尾静脉注射质粒巨噬细胞-粒细胞集落刺激因子诱导扩增小鼠肝脏CD11c+树突状细胞

目的 探讨载粒巨噬细胞-粒细胞集落刺激因子(GM-CSF)基因质粒在小鼠体内扩增肝脏CD11c+树突状细胞(DC)的方法.方法 采用快速尾静脉椎注法将含20 μg GM-CSF基因质粒的生理盐水2.0 ml导入小鼠肝脏内,对照组注射增强型绿色荧光蛋白(EGFP)基因.第7天取肝,胶原酶消化、密度梯度离心、磁珠标记等分选出DC.Giemsa染色作形态学观测,采用流式细胞术分析其免疫表型.结果 实验组小鼠肝脏非实质细胞(NPC)大量增殖,主要分布于门静脉及其周围区域,质粒处理组中CD11c+DC比例较对照组显著增多(29.31％比6.77％,P＜0.05).Giemsa染色显示两组DC细胞核形状不规则,胞质无颗粒,然而实验组DC较对照组有明显凸起.流式细胞仪检测结果显示实验组DC较对照组明显成熟,CD40、CD80、CD86表达显著增高(P＜0.05).结论 经快速尾静脉推注质粒GM-CSF的方法可显著可靠地扩增肝脏CD11c+DC的数量.     

树突状细胞在无精子症睾丸组织中的免疫表型分析

目的探讨树突状细胞(Dendritic cell,DC)在非梗阻性无精子症患者睾丸中的免疫表型及其分子机制。方法采用免疫组织化学染色法检测10例正常人及25例无精子症患者睾丸中CD3,CD1a,CD11c,CD123,DC-SIGN(DC-specific ICAM-grabbing non-integrin),CD83,HLA-DR表达水平,并进行体视学分析。结果正常组及无精子症组均有CD1a、CD11c、DC-SIGN、HLA-DR表达,并主要分布于睾丸间质。无精子症组CD1a、CD11c、DCSIGN、HLA-DR表达水平较正常组显著增高,差异有显著性(P0.05)。正常组无CD123及CD83表达,无精子症组CD123、CD83高表达。结论非梗阻性无精子症患者睾丸中CD1a+朗格汉斯细胞(Langerhans cell,LC)、DCSIGN+间质型DC(Stromal DC)、CD123+浆细胞样DC(Plasmacytoid DC,pDC)及CD11e+髓样DC(Myeloid DC,mDC)表达水平显著增高并趋向分化成熟,提示DC在无精子症发生发展过程中可能起重要作用。     

次级淋巴趋化因子(SLC/CCL21)基因与肿瘤裂解产物构建树突状前列腺癌瘤苗的抗肿瘤免疫作用研究

目的 探讨转染次级淋巴趋化因子基因的树突细胞(DC)瘤苗在小鼠前列腺癌中的抗肿瘤效应.方法 通过脂质体法将次级淋巴趋化因子基因转染至小鼠骨髓来源的树突状细胞,构建DC瘤苗;逆转录-聚合酶链反应检测SLC;种瘤24 d后SLC组的瘤体平均体积为(1430±86)mm3,45 d后仍有50%的荷瘤小鼠存活,与其他两组比较差异有统计学意义(P＜0.05);免疫组织化学荧光染色可见SLD组中CD4+、CD8+T细胞和CD11+DC的浸润率分别为(15.24±0.67)%、(¨.02±0.73)%和(14.50±0.51)%,与DC组比较差异有统计学意义(P＜0.05).结论 转染SLC的DC瘤苗能有效诱导抗肿瘤的免疫效应,其免疫效应是通过趋化大量CD4+、CD8+T细胞及CD11+DC至肿瘤部位而发挥作用.     

慢性肝损伤时肝内干细胞的增殖

目的：采用免疫组织化学的方法研究慢性肝损伤时肝干细胞在肝脏内的分布和增值,初步探讨肝脏的损伤修复与肿瘤发生的细胞生物学机制。方法：3,-me-DAB喂食大鼠四周,建立应激模型刺激大鼠肝内干细胞的迅速增殖,取材、固定制成石蜡切片,ABC法检测肝干细胞特异性的表面标记蛋白CD34、C-11、CK19、OV6和神经前体细胞的特异性表面标记Nestin在大鼠肝脏内的表达。结果：大鼠肝实质结构改变显著,汇管区内结缔组织细胞大量增生,浸润周围肝组织形成假小叶。靠近界板处断续的排列着卵圆样细胞分别表达CD34、CK19、OV6和Nestin,阳性细胞的形态和分布特点相似,而且具有典型的干细胞的特点。此外,肝实质内可见大量的单个核样干细胞分别表达OV6、CD34、Nestin和CK19。这些细胞类似造血系统来源的单核细胞分布在肝索、肝血窦、肝内血管、增生的小叶间胆管和胆管之间,多见于汇管区的结缔组织内。结论：3’-me-DAB作用后,肝内存在着多种干细胞,而且具有空间分布的规律性。增生的干细胞在损伤应激下继续增殖分化为肝实质细胞,参与肝脏的组织修复,同时成为引发肝脏肿瘤的可能原因之一,具体机制还需要进一步的深入研究。     

结肠癌术后联合树突状细胞免疫治疗的临床研究

目的 评价结肠癌术后联合树突状细胞(DC)免疫治疗的临床疗效.方法 将40例接受结肠癌D3根治术并进行一次化疗的患者分为两组,一组在化疗后不进行DC免疫治疗;一组在术中采集新鲜肿瘤组织样本,并在化疗后进行自体肿瘤抗原负载DC免疫治疗.采集自体外周血,诱导制备自体肿瘤抗原负载的DC,进行4次免疫注射为1个疗程,前2次每周进行注射,后2次隔周进行注射.比较两组治疗前后细胞因子水平的变化,同时对治疗组进行迟发性超敏反应(DTH)检测及随访,观察患者的免疫应答与临床疗效.结果 制备获得成熟DC(mDC),细胞活率>95%,CD11c+CD14-细胞平均为90.24%±2.73%,CD11c+ HLA-DR+细胞平均为83.58%4±1.36%,CD80+细胞平均为87.92%±4.41%,CD83+细胞平均为62.48%±4.45%,CD86+细胞平均为97.72%±3.86%.治疗组患者细胞因子水平比对照组明显升高,差异有统计学意义(P<0.05),其中尤以IFN-γ升高最为明显(P<0.01).15例进行DTH检测的患者中有8例呈阳性,经过6～36个月随访,治疗组有1例患者复发,常规治疗组有1例复发,1例死亡.两组的中位无疾病进展期分别是22个月和17个月,差异有统计学意义(P<0.05).此外在DC治疗组中DTH阳性的患者无1例出现复发及转移.结论 结肠癌术后联合DC治疗可以改善患者机体的免疫功能,激发特异性免疫应答,取得了一定的临床疗效.     

RNA干扰技术阻断CD40/CD40L共刺激通路对小鼠移植心存活时间的影响

目的 探讨慢病毒介导RNA干扰(RNAi)技术阻断CD40/CD40L共刺激通路对小鼠移植心存活时间的影响.方法 以针对小鼠CD40基因的RNAi慢病毒载体在体外感染供者骨髓来源的树突状细胞(DC),制备低表达CD40的耐受性DC(Tol-DC).荧光实时定量聚合酶链反应及流式细胞术检测DC感染前后CD40 mRNA及DC表面抗原CD40、CD11c和MHCⅡ的表达.建立小鼠异位腹腔心脏移植模型.在小鼠异位心脏移植前7 d,经静脉给受者输注体外制备的低表达CD40的Tol-EC(慢病毒感染DC注射组),并设置单纯移植对照组和未感染DC注射组作为对照.观察各组移植心的存活时间,评定各组术后第7天移植心排斥反应的病理分级.结果 CD40-RNAi慢病毒载体在体外感染DC 48 h后,CD40 mRNA表达明显受到抑制,抑制率为80.9%;CD40表达明显下降,由(74.37±4.08)%降至(40.07±4.03)%(P＜0.05).单纯移植对照组、未感染DC注射组和慢病毒感染DC注射组移植心存活时间分别为:(8±2)d、(9±1)d和(14±4)d,慢病毒感染DC注射组移植心存活时间明显延长,并且移植心排斥反应病理分级显著降低,差异有统计学意义(P＜0.05).结论 阻断CD40/C40L共刺激通路可抑制异系T淋巴细胞的活化,从而抑制急性排斥反应,延长小鼠移植心的存活时间.     

转染RhoA基因对树突状细胞抗胃癌功能的影响

目的 研究转染RhoA基因对树突状细胞(DC)免疫功能的影响,观察修饰后的DC在体外诱导高效而特异的抗胃癌免疫效应.方法 用增强型绿色荧光蛋白标记的RhoA重组腺病毒载体作为介质,将RhoA基因转染入DC,用RT-PCR法检测培养上清RhoA基因的表达.检测这种DC分泌细胞因子IL-12、TNF-α的功能,以及表面分子CD1α、CD83、MHC-Ⅱ、CD80、CD86的表达,用MTT法诱导人特异的细胞毒性T淋巴细胞的能力. 结果培养上清中均可以检测到RhoA基因表达;在这种转基因DC的上清中IL-12、TNF-α 含量分别为(301±24)和(418±64)pg/ml,明显比非转染的DC组高,P＜0.05;转基因DC表面高表达CD1α(70.13±0.03)、CD83(68.10±0.03)、MHC-Ⅱ(69.73±0.13)、CD80(78.73±0.25)、CD86(74.20±0.05),而在非转染的DC中是低表达的;经转染RhoA基因的DC提呈的T细胞对胃癌细胞的杀伤率为87%,而未修饰的DC杀伤作用较低. 结论RhoA基因转染修饰的DC能诱导细胞毒性T淋巴细胞的特异性,显著地提高DC的抗原提呈功能,在体外能诱导高效而特异的抗胃癌免疫效应.     

GM-CSF调节树突状细胞对移植免疫应答的影响

目的　观察GM CSF对移植免疫应答的影响 ,探讨树突状细胞 (DC)亚群在其中的作用。方法　BALB/C小鼠每日给予 10 μgrhGM CSF ,皮下注射 ,6h后收集外周血 ,分离DC ,流式细胞技术检测DC1(CD8a CD11c ) /DC2 (CD8a CD11c )的比例变化 ;再给予C5 7BL/ 6的外周血单个核细胞 (PBMC)致敏后 ,检测小鼠Th1和Th2细胞因子的变化 ,进行单向混合淋巴细胞反应(MLR) ;并且行小鼠同种异体心脏移植了解移植免疫应答的变化。结果　rhGM CSF刺激后 ,外周血DC1与DC2的比值显著升高 (17.9± 7.6vs 3 .9± 1.2 ,P <0 .0 1) ,体内Th1细胞因子水平明显升高 ,MLR强度增强 ,同种异体小鼠移植心脏存活时间缩短 [(6.2± 1.2 )dvs (7.7± 1.0 )d(P <0 .0 5 ) ]。结论　GM CSF体内应用可以增加DC1绝对数和其与DC2的比值 ,使机体免疫应答向Th1方向倾斜 ,增强移植免疫排斥反应。     

CD117与CD34在胃肠道间质瘤中的表达

目的探讨胃肠道间质瘤的临床病理和免疫组化特征.方法观察40例间质瘤的病理形态特征,并用免疫组化S-P法检测CD117与CD34的表达情况.结果镜下梭形细胞为主型30例(75%),上皮样细胞为主型8例(20%),混合细胞型2例(5%).免疫组化显示CD117与CD34的阳性率分别为90%和83%,其表达率与肿瘤大小、核分裂数及组织学类型无关.结论联合检测CD117与CD34可以提高间质瘤的诊断准确率,但不能判断良恶性程度.     

肝硬化与肝脏免疫系统(文献综述)

肝硬化不但存在全身免疫功能紊乱 ,而且肝脏本身免疫也出现异常。本文综述肝内免疫功能变化。肝内CD4+ /CD8+ 细胞比例下降 ,淋巴细胞随病变不同而分布不同 ,坏死区CD8+ 细胞占优势 ,汇管区以CD4+ 细胞增多为主 ;早期Th1细胞占优势 ,之后逐渐向Th2细胞漂移。晚期多种细胞因子mRNA表达上调。肝内NK细胞、巨噬细胞增多 ,随着疾病的进展而逐渐减少     

Characterization of interstitial dendritic cells in human liver

Sensitive immunofluorescence and immunoperoxidase techniques were used to test an extensive range of monoclonal antibodies for reactivity with Kupffer cells and interstitial dendritic cells (DCs) in cryostat-cut sections of human liver. Leucocytes with a dendritic cell morphology were identified with CD45 (antileucocyte common) reagents in portal tracts, predominantly around bile ducts, and these cells stained strongly for the HLA-DP, DQ, and DR antigens. Kupffer cells stained less intensely with anti-class-II reagents, particularly anti-HLA-DQ. The interstitial DCs expressed the LFA-1 antigen but failed to stain with CD11b, CD11c, and the defined T and B cell CD antibodies; nor did they stain with antibodies to FcR1, FcR11, FcRIII, or the C3b receptor. Of the myeloid monoclonal antibodies available from the 3rd Leucocyte Differentiation Antigen Workshop, only Y2/131, Ki-M7, Ki-M8, and a minority of CD14 antibodies stained DCs, whereas Kupffer cells showed a wider reactivity with antimacrophage antibodies including those of workshop groups 11, 15, 16, and other unique antibodies. A 2nd probable DC population was identified in the liver capsule that had a similar phenotype to portal interstitial DCs. Although some minor phenotypic differences between liver portal DCs and the phenotypes of Langerhans cells and isolated tonsil DCs were noted, our results support the view that there is a unique hemopoietic lineage of DCs. The presence of DCs, which stimulate strong allogeneic T cell responses, in the portal triads is consistent with the fact that the histologic changes of graft-versus-host disease seen in bone marrow transplantation and the lymphocytic infiltrate in a rejecting liver allograft occur predominantly in the periportal region.     

大鼠树突状细胞CD86分子小干扰RNA慢病毒载体构建及其功能

目的 观察针对大鼠树突状细胞(DCs)表面共刺激分子CD86的小干扰RNA(siRNA)慢病毒载体转染骨髓来源大鼠DCs后,CD86分子mRNA水平变化及DC刺激T淋巴细胞增殖能力的变化.方法 将针对大鼠DCs表面共刺激分子CD86的siRNA慢病毒载体转染骨髓来源大鼠DCs,逆转录.聚合酶链反应(RT-PCR)方法 检测CD86分子mRNA水平,MLR检测转染后的树突状细胞刺激T淋巴细胞增殖能力的变化.结果 转染组CD86分子mRNA水平较未转染组及阴性对照组有明显下降.MLR中各实验组DC与细胞1:1、1:10、1:50混合72 h后492 nm吸光度值分别为,未转染组:0.876±0.117、0.582±0.085、0.472±0.034;阴性对照组:0.870±0.140、0.541±0.066、0.438±0.067;转染组:0.394±0.143、0.294±0.032、0.218±0.015.表明转染后的DCs刺激T淋巴细胞增殖的能力较未转染组及阴性对照组显著降低.结论 实验所用针对CD86分子的siRNA慢病毒载体,可以特异性的抑制大鼠树突状细胞CD86基因的表达,降低树突状细胞对T淋巴细胞的刺激增殖能力.     

CD4+ CD25+ regulatory T cells suppressed the indirect xenogeneic immune response mediated by porcine epithelial cell pulsed dendritic cells

Nishimura T, Onda M, Takao S. CD4⁺ CD25⁺ regulatory T cells suppressed the indirect xenogeneic immune response mediated by porcine epithelial cell pulsed dendritic cells. Xenotransplantation 2010; 17: 313–323. © 2010 John Wiley & Sons A/S. Abstract: Background: CD4⁺ CD25⁺ regulatory T cells have been reported to suppress T cell‐mediated xenogeneic immune responses. Although the direct T cell response to xenogeneic cells is important, the indirect xenogeneic immune response mediated by dendritic cells (DCs) is also likely involved in rejection. We have generated an in vitro indirect immune reaction model and evaluated the effect of CD4⁺ CD25⁺ regulatory T cells on this system. Methods: Human DCs were generated from peripheral blood and cultured with X‐ray‐irradiated porcine kidney epithelial cells. Porcine cell‐pulsed DCs were mixed with autologous CD4⁺ T cells, CD4⁺ CD25^? T cells and/or CD4⁺ CD25⁺ T cells. After 7 days of culture, T cell proliferation was measured. Results: The co‐culture of human DCs and X‐ray‐irradiated porcine epithelial cells resulted in observable DC phagocytic activity within 2 days. These porcine cell–pulsed DCs stimulated CD4⁺ T cell proliferation much more potently than unpulsed DCs or porcine cells. This proliferation was blocked by CTLA4‐Ig or an anti‐HLA‐DR antibody. CD4⁺ CD25⁺ regulatory T cells also suppressed CD4⁺ CD25^? T cell proliferation in response to porcine cell‐pulsed DCs. Conclusions: An in vitro model of the indirect xenogeneic immune response was established. Porcine cell‐pulsed DCs stimulated CD4⁺ T cells, and CD4⁺ CD25⁺ regulatory T cells suppressed this response.     

自然成熟型树突状细胞对 CD4+CD25+调节性 T细胞扩增的影响

目的：探讨自然成熟型树突状细胞对CD4^＋CD25^＋调节性T细胞扩增机制。方法：提取DAB／2小鼠脾脏及肝脏细胞,流式细胞仪分离树突状细胞,测定其纯度及表型,加入C3H／HeJ小鼠提取的CD4^＋CD25^＋调节性T细胞混合培养,测定其增殖活性。利用CD4^＋CD25-T细胞测定扩增后的CD4^＋CD25^＋调节性T细胞的免疫抑制活性。结果：成熟型树突状细胞表达高水平的共刺激分子CD40、CD80及CD86,对CD4^＋CD25^＋调节性T细胞扩增效果明显。与新鲜分离的CD4^＋CD25^＋调节性T细胞一样,扩增的CD4^＋CD25^＋调节性T细胞高表达Foxp3,而且均保持了其抑制活性。结论：自然成熟型树突状细胞能扩增CD4^＋CD25^＋调节性T细胞,且扩增后的调节性T细胞保持了其表达活性和抑制活性。     

Graded function of CD80 and CD86 in initiation of T-cell immune response and cardiac allograft survival.

CD28 and cytotoxic T-lymphocyte antigen-4 (CTLA-4), which have opposing functions in T-cell responses, share the two ligands, CD80 (B7-1) and CD86 (B7-2). To understand the functions of CD80 and CD86, respectively, CD80(low) dendritic cells (DCs) and CD86(low) DCs were prepared by using RNA interference. Then CD80 and CD86 functions were analysed by in vitro mixed lymphocyte reaction and cytokine production assay. Effect on cardiac allograft survival was assayed in vivo. In this study, graded stimulatory function of CD80 and CD86, stronger inhibition of proliferation, and stronger prolongation of transplant survival were observed when CD80 and CD86 were blocked simultaneously.     

Sequential delivery of maturation stimuli increases human dendritic cell IL-12 production and enhances tumor antigen-specific immunogenicity

BACKGROUND: Despite the increasing use of dendritic cells (DCs) in clinical trials, questions regarding the optimal means of DC preparation, in particular how to achieve optimal maturation, remain unanswered. We hypothesized that delivering two separate sequential maturation signals to DC in vitro, mimicking the process of DC maturation that occurs in vivo, would enhance the ability of DCs to generate antigen-specific effector T cells in an experimental in vitro antimelanoma model. MATERIALS AND METHODS: Human monocyte-derived DCs were transfected with mRNA encoding melanoma-associated antigen Mart-1 (MART) or influenza M1 matrix protein (M1). After mRNA transfection, DCs were left untreated or exposed to different maturation stimuli either added simultaneously or delivered sequentially 18 h after first stimulation. Phenotypic DC cell-surface marker changes and IL-12 secretion were analyzed. Specific antigen presentation by DCs was measured by IFN-gamma release Elispot assay using a CD8(+) MART peptide-specific T cell clone. RNA-transfected and treated DCs were cultured with autologous naive T cells and the induction of antigen-specific effector T cells were assessed by IFN-gamma release Elispot assay. RESULTS: DCs transfected and matured had increased cell-surface expression of CD40 and costimulatory molecules CD80, and CD86. DCs matured and further treated by soluble CD40 ligand (sCD40L) had a 10- and 2-fold increase in MART antigen presentation compared to untreated (immature) DCs and DCs treated only with a first maturation signal, respectively (Elispot P = 0.02). Delivery of sequential maturation stimuli resulted in maximal DC IL-12 secretion compared to simultaneous stimuli. Last, generation of antigen-specific effector T cells more than doubled with the sequential addition of sCD40L to mature DC stimulators (Elispot P = 0.009). CONCLUSIONS: Maturation of DCs following mRNA transfection increases expression of cell-surface costimulatory molecules. Delivery of a second sequential maturation stimulus enhances antigen presentation, increases IL-12 secretion, and augments immunogenicity as evidenced by generation of tumor antigen-specific effector T cells. This strategy should be considered in the future development of RNA-based DC vaccine strategies for the treatment of cancer.     

Effects of cyclophilin A on myeloblastic cell line KG-1 derived dendritic like cells (DLC) through p38 MAP kinase activation

BACKGROUND: Cyclophilin A (CypA) is a ubiquitously distributed intracellular protein as well as a secreted protein and has recently been reported to be an immunomodulatory molecule. The objective of this study was to determine the effect of CypA on dendritic cell (DC) differentiation, activation, and functional maturation. The role of p38 MAP kinase in DC functions was also investigated. MATERIALS AND METHODS: KG1 cells (CD34+ human myeloblastic cell line) were treated with cytokines (GM-CSF+IL-4) and/or CypA and expression of cell surface markers was analyzed by FACS analysis. The antigen-uptake capacity of different DCs was determined by FITC-dextran uptake assay. Antigen-presentation capacity of DCs was determined by allogeneic mixed lymphocyte reaction (MLR) by [3H] thymidine incorporation assay. To assess the T cell polarization stimulated by KG1 derived DCs, various Th1 and Th2 cytokines secreted by allostimulated CD4+ and CD8+ T cells were determined by Bioplex cytokine assay. Total and phosphorylated p38 MAPK activity in CypA treated DCs was detected by Bioplex p38 total and phosphoprotein assay. RESULTS: During the differentiation of KG1 cells to immature DCs, cell surface expression of CD11b was increased by 30.6% for CypA alone, 55% for CypA plus cytokines, and 44% for cytokines alone. Similarly, CypA alone increased the cell surface expression of CD11c by 59% as compared to CypA plus cytokines (68%) and cytokines alone (50%). CypA up-regulated the antigen uptake capacity of the immature DCs to a greater extent (5 times) as compared to cytokines alone (2.5 times). Moreover, CypA augmented the capacity of DCs to present antigens to allogenic CD8+ T cells, and also increased the secretion of Th1 type cytokines TNF-alpha and IFN-gamma from the allogenic CD4+ T cells. Furthermore, CypA induced the phosphorylation and hence activation of MAP kinase p38. Pre-treatment with SB-203580, a p38 inhibitor, significantly reduced MLR stimulatory capacity of CypA-induced DCs in both CD8+ and CD4+ T cells (P < 0.05). CONCLUSIONS: CypA enhances DC differentiation and maturation by up-regulating CD11b and CD11c expression. CypA can also augment DC antigen uptake and antigen presentation, which may be mediated by the p38 signaling pathway.     

Analysis of INF-gamma, TNF-alpha and dendritic cells to predict hepatitis C virus recurrence in liver transplant patients

INTRODUCTION: Hepatitis C virus (HCV) infection is one of the leading causes of chronic liver disease and the reason for more than 50% of liver transplantations (OLT). Recurrent HCV infection occurs in almost all transplant recipients and has an unfavorable course. Although immunosuppressive agents are necessary to avoid allograft rejection, these drugs may favor viral replication facilitating viral-mediated graft injury. METHODS: To predict the evolution of two HCV(+) patients who underwent OLT, we studied INF-gamma and TNF-alpha production and the maturation capacity of dendritic cells (DCs) at three time points: before transplantation (Pre-Tx) and at 2 (2M) and 6 (6M) months after transplantation. Cytometric bead assays were used to quantify INF-gamma and TNF-alpha production in the supernates of mixed leukocyte reactions (MLR) between spleen cells from the liver donor and CD4(+) cells from the recipients. Immature and mature DCs were generated in vitro from patient monocytes. RESULTS: The one patient who experienced recurrent HCV showed loss of CD4(+) responses to donor antigens and INF-gamma and TNF-alpha production after OLT. In contrast, the other patient maintained detectable levels of these cytokines after OLT. It was possible to generate mature DCs from monocytes with the aid of CD40L in both cases, but decreased expression of HLA-DR, CD80, and CD86 markers was observed upon posttransplantation analyses in the patient with recurrent HCV. CONCLUSION: Loss of the proliferative response as well as INF-gamma and TNF-alpha production, together with a decreased HLA-DR, CD80, and CD86 (markers of mature DCs), indicated an inadequate immune response to viral progression in the liver transplant recipient with relapsing HCV infection.     

Antigen presentation by dendritic cells in renal lymph nodes is linked to systemic and local injury to the kidney

BACKGROUND: Dendritic cells (DCs) uniquely serve as conduits between innate and cognate arms of the immune system. The normal kidney contains an extensive population of interstitial DCs but their role in the pathogenesis of acute renal injury is not known. METHODS: Renal DCs were studied by flow cytometric analysis of collagenase-digested mouse kidneys, by immunohistochemistry, and by immunofluorescence microscopy. In vivo ingestion by DCs of intravenously administered fluorescein isothiocyanate (FITC)-dextran particles was examined. A model antigen system (presentation of ovalbumin-derived peptide to TCR transgenic CD4+ T-cells) was employed to examine the influence of systemic (lipopolysacchride injection) and localized (unilateral renal artery clipping) renal injury on DC-mediated T-cell activation in the renal lymph nodes (RLNs). RESULTS: Renal DCs were shown to constitute the predominant source of T-cell stimulatory capacity within the kidney, and to avidly ingest both filtered and non-filtered particles. Lipopolysaccharide resulted in disappearance of DCs from the renal interstitium within 48 hours. This was accompanied by increased renal lymph node DCs, some of which contained intracellular Tamm-Horsfall Protein, indicating abnormal trafficking of kidney-specific antigens following renal injury. Lipopolysaccharide enhanced DC-mediated proliferation of ovalbumin-specific CD4(+ve) T-cells within the draining RLN. Unilateral renal ischemia augmented the capacity for DC-mediated T-cell activation in the lymph nodes draining both the ischemic and nonischemic kidney. CONCLUSION: Renal DCs respond to systemic or localized acute renal injury by increasing the traffic of protein antigens from kidney to RLN, resulting in a concomitant increased potential for localized activation of antigen-specific CD4(+ve) T-cells.     

Recipient Dendritic Cells,But Not B Cells,Are Required Antigen‐Presenting Cells for Peripheral Alloreactive CD8+ T‐Cell Tolerance

Induction of mixed allogeneic chimerism is a promising approach for achieving donor‐specific tolerance, thereby obviating the need for life‐long immunosuppression for solid organ allograft acceptance. In mice receiving a low dose (3Gy) of total body irradiation, allogeneic bone marrow transplantation combined with anti‐CD154 tolerizes peripheral CD4 and CD8 T cells, allowing achievement of mixed chimerism with specific tolerance to donor. With this approach, peripheral CD8 T‐cell tolerance requires recipient MHC class II, CD4 T cells, B cells and DCs. Recipient‐type B cells from chimeras that were tolerant to donor still promoted CD8 T‐cell tolerance, but their role could not be replaced by donor‐type B cells. Using recipients whose B cells or DCs specifically lack MHC class I and/or class II or lack CD80 and CD86, we demonstrate that dendritic cells (DCs) must express CD80/86 and either MHC class I or class II to promote CD8 tolerance. In contrast, B cells, though required, did not need to express MHC class I or class II or CD80/86 to promote CD8 tolerance. Moreover, recipient IDO and IL‐10 were not required. Thus, antigen presentation by recipient DCs and not by B cells is critical for peripheral alloreactive CD8 T cell tolerance.