耐受性树突状细胞在自身免疫中的作用

树突状细胞(dendritic cell,DC)是体内功能最强的专职抗原递呈细胞,在中枢及外周免疫耐受的形成和维持中起关键作用,可由多种方式修饰而诱导外周耐受.耐受性树突状细胞通过诱导免疫耐受已成为自身免疫病治疗的有力工具和靶点.     

调节性树突状细胞研究进展

树突状细胞(dendritic cells,DCs)是体内作用最强的抗原递呈细胞,成熟DCs能够加工和递呈各种抗原,并通过一些固有免疫受体如Toll样受体识别病原微生物表达的模式分子,以及通过主要组织相容件抗原复合物(MHC)和共刺激分子的表达,引起初始T细胞的活化、增殖.然而,越来越多的证据表明,体内存在着能够负向调节免疫应答强度、维持免疫耐受的DCs,并且命名为调节性DCs(regulatory DCs).     

树突状细胞与免疫负向调控

以往多数学者认为树突状细胞(dendriticcells,DC)具有激活免疫的功能,但是,近年来愈来愈多的实验证明,DC具有负相调节免疫的功能,其可通过诱导T细胞失能、使免疫反应偏移、诱导调节性T细胞形成及促使活化的T细胞凋亡等方式使机体达到免疫稳定,但同时DC这些特性又会被病原体和肿瘤所利用而达到免疫逃逸。以下综述了各种状态下的DC与免疫负向调控的关系、DC参与免疫负向调控的机制等方面的研究进展。     

IL-37抑制脂多糖诱导的小鼠树突状细胞活化

目的探讨白细胞介素37(IL-37)对细菌脂多糖(LPS)诱导的小鼠树突状细胞(DC)活化的调节作用。方法应用GM-CSF和IL-4诱导小鼠骨髓细胞向DC分化,抗CD11c磁珠分选DC。IL-37预处理DC后,进行LPS刺激。流式细胞术检测DC表面共刺激分子(CD80、CD86)表达水平,实时荧光定量PCR检测肿瘤坏死因子α(TNF-α)、IL-6和IL-1αmRNA表达水平,流式细胞微球芯片试剂盒(CBA试剂盒)检测细胞培养上清中IL-1α、IL-6、TNF-α等因子的浓度。结果 DC诱导成功,磁珠分选能够获得高纯度的DC(>90%)。IL-37降低LPS诱导的DC表面共刺激分子CD80、CD86的表达,并抑制DC合成IL-1α、IL-6、TNF-α。结论 IL-37可以通过降低共刺激分子和炎症因子的表达抑制LPS刺激的DC活化。     

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。     

肝X受体对小鼠耐受性树突状细胞的诱导作用

为研究肝X受体(LXR)对小鼠骨髓来源耐受性树突状细胞的诱导作用,取C57BL/6纯系小鼠股骨骨髓,将骨髓细胞置于含rmGM-CSF(20ng/ml)、rmIL-4(20ng/ml)、10%FBS、含/或不含LXR激动剂TP0901317(5μmol/L)的RPMI1640培养基中生长。于第7天时检测细胞表型,指标包括:CD11c、CD80、CD86、MHCⅡ、CCR7、PD-L1等;同日加入LPS(100ng/ml)促成熟。LPS作用第3天时,检测细胞表型。以MACS分选未成熟和成熟CD11c+细胞,以丝裂霉素C处理细胞。另取BALB/c小鼠脾脏,MACS分选CD4+T淋巴细胞。将CD11c+细胞与CD4+T细胞混合培养,CCK-8法检测T细胞增殖情况。ELISA法检测细胞培养上清中IL-10水平。研究发现,TP0901317处理组:培养第7天时,CD11c+细胞约为70.2%;CD80、CD86和MHCⅡ在CD11c+细胞上为中低表达,表达水平在40.2%~50%;CD11c+CCR7+细胞约占78%;CD11c+PD-L1+细胞约占90%。以LPS处理促成熟第3天时,CD11c+细胞约为85%;CD80、CD86和MHCⅡ在CD11c+细胞上的表达水平没有明显差异;CD11c+CCR7+细胞约占86%;CD11c+PD-L1+细胞约占99%。混合淋巴细胞反应显示,TP0901317处理组:成熟CD11c+细胞与未成熟细胞一样,均没有刺激CD4+T细胞增殖的能力。而在dTP0901317未处理组:成熟CD11c+细胞具有很强的刺激CD4+T细胞增殖的能力。ELISA检测结果显示,与TP0901317未处理组比较,TP0901317处理组CD11c+细胞能够产生更高水平的IL-10,具有显著意义(P0.05)。故而可以认为LXR活化能够诱导小鼠骨髓细胞向耐受性树突状细胞分化。     

浆细胞样树突状细胞与免疫耐受

浆细胞样树突状细胞(PDC)来源于淋巴系干细胞,其表面标志、功能有别于髓系DC,不仅在抗病毒免疫中发挥重要作用,而且通过多种途径诱导T细胞失能和调节性T细胞的形成,从而参与免疫耐受的诱导.PDC诱导T细胞免疫耐受的分子机制与吲哚胺2,3-双加氧酶(IDO)-色氨酸代谢通路和具有抑制功能的膜分子密切相关.深入阐明PDC诱导耐受的机制,将为免疫耐受异常相关的疾病的治疗提供新方案.     

小鼠胸腺树突状细胞系MTSC4诱导早期T细胞株C320…

通过流式细胞仪分析了我室自建的小鼠胸腺树突状细胞系ＭＴＳＣ４与小鼠肿瘤性早期Ｔ细胞株Ｃ３２０细胞共育后，Ｃ３２０细胞表达ＩＬ－２Ｒ的状态，分析了ＣｏｎＡ和ＰＨＡ对Ｃ３２０及与ＭＴＳＣ４共育后的Ｃ３２０表达ＩＬ－２Ｒ的诱导促进作用以及ＩＬ－２Ｒ＾＋Ｃ３２０细胞在脱离外源性刺激后其比例的变化，ＭＴＳＣ４及ＣｏｎＡ和ＰＨＡ在不同程度上抑制Ｃ３２０细胞的无限制增殖，ＣｏｎＡ和ＰＨＡ对与ＭＴＳＣ４共育后的Ｃ     

肝X受体激动剂GW3965对应激小鼠海马小胶质细胞活化的影响

目的:研究肝X受体（LXRs）激动剂GW3965对慢性不可预知性应激（CUS）抑郁模型小鼠海马CA1、CA2/3和DG区内小胶质细胞密度和神经炎症的作用。方法:选取4～6周龄的雄性C57BL/6J小鼠,适应性喂养1周后,随机分为对照组（control）、对照+GW组（GW）、抑郁模型组（CUS）以及抑郁模型+GW组（CUS+GW）。对CUS组和CUS+GW组小鼠进行10周的CUS干预;从第7周起,对GW组和CUS+GW组小鼠进行4周的GW3965给药。第10周末进行行为学测试后运用免疫荧光方法评估小鼠海马各亚区内小胶质细胞的密度,并采用Western Blot检测海马炎症因子的水平。结果:10周的CUS干预显著减少C57小鼠的体重以及糖水偏好实验结果,并显著增加强迫游泳实验中小鼠的不动时间;4周的GW3965治疗可以逆转以上结果。CUS干预显著增加小鼠海马CA1区、CA2/3区和DG区内Iba1⁺小胶质细胞密度,以及海马炎症因子IL-1β、TNF-α和转录因子NF-κB的蛋白表达水平,显著降低抗炎介质CD206的蛋白表达水平;而GW3965治疗可逆转上述变化。结论...     

Synthetic liver X receptor agonist T0901317 attenuates high glucose-induced oxidative stress,mitochondrial damage and apoptosis in cardiomyocytes

The aim of the present study was to investigate the protective effects of T0901317 (T0), a potent agonist of liver X receptors (LXRs), on high glucose-induced oxidative stress and apoptosis in H9c2 cardiac cells. Exposure of H9c2 cells to high glucose alone, not only caused a significant increase in apoptosis and reactive oxygen species (ROS) generation, but also led to a decrease in mitochondrial membrane potential (ΔΨm), release of cytochrome c, decrease in Bcl-2, increase in Bax expression and the activation of caspase-3, caspase-9, poly (ADP-ribose) polymerase (PARP) and nuclear factor (NF)-κB. However, pretreatment with T0 effectively decreased apoptosis, reduced the levels of ROS, abrogated ΔΨm, inhibited cytochrome c release and NF-κB activation, increased Bcl-2 and decreased Bax expression. In conclusion, our data suggest that T0 exerts protective effects against high glucose-induced apoptosis in H9C2 cardiac muscle cells via inhibition of ROS production, mitochondrial death and NF-κB activation.     

Prolonged survival effects induced by immature dendritic cells and regulatory T cells in a rat liver transplantation model

BackgroundDendritic cells (DCs) and regulatory T (Treg) cells are crucial for inducing immune tolerance. However, the suppressive function of infused Treg cells and immature DCs (imDCs) following solid organ transplantation remains unclear.MethodsImDCs derived from DA-donor rats and Treg cells isolated from spleens of Lewis rats were prepared. A heterotopic liver transplantation model was established to examine the immune tolerance effects of infusion of Treg-imDCs, imDCs and Treg cells individually. Th1/Th2 cytokines and TRAL were detected by ELISA. The overall rejection grade was assessed and the rejection activity index (RAI) was calculated. TUNEL-positive lymphocytes were detected in the portal area in liver sections.ResultsThe infusion of Treg-imDCs was more effective than imDCs or Treg cells individually. Moreover, the expression of IL-10 and TGF-β1 was significantly up-regulated, and IL-12 expression was significantly down-regulated, especially in the Treg-imDCs group. The percentage of TUNEL-positive cells was significantly higher in the Treg cells and imDCs groups. The RAI values in Treg-imDCs group on days 3 and 7 were lower than control, imDCs and Treg cells groups individually (p < 0.05). Both TBIL and ALT levels in the Treg-imDCs and imDCs groups were significantly lower than those of the control and Treg cells groups, and serum TRAL levels increased significantly 10 days after transplantation in the imDC and Treg-imDC groups compared with the control and Treg cells groups (P < 0.001).ConclusionThese data demonstrated that infusion of Treg cells and/or imDCs induces alloantigen tolerance and prolongs liver allograft survival. The infusion of Treg-imDCs was more effective than imDCs or Treg cells individually. ImDCs synergize with Treg cells in inducing and maintaining the feedback loop between imDCs and Treg cells in vivo.     

Liaison between natural killer cells and dendritic cells in human gestation

A successful pregnancy relies on immunological adaptations that allow the fetus to grow and develop in the uterus, despite being recognized by maternal immune cells. Among several immunocompetent cell types present within the human maternal/fetal interface, DC-SIGN~ dendritic cells （DCs） and CD56＋ natural killer （NK） cells are of major importance for early pregnancy maintenance, not only generating maternal immunological tolerance but also regulating stromal cell differentiation. Previous reports show the presence of NK-DC cell conjugates in first trimester human decidua, suggesting that these cells may play a role in the modulation of the local immune response within the uterus. While effective immunity is necessary to protect the mother from harmful pathogens, some form of tolerance must be activated to avoid an immune response against fetal antigens. This review article discusses current evidence concerning the functions of DC and NK cells in pregnancy and their liaison in human decidua.     

调节性DC与调节性T细胞的相互作用

近年来研究发现调节性树突状细胞(Dendritic cells,DC)能够下调免疫应答和介导外周免疫耐受,调节性DC诱导的免疫耐受与其未成熟或半成熟状态密切相关。大量研究表明调节性DC和调节性T细胞(Regulatory T cells,Treg)之间存在着复杂的双向调控:调节性DC可扩增和诱导产生Treg,还可影响Treg向局部组织和外周淋巴器官归巢;Treg则妨碍DC与非调节性T细胞的结合并抑制DC的活化、成熟和刺激T细胞增殖的能力。总之,调节性DC与Treg相互协同以精细调控机体的免疫应答。     

小鼠树突细胞LTB4-BLT的表达

目的探讨树突细胞(DC)白三烯B4(LTB4)-白三烯B4受体(BLT)信号通路LTB4-BLT(包括LTB4-BLT1和LTB4-BLT2)存在状态。方法分离正常小鼠骨髓细胞,体外用细胞因子(IL-4,GS-CSF)诱导、分化为DC,脂多糖(LPS)刺激其成熟。光镜观察细胞形态和流式细胞术进行DC表型分子鉴定。ELISA方法检测幼稚、成熟DC培养液中LTB4含量;RT-PCR方法检测幼稚和成熟DC BLT1和BLT2 mRNA表达。结果DC培养的2、4和6 d(DC幼稚状态)及8 d(LPS刺激后DC成熟状态),培养液中LTB4含量分别为(10.667±2.394)ng/L、(7.089±1.810)ng/L、(3.222±0.995)ng/L及(14.217±3.396)ng/L。随DC分化进程,培养液中LTB4含量呈递减趋势,而成熟DC分泌LTB4含量比幼稚DC明显增高(P<0.05);RT-PCR示成熟状态和幼稚状态DC均表达BLT1和BLT2 mRNA,且成熟比幼稚状态DC mRNA表达水平增强(P<0.05)。结论DC可通过分泌LTB4和表达BLT而建立自身LTB4-BLT信号通路,为进一步研究DC LTB4-BLT1和LTB4-BLT2这2条信号通路在炎症反应和免疫调节中的作用提供了实验依据。