慢性乙型肝炎患者树突状细胞体外功能恢复及诱导T细胞反应研究

目的 研究慢性乙型肝炎(CHB)患者外周血树突状细胞(DC)和T细胞体外功能,并尝试恢复功能的方法.方法 12例CHB患者作为研究对象,10例健康人作为正常对照研究.对外周血DC进行表型分析和混合淋巴细胞反应(MLR)测定,并分别用HBsAg或HBcAg作为抗原负载DC,后用ELIspot法检测产生IFN-γ的细胞频数.结果 CHB患者外周血DC共刺激分子水平表达降低,刺激MLR能力不足.经过体外补充促成熟细胞因子,DC缺陷能够得到部分纠正.成熟DC较不成熟Dc刺激MLR和诱导产生IFN-γ的T细胞能力强,HBcAS比HBsAS有更强的免疫原性.结论 慢性CHB患者外周血DC功能缺陷,能够通过补充促成熟因子纠正.成熟DC比不成熟DC显示出更强的MLR反应和诱导IFN-γ产生细胞的能力,这提示HBV蛋白负载DC作为治疗性疫苗具有可行性.     

pCP能够增强树突状细胞对乙肝表面抗原肽提成能力

目的:研究对氯苯酚(pCP)对乙肝疫苗反应性差志愿者外周血分离、诱导的DC细胞对乙肝表面抗原肽(HB-sAg)的负载及抗原提呈能力的影响.方法:用梯密度离心法分别分离10例对乙肝疫苗反应性差志愿者外周血单核细胞,黏附的单核细胞培养液中加入HBsAg、rhGM-CSF、rhIL-4、pCP培养7 d诱导成熟的DC细胞(实验组),培养体系中不加入pcP为阴性对照组,不加入pCP及HBsAg为空白对照组,ELISA实验检测各自上清其IL-12水平;培养7 d后DC细胞与自身T淋巴细胞共培养3 d后收集上清,ELISA实验检测其IFN-γ含量.结果:IL-12的水平在实验组(265.68±16.21)ng/L明显高于阴性对照组(168.76±10.01)ng/L(P<0.05)及空白对照组(87±5.79)ng/L(P<0.05);与自身T淋巴细胞共培养3 d后,上清中IFN-γ水平在实验组(773.04 ±32.73)mg/L也明显高于阴性对照组(573.59±26.11)mg/L(P<0.05)及空白对照组(362.81±24.27)mg/L(P<0.05).结论:pCP能够有效增强乙肝疫苗反应性差志愿者外周血分离、诱导的DC细胞埘HBsAg的负载及抗原提成能力,这种效应也能明显增强成熟的CD细胞对自身T淋巴细胞的刺激力,有望成为乙肝疫苗佐剂提高其临床效率.     

PTD-HBcAg融合蛋白经树突状细胞诱导特异性CTL抑制HBV的体外研究

目的:探讨经PTD-HBcAg融合蛋白致敏的树突状细胞(DCs)体外诱导特异性细胞毒T淋巴细胞(CTLs)对HBV的抑制作用.方法:体外分离培养小鼠髓源性DC,加入融合蛋白刺激DC成熟后与T淋巴细胞共培养,ELISA 法检测T淋巴细胞上清中IL-2、IL-4、IL-10和INF-γ的分泌水平,流式细胞术检测胞内细胞因子水平,乳酸脱氢酶释放试验检测特异性CTL活性,并对HepG2.2.15细胞上清中HBsAg及HBV DNA水平进行检测.结果:经不同融合蛋白刺激的DCs能有效促进T淋巴细胞的细胞因子分泌,同时融合蛋白PTD-HBcAg组中IL-2(552.7±117.5 ng/L)和INF-γ(150.6±7.945 ng/L)明显高于HBcAg组中IL-2(420±12.47 ng/L)和INF-γ(107.5±12.19 ng/L)分泌.流式细胞计数术检测的PTD-HBcAg融合蛋白诱导CTL细胞水平明显高于对照组.经PTD-HBcAg融合蛋白诱导的CTL比HBcAg有明显的特异性杀伤作用(P＜0.05),同时对HBsAg及HBV DNA水平有明显的抑制作用.结论:经PTD-HBcAg融合蛋白致敏的DCs能有效刺激T淋巴细胞分泌细胞因子及增加细胞毒T淋巴细胞的表达,并增强特异性CTL活性及对HepG2.2.15细胞上清中HBsAg及HBV DNA水平的抑制.     

重组人可溶性CD40配体对树突状细胞体外分化、成熟及功能的影响

用Ficoll密度离心及贴壁法获得外周血单个核细胞 (PBMC ) ,PBMC经细胞因子组合诱导分化成树突状细胞 (DC ) :GM CSF (10 0ng/ml)与IL 4 (5 0ng/ml)诱导 5d后 ,分别加入TNF α (10ng/ml)或rhsCD4 0L (2 μg/ml)继续培养 4d ;倒置显微镜下观察DC形态 ,免疫荧光标记和流式细胞术分析DC表型 (CD1a、CD80、CD83、HLA DR、CD14、CD16、CD19)及摄取FITC Dextran抗原的能力 ;3 H TdR掺入法检测DC刺激自体混合淋巴细胞体外增殖反应 (MLR )能力 ;ELISA法分析DC培养上清中IL 12的水平 ;Trans well细胞趋化实验检测DC对自体外周T淋巴细胞的趋化能力。发现经rhsCD4 0L刺激的DC表面分子 (CD1a、CD80、CD83、HLA DR )的表达水平高于经典的细胞因子组合组 (GM CSF +IL 4 +TNF α ) ,同时rhsCD4 0L刺激后的DC摄取FITC Dextran的能力下降而刺激自体MLR和分泌IL 12的能力明显提高 ;而且rhsCD4 0L诱导的DC表面趋化因子受体CXCR4的表达水平及对自体外周T淋巴细胞的趋化能力均强于TNF α或FL激发的DC。rhsCD4 0L在体外不仅具有显著的诱导DC分化 ,促进DC成熟的功能 ,而且经rhsCD4 0L作用的DC能更有效地激发T淋巴细胞     

荷载人生存素的多表位树突状细胞疫苗的抗肿瘤活性研究

目的:观察荷载人生存素(survivin)的多表位树突状细胞(DC)疫苗的抗肿瘤活性.方法:分别将含4个sur-vivin的HLA-A2类限制性CD8+ CTL表位和1个CD4+ Th细胞表位的重组真核表达质粒pPIRESneo3.0-survivin(4)/Th,以及含4个CD8+ CTL表位的重组质粒pPIRESneo3.0-survivin (4),转染人DC并制备DC疫苗.实验分为survivin(4)/Th组、survivin (4)组、空质粒组、未转染DC与T细胞共培养组和单独T淋巴细胞组.DC疫苗作用后,MCF-7细胞的凋亡率明显高于survivin(4)组(P＜0.05),亦明显高于空质粒组、未转染DC与T细胞共培养组和单独T淋巴细胞组(P＜0.05).运用流式细胞术(FCM)分别检测DC表面CD83、CD86、T淋巴细胞表面CD4、CD8a的表达以及DC疫苗作用后MCF-7乳腺癌细胞的凋亡.用ELISA法检测上清中IFN-γ的含量.用四甲基偶氮唑蓝(MTT)比色法检测DC疫苗诱导的CTL对MCF-7细胞的抑制率.结果:流式细胞术检测显示,人DC高表达CD83、CD86;人外周血T淋巴细胞高表达CD4、CD8a;survivin (4)/Th组IFN-γ的含量[(66.50±3.34) ng/L]明显高于survivin(4)组[(46.10±1.35)ng/L]、空质粒组[(25.17±0.32) ng/L]、未转染DC与T细胞共培养组[(25.47±0.95)ng/L]和单独T淋巴细胞组[(23.73 +0.50)ng/L],P＜0.05.survivin (4)/Th组中MCF-7细胞的抑制率明显高于survivin (4)组、空质粒组、未转染DC与T细胞共培养组和单独T淋巴细胞组(P＜0.05).DC疫苗作用后,MCF-7细胞的凋亡率[ (10.63±0.29)％]明显高于survivin(4)组(P＜0.05),亦明显高于空质粒组、未转染DC与T细胞共培养组和单独T淋巴细胞组(P＜0.05).结论:荷载多个survivin的CD8+ CTL表位的树突状细胞肿瘤疫苗具有很强的抗肿瘤活性,CD4+ Th细胞对CD8+ CTL的抗肿瘤方面有明显的促进作用.     

腺病毒介导HSP70-HBsAg嵌合基因转染树突状细胞及生物学特性分析

目的 分析携带热休克蛋白70(HSP70)和乙肝表面抗原(HBsAg)嵌合基因的腺病毒表达载体感染人外周血诱导培养树突状细胞(DC)后其生物学特性的改变.方法 从正常人外周血中分离单个核细胞,经Ad-HSP70-HBsAg感染刺激后.在含细胞因子粒细胞巨噬细胞集落刺激因子(GM-CSF)、白介素-4(IL-4)、肿瘤坏死因子(TNF-α)的培养液体中体外诱导培养DC;采用荧光倒置显微镜、RT-PCR、流式细胞仪(FACS)和混合淋巴细胞反应(MLR)试验对人外周血来源的DC进行生物学特性分析.结果 Ad-HSP70-HBsAg感染后的DC能够有效表达示踪蛋白GFP和转录基因HSP70-HBsAg,病毒感染组和对照组的DC在细胞形态、DC细胞表面分子表达和刺激同种异体的人外周血幼稚型T细胞增殖能力的方面无明显差别.结论 Ad-HSP70-HBsAg可有效转染DC,感染后的病毒对DC的生长和生物学特性无显著影响.     

卵巢癌细胞株冻融抗原负载的树突状细胞诱导CTL抗卵巢癌免疫应答的体外研究

目的研究卵巢癌冻融抗原负载的树突状细胞(dendriticcells,DC)诱导细胞毒性T淋巴细胞(CTL)体外杀伤卵巢癌细胞的细胞毒性效应。方法利用免疫磁珠分离法(MACS)分离纯化脐血CD34 细胞并在体外诱导分化为DC,用反复冻融法从卵巢癌细胞系SKOV3中提取的可溶性相关抗原负载DC。流式细胞学检测负载抗原后DC表面各种分化相关抗原的表达,ELISA法检测DC上清中IL12的表达,混合淋巴细胞反应(MLR)测定DC体外刺激T细胞增殖的能力,MTT法检测抗原负载DC激活的抗原特异性CTL对卵巢癌细胞的杀伤作用。结果与未经抗原负载的DC相比,经卵巢癌抗原负载的DC不仅能更高地表达各种DC分化相关抗原CD1α(73.35%±2.94%vs34.1%±2.35%)、CD83(73.9%±8.46%vs54.68%±3.26%)、CD80(91.95%±2.48%vs52.53%±3.18%)、HLADR(70.05%±2.35%vs48.7%±2.07%)以及CD54(88.9%±5.52%vs71.45%±2.29%),同时具有更强的刺激同种异体T淋巴细胞增殖和IL12分泌的能力(P均<0.05)。此外,卵巢癌细胞SKOV3冻融抗原负载DC激活的CTL在体外对SKOV3的杀伤率为77.35%,显著高于未经抗原负载的DC(P=0.0001)。结论经卵巢癌细胞冻融抗原负载DC激活的CTL在体外具有更强的增殖能力和杀伤卵巢癌细胞的作用。     

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。     

胰腺癌患者树突状细胞诱导I型调节性T细胞的特征及其意义

为了检测胰腺癌患者树突状细胞(dendritic cells,DC)诱导I型调节性T细胞(typeⅠregulatory T cells,Tr1)的特征、功能及其临床意义。采用外周血单核细胞来源的未成熟DC,诱导同种异体初始T细胞分化为Tr1,ELISA、流式细胞仪检测Tr1细胞因子表达水平。用混合淋巴细胞反应(mixed lymphocyte reaction,MLR)检测Tr1的免疫抑制功能。结果:经胰腺癌患者DC诱导分化的Tr1分泌IL-10(P<0.05)和TGF-β(P<0.01)水平高于正常对照组。IL-10胞内染色结果也表明,分泌IL-10的Tr1在胰腺癌组明显增加(P<0.01)。胰腺癌患者DC诱导的Tr1抑制MLR增殖的能力也明显增强(P<0.01)。胰腺癌患者DC诱导同种异体Tr1分化的能力明显增强,提示过度Tr1活化可能与胰腺癌的病理形成有关。     

人树突状细胞体外经HBsAg刺激后的抗病毒作用

目的观察人树突状细胞(DCs)经表面抗原(HBsAg)刺激、体外诱导自身特异性T淋巴细胞增殖后,对2.2.15细胞中HBeAg和HBsAg的特异性免疫抑制作用。方法 用粒细胞-巨噬细胞集落刺激因子(GM-CSF)、白介素-4(IL-4)和肿瘤坏死因子(TNF-a)分化、诱导人外周血PBMC中的DCs,在DCs成熟前加入纯的HBsAg刺激,将成熟后的DCs体外与自身T淋巴细胞共培养,同时不加HBsAg刺激的DCs与T细胞共培养、T细胞加纯的HBsAg共培养以及单纯T细胞作对照,5 d后收集T细胞,分组加入2.2.15细胞培养液中,分别收集第1天、3天、5天和7天的培养上清液,检测其HBeAg和HBsAg的分泌情况。结果经抗原刺激后的DCs可以有效提呈病毒抗原,正常人与慢性乙肝患者负载抗原后的DCs刺激T淋巴细胞增殖的能力[cpm分别为(46 700±7 850)和(38 628±5 427)]明显高于未负载抗原的DCs[cpm分别为(40 450±4 645和33 924±4 498)]及对照组PBMC[cpm分别为(5 947±476)和(5 089±233)],P<0.01。负载抗原的DCs有强烈的免疫应答活性,并且其免疫刺激能力似乎与负载的抗原量成正比;经抗原刺激激活的T细胞可以有效地抑制HBeAg的表达,但对HBsAg未发现有明显的抑制作用。结论体外经HBsAg刺激后的DCs可有效地提呈病毒抗原,并可进一步激活T细胞产生,同时能显著地抑制2.2.15细胞上清     

氧化修饰低密度脂蛋白可诱导人单核细胞源树突状细胞形成泡沫细胞

目的： 探讨氧化修饰低密度脂蛋白（ox-LDL）对人单核细胞源树突状细胞（DC）功能的影响。 方法： 采用免疫磁珠法分离人外周血CD14+单核细胞，经含rhGM-CSF（100 μg/L）和rhIL-4（20 μg/L）的Cellgro培养，使其分化为DC。DC与100 mg/L天然的或氧化修饰的LDL孵育72 h后，采用透射电镜和尼罗红染色观察细胞内脂质沉积，流式细胞术检测DC表型（CD1a，CD40，CD86，HLA-DR），混合T淋巴细胞反应检测DC对淋巴细胞增殖的影响，FITC-dextran检测DC吞噬功能，ELISA检测细胞培养上清Th1/Th2 (IL-12/IL-2)细胞因子的浓度。 结果： ox-LDL可诱导DC形成泡沫细胞，而天然的LDL无此作用。经ox-LDL处理的DC吞噬作用明显弱于天然的LDL，而对T细胞增殖作用却明显强于天然的LDL；可明显上调CD80(72.4±9.6 vs 89.5±10.1, P<0.01), CD86(67.2±8.8 vs 80.2±11.6, P＜0.01), HLA-DR(80.6±9.8 vs 86.6±10.8, P<0.01) 和CD1a(40.2±10.3 vs 60.2±9.3, P<0.01)的表达，明显促进DC细胞因子IL-12［(44.3±8.9)ng/L vs (65.1±10.4)ng/L, P<0.05］的分泌，但却降低IL-2［(43.6±7.8）ng/L vs （10.0±4.5）ng/L, P<0.01］。 结论： DC可通过摄取ox-LDL形成泡沫细胞，而后者与成熟DC的功能相似，说明DC可能是泡沫细胞新的来源，在动脉粥样硬化免疫病理发生中具有重要的作用。     

Blood dendritic cells in patients with chronic lymphocytic leukaemia

Myeloid and plasmacytoid dendritic cells (MDC, PDC) play a key role in the initiation of immune responses. We found a reduction of both DC subsets in 42 patients with chronic lymphocytic leukaemia (CLL) at diagnosis (P<0.0001 and 0.0001 vs. controls, respectively), likely related to the high secretion of CCL22 and CXCL12 (P=0.04 and 0.008 vs. controls, respectively) by leukaemic cells. However, CD14+ monocytes from CLL patients could give rise to functional IL-12p70-secreting monocyte-derived DCs, capable of inducing a type 1 polarization immunostimulatory profile. These monocyte-derived DCs from CLL patients efficiently migrate in response to CCL19/MIP-3beta chemokine, suggesting that functional autologous DCs can be generated for immunotherapeutic purposes to circumvent DC defects in CLL.     

Altered phenotype and function of dendritic cells in children with type 1 diabetes

The importance of dendritic cells (DC) in the activation of T cells and in the maintenance of self-tolerance is well known. We investigated whether alterations in phenotype and function of DC may contribute to the pathogenesis of Type 1 diabetes (T1DM). Mature DC (mDC) from 18 children with T1DM and 10 age-matched healthy children were tested. mDC, derived from peripheral blood monocytes cultured for 6 days in presence of interleukin (IL)-4 and granulocyte-macrophage colony stimulating factor (GM-CSF) and stimulated with lipopolysaccharide (LPS) for the last 24 h, were phenotyped for the expression of the co-stimulatory molecules B7.1 and B7.2. In six patients and six controls allogenic mixed leucocyte reaction (AMLR) was performed using mDC and cord blood-derived naive T cells at a DC/T naive ratio of 1 : 200. Proliferation was assessed on day 7 by [(3)H]-thymidine incorporation assay. Mature DC derived from patients showed, compared with controls, a reduced expression of B7.1 [mean of fluorescence intensity (MFI): 36.2 +/- 14.3 versus 72.9 +/- 34.5; P = 0.004] and B7.2 (MFI: 122.7 +/- 67.5 versus 259.6 +/- 154.1; P = 0.02). We did not find differences in the HLA-DR expression (P = 0.07). Moreover, proliferative response of allogenic naive T cells cultured with mDC was impaired in the patients (13471 +/- 9917.2 versus 40976 +/- 24527.2 cpm, P = 0.04). We also measured IL-10 and IL-12 concentration in the supernatant of DC cultures. Interestingly, we observed in the patients a sevenfold higher level of IL-10 (P = 0.07) and a ninefold lower level of IL-12 (P = 0.01). Our data show a defect in the expression of the co-stimulatory molecules and an impairment of DC priming function, events that might contribute to T1DM pathogenesis.     

Differentiation of monocytes into CD1a- dendritic cells correlates with disease progression in HIV-infected patients

Monocyte differentiation into dendritic cells (DCs) depends on microenvironmental conditions. In this study, the capacity of human monocytes to differentiate into mature DCs and their ability to induce an antiviral immune response was investigated in HIV-infected patients. In healthy subjects, monocytes differentiate into CD1a+ DCs in the presence of granulocyte macrophage colony-stimulating factor and interleukin (IL)-4 and matured in the presence of lipopolysaccharide. Here, we found that in 30% and 45% of HIV-infected white and African subjects, respectively, monocytes gave rise to a homogeneous CD1a* DC population. In the patients who gave rise only to the CD1a* DCs, this population spontaneously produced IL-10 but not IL-12, and induced a T helper 2-like immune response when cultured with human T cells isolated from cord blood mononuclear cells. In patients with monocytes differentiated into CD1a* DCs, a high percentage of HIV-specific CD4 T cells producing IL-4 were seen in the peripheral blood. Furthermore, differentiation of monocytes into DCs with CD1a* phenotype correlated with low CD4 T-cell counts and high viral loads in HIV-infected subjects. These results suggest that the differentiation of monocytes into CD1a* DCs may be a phenotypic marker associated with progression of the disease.     

Natural killer cells prime the responsiveness of autologous CD4+ T cells to CTLA4-Ig and interleukin-10 mediated inhibition in an allogeneic dendritic cell-mixed lymphocyte reaction

Cytotoxic T-lymphocyte antigen 4 immunoglobulin (CTLA4-Ig) and interleukin (IL)-10 are immunomodulatory molecules which target CD28 costimulation by acting either directly or indirectly on the CD80/86 receptors on dendritic cells (DCs). This study examined the effect of combined treatment with CTLA4-Ig and IL-10 on T-cell responsiveness in a dendritic cell-mixed lymphocyte reaction (DC-MLR). T cells derived from nylon wool enrichment (NWT cells) demonstrated 15% (P = 0.006) and 10% (P = 0.0015) inhibition of proliferation with suboptimal doses of IL-10 (5 ng/ml) and CTLA4-Ig (20 ng/ml), respectively. Combined treatment with both agents resulted in 38% inhibition (P = 0.004) of the MLR response compared with untreated controls. In contrast to NWT cells, which consisted of CD4+, CD8+ and CD56+ (NK) cells, purified CD4+ T cells were less responsive to immunomodulation by CTLA4-Ig and IL-10. Repletion of the CD4+ T cells with NK cells restored IL-10 and CTLA4-Ig mediated immunomodulation, suggesting a role for NK cells in the regulation of DC-T-cell interactions. The specific effect of NK cells on DC activation was demonstrated by CD80 up-regulation on DCs in the absence of T cells. However, in the absence of DCs, NK cells augmented the proliferation of autologous CD4+ T cells stimulated by anti-CD3 monoclonal antibody (mAb), which was blocked by CTLA4-Ig. It is proposed that, in the MLR, immunomodulation by suboptimal CTLA4-Ig and IL-10 is influenced by cellular interactions of NK cells with DCs and T cells involving DC lysis and costimulation. Thus, NK cells prime both DCs and T cells to low doses of CTLA4-Ig and IL-10 during alloimmune responses, providing evidence for the potential interaction between innate and adaptive immunity.     

激素预处理树突状细胞对哮喘Th2型反应的影响

目的： 研究激素预处理的树突状细胞（DCs）对哮喘DCs与T细胞共培养上清液中T辅助细胞1(Th1)和Th2型细胞因子的影响及其机制。方法: 采集哮喘组和健康组外周血,分别常规培养和加入地塞米松培养至成熟DCs。将2组常规培养和地塞米松预处理的DC-T细胞共培养72 h。流式细胞仪测定2组常规培养或地塞米松培养成熟DCs的表型。酶联免疫吸附试验（ELISA）检测DC-T细胞共培养上清液中白细胞介素-5(IL-5)和干扰素-γ（IFN-γ）的含量。结果: 哮喘组常规培养的DC-T细胞共培养上清液中IL-5水平高于健康组（P<0.01）,其IFN-γ含量较健康组有减少的趋势,但无显著差异（P>0.05）;地塞米松预处理的DC-T细胞上清液中IL-5水平低于常规培养组（P<0.01）。无论哮喘组或健康组,地塞米松预处理的DC-T细胞共培养上清液中IFN-γ水平均低于未用地塞米松预处理的DC-T细胞共培养上清液（P<0.01）。2组地塞米松预处理的DCs均部分抑制了肿瘤坏死因子-α(TNF-α)所诱导的DCs表型CD83上调（P<0.01）,而上调了CD14的表达（P<0.01）。结论: 哮喘患者常规培养的DCs与同种自体T细胞共培养后呈Th2型反应,地塞米松预处理的DCs可使Th2型反应减弱,其机制可能与地塞米松影响DCs的分化、成熟有关。     

IL-6 produced by type I IFN DC controls IFN-gamma production by regulating the suppressive effect of CD4+ CD25+ regulatory T cells

The dendritic cell family is composed of different subsets differentially governing the immune response. Type I interferon (IFN) dendritic cells (DC) are endowed with the ability to trigger both Th1 and Th2 type responses. In view of the pivotal role of regulatory T cells in limiting the effectiveness of effector cells, we analyzed the interactions between these cells and type I IFN DC. DC were generated from monocytes in the presence of IFN-beta and interleukin (IL)-3 (DCI3) or granulocyte macrophage-colony-stimulating factor and IL-4 (DCG4) and activated by poly(I:C). Despite the release of lower amounts of IL-12 after maturation, DCI3 were able to induce a higher IFN-gamma production by T lymphocytes during the mixed leucocyte reaction (MLR) as compared with DCG4. mRNA analysis disclosed that DCI3 overtranscribed the IL-6 gene and secreted high amounts of the protein. Neutralization of IL-6 revealed that this cytokine specifically contributed to the IFN-gamma release induced by DCI3. Finally, depletion of CD25+ T cells before the MLR identified these cells as a target for IL-6. We conclude that DCI3 are endowed with the property of regulating the suppressive effect of regulatory T cells through high IL-6 production. This novel mechanism of T cell control is relevant for the use of DCI3 in vaccination strategies.     

Both Dendritic Cells and Monocytes Induce Autologous and Allogeneic T Cells Receptive to Interleukin 2

Activation of resting T cells to proliferate is usually accompanied by their expression of interleukin 2 receptors (IL-2R) and secretion of (IL-2). We studied the mechanisms by which human blood-derived dendritic cells (DC) and monocytes induce IL-2R and stimulate IL-2 secretion in autologous and allogeneic mixed luecocyte reaction (auto- and allo-MLR, respectively). We found that only DC were fully effective as stimulator cells in MLR. DC stimulated both autologous and allogeneic T cells to express high-affinity IL-2R, secrete IL-2, and vigorously proliferate in MLR. The stimulatory properties of monocytes were more complicated: although they stimulated the proliferation in allogeneic MLR, the proliferation rates, duration, and amount of IL-2 secretion were different than in DC-induced MLR. Autologous T cells did not proliferate in response to monocytes, but were induced to express the low-affinity IL-2R. If the cultures were supplemented with exogenous recombinant IL-2, the proliferative responses to DC and monocytes in auto- and allo-MLR were of the same magnitude, indicating that the responsiveness to IL-2 was stimulated by both the stimulator cells. The stimulator cell number was important, since large numbers of monocytes, but not of DC, were suppressive to the proliferative responses. Thus, we concluded that the higher capacity of DC, as compared to monocytes, to stimulate T-cell proliferation is based primarily on the more efficient stimulation of IL-2 secretion.     

T-cell abnormalities in inflammatory bowel disease are mediated by interleukin 2

Inflammatory bowel disease (IBD) may be an immunologically mediated disorder in which T cells are unable to respond appropriately to cell surface-associated antigens. To test this possibility, 37 patients with IBD, 24 with Crohn's disease and 13 with ulcerative colitis who were not being treated with immunosuppressive therapy were studied. The ability of T cells to proliferate in response to autologous or allogeneic cells, i.e., the autologous or allogeneic mixed-lymphocyte reaction (MLR) was tested. The autologous MLR was depressed using patient cells compared to control cells, regardless of disease type or activity (1564 +/- 223 cpm versus 3300 +/- 381 cpm, P less than 0.05) while the allogeneic MLR was depressed in patients with active disease only (29,833 +/- 2871 cpm versus 46,799 +/- 3340 cpm, P less than 0.01). The ability of T cells to recognize and lyse allogeneic cells, allogeneic cell-mediated lympholysis (CML), was also low in patients with active disease (24 +/- 4% versus 37 +/- 3%, P less than 0.05). Since T-cell proliferation and cytotoxicity depend upon adequate production of and response to a T-cell growth factor, interleukin 2 (IL-2), IL-2 production and responsiveness in IBD were studied. IL-2 production by patient T cells in response to phytohemagglutinin was only 39% of control values, P less than 0.05. The response to IL-2 was measured by the increase in T-cell proliferation in the autologous MLR in medium alone or medium supplemented with IL-2. Control T-cell proliferation rose from 3300 +/- 381 cpm to 10,761 +/- 428 cpm with exogenous IL-2 (P less than 0.001). Patient T-cell proliferation rose from 1564 +/- 223 cpm to 6817 +/- 771 cpm with IL-2 (P less than 0.001) but did not reach the level of the IL-2-supplemented control autologous MLR (P less than 0.05). In addition, the percentage of activated patient T cells having Tac antigen (IL-2 receptor) was depressed (P less than 0.05). These findings did not vary with disease type or activity. It is concluded from these data that peripheral blood T lymphocytes from patients with IBD have a diminished response to cell surface antigens which is associated with a decrease in IL-2 production and receptor generation. These defects may be responsible for the depressed T-cell proliferation and cytotoxicity that accompany IBD.