MBL对LPS诱导树突状细胞成熟的调节作用

目的 探讨甘露聚糖结合凝集素对细菌脂多糖诱导的人外周血单核细胞来源树突状细胞（MoDC）成熟的影响。方法 从健康成人外周血分离能黏附塑料的单核细胞，在rhGM-CSF和rhIL-4条件下培养5d，然后在有或无LPS和不同质量浓度（10～100mg／L）天然人MBL条件下继续培养2d。用倒置显微镜观察DC的形态，以FACS分析DC的表型，用MTT法测定DC刺激同种异体T细胞增殖的能力，以酵母多糖颗粒吞噬试验评估DC的抗原摄取能力，用ELISA检测DC培养上清液中TNF-α和IL-12p40＋p70的含量。结果 MBL以剂量依赖方式下调LPS诱导人MoDC表面分子CD83和CD86表达，增强其摄取酵母多糖颗粒的能力，降低其激发初始T细胞增殖的能力，并抑制其LPS诱导的TNF-α和IL-12 p40＋p70分泌，但MBL质量浓度低至10mg／L时对LPS诱导DC成熟作用几无影响。结论 高质量浓度MBL能抑制LPS诱导的DC成熟过程，提示其可能在LPS引发疾病包括败血症或感染性休克中具有调节作用，亦提供了分析DC分化成熟有关信号途径的新手段。     

吗啡持续刺激对小鼠树突状细胞成熟的影响

为研究吗啡持续刺激对C57BL/6小鼠骨髓来源的树突状细胞成熟的影响.体外培养C57BL/6小鼠骨髓来源的树突状细胞,在培养过程中给予吗啡刺激,应用流式细胞术检测细胞表型CD11c、Ia、CD86的变化.吗啡干预各组树突状细胞中细胞表型CD11c、Ia、CD86表达较对照组显著升高.吗啡持续刺激能够促进小鼠树突状细胞的...     

MyD88 RNA干扰抑制小鼠骨髓树突状细胞成熟的实验研究

目的：针对小鼠骨髓树突状细胞（DC）髓性分化因子88（MyD88）,采用RNA干扰技术抑制其合成,观察脂多糖（LPS）刺激后DC生物学活性的变化,探讨获得耐受性DC的方法,为DC的临床应用提供新思路和理论依据。方法：培养小鼠骨髓源性DC,分为对照组、LPS组及RNA干扰组,对照组不予任何处理,LPS组加入终浓度为1μg/ml的LPS,RNA干扰组于加入MyD88 siRNA12小时后给予1μg/mlLPS刺激,继续培养3天。免疫细胞化学检测DCMyD88、核因子-κB（NF-κB）的表达,Western blot检测DCMyD88的表达;流式细胞术检测DC细胞表面CD80、CD86及MHC-Ⅱ分子的变化,ELISA法检测各组DC分泌TNF-α。IFN-γ和IL-12的浓度,混合淋巴细胞培养检测T细胞增殖能力。结果：LPS促进DC高表达CD80、CD86及MHC-Ⅱ分子,促进Th1型细胞因子释放、MyD88高表达及NF-κB核移位,并诱导T细胞增殖,MyD88 siRNA可阻断LPS的这些效应。结论：MyD88 siRNA可抑制DC成熟,产生耐受性DC,增强同种未成熟DC的免疫耐受诱导作用,为进一步研究DC的临床应用奠定了基础。     

HBeAg对小鼠骨髓源性树突状细胞成熟的影响

目的 探讨HBe Ag对LPS诱导小鼠骨髓源性树突状细胞(DC)成熟的影响。方法 体外诱导C57BL/6小鼠骨髓细胞分化成未成熟树突状细胞,经CD11c磁珠分选纯化后将DCs随机分为空白对照组、LPS刺激组、HBe Ag+LPS刺激组。流式检测DC表型变化,混合淋巴反应(MLR)检测DC促T淋巴细胞增殖能力,酶联免疫法(ELISA)检测细胞上清液中IL-12的分泌水平,Western blot检测p38磷酸化水平,并设置SB203580组为阳性对照探讨细胞IL-12分泌的可能调节机制。结果 LPS刺激未成熟DC引起细胞表面MHC-Ⅱ、CD86表达升高,刺激同种异体淋巴细胞增殖能力增强,IL-12分泌量增高。HBe Ag可抑制LPS促进DC表面MHC-Ⅱ、CD86表达升高和促淋巴细胞增殖能力增强的作用。LPS刺激DC可引起p38磷酸化水平升高,并呈时间依赖性;HBe Ag或SB203580预处理细胞再予LPS刺激,磷酸化p38表达和IL-12分泌较单纯LPS刺激组明显下降。结论 HBe Ag对LPS引起的树突状细胞的成熟有一定的抑制作用,且HBe Ag可能通过抑制p38MAPK信号通路下调LPS诱导的树突状细胞IL-12的产生。     

早期脂多糖干预对大鼠树突状细胞表型和功能的影响

目的探讨早期脂多糖(LPS)干预对大鼠树突状细胞(DC)表型和功能的影响。方法用rrIL-4和rrGM-CSF体外诱导骨髓前体细胞,成熟组于第6天加入LPS1μg/mL,干预组分别于第0、3、6天连续加入LPS1μg/mL,对照组不加LPS,第7天收集细胞。采用免疫细胞化学方法、流式细胞术、同种淋巴细胞刺激试验和RT-PCR进行表型和功能鉴定。结果与对照组相比,MHC-Ⅱ、CD80、CD86、IL-12的表达和刺激同种T淋巴细胞增殖的能力在成熟组明显增高而干预组明显降低(P<0.01),Dextran-FITC摄取能力在成熟组明显降低而干预组明显增高(P<0.01)。结论早期LPS干预可抑制大鼠DC成熟,获得纯度更高的未成熟DC,为进一步研究免疫耐受奠定了基础。     

RNA干扰抑制MyD88表达对小鼠骨髓树突状细胞生物学活性的影响

目的:采用RNA干扰技术抑制小鼠骨髓树突状细胞(DC)髓样分化因子88(MyD88)的表达,并检测其对细胞生物学活性的影响,为DC的临床应用奠定基础。方法:针对MyD88基因,采用化学合成法合成3对MyD88 siRNA(序列1、序列2及序列3),并转染DC2.4细胞。采用半定量RT-PCR及Western blot分别从mRNA和蛋白质水平检测DCMyD88的表达情况,筛选其中一对高效RNA(序列3)转染DC2.4细胞(RNA干扰组),以未转染RNA的DC2.4细胞作为对照组,分别给予1 mg/L的脂多糖(LPS)刺激。流式细胞术(FCM)检测DC细胞表面CD80、CD86及MHC-Ⅱ分子的变化,ELISA法检测DC分泌肿瘤坏死因子-α(TNF-α)、干扰素-γ(IFN-γ)和白介素-12(IL-12)的浓度,免疫细胞化学检测DC核因子-κB(NF-κB)的表达,混合淋巴细胞培养检测T细胞增殖能力,观察RNA干扰对LPS促DC成熟的影响。结果:与空白对照组相比,序列2组及序列3组DC的mRNA和蛋白质表达分别降低90%和85%、92%和88%,差异有统计学意义;脂质体对照组、无义siRNA对照组及序列1组DC的mRNA和蛋白质表达无显著差异。经LPS刺激后,与对照组相比,RNA干扰组CD80、CD86及MHC-Ⅱ分子的表达,TNF-α、IFN-γ及IL-12的浓度及T细胞增殖能力均显著下降,且未见明显NF-κB核转位。结论:RNA干扰技术能显著下调小鼠DC MyD88的表达,并显著抑制LPS促DC成熟的效应,为以DC MyD88为靶向、相关疾病的基因治疗提供了新思路和手段。     

Lewis大鼠骨髓来源成熟和未成熟树突状细胞的提取与鉴别

背景：树突状细胞在未成熟阶段表现出极强的抗原吞噬功能,它可以在免疫耐受、癌症的免疫治疗等方面都表现出极大的优越性。但由于未成熟树突状细胞在生物体内含量极微,这就严重限制了它在临床、科研方面的应用。目的：提取鉴别Lewis大鼠骨髓来源成熟和未成熟树突状细胞。方法：从Lewis大鼠骨髓中分离骨髓前体细胞,应用20 ng/m L粒细胞集落刺激因子、10 ng/m L白细胞介素4培养7 d诱导为未成熟树突状细胞,然后在未成熟树突状细胞中加入1μg/m L脂多糖继续培养2 d诱导为成熟树突状细胞。采用荧光倒置显微镜观察树突状细胞形态,流式细胞仪鉴定成熟和未成熟树突状细胞表面特异性分子,ELISA检测成熟和未成熟树突状细胞培养上清白细胞介素10、白细胞介素12和白细胞介素17A因子的分泌水平,混合淋巴细胞反应检测成熟和未成熟树突状细胞对T淋巴细胞的刺激反应。结果与结论：(1)普通荧光倒置显微镜下观察树突状细胞具有明显的突起结构;(2)流式细胞仪可见未成熟树突状细胞低表达CD40、CD86等共刺激分子;相反,成熟树突状细胞高表达上述共刺激分子;(3)未成熟树突状细胞的白细胞介素10、白细胞介素17A...     

黄芪多糖对树突状细胞表型及功能成熟的影响

目的 通过体外试验研究黄芪多糖（Astragalus mongholicus, ASP） 对树突状细胞（dendritic cells，DC）功能调节的机制，为进一步阐明黄芪多糖的免疫学活性提供依据。方法 应用流式细胞仪检测技术、扫描电镜技术、酶联免疫吸附试验检测DC表型和功能的各种指标。结果 本实验应用小鼠骨髓来源的DC，通过体外试验证明了黄芪多糖能够提高DC表面分子CD11c和MHCⅡ的表达，并且呈黄芪多糖浓度依赖性；空白组DC的吞噬功能很强，LPS组DC和黄芪多糖处理组DC吞噬功能都明显下降；黄芪多糖能够促进DC白细胞介素-12（IL-12）的表达；电镜观察DC的超微结构，可见黄芪多糖处理组DC突起增多，形态上更加成熟。结论 本实验结果证实了黄芪多糖能促进小鼠骨髓来源的DC表型及功能的成熟。     

猪苓多糖刺激/诱导小鼠树突状细胞成熟

研究猪苓多糖对小鼠骨髓树突状细胞(DC)表型及功能成熟的影响。从小鼠骨髓中分离单个核细胞(MNC),用rmGM-CSF、IL-4培养5 d后,实验组加入猪苓多糖(50μg/ml),空白对照组加等量RPMI 1640,阳性对照组加LPS(1μg/ml),3组分别同时作用48 h。扫描电镜观察其体外培养过程中的形态特征,流式细胞仪(FACS)分析其表型特征,混合淋巴细胞反应(MLR)检测其功能。用猪苓多糖刺激的小鼠骨髓MNC具典型的DC形态;细胞表达I-A/I-E、CD11c和分泌IL-12能力比空白对照组增加,具有极强的激发MLR的能力,显示成熟DC的特征。猪苓多糖可以促进体外培养的小鼠骨髓DC的成熟,促进DC诱导的免疫应答启动。     

Jagged-1对骨髓来源树突状细胞生成细胞因子的影响

目的:探讨可溶性Jagged-1/Fe嵌合蛋白(Jagged-1)对重组小鼠粒细胞-巨噬细胞集落刺激因子(rmGM-CSF)和白细胞介素4(rmIL-4)体外诱导小鼠骨髓来源树突状细胞(DC)产生细胞凶子的影响.方法:建立rmCM-CSF和rmIL-4体外诱导DC的模型,观察Jagged-1/Fc对DC分化的形态学影响.通过Luminex蛋白液相芯片技术和ELlSA检测其细胞因子的表达水平,藉MTT法测定可溶性Jagged-1/Fc诱导的DC对同种异基因淋巴细胞增殖的刺激能力.结果:除了TGF-β,Jag-ged-1/Fc诱导的DC与细菌脂多糖(LPS)或酵母聚糖A诱导的DC不同,表现为生成TNF-α的水平明显降低,IL-4显著增高,而IL-10、IL-6、IL-2、IL-12和IFN-γ的水平与对照组无明显差异.γ分泌酶抑制剂DAFT能逆转Jagged-1/Fc抑制DC生成TNF-α.混合淋巴细胞反应显示Jagged-1/Fc诱导的DC对T细胞增殖的刺激能力最弱,LPS诱导的DC的刺激能力最强.结论:Jagged-1/Fc诱导的DC倾向介导免疫耐受,指导初始T细胞向Th2细胞偏离.     

LPS介导的树突状细胞成熟过程中的表型变化

目的:探讨树突状细胞成熟过程中,DC表面MHC分子和共刺激分子的表达变化及MHCⅡ的胞内分布变化。方法:制备小鼠骨髓来源的树突状细胞,LPS分别刺激0、3、6、12和24小时,荧光抗体标记后,用流式细胞仪检测MHCⅠ、MHCⅡ分子和CD86、CD80、CD40等共刺激分子在细胞表面的表达,同时以激光共聚焦显微镜观察MHCⅡ的胞内分布变化。结果:在LPS刺激后,DC细胞表面的不同表型分子,其表达水平随时间延长有不同的上升趋势。同时在未成熟DC中,MHCⅡ主要集中在细胞核附近,LPS刺激后,MHCⅡ朝细胞外围扩散,到刺激12小时,有较多的MHCⅡ出现在细胞表面。结论:LPS介导的树突状细胞成熟过程中的表型分子有不同的变化趋势。     

人外周血单核细胞来源树突状细胞的成熟诱导

目的：探讨诱导树突状细胞成熟的最优方法。方法：以细胞因子GM-CSF和IL-4体外诱导人单核细胞来源的树突状细胞，分别采用CD40L、LPS、TNF-α、细胞因子鸡尾酒法（TNF-α、IL-6、IL-1β、PGE2）诱导成熟，24小时后收获DCs以流式细胞仪检测其成熟表型CD80、CD83、CD86、HLA-DR和FITC-Dextran的内吞能力，ELISA法检测其IL-12的分泌，MTT法检测其刺激淋巴细胞增殖活性。结果：CD40L、LPS、TNF-α、鸡尾酒法均可诱导DCs的成熟，其中以鸡尾酒法诱导成熟的效果最优，CD83的表达率为66.91%（P〈0.05）；成熟DCsFITC-Dextran的内吞能力明显下降；成熟DCsIL-12分泌量明显高于未成熟DCs，其中鸡尾酒法诱导成熟的DCs的IL-12分泌量最高，成熟的DCs有较强的刺激淋巴细胞增殖能力。结论：细胞因子鸡尾酒法是诱导DCs成熟的最佳方法。     

Factors involved in the maturation of murine dendritic cells transduced with adenoviral vector variants

Adenoviral vector (Ad)-mediated gene transfer is an attractive method for manipulating the immunostimulatory properties of dendritic cells (DCs) for cancer immunotherapy. DCs treated with Ad have phenotype alterations (maturation) that facilitate T cell sensitization. We investigated the mechanisms of DC maturation with Ad transduction. Expression levels of a maturation marker (CD40) on DCs treated with conventional Ad, fiber-modified Ads (AdRGD, AdF35, AdF35DeltaRGD), or a different serotype Ad (Ad35) were correlated with their transduction efficacy. The alphav-integrin directional Ad, AdRGD, exhibited the most potent ability to enhance both foreign gene expression and CD40 expression, and induced secretion of interleukin-12, tumor necrosis factor-alpha, and interferon-alpha in DCs. The presence of a foreign gene expression cassette in AdRGD was not necessary for DC maturation. Maturation of DCs treated with AdRGD was suppressed by destruction of the Ad genome, inhibition of endocytosis, or endosome acidification, whereas proteasome inhibition increased CD40 expression levels on DCs. Moreover, inhibition of alphav-integrin signal transduction and blockade of cytokine secretion affected the maturation of DCs treated with AdRGD only slightly or not at all, respectively. Thus, our data provide evidence that Ad-induced DC maturation is due to Ad invasion of the DCs, followed by nuclear transport of the Ad genome, and not to the expression of foreign genes.     

Activation of src-family tyrosine kinases by LPS regulates cytokine production in dendritic cells by controlling AP-1 formation

The role of src-family tyrosine kinases in LPS-induced DC maturation has not been fully addressed. We show that LPS induces activation of c-Src and Lyn in human DC. Inhibition of these kinasesby PP1 uncoupled LPS-induced cytokine production from the up-regulation of costimulatory molecules, resulting in DC still capable of stimulating T cell proliferation but much less efficient in inducing Th1 differentiation. This is the first example of a pharmacological inhibitor able to modulate the capacity of DC to induce a particular type of immune response. Inhibition of src-family kinases impaired phosphorylation and accumulation of c-Jun, leading to reduced formation of AP-1 complexes upon LPS stimulation. Thus, src-kinases control cytokine production in LPS-induced DC maturation through a timely formation of AP-1.     

Murine polyomavirus-like particles induce maturation of bone marrow-derived dendritic cells and proliferation of T cells

We analysed the effects of murine polyomavirus-like particles (PLPs) on bone marrow-derived dendritic cells (BMDCs) and T cells in vitro. BMDCs activated with PLPs up-regulated CD40, CD80, CD86 and major histocompatibility complex (MHC) class II surface markers and produced proinflammatory cytokines. Chimeric PLPs [expressing the ovalbumin (OVA)-peptides OVA(257-264) or OVA(323-339)], but not wildtype PLPs, activated OVA-specific CD8 T cells and OVA-specific CD4 T cells, respectively, indicating both MHC class I and II presentation of the peptides by antigen-presenting cells. Our results suggest that PLPs may be used as vaccine adjuvants priming dendritic cells to induce potent T cell responses.     

Effects of human plasma proteins on maturation of monocyte-derived dendritic cells

Dendritic cells (DC) are a promising tool for vaccine therapy due to their unique properties as antigen presenting cells and their ability to prime naïve T cells. Increasing evidence suggests that maturation stage of DC critically influences the fate of the immune response. Generation of monocyte-derived DC for clinically applicable immunotherapy requires the use of well-defined components and stringent culture conditions. An alternative strategy is to use human autologous serum. However, its constituents are not stable and reflect the inflammatory condition of the donor. In order to investigate whether DC properties are influenced by proteins present in the plasma, we matured human monocyte-derived DC with four main plasma components: fibrinogen, fibronectin, plasminogen or C-reactive protein. These purified proteins were added at various concentrations on day 6 after the initial differentiation induced by IL-4 and GM-CSF. The maturation was assessed by phenotyping of maturation-associated marker (CD83) and co-stimulatory molecule CD86 as well as IL-12 production. Functional properties of DC were assessed by endocytic activity and mixed leukocyte culture. Our results indicate that fibrinogen had DC-maturation effect comparable to poly-I:C, TNF-α and PGE₂ as a positive control, but it failed to induce IL-12 production. The other plasma proteins had no effect on DC maturation. CRP at high concentration had rather inhibitory effect on DC induced lymphocyte function. We conclude that none of the tested plasma components and acute phase proteins sufficiently induce fully competent mature DC. This finding is important for the preparation of human DC-based vaccines supplemented by autologous sera.     

Involvement of leptin signaling in the survival and maturation of bone marrow-derived dendritic cells

Previous studies demonstrated that lymphocyte development is impaired in leptin receptor (Ob-R)-deficient db/db mice. However, it remains unclear whether or not leptin signaling plays a physiological role in dendritic cell (DC) development and function. In this study, we first detected Ob-R expression in murine DC. Using db/db mice at a pre-diabetic stage, we demonstrate that the total number of DC generated from bone marrow (BM) cultures is significantly lower than in WT controls. Similarly, selective blockade of leptin with a soluble mouse Ob-R chimera (Ob-R:Fc) inhibited DC generation in wild-type BM cultures. The reduced DC yield in db/db BM culture was attributed to significantly increased apoptosis, which was associated with dysregulated expression of Bcl-2 family genes. Moreover, db/db DC displayed markedly reduced expression of co-stimulatory molecules and a Th2-type cytokine profile, with a poor capacity to stimulate allogeneic T cell proliferation. Consistent with their impaired DC phenotype and function, db/db DC showed significantly down-regulated activities of the PI3K/Akt pathway as well as STAT-3 and IkappaB-alpha. In conclusion, our findings demonstrate the involvement of leptin signaling in DC survival and maturation.     

Rapid and coordinated switch in chemokine receptor expression during dendritic cell maturation

Dendritic cells (DC) migrate into inflamed peripheral tissues where they capture antigens and, following maturation, to lymph nodes where they stimulate T cells. To gain insight into this process we compared chemokine receptor expression in immature and mature DC. Immature DC expressed CCR1, CCR2, CCR5 and CXCR1 and responded to their respective ligands, which are chemokines produced at inflammatory sites. Following stimulation with LPS or TNF-α maturing DC expressed high levels of CCR7 mRNA and acquired responsiveness to the CCR7 ligand EBI1 ligand chemokine (ELC), a chemokine produced in lymphoid organs. Maturation also resulted in up-regulation of CXCR4 and down-regulation of CXCR1 mRNA, while CCR1 and CCR5 mRNA were only marginally affected for up to 40 h. However, CCR1 and CCR5 were lost from the cell surface within 3 h, due to receptor down-regulation mediated by chemokines produced by maturing DC. A complete down-regulation of CCR1 and CCR5 mRNA was observed only after stimulation with CD40 ligand of DC induced to mature by LPS treatment. These different patterns of chemokine receptors are consistent with “inflammatory” and “primary response” phases of DC function.     

缺氧/复氧对小鼠骨髓树突状细胞表型及生物学活性的影响

目的 探讨缺氧/复氧对小鼠骨髓树突状细胞(DC)表型及生物学活性的影响.方法 培养小鼠骨髓源性DC,分为对照组及缺氧/复氧组,对照组在正常培养条件下培养,缺氧/复氧组给予缺氧气体培养4 h,然后在正常培养条件下继续培养1 d.应用流式细胞仪检测DC表面CD80、CD86、MHC Ⅱ分子的变化,ELISA法检测DC分泌TNF-α、IFN-γ和IL-12的浓度,混合淋巴细胞培养检测T细胞增殖能力,免疫细胞化学检测Dc核因子-κB(NF-κB)的表达.结果 缺氧/复氧可促进DC高表达CD80、CD86、MHC Ⅱ分子,促进Th1型细胞因子释放、NF-κB高表达及核移位,并诱导T细胞增殖.结论 缺氧/复氧可刺激DC高表达表面分子,具有明显的免疫刺激活性.