CTL)细胞毒活性的影响。方法:采用脂质体转染法,将质粒pG/CTLA4Ig转入DC。采用ELISA和SDS-PAGE鉴定转染质粒pG/CTLA4Ig的DC培养上清。以C57BL/6小鼠的单个核细胞作为反应细胞,以未修饰的DC及修饰的DC作为刺激细胞,共培养6 d,用MTT比色法检测细胞的增殖。用乳酸脱氢酶法和ELISA法,分别测定细胞毒活性及T细胞凋亡。结果:CTLA4Ig融合蛋白和修饰的DC,对同种细胞刺激的增殖反应有明显地抑制作用;而未修饰的DC可显著诱导淋巴细胞增殖反应。CTLA4Ig融合蛋白和修饰的DC,对特异性CTL的细胞毒活性有明显地抑制作用,且可诱导T细胞凋亡。结论:稳定表达CTLA4Ig融合蛋白的DC,对T细胞增殖和对CTL的细胞毒活性具有明显地抑制作用,并可诱导T细胞凋亡。     

CTLA4Ig修饰树突状细胞对实验动物淋巴细胞增殖及胞毒效应的影响

目的：探讨CTLA4Ig修饰的DC对实验动物免疫功能的影响。方法：将经CTLA4Ig基因修饰或未修饰Dc腹腔注射C57BL／6致敏小鼠，以致敏或未致敏C57BL／6单个核细胞作为反应细胞，以未修饰DC细胞及修饰DC为刺激细胞，共培养6天，采用MTT比色法检测细胞增殖，乳酸脱氢酶法测定细胞毒活性。结果：CTLA4Ig融合蛋白对未修饰DC致敏或未致敏小鼠的同种细胞刺激的增殖反应有明显的抑制作用。CTLA4Ig修饰DC诱导不同组小鼠淋巴细胞增殖反应均明显降低，CTLA4Ig融合蛋白对CTL细胞毒活性有显著抑制作用。CTLA4Ig修饰DC对不同组小鼠CTL细胞毒活性均具有抵抗作用，未修饰DC细胞对未致敏小鼠以及未修饰DC对致敏小鼠CTL细胞毒活性敏感。结论：稳定表达CTLA4Ig融合蛋白的DC诱导显著降低同种小鼠淋巴细胞的增殖反应和对CTL细胞毒活性的抵抗。     

The proteolytic activity of the major dust mite allergen Der p 1 conditions dendritic cells to produce less interleukin-12: allergen-induced Th2 bias determined at the dendritic cell level

BACKGROUND: The proteolytic activity of the house dust mite allergen Der p 1 has recently been shown to bias Th cell subset development in favour of Th2. Apart from its direct effect on T cells, it is conceivable that the proteolytic activity of Der p 1 may induce the generation of dendritic cells (DCs) that favour a Th2 response. OBJECTIVE: To study the effect of the proteolytic activity of Der p 1 on DC functions; namely cell surface phenotype, IL-12 production and ability to favour a Th2 response. METHODS: We have generated immature DCs from peripheral blood monocytes, matured them with LPS in the presence of either proteolytically active or inactive Der p 1 and compared their functions using flow cytometric analysis. RESULTS: Here we demonstrate for the first time that DCs that have been matured in the presence of proteolytically active Der p 1 produce significantly less IL-12, compared to DCs that have been matured in the presence of proteolytically inactive Der p 1. The suppression of IL-12 production was due to the cleavage of CD40 by the proteolytic activity of Der p 1, hence rendering the DCs less responsive to stimulation through the CD40L-CD40 pathway. Furthermore, we demonstrate that DCs that have been matured in the presence of proteolytically active Der p 1 induce the production of significantly less IFN-gamma and more IL-4 by CD4 T cells, compared to DCs that have been matured in the presence of proteolytically inactive Der p 1. CONCLUSIONS: Collectively, our data provide compelling evidence for the role of the proteolytic activity of Der p 1 in directing DCs to induce Th2 subset development.