他克莫司处理供者树突状细胞在诱导大鼠同种心脏移植免疫耐受中的作用

背景：诱导供者特异性免疫耐受被认为是最终克服器官移植后排斥反应的有效途径，近年来关于未成熟树突状细胞在诱导免疫耐受中的重要作用日益受到关注。 目的：观察他克莫司处理的供者未成熟树突状细胞对大鼠同种异体心脏移植免疫耐受的影响，分析未成熟树突状细胞诱导免疫耐受的作用途径。 设计：随机对照动物实验。 材料：实验于2006-04/2006-12在青岛大学医学院附属医院动物实验中心完成。以45只Wistar大鼠为供体，45只SD大鼠为受体，行颈部心脏移植45例次。按随机数字表法分为3组，每组15例次，进行不同的预处理。 方法：对照组、未经他克莫司处理组及他克莫司处理组移植前7 d分别经尾静脉注射生理盐水、供者未成熟树突状细胞和他克莫司处理的未成熟树突状细胞。分别测定移植后SD大鼠与Wistar大鼠及第3品系Lewis大鼠的单向混合淋巴细胞反应。 主要观察指标：各组受体大鼠移植心脏存活时间、心肌病理及血清白细胞介素2、白细胞介素4、白细胞介素10、γ-干扰素含量变化。 结果：①未经他克莫司处理组大鼠的移植心脏存活时间较对照组明显延长（P < 0.01），他克莫司处理组大鼠的移植心脏存活时间进一步延长（P < 0.05）。②混合淋巴细胞培养结果显示为供者特异性。③各组大鼠血清白细胞介素2、γ-干扰素、白细胞介素4、白细胞介素10含量差异具有显著性意义（P < 0.01）。代表Th1的白细胞介素2、γ-干扰素水平明显降低，代表Th2的白细胞介素4、白细胞介素10水平明显增高。 结论：未成熟树突状细胞能够诱导同种异体大鼠心脏移植免疫耐受；他克莫司处理的未成熟树突状细胞能够加强这种免疫耐受，且这种耐受是供者特异性的。其可能主要通过调节T细胞免疫应答类型（Th1至Th2的免疫偏移）、诱导调节性T细胞和诱导T细胞失能等途径来参与免疫耐受的形成。     

不同质量浓度粒巨噬细胞集落刺激因子对Lewis大鼠骨髓源性树突状细胞

背景：体内成熟和不成熟树突状细胞(dendritic cells, DC)数量极少,仅占外周血单核细胞的1%,占脾细胞的0.2%~0.5%,几乎不能直接从体内分离出大量的纯化的DC,要获得足够的DC,只有依靠体外培养增殖。 目的：以不同剂量粒巨噬细胞集落刺激因子诱导分化获得大鼠骨髓源性DC,拟建立合适的大鼠骨髓源性未成熟DC的培养方法。 设计、时间及地点：随机对照动物实验,于2007-06/2008-05在苏州大学附属第一医院临床免疫学实验室和附属儿童医院骨科实验室完成。 材料：雄性SPF级Lewis大鼠用于培养骨髓源性DC,雄性SPF级Brown Norway大鼠用于混合淋巴细胞反应实验。 方法：采用密度梯度离心法从Lewis大鼠股骨和胫骨获取骨髓源性单个核细胞,分别以2.5,5,10,20 µg/L粒巨噬细胞集落刺激因子和5 µg/L白细胞介素4诱导分化获得大鼠骨髓源性DC,采用黏附法纯化DC。 主要观察指标：以流式细胞仪分析DC表型。混合淋巴细胞反应中以Lewis大鼠DC作为刺激细胞,以Brown Norway大鼠脾脏T细胞作为反应细胞,检测其刺激同种T细胞增殖能力。ELISA测定分泌细胞上清液中白细胞介素12、干扰素水平。 结果：随粒巨噬细胞集落刺激因子质量浓度的增高,诱导的细胞获得率逐渐升高,但DC比例逐渐下降。CD86、MHC-II表达阳性率随培养时间延长逐渐增加。培养第5,7天,DC不能有效刺激同种异体T细胞的增殖反应,培养第13天,DC刺激同种异体T细胞的增殖反应能力明显增强(P < 0.01)。培养7 d以后,DC上清液中白细胞介素12水平明显增高(P < 0.01),脂多糖刺激以后升高更加明显(P < 0.01)。脂多糖刺激后DC表型MHCII、CD86表达明显增加,白细胞介素12分泌增加,刺激同种T细胞增殖能力轻度增强。 结论：5 µg/L粒巨噬细胞集落刺激因子为诱导大鼠骨髓源性未成熟DC的最佳剂量,培养9 d可以获得足够数量和纯度的未成熟DC。 关键词：     

系统性红斑狼疮患者血清IFN-α和IL-6的共同作用对造血干细胞定向分化为树突状细胞的影响

背景：系统性红斑狼疮与树突状细胞的功能活化密切相关。在体内,树突状细胞来源于造血干细胞,其分化成熟的过程受多种因素的影响。系统性红斑狼疮患者血清中存在细胞因子网络失调,以往研究多关注于单一因子的参与作用。 目的：课题创新性提出和观察系统性红斑狼疮患者血清α干扰素和白细胞介素6共同作用下对CD34+造血干细胞定向分化为树突状细胞的影响。 设计、时间及地点：分组对比观察,完全随机细胞学体外实验,于2006-05/2008-10在南京医科大学微生物与免疫学实验室完成。 材料：外周血标本取自50例就诊于南京医科大学第一附属医院风湿免疫科的系统性红斑狼疮患者,以及30例南京医科大学的健康志愿献血者。15份脐血标本取自南京医科大学附属南京妇幼保健院健康足月顺产的新生儿,产妇及其家属均对实验知情同意。 方法：无菌采集系统性红斑狼疮患者和正常对照者的外周静脉血,根据正常人血清中α干扰素、白细胞介素6的浓度,采用百分位数法求得血清α干扰素、白细胞介素6浓度的95%参考值范围,并以浓度超过此范围为异常升高。取新生儿脐血,Ficoll-Hypaque密度梯度离心法分离脐血单个核细胞,免疫磁珠法纯化CD34+造血干细胞,并诱导其定向分化为树突状细胞。在培养过程中设立6组,分别加入：正常对照血清、α干扰素升高的系统性红斑狼疮血清、白细胞介素6升高的系统性红斑狼疮血清、α干扰素和白细胞介素6同时升高的系统性红斑狼疮血清、混合α干扰素及白细胞介素6中和抗体的系统性红斑狼疮血清、混合外源性α干扰素和白细胞介素6的正常对照者血清,各组血清体积分数均为10%,培养14 d。 主要观察指标：流式细胞仪检测树突状细胞的表型,ELISA法检测树突状细胞分泌细胞因子的水平,混合淋巴细胞反应检测树突状细胞刺激同种异体T细胞增殖的能力,及其对T细胞亚群分化率影响。 结果：①与正常血清对照比较,α干扰素、白细胞介素6及二者同时升高的系统性红斑狼疮血清、混合外源性α干扰素和白细胞介素6的正常对照者血清诱导培养的树突状细胞其HLA-DR,CD80,CD86的表达均明显升高(P < 0.05),分泌白细胞介素12 的水平均明显降低(P < 0.05),刺激T细胞增殖能力均明显增强(P < 0.05)。混合α干扰素及白细胞介素6中和抗体的系统性红斑狼疮血清诱导培养的树突状细胞上述各项指标均恢复至正常血清对照水平。②与正常血清对照比较,白细胞介素6升高的系统性红斑狼疮血清其CD3+CD8−IFN-γ+、CD3+CD8+IFN-γ+细胞亚群百分率明显下降(P < 0.05);α干扰素升高的系统性红斑狼疮血清、α干扰素和白细胞介素6同时升高的系统性红斑狼疮血清、混合外源性α干扰素和白细胞介素6的正常对照者血清其CD3+CD8−IFN-γ+和CD3+CD8+IFN-γ+细胞亚群百分率均明显升高(P < 0.05)。 结论：系统性红斑狼疮血清α干扰素和白细胞介素6的共同作用对CD34+造血干细胞定向分化为树突状细胞产生了异常影响,可促进树突状细胞的表型成熟和功能活化,并间接影响T细胞亚群的分化,可能参与系统性红斑狼疮的发病。     

免疫耐受性树突状细胞在移植免疫中的作用及其分子机制

新的研究发现一种半成熟树突状细胞亚群,其高表达主要组织相容性复合体II、中等表达CD40、CD80和CD86等分子,在自身免疫性疾病中表现出诱导免疫耐受的潜能,其与未成熟树突状细胞一道被认为是致耐受细胞。这使过去将树突状细胞分为未成熟和成熟两种类型的概念受到挑战。但是,它们在移植免疫中的具体作用和机制仍未完全明了。文章对致耐受树突状细胞的体内迁移过程、在移植免疫中分子机制和体外获得等方面的最新进展进行综合分析和热点追踪,为进一步理解和研究致耐受树突状细胞在移植免疫反应中的作用拓宽视野。     

小鼠脾脏树突状细胞的体外扩增与培养

背景：脾脏来源的树突状细胞诱导周期长，产量相对较少，相关报道亦较少。 目的：建立简便的体外扩增小鼠脾脏树突状细胞的方法。 设计、时间及地点：细胞形态学观察实验，于2007-02/09在华北石油总医院中心实验室完成。 材料：健康BALB/C小鼠、C57小鼠及粒细胞-巨噬细胞集落刺激因子、白细胞介素4。 方法：无菌手术取C57小鼠脾脏，用1 mL注射器抽取Hanks液，刺入脾脏并反复冲洗，获取单个核细胞，用0.1 g/L粒-单核细胞集落刺激因子、白细胞介素4的H-DMEM培养，8 d后即得成熟的树突状细胞。同时无菌取BABL/C小鼠脾脏制备单细胞悬液，收集非黏附细胞调整密度后作为反应细胞。再将两种细胞混合培养。 主要观察指标：成熟树突状细胞的形态学观察，并对其表面CD11c，CD86及MHC-Ⅱ类分子进行检测。并计算两种细胞混合培养后的吸光度值。 结果：体外诱导培养8 d后获得大量成熟的树突状细胞，细胞表面具有典型的树枝状突起，高表达树突状细胞相对特异性表面分子CD11c（78.46%）、 CD86(87.24%)及MHC-Ⅱ(92.65%)，同时具有较强的刺激同种异基因混合淋巴细胞增殖的能力。 结论：联合应用粒细胞-巨噬细胞集落刺激因子和白细胞介素体外诱导培养小鼠脾脏细胞，可生成大量功能成熟的树突状细胞。     

过敏性紫癜患儿外周血树突状细胞功能变化及黄芪的体外干预

背景：树突状细胞在过敏性紫癜发病机制中可能具有重要的地位。已有报道黄芪在体内可以纠正过敏性紫癜患儿的Th1/Th2失衡,但目前关于黄芪在树突状细胞水平对过敏性紫癜病免疫功能调节的影响尚不清楚。 目的：观察过敏性紫癜患儿外周血树突状细胞功能变化及黄芪对其的影响。 设计、时间及地点：病例对照分析,于2005-10/2007-12在青岛大学医学院附属医院儿科研究所完成。 材料：急性期过敏性紫癜患儿外周静脉血28份作为过敏性紫癜组,以门诊体检的健康同龄儿童外周静脉血18份作为正常对照组。黄芪水提剂由四川百利药业有限公司提供。 方法：采用密度梯度离心法获取过敏性紫癜患儿及健康儿童外周血单个核细胞,获取的外周血单个核细胞体外经重组人粒-巨噬细胞集落刺激因子、重组人白细胞介素4、重组人肿瘤坏死因子α以诱生树突状细胞,并培养8 d,其中过敏性紫癜组又分成2组：对照组和黄芪干预组。 主要观察指标：ELISA法检测过敏性紫癜患儿及健康儿童血浆γ-干扰素和白细胞介素4水平及培养上清液中白细胞介素10,12,18水平,流式细胞仪检测树突状细胞表面CD83、CD86（B7-2）和CD80（B7-1）的表达率。 结果：过敏性紫癜患儿急性期外周血中Th1型细胞因子γ-干扰素水平减少,Th2型细胞因子白细胞介素4水平增加,γ-干扰素/白细胞介素4比值明显降低。过敏性紫癜患儿外周血单个核细胞经诱导培养的树突状细胞表面CD86表达率较正常对照组明显升高,且两组CD86表达率与血浆白细胞介素4水平皆呈显著正相关,与γ-干扰素/白细胞介素4比值皆呈显著负相关;CD80表达率明显低于正常对照组,且两组CD80表达率与血浆γ-干扰素水平及γ-干扰素/白细胞介素4比值均呈显著正相关。过敏性紫癜患儿树突状细胞分泌白细胞介素12水平低于正常对照组（P < 0.05）,而白细胞介素10,18水平均高于正常对照组（P < 0.05）,两组树突状细胞分泌白细胞介素12水平与血浆γ-干扰素水平皆呈显著正相关(P < 0.01),与γ-干扰素/白细胞介素4比值皆呈正相关(P < 0.01,P< 0 .05);白细胞介素10分泌水平与其血浆白细胞介素4水平皆呈显著正相关(P均< 0.01),与γ-干扰素/白细胞介素比值皆呈负相关(P < 0.01,P < 0.05);白细胞介素18分泌水平与其血浆白细胞介素4水平皆呈显著正相关(P均< 0.01),与γ-干扰素/白细胞介素4比值皆呈负相关(P < 0.01,P < 0.05)。黄芪干预组树突状细胞表面CD83、CD86和CD80的表达率与对照组差异不显著,树突状细胞分泌白细胞介素12水平高于对照组（P < 0.01）,白细胞介素10,18水平均低于对照组（P < 0.05,P < 0.01）。 结论：①过敏性紫癜患儿外周血树突状细胞存在明显功能紊乱,表现为CD86表达率升高、CD80降低,白细胞介素12分泌减少、白细胞介素10 和白细胞介素18增加,上述变化与Th1/Th2失衡关系密切。②黄芪主要是通过改变过敏性紫癜患儿树突状细胞分泌细胞因子的水平来调节其功能。     

人外周单个核细胞来源树突细胞成熟与肺炎支原体膜脂蛋白的影响*★

目的：实验着眼于肺炎支原体膜脂蛋白对人外周血单个核细胞来源的树突细胞的表型(CD83，CD86)及分泌细胞因子的作用，探讨肺炎支原体加重哮喘的机制是否是改变了树突细胞的性状。 方法：①对象：所有外周血采自正常人，志愿献血者为武汉大学医学院2005级硕士博士研究生6人；实验用肺炎支原体膜脂蛋白购自广州华银医药科技有限公司。②实验过程及分组：从肘静脉采集志愿者20 mL新鲜全血，以不连续密度梯度离心法及贴壁法获取单核细胞，加入重组人粒细胞-巨噬细胞集落刺激因子，重组人白细胞介素4培养5 d得到不成熟树突细胞后，分别予肺炎支原体膜脂蛋白，脂多糖和空白刺激再培养2 d。③评估：用流式细胞仪检测各组树突细胞表面表达CD83，CD86的情况，用酶联免疫吸附法检测各组树突细胞分泌白细胞介素12的水平。 结果：①肺炎支原体膜脂蛋白组树突细胞表达CD83，CD86高于未刺激组(P < 0.01,P < 0.01)；脂多糖组树突细胞表达CD83，CD86高于未刺激组(P < 0.01,P < 0.01)；肺炎支原体膜脂蛋白组树突细胞表达CD83较脂多糖组无差异，表达CD86高于脂多糖组(P < 0.05)。②肺炎支原体膜脂蛋白组树突细胞分泌白细胞介素12高于未刺激组(P < 0.01)；脂多糖组树突细胞分泌白细胞介素12高于未刺激组(P < 0.01)；肺炎支原体膜脂蛋白组树突细胞分泌白细胞介素12低于脂多糖组(P < 0.05)。 结论：肺炎支原体膜脂蛋白可刺激未成熟树突细胞分化成熟，但较脂多糖刺激的不同，前者刺激成熟的树突细胞在呈递抗原给T细胞时，可进一步使T细胞向Th2极化，导致Th1/Th2平衡失调，从而加重哮喘。     

草分支杆菌对人脐血树突状细胞体外扩增的影响

背景：树突状细胞因其强大的抗原提呈能力而在机体抗肿瘤作用的中心地位逐渐受到重视，但如何能有效获得足够数量有功能的树突状细胞成为目前研究的重点，尤其是有关低毒免疫调节剂的报道较少。 目的：观察草分支杆菌F.U.36(乌体林斯，Utilins)对人脐血来源树突状细胞体外扩增的影响。 方法：应用Ficoll-Hypaque法分离人脐血单个核细胞，分别用乌体林斯，细胞因子(重组人粒细胞-巨噬细胞集落刺激因子+重组人肿瘤坏死因子α+重组人白细胞介素4)，细胞因子联合乌体林斯进行干预，并以RPMI-1640培养液诱导培养人脐血单个核细胞作为对照组，诱导培养树突状细胞，并于倒置显微镜下观察其生长情况及形态。培养第9天，采用流式细胞仪检测各组人树突状细胞特异性表型CD1a及MHC-Ⅱ分子HLA-DR的变化，并将细胞涂片行瑞氏-姬姆萨染液染色，油镜下观察摄片。 结果与结论：除对照组外，实验各组均得到高表达CD1a及HLA-DR的典型树突状细胞。乌体林斯组CD1a及HLA-DR阳性细胞比例亦明显高于对照组而低于细胞因子组 (P < 0.05)，联合组HLA-DR阳性细胞比例高于细胞因子组(P < 0.05)。结果提示，草分支杆菌F.U.36(乌体林斯)不仅能促进脐血树突状细胞体外扩增，还能协同细胞因子促进树突状细胞成熟。     

小鼠骨髓树突状细胞的培养扩增及生物学特性分析

背景：树突状细胞是目前已知功能最强的专职性抗原递呈细胞，但树突状细胞在体内分布广泛且数量较少，获得大量的树突状细胞是研究树突状细胞特性和功能的前提。 目的：建立小鼠骨髓源树突状细胞体外培养和扩增方法，观察其形态和相关特征。 设计、时间及地点：树突状细胞形态学观察实验，于2006-08/2007-05在中山大学中山眼科中心实验室完成。 材料：健康雌性C57BL/6小鼠。 方法：在无菌条件下提取C57BL/6鼠骨髓细胞，分离单个核细胞，以小鼠重组粒细胞-巨噬细胞集落刺激因子和白细胞介素4协同诱导下培养，加用磷酸脂多糖刺激，分成磷酸酯多糖-树突状细胞和单纯树突状细胞组，前者在培养加入磷酸酯多糖，后者不加。 主要观察指标：应用光镜和电镜下观察树突状细胞的形态，流色细胞仪检测鉴定其生物学特征。 结果：体外培养2 周后具有典型的树突状细胞形态，光镜下显示细胞表面不规则，呈树突状突起，电镜下可见培养的细胞具有典型树突状细胞的形态特征，流式细胞鉴定为髓系树突状细胞，高表达MHC II类分子及共刺激分子(MHC II，CD80，CD83，CD11 c)。单纯树突状细胞组的细胞中度表达MHCⅡ类分子，低水平表达共刺激分子，刺激T细胞增殖的能力较弱；磷酸酯多糖-树突状细胞组细胞高水平表达MHCII类分子和共刺激分子。 结论：实验所采用的树突状细胞体外原代培养的方法能在体外培养出大量的未成熟树突状细胞，具有典型树突状细胞的形态特征及较高的纯度。     

耐受性树突状细胞体外培养的基本特征

背景：树突状细胞是体内最重要的抗原提呈细胞,在免疫调节中扮演着免疫应答和免疫耐受的双重角色,对维持机体的免疫平衡起重要作用。 目的：探讨耐受性树突状细胞的体外培养方法,观察不同培养条件下耐受性树突状细胞的基本特征。 设计、时间及地点：以细胞为观察对象,随机分组设计,于2006-09/2008-02在南昌大学第一附属医院中心实验室完成。 材料：8周龄的Balb/c纯系雄性小鼠,体质量20~25 g,用于分离和制备骨髓单个核细胞。 方法：将小鼠骨髓单个核细胞分为5组在不同的培养体系中进行体外诱导培养：空白对照组(不加任何因子)、树突状细胞组(粒-巨噬细胞集落刺激因子+白细胞介素4)、血管活性肠肽组(粒-巨噬细胞集落刺激因子+血管活性肠肽)、地塞米松组(粒-巨噬细胞集落刺激因子+地塞米松)、血管活性肠肽+地塞米松组(粒-巨噬细胞集落刺激因子+血管活性肠肽+地塞米松)。 主要观察指标：光镜下动态观察细胞形态,流式细胞仪检测细胞CD80、CD86、CD40、CD11c表达,四甲基偶氮唑盐法检测树突状细胞刺激淋巴细胞增殖的活性,特异性夹心酶联免疫分析测定树突状细胞上清液中白细胞介素10、白细胞介素12的水平。 结果：①利用粒-巨噬细胞集落刺激因子、白细胞介素4、血管活性肠肽、地塞米松、脂多糖等因子体外培养能生成具有典型树枝状突起的树突状细胞。②树突状细胞组、血管活性肠肽组、地塞米松组、血管活性肠肽+地塞米松组CD11c的表达高于空白对照组(P < 0.05)。血管活性肠肽组、地塞米松组、血管活性肠肽+地塞米松组CD40、CD80和CD86表达,淋巴细胞增殖活性及培养上清液白细胞介素12水平均低于树突状细胞组(P < 0.05),血管活性肠肽组以质量浓度为40 μg/L、地塞米松组以10 μg/L减低明显,其中血管活性肠肽+地塞米松组在血管活性肠肽质量浓度为40 μg/L、地塞米松为10 μg/L条件下为最低,差异具有显著性意义(P < 0.05)。③血管活性肠肽组、地塞米松组、血管活性肠肽+地塞米松组细胞培养上清液中白细胞介素10水平均高于树突状细胞组(P < 0.05),血管活性肠肽组以质量浓度为40 μg/L,地塞米松组以10 μg/L升高明显,其中血管活性肠肽+地塞米松组在血管活性肠肽质量浓度为40 μg/L、地塞米松为10 μg/L条件下为最高,差异具有显著性意义(P < 0.05)。 结论：①小鼠骨髓单个核细胞体外经粒-巨噬细胞集落刺激因子、血管活性肠肽或/和地塞米松、脂多糖联合诱导培养生成致耐受性树突状细胞。②与常规诱导培养树突状细胞方法比较,耐受性树突状细胞具有CD40、CD80、CD86表达低,刺激淋巴细胞增殖弱的特点;耐受性树突状细胞培养体系上清液白细胞介素10水平高而白细胞介素12水平低。③粒-巨噬细胞集落刺激因子、血管活性肠肽+地塞米松、脂多糖联合诱导培养生成耐受性树突状细胞效果较佳,其中以血管活性肠肽40 μg/L、地塞米松10 μg/L的培养条件为最好。     

Atorvastatin-modified dendritic cells in vitro ameliorate experimental autoimmune myasthenia gravis by up-regulated Treg cells and shifted Th1/Th17 to Th2 cytokines

Conventional therapies for autoimmune diseases produce nonspecific immune suppression, which are usually continued lifelong to maintain disease control, and associated with a variety of adverse effects. In this study, we found that spleen-derived dendritic cells (DCs) from the ongoing experimental autoimmune myasthenia gravis (EAMG) rats can be induced into tolerogenic DCs by atorvastatin in vitro. Administration of these tolerogenic DCs to EAMG rats on days 5 and 13 post immunization (p.i.) resulted in improved clinical symptoms, which were associated with increased numbers of CD4⁺CD25⁺ T regulatory (Treg) cells and Foxp3 expression, decreased lymphocyte proliferation among lymph node mononuclear cells (MNC), shifted cytokine profile from Th1/Th17 to Th2 type cytokines, decreased level of anti-R97–116 peptide (region 97–116 of the rat acetylcholine receptor α subunit) IgG antibody in serum. These tolerogenic DCs can migrate to spleen, thymus, popliteal and inguinal lymph nodes after they were injected into the EAMG rats intraperitoneally. Furthermore, these tolerogenic DCs played their immunomodulatory effects in vivo mainly by decreased expression of CD86 and MHC class II on endogenous DCs. All these data provided us a new strategy to treat EAMG and even human myasthenia gravis (MG).     

Blockade of CD40/CD40 ligand interactions prevents induction of factor VIII inhibitors in hemophilic mice but does not induce lasting immune tolerance.

Patients with severe hemophilia A frequently develop neutralizing anti-factor VIII antibodies after replacement therapy with factor VIII (FVIII). In a search for new strategies to induce immune tolerance against FVIII in these patients, we used a murine model of hemophilia A to investigate the importance of CD40/CD40 ligand (CD40L) interactions for the initiation of the anti-FVIII immune response. We focused our attention in particular on the induction of neutralizing anti-FVIII antibodies and the Th1/Th2 polarization of FVIII-specific T cells. The development of anti-FVIII antibodies was analyzed by ELISA systems (detection of total anti-FVIII antibodies) and Bethesda assays (determination of neutralizing anti-FVIII antibodies). Factor VIII-specific T cells were characterized by multiparameter flow cytometry and cytokine ELISAs for the detection of cytokine production in splenic CD4+ T cells after in vitro restimulation with FVIII. Hemophilic mice received four doses of FVIII and anti-CD40L antibody MR1 (24 h before FVIII). Subsequently mice received four doses of FVIII only. The induction of neutralizing anti-FVIII antibodies in hemophilic mice after treatment with human FVIII could be prevented completely by a blockade of CD40/CD40L interactions using MR1. Furthermore, FVIII-specific T-cell responses that included both Th1 and Th2 cells were suppressed when mice were treated with FVIII and MR1. The initial blockade of CD40/CD40L interactions was, however, not sufficient to induce a lasting immune tolerance against FVIII. The immune suppression was abolished and both neutralizing anti-FVIII antibodies and FVIII-specific T cells developed when treatment with FVIII was continued after the omission of MR1. In addition, there were no alterations in the Th1/Th2 polarization induced by the initial blockade of CD40/CD40L interactions.     

Mature bone marrow-derived dendritic cells polarize Th2 response and suppress experimental autoimmune encephalomyelitis

Distinct subsets of dendritic cells (DCs) based on the origin, phenotypes, and the nature of the signals that promote DC maturation can determine polarized immune responses of T cells. In this study, DCs were cultured from mouse bone marrow (BM) progenitors in granulocyte-macrophage colony-stimulating factor (GM-CSF). To generate mature DCs (mDCs), lipopolysaccharide (LPS) was used in the culture for 24 h. LPS-stimulated DCs were phenotypically mature, which exhibited strongly upregulated CD40, B7.1, and B7.2 compared to non-LPS-stimulated immature DCs (imDCs). Both mDCs and imDCs expressed high levels of MHC class II but low level of CD54. mDCs produced higher levels of IL-10 and lower IL-12 compared to imDCs. No IFN-gamma or IL-4 was found in both groups. When mDCs were injected intraperitoneally (i.p.) to the mice with experimental autoimmune encephalomyelitis (EAE), the severity of clinical signs and inflammation in the CNS was significantly suppressed compared to imDC-injected mice (p<0.01) and PBS-injected mice (p<0.02). Moreover, lymphocytes from mDC-injected mice produced lower level of IL-12, IFN-gamma, but higher level of IL-10, compared to imDC-injected and non-DC-injected mice. We conclude that BM-mDCs, but not BM-imDCs, promote Th2 differentiation and have the potential for suppression of inflammatory demyelination.     

白介素-12家族与实验性自身免疫性脑脊髓炎的研究进展

实验性自身免疫性脑脊髓炎(EAE)是自身反应性CD4+T细胞,即辅助性T细胞(Th细胞)介导的自身免疫性中枢神经系统脱髓鞘性炎症,在EAE的发病中,Th细胞分泌的细胞因子起了重要的调节作用。白介素-12(IL-12)家族由IL-12和最近发现的白介素-23(IL-23)、白介素-27(IL-27)组成,是一类结构相似、具有共价结合的杂化双链的细胞因子,在细胞免疫尤其是Th1型炎症反应中,起重要的调节作用。本文综合论述了IL-12家族各成员与EAE的关系的研究,揭示了各因子在EAE发生发展中的作用。     

Cytokine phenotype of human autoreactive T cell clones specific for the immunodominant myelin basic protein peptide (83–99)

Experimental allergic encephalomyelitis (EAE), an animal model resembling multiple sclerosis (MS), is mediated by myelin antigen-specific CD4+ T cells secreting cytokines such as interferon-γ (IFN-γ), tumor necrosis factor-β (TNF-β), and the proinflammatory cytokine TNF-α—all associated with the T-helper-1 (Th1) T cell subset. Based on numerous similarities between MS and EAE, it has been postulated that Th1-like T cells are involved in the pathogenesis of MS. Production of proinflammatory cytokines such as IFN-γ and, in particular, TNF-α/β by autoreactive T cells is considered crucial for the initiation and amplification of inflammatory brain lesions and possibly also for direct myelin damage. In contrast, regulatory cytokines such as interleukin-4 (IL-4), IL-10, and IL-13, which are associated with the Th2-like phenotype, may play a role in the resolution of relapses. Although the human T cell response to myelin basic protein (MBP) is well characterized in terms of antigen specificity, HLA restriction, and T cell-receptor (TCR) usage, little is known about the cytokine pattern of these autoreactive T cells. To gain such information, conditions for studying cytokine secretion by human autoreactive T cell clones (TCC) were established. The cytokine secretion profile of human autoreactive CD4+ TCC, specific for myelin basic protein peptide (83–89) [MBP(83–99)], a candidate autoantigen in MS, was investigated. Our results show that TCC cytokine production in long-term culture was stable. In addition, the correlation of various cytokines within specific TCC revealed differences compared to murine T cells. The comparison of 30 human MBP(83–99)-specific TCC demonstrated heterogeneity in cytokine secretion, with a continuum between Th1- and Th2-like cells rather than distinct Th1 or Th2 subsets. These data are important for further investigation of the potential role of cytokines in the inflammatory process of MS, and provide a powerful tool to investigate therapeutic interventions with respect to their influence on cytokine secretion of autoreactive T cells. © 1996 Wiley-Liss, Inc.     

Reduced Th1 and enhanced Th2 immunity after immunization with Alzheimer's beta-amyloid(1-42)

It has been demonstrated that immunization of transgenic mouse models of Alzheimer's disease (AD) with amyloid-beta(1-42) peptide (Abeta(1-42)) results in prevention of Abeta plaque formation and amelioration of established plaques in the brain. As the response of the T lymphocyte helper (Th) arm of the immune response had not yet been investigated after Abeta immunization, we i.p. immunized C57BL/6 mice with Abeta(1-42), Abeta(1-40), or phosphate-buffered saline (PBS), and examined markers of Th1 and Th2 immune responses in spleen and in splenocytes from these mice. Spleens from Abeta(1-42)-immunized mice demonstrated decreased interleukin-12 receptor beta chain expression compared to mice immunized with Abeta(1-40) or PBS. Consistently, following stimulation with concanavalin A or anti-CD3 antibody, primary splenocytes from Abeta(1-42)-immunized mice demonstrated elevated secretion of interleukin-4 and interleukin-10, and decreased levels of interferon-gamma. To validate this Th1-->Th2 shift in a transgenic mouse model of AD, we immunized Tg APP(sw) mice (line 2576) with Abeta(1-42) and found decreased Th1 (interleukin-2 and interferon-gamma) and elevated Th2 (interleukin-4 and interleukin-10) cytokines in their stimulated primary splenocytes. Interferon-gamma was markedly reduced and interleukin-10 was increased in blood plasma from these mice, effects that were associated with dramatically mitigated Abeta deposition after Abeta(1-42) immunization. Taken together, these results show enhanced Th2 and down-regulated Th1 immunity following immune challenge with Abeta(1-42).     

Defective regulation of IFNgamma and IL-12 by endogenous IL-10 in progressive MS

BACKGROUND: MS is a chronic inflammatory disease of the CNS postulated to be a Th1 type cell-mediated autoimmune disease. There is increased interferon-gamma (IFNgamma) secretion in MS, and IFNgamma administration induces exacerbations of disease. IFNgamma expression is closely regulated by a number of cytokines produced by different cells of the immune system. Interleukin-12 (IL-12) is a major factor leading to Th1-type responses, including IFNgamma secretion, and there is increased secretion of IL-12 in MS. IL-10 is a potent inhibitor of both IL-12 and IFNgamma expression. METHODS: The authors investigated cytokine production and proliferative responses of peripheral blood mononuclear cells stimulated with soluble anti-CD3 in healthy controls and patients with stable relapsing-remitting MS or progressive MS. RESULTS: The authors found that T cell receptor-mediated IFNgamma and IL-10 secretion were increased in progressive MS, whereas IL-4 and IL-2 secretion and lymphocyte proliferative responses were normal. Anti-IL-12 antibody suppressed raised IFNgamma in progressive MS but did not affect raised IL-10. In addition, neutralization of endogenous IL-10 upregulated IFNgamma in controls but not progressive MS. IL-10 was produced by CD4+ cells whereas IFNgamma was produced by both CD4+ and CD8+ cells. There were no differences in IL-10 receptor expression in MS patients. CONCLUSIONS: These abnormalities in IL-10 regulation were not seen in the relapsing-remitting form of MS. Thus, the defect in regulation of both IL-12 and IFNgamma production by endogenous IL-10 in progressive MS could be an important factor involved in the transition of MS from the relapsing to the progressive stage and has implications for treating MS patients with exogenous IL-10.     

Sleep associated regulation of T helper 1/T helper 2 cytokine balance in humans

Recent human studies suggested a supportive influence of regular nocturnal sleep on immune responses to experimental infection (vaccination). We hypothesized here that sleep could ease such responses by shifting the balance between T helper 1 (Th1) and T helper 2 (Th2) cytokine activity towards Th1 dominance thereby favoring cellular over humoral responses to infection. We compared the Th1/Th2 cytokine balance in 14 healthy men during regular nocturnal sleep (between 23:00 and 07:00 h) and while remaining awake during the same nocturnal interval, in a within-subject cross-over design. Blood was collected every 2 h. Production of T cell derived cytokines--interferon-gamma (IFN-gamma), interleukin-2 (IL-2), interleukin-4 (IL-4), and tumor necrosis factor-alpha (TNF-alpha)--was measured at the single cell level using multiparametric flow cytometry. Also, several immunoactive hormones--prolactin, growth hormone (GH), thyroid stimulating hormone (TSH), cortisol, and melatonin--were measured, the release of which is known to be regulated by sleep. Compared with wakefulness, early nocturnal sleep induced a shift in the Th1/Th2 cytokine balance towards increased Th1 activity, as indicated by an increased (p <.05) ratio of IFN-gamma/IL-4 producing T helper cells. However, the Th1 shift was only of moderate size and replaced by Th2 dominance during late sleep (p <.05). It could be mediated via release of prolactin and GH which both were distinctly increased during sleep (p <.001). Though unexpected, the most pronounced effect of sleep on T cell cytokine production was a robust decrease in TNF-alpha producing CD8+ cells probably reflecting increased extravasation of cytotoxic effector and memory T cells.     

CD40 engagement stimulates IL-12 p70 production by human microglial cells: basis for Th1 polarization in the CNS

The APC-derived cytokine interleukin (IL)-12 polarizes CD4 T cells towards the pro-inflammatory Th1 phenotype and has been shown to be crucial for the development of EAE in rodents. In this study we demonstrate that production of IL-12 by human adult CNS-derived microglial cells can be triggered by cell contact with activated T cells. Microglial activation and IL-12 production can be blocked by anti-CD154 mAbs. IL-12 production could also be induced by direct engagement of CD40 on microglia using a CD40 agonist. IL-12 secretion by microglia is significantly reduced by TNF and IFN-gamma antagonists showing that the IL-12 production is subject to regulation by auto- and paracrine stimuli.     

Th1 polarization of CD4+ T cells by Toll-like receptor 3-activated human microglia

ABSTRACT: Toll-like receptors (TLRs) are expressed by human microglia and translate environmental cues into distinct activation programs. We addressed the impact of TLR ligation on the capacity of human microglia to activate and polarize CD4 T cell responses. As microglia exist under distinct states of activation, we examined both ramified and ameboid microglia isolated from adult and fetal CNS, respectively. In vitro, ligation of TLR3 significantly increased major histocompatibility complex and costimulatory molecule expression on adult microglia and induced high levels of interferon-alpha, interleukin-12p40, and interleukin-23. TLR4 and, in particular, TLR2 had a more limited capacity to induce such responses. Coculturing allogeneic CD4 T cells with microglia preactivated with TLR3 did not increase T cell proliferation above basal levels but consistently led to elevated levels of interferon-gamma secretion and Th1 polarization. Fetal microglial TLR3 responses were comparable; in contrast, TLR2 and TLR4 decreased major histocompatibility complex class II expression on fetal cells and reduced CD4 T cell proliferation to levels below those found in untreated cocultures. All 3 TLRs induced comparable interleukin-6 secretion by microglia. Our findings illustrate how activation of human microglia via TLRs, particularly TLR3, can change the profile of local CNS immune responses by translating Th1 polarizing signals to CD4 T cells.