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.     

体外培养人树突状细胞分化成熟特性分析

目的 利用人脐血CD34^＋干细胞诱导分化树突状细胞（DC）,并对DC分化发育过程的生物学特性进行鉴定和分析.方法通过SCF、GM-CSF、TGF-β1、Flt-3L及TNF-α体外培养体系,从脐血CD34^＋造血干细胞中诱导扩增获得DC.采用倒置显微镜和电镜观察DC形态学特征,流式细胞仪检测DC细胞表型及胞内活性氧（ROS）水平,MTT比色法检测DC刺激同种异体T细胞增殖能力;ELISA法检测DC培养上清液中IL-12含量.结果CD34^＋细胞培养5至7 d,细胞呈现DC典型树突状形态,处未成熟状态,再经TNF-α诱导及继续培养至14 d,DC发育成熟.未成熟DC表达模式识别受体CD209（DC-SIGN）,且胞内蓄积适量ROS,具备了细胞吞噬能力.成熟DC除仍高表达DC-SIGN,其表面黏附共刺激分子CDllc、CD54、CD83、CD80、CD86表达上调,细胞因子IL-12分泌增加,且具明显的体外刺激T细胞增殖能力,符合于抗原递呈细胞特征.此外,未成熟和成熟DC基本不表达黏附分子P-、E-选择素,但未成熟和成熟DC分别高表达和低表达L-选择素.结论建立人DC体外模型及其分化发育生物学特性分析,为进一步研究DC功能,以及利用DC调控免疫应答用于疾病防治提供了基础.     

郎格罕氏细胞分化发育研究进展

郎格罕氏细胞是位于上皮细胞中的一种抗原提呈细胞,在人体的免疫防御系统中起着重要的作用。LC来源于骨髓,大量实验证实,由外周血分离得到的CD34^ 干细胞在GM－CSF、TNF－α和TGF－β1的作用下在体外生成具有典型特征的LC,外周血CD14^＋MO在一定条件下亦能分化发育为LC。位于非淋巴细胞中的未成熟LC能摄取和加工处理抗原,同时分泌各种免疫因子,并在抗原的刺激下移向次级淋巴组织,发育成熟。LPS能通过诱导未成熟DC细胞核内产生NF－kB转录因子,并在NF－kB作用下上调MHC和共刺激分子的表达,从而使未成熟DC发育成熟。成熟的LC能提呈抗原并活化处女型T细胞,从而启动免疫应答。     

天花粉蛋白联合CD40信号激发的人MoDC介导Th2细胞分化的研究

探讨天花粉蛋白(Tk)联合CD40信号诱导人单核细胞来源DC(MoDC)的成熟活化及其介导Th2细胞分化的作用和机制。采用GM-CSF和IL-4联合方案体外诱导人MoDC,并利用鼠抗人CD40激发型单抗(5C11)刺激负载了Tk的DC制备成熟DC。采用免疫荧光标记和流式细胞术分析DC表型(CD80、CD83、CD86、CD14、PDL1)及其摄取FITC-Dextran的能力;ELISA法测定DC上清中IL-12p70的含量;胞内染色和流式细胞术检测经成熟DC活化的T细胞中CD4~+IFN-γ~+T和CD4~+IL-4~+T的比例。实验结果显示单独Tk不能刺激DC完全成熟,用Tk负载DC后必须联合外源性成熟刺激信号(如5C11),才能有效促进DC成熟,表现在CD80、CD83、CD86的上调表达,CD14下调表达,DC摄取FITC-Dextran的能力降低。与CD40信号单独诱导组相比,Tk联合CD40信号诱导的成熟DC表面PDL1分子呈下调表达,分泌IL-12的能力显著降低,明显提高T细胞中CD4~+IL-4~+T的比例。由此表明负载了Tk的成熟MoDC体外能有效介导Th2细胞分化。     

056 树突状细胞与T辅助细胞分化

病原体感染或抗原刺激可诱导树突状细胞(DC)分化为DC1和DC2并迁移进入淋巴组织,在淋巴组织中,DC1和DC2通过抗原特异性信号(递呈抗原)、协同刺激信号(诱导Th充分活化)和分化或极化信号(主要是IL-12,也包括DC的表面分子)分别诱导Th分化为Th1和Th2,各种抗原相关的、感染组织相关的和免疫相关的因素通过调节IL-12的分泌水平和协同刺激分子的表达水平,或调节Th对DC的敏感性而调控Th的分化.这些相互作用使机体能快速选择合适的免疫应答方式清除相应的抗原.本文介绍了DC诱导Th分化机理的最新进展.     

郎格罕氏细胞分化发育研究进展

郎格罕氏细胞是位于上皮组织中的一种抗原提呈细胞 ,在人体的免疫防御系统中起着重要的作用。LC来源于骨髓 ,大量实验证实 ,由外周血分离得到的CD34 干细胞在GM CSF、TNF α和TGF β1的作用下在体外生成具有典型特征的LC ,外周血CD14 MO在一定条件下亦能分化发育为LC。位于非淋巴组织中的未成熟LC能摄取和加工处理抗原 ,同时分泌各种免疫因子 ,并在抗原的刺激下移向次级淋巴组织 ,发育成熟。LPS能通过诱导未成熟DC细胞核内产生NF κB转录因子 ,并在NF κB作用下上调MHC和共刺激分子的表达 ,从而使未成熟DC发育成熟。成熟的LC能提呈抗原并活化处女型T细胞 ,从而启动免疫应答     

粒细胞集落刺激因子诱导的供者外周血中两种不同亚群树突状细胞免疫生物学特性的研究

目的 从粒细胞集落刺激因子(G-CSF)诱导的供者外周血中分离出CD1c+的髓细胞性DC(MDC)、CD304+类浆细胞样DC(PDC)两类DC亚群,并对其生物学特性进行分析和研究.方法 免疫磁珠法分离出MDC、PDC,分别用TNF-α、CpG2006OND诱导成熟,检测各DC亚群的表型、对同种异基因淋巴细胞的刺激反应.结果 分选的DC纯度均＞95%,MDC表达HLA-DR、CD11c、CD33、CD4,PDC表达HLA-DR、CD4、CD45RA,诱导成熟的两类DC的CD40、CD80表达均明显增高;混合淋巴细胞反应(MLR)显示:MDC具有很强的刺激淋巴细胞增殖能力,PDC刺激能力很弱;各组上清液中IFN-r均增加,MDC、mMDC组增高最为明显;PDC、mPDC刺激组上清液中IL-10明显增高;MDC、mMDC刺激后,胞浆内表达IFN-r的CD4+T细胞均明显增高;PDC、mPDC有上调CIM+CD25high调节性T细胞(Treg)作用;Foxp3 mRNA的表达在各组间无明显的差异.结论 采集的供者外周血中两类DC亚群虽然HLA-DR高表达,但仍处于非成熟状态,在合适的条件下分化成熟;无论MDC成熟与否均表现出很强的刺激T细胞增殖能力,使T细胞分泌IFN-r增加,其分泌的增加可能是促进向TH1极化的结果.PDC可能并不像MDC一样有效地捕获、处理和负载抗原到MHC分子上,因此提呈抗原效率低,表现出对T细胞的弱刺激增殖特性;PDC虽然也可以促进T细胞分泌IFN-r,但似乎并非是通过TH1细胞;PDC并不能促进TH2类因子IL-4的分泌,对TH2的极化作用可能表现在IL-10的分泌上;PDC有诱导CD4+CD25highTreg的作用.     

MBL对树突状细胞体外分化成熟的影响

目的: 探讨甘露聚糖结合凝集素 (MBL)对人外周血单核细胞来源的树突状细胞 (MoDC)分化成熟的影响。方法: 以天然人MBL刺激MoDC, 在倒置显微镜下观察DC的形态; 用FACS分析DC的表型; 用 3H- TdR掺入法测定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培养上清中IL- 12和TNF- α的含量。结果: MBL刺激的DC表面分子CD1a、CD83、CD40、CD80、CD86和MHC DR的表达均上调,摄取酵母多糖颗粒的能力降低, 激发初始T细胞增殖的能力加强, 分泌的IL- 12增多但几乎不分泌TNF- α。结论: MBL能诱导DC分化成熟, 提示其可能通过调节DC的功能而参与获得性免疫应答。     

CpG ODN促进树突状细胞成熟的实验研究

目的：研究CpG ODN对小鼠骨髓来源的树突状细胞(bone marrow—derived dendritic cells,BMDC)分化成熟的影响。方法：以含非甲基化CpG基序的寡核苷酸(unmethylated CpG motif containing oligonucleotides,CpG ODN)刺激BMDC，流式细胞术检测DC膜表面CD80表达，ELISA检测DC分泌IL-l2水平，MTT法测定CpG ODN活化的DC刺激T细胞培殖能力。结果：CpG ODN可显著刺激DC表达CD80，分泌IL-l2，增强DC刺激T细胞增殖的能力。结论：CpG ODN可以有效促进DC的功能成熟。     

补体C5b-9复合物促进树突状细胞成熟

探讨补体C5b-9复合物对树突状细胞成熟及免疫学功能的影响。rhGM-CSF+rhIL-4体外诱导单核细胞分化为不成熟树突状细胞,体外于不成熟树突状细胞表面用补体蛋白纯品组装CSb-9,37℃,5%CO_2温育96 h,流式分析细胞表型及抗原捕获能力;与同种异体CD4~+和CD8~+T细胞共培养检测其免疫刺激功能;ELISA检测细胞因子分泌。结果显示,亚溶解型C5b-9处理DC表面标志CD83、HLA、CD80、CD86、B7-H1、B7-H3、B7-H4以及BTLA等表达上调;DC分泌IL-12及TNF-α上调,抗原捕获能力降低;C5b-9处理DC刺激CD4~+T细胞活化及分泌IFN-γ、IL-2能力增强。结论:补体C5b-9复合物可以促进树突状细胞成熟,衔接天然免疫和特异性免疫。     

Intravenous immunoglobulin modulates the maturation of TLR 4-primed peripheral blood monocytes

Intravenous immunoglobulin (IgIV) has immune modulating effects on the differentiation and function of dendritic cells (DC). Peripheral blood CD14+ monocytes were induced to differentiate into immature DC with IL-4/GM-CSF. DC maturation was analyzed by flow cytometry, and function assessed for antigen uptake and antigen processing. IgIV added during the differentiation process induced immature DC to differentiate into a mature DC with increased expression of CD83 and CCR7. A "priming" step with low concentrations of LPS or other TLR agonists that utilize the myD88 signaling pathway was necessary to observe these changes. These modulated DCs had reduced antigen uptake, but exhibited increased antigen presentation. Treatment of the IgIV with pepsin to generate F(ab')2 fragments abrogated these effects on DC maturation and function. The enhanced differentiation of PBM into DC required two signals: an initial exposure to low concentrations of LPS followed by IVIG. The second signal with IVIG was Fc dependent.     

Gp130分子的活化在树突状细胞分化和成熟中的意义

目的 :研究激发型抗gp130分子单抗B S12对树突状细胞 (DC)分化成熟和功能的影响。方法 :人外周血单核细胞在GM CSF和IL 4作用下分化为未成熟DC后 ,加入B S12单抗 ,观察它对DC表型、摄取抗原的能力以及DC分泌IL 12、进行混合淋巴细胞反应及趋化T细胞能力的影响 ;同时比较B S12和激发型抗CD4 0单抗 5C11对DC的作用。结果 :激发型抗gp130分子单抗B S12作用于未成熟DC ,可以上调DC上CD1a和共刺激分子CD80、CD86以及成熟DC的标志CD83分子的表达 ,下调CD14的表达 ,降低DC摄取抗原的能力 ,增强DC分泌IL 12、进行混合淋巴细胞反应及趋化T细胞的能力 ,但这些作用都稍弱于 5C11对DC的作用。结论 :未成熟DC上gp130分子的直接活化可以诱导DC的分化和功能成熟。     

Chemokine programming dendritic cell antigen response: part II – programming antigen presentation to T lymphocytes by partially maintaining immature dendritic cell phenotype

In a companion article to this study,¹ the successful programming of a JAWSII dendritic cell (DC) line's antigen uptake and processing was demonstrated based on pre‐treatment of DCs with a specific ‘cocktail’ of select chemokines. Chemokine pre‐treatment modulated cytokine production before and after DC maturation [by lipopolysaccharide (LPS)]. After DC maturation, it induced an antigen uptake and processing capacity at levels 36% and 82% higher than in immature DCs, respectively. Such programming proffers a potential new approach to enhance vaccine efficiency. Unfortunately, simply enhancing antigen uptake does not guarantee the desired activation and proliferation of lymphocytes, e.g. CD4⁺ T cells. In this study, phenotype changes and antigen presentation capacity of chemokine pre‐treated murine bone marrow‐derived DCs were examined in long‐term co‐culture with antigen‐specific CD4⁺ T cells to quantify how chemokine pre‐treatment may impact the adaptive immune response. When a model antigen, ovalbumin (OVA), was added after intentional LPS maturation of chemokine‐treated DCs, OVA‐biased CD4⁺T‐cell proliferation was initiated from ~ 100% more undivided naive T cells as compared to DCs treated only with LPS. Secretion of the cytokines interferon‐γ, interleukin‐1β, interleukin‐2 and interleukin‐10 in the CD4⁺ T cell : DC co‐culture (with or without chemokine pre‐treatment) were essentially the same. Chemokine programming of DCs with a 7 : 3 ratio of CCL3 : CCL19 followed by LPS treatment maintained partial immature phenotypes of DCs, as indicated by surface marker (CD80 and CD86) expression over time. Results here and in our companion paper suggest that chemokine programming of DCs may provide a novel immunotherapy strategy to obviate the natural endocytosis limit of DC antigen uptake, thus potentially increasing DC‐based vaccine efficiency.     

Glucocorticoids increase the endocytic activity of human dendritic cells.

We have investigated the effect of glucocorticoids (GC) on antigen uptake molecule expression and on endocytic activity of human dendritic cells (DC). Human monocyte-derived DC were differentiated in vitro for 7 days with granulocyte macrophage colony stimulating factor and IL-4 in the presence or absence of dexamethasone 10(-8) M (Dex). Dex-treated DC showed an enhancement of mannose receptor (MR)-mediated endocytosis (measured as uptake of FITC-dextran) and of fluid-phase endocytosis [measured as uptake of Lucifer yellow (LY)] The effect was dose dependent and correlated with the length of exposure to Dex. The expression of receptors involved in antigen capture was investigated by FACS analysis. Dex up-regulates MR, CD16 and CD32 expression on DC. After maturation with tumor necrosis factor-alpha or CD40 ligand in Dex-treated DC, despite a reduction induced by maturation the endocytic activity of FITC-dextran and LY, the expression of MR, CD16 and CD32 remained higher than in control DC. In view of the fact that antigen capture was increased in cells cultured with Dex, we evaluated the ability to present soluble antigen that needs to be taken up and processed. Cells differentiated in the presence of Dex showed much lower efficiency in presenting tetanus toxin to specific autologous T cell lines. In conclusion our data suggest a new mechanism by which GC may influence immune responses. In fact with the increase in endocytic activity, Dex favors the scavenging of antigen from the external milieu, decreasing antigen concentration and availability, and simultaneously inhibiting the capacity to stimulate T cells.     

Interleukin-10-modulated immature dendritic cells control the proinflammatory environment in multiple sclerosis

Multiple sclerosis (MS) is a disabling, inflammatory, demyelinating disease of the central nervous system considered to be mediated by autoreactive T cells. Dendritic cells (DC), being professional antigen‐presenting cells, play a pivotal role in the decision between T‐cell activation and anergy. It has been suggested that mature DC (mDC) induce immunity, whereas immature DC (imDC) have the potential to induce tolerance. In this study, we investigated the effects of autologous imDC versus autologous mDC on lymphocytes with respect to the expression of functionally important cell‐surface molecules and production of cytokines. Our aims were to investigate whether the maturation status of DC differs between MS and healthy controls (HC) and to explore whether the effects of DC on T‐cell responses differ between MS and HC. DC were generated from adherent blood mononuclear cells from patients with MS and HC. imDC were obtained by culture with either granulocyte–macrophage colony‐stimulating factor (GM‐CSF) + interleukin‐4 (IL‐4) or GM‐CSF + IL‐4 + IL‐10. mDC were obtained by adding lipopolysaccharide to DC cultures. Upon coculture with autologous lymphocytes, mDC activated the autologous T cells as reflected by increased CD25 and cytotoxic T‐lymphocyte antigen‐4 expression on CD4⁺ T cells together with the increased production of both T helper 1 (Th1) (IL‐2 and interferon‐γ) and Th2 (IL‐10 and IL‐4) cytokines. Unmodulated naïve imDC induced the production of only IL‐4. An exposure of imDC to IL‐10 induced the production of IL‐4 as well as IL‐10 by autologous lymphocytes. We hypothesize that such imDC are important in controlling the proinflammatory environment in vivo in patients with MS.     

调节性DC分泌的外体诱导免疫耐受功能的体外研究

为了探讨树突状细胞(DC)分泌的外体(Dex)在诱导T细胞免疫耐受中的作用,体外研究采用供体Dex降低同种异体移植排斥的可能性。从正常人外周血单个核细胞中诱导培养未成熟DC(imDC),用TGF-β1联合IL-10诱导调节性DC,LPS诱导DC成熟。采用流式细胞术方法观察TGF-β1和IL-10对DC表型、吞噬功能的影响;采用超速离心和超滤的方法提纯Dex;Western blot方法检测imDC分泌的Dex(imDex)与调节性DC分泌的Dex(rDex)表达的相关分子;通过CCK-8法分析异源iDex和mDex在混合淋巴细胞反应(MLR)中的生物学功能,并比较rDex与iDex诱导免疫耐受的能力。结果显示,TGF-β1和IL-10可下调DC表面的共刺激分子CD80、CD83、CD86的表达,并诱导调节性DC分泌更多的rDex;异源的mDC分泌的Dex(mDex)在mDC存在时增强MLR,而异源的imDex在imDC存在时一定程度上抑制MLR,rDex诱导的抑制T细胞增殖作用显著强于iDex;rDex表达更多的FasL,提示TGF-β1和IL-10诱导的调节性DC分泌的rDex在免疫耐受中发挥重要作用,有望应用于同种异体移植抗免疫排斥。     

人膜型LIGHT分子对Mo-DC成熟和T细胞激活的调节作用

利用我们建立的表达人膜型LIGHT分子的基因转染细胞(L929/LIGHT)探讨LIGHT/HVEM信号体外对Mo-DC诱导分化的影响,并进一步研究其对T细胞活化和抗凋亡的共刺激作用。从健康人外周血中分离的单核细胞经GM-CSF联合IL-4诱导形成Mo-DC,流式细胞术分析Mo-DC诱导过程中HVEM和LIGHT的表达;基因转染细胞L929/mock、L929/LIGHT、L929/CD40L或L929/LIGHT联合L929/CD40L,分别经丝裂霉素处理后,与GM-CSF联合IL-4诱导的Mo-DC共育,流式细胞术检测Mo-DC细胞表面成熟标志CD83和CD86的表达,利用FITC-Dextran分析Mo-DC对抗原的摄取能力;L929/LIGHT或L929/mock经丝裂霉素处理后,与抗人CD3单抗激发的T细胞共育,流式细胞术分析CD4+和CD8+T细胞表面活化标志CD25的表达,Annexin V和PI双标记分析T细胞的凋亡率。结果表明,高表达HVEM的单核细胞在诱导形成成熟Mo-D(iDC)的过程中下调了HVEM的表达,成熟Mo-DC(mDC)又上调表达HVEM,而LIGHT在Mo-DC分化过程中呈短暂的诱导性表达;基因转染细胞L929/LIGHT及其联合L929/CD40L能上调Mo-DC表面共刺激分子CD83和CD86的表达,并下调Mo-DC对FITC-Dextran的摄取能力;L929/LIGHT细胞能上调CD4+、CD8+T细胞CD25的表达,并增强T细胞抗凋亡能力。因此,基因转染细胞L929/LIGHT表面表达的人膜型LIGHT分子介导的LIGHT/HVEM共刺激信号对Mo-DC的诱导成熟和T细胞活化及抗凋亡能力具有促进作用。     

Role of CD40 ligation in dendritic cell semimaturation

ABSTRACT: DC are among the first antigen presenting cells encountering bacteria at mucosal surfaces, and play an important role in maintenance of regular homeostasis in the intestine. Upon stimulation DC undergo activation and maturation and as initiators of T cell responses they have the capacity to stimulate naive T cells. However stimulation of naive murine DC with B. vulgatus or LPS at low drives DC to a semimature (sm) state with low surface expression of activation-markers and a reduced capacity to activate T-cells. Additionally semimature DC are nonresponsive to subsequent TLR stimulation in terms of maturation, TNF-alfa but not IL-6 production. Ligation of CD40 is an important mechanism in enhancing DC maturation, function and capacity to activate T-cells. We investigated whether the DC semimaturation can be overcome by CD40 ligation. Upon CD40 ligation smDC secreted IL-12p40 but not the bioactive heterodimer IL-12p70, additionally CD40 ligation of smDC resulted in increased levels of IL-6 but not an increase expression of CD40. Analysis of the phosphorylation pattern of MAP kinases showed, that in smDC the CD40 ligation induced p38 phosphorylation is inhibited, in contrast phosphorylation of ERK upon CD40 ligation was independent of the DC maturation state. Our data show that the semimature differentiation state of DC can not be overcome by CD40 ligation. We suggest that the inability of CD40 ligation in overcoming DC semimaturation might contribute to the tolerogenic phenotype of semimature DC and at least partially account for maintenance of intestinal immune homeostasis.     

Interleukin-10 does not affect phagocytosis of particulate antigen by bone marrow-derived dendritic cells but does impair antigen presentation

Dendritic cells (DC) are important initiators of an immune response so understanding the factors controlling antigen acquisition and presentation has important consequences for the use of these cells in vaccines and other forms of immunotherapy. We investigated the factors that influence phagocytosis by immature bone marrow-derived DC (BMDC) and the effect of interleukin-10 (IL-10) on this process. Two sizes of fluorescent particles and recombinant bacillus Calmette-Guèrin expressing the green fluorescent protein (rBCG) were used as particulate antigens. The percentage of cells taking up the antigen was found to be dependent on the size and dose of the particles, and the length of exposure to them. BMDC exposed to IL-10 at various concentrations for different periods exhibited no distinguishable change in antigen uptake. However, if BMDC treated with IL-10 and rBCG were then exposed to a second dose of particulate antigen, uptake was increased compared with those BMDC not treated with IL-10. The expression of major histocompatibility complex class II, CD80, CD86 and CD11c by BMDC after phagocytosing rBCG or inert beads, was inhibited when the BMDC were pretreated with IL-10. In contrast, the expression of CD25 was increased. BMDC that had taken up BCG or purified protein derivative (PPD) were able to stimulate primed T-cell proliferation but this was severely inhibited if the BMDC were cultured with IL-10 before exposure to the antigen. This work suggests that although IL-10 does not affect the phagocytic capacity of BMDC, it does inhibit maturation of the cells and consequently, T-cell activation.