The Effect of Beta Interferon on Dendritic Cells and Cytokine Synthesis by CD4+ T Cells

Background: Dendritic cells (DC) are a key regulator of the immune response, and interferon- beta (IFN-β) is considered an immunomodulatory molecule for DC. Objective: The purpose of this study was to evaluate the ability of IFN-β treated DC to induce cytokine secretion by CD4+ T cells. Methods: Dendritic cells were generated from blood monocytes with granulocyte-monocyte colony-stimulating factor and interleukin-4 with or without IFN-β. We analyzed the production of CD4+ T helper cytokines (IL-17, IFN- γ and IL-10) in the supernatant of the dendritic cell-T cell co- cultures by ELISA. We also studied the effects of HLA-G and costimulatory molecules on immature and mature DC. Results: IFN-γ and IL-17 decreased significantly in the presence of HLA-Gbearing DC compared to control cultures (p<0.05). Conclusion: Using the mixed leukocyte reaction, we found that DC treated with IFN-β mediated the inhibition of T cell activation via cytokine production. We conclude that this is important for preventing overactivation of the immune system.     

Effect of Cytomegalovirus Recombinant Phosphoprotein 150 (pp150) on Function and Maturation of Murine Dendritic Cells: an In-Vitro Study

Background: Tegument protein pp150 of cytomegaloviruses (CMVs) plays a vital role in all stages of viral life cycle, representing the most important tegument protein candidate for HCMV treatment. However, the exact role of pp150 in immune regulation is yet to be elucidated. Objective: To examine the effects of pp150 on the maturity and function of murine dendritic cells (DCs). Methods: Maturity status (CD40, CD86, and MHC-II expression) and phagocytic capacity of DCs (dextran uptake assay) were characterized. Gene expression profiles of ROR-γ, GATA-3, T-bet, and FOXP-3 as well as the protein expression of INF-γ (Th1), IL-4 (Th2), IL-35 (Treg), IL-17A (Th17), IL-22, TNF-α, IL-6, and IL-2 were evaluated in T cells co-cultured with DCs. Results: A significant increase in CD40, CD86, and CCR7 expression and a reduction in the phagocytosis rate were observed in pp150-stimulated DCs compared with unstimulated DCs. T cells co-cultured with stimulated DCs showed higher expressions of ROR-γ, IL-6, IL-2, IL-17A, IL-22, and TNF-α. Conclusion: Despite improvements in maturity status, pp150-stimulated DCs does not seem to be able to induce Th1 or Th2 immunity. In fact, Th17 and its mediators, IL-17A and IL-22, might be the main inflammatory factors involved in pp150-stimulated DC's action mechanism. However, it is necessary to conduct further investigations to corroborate these observations.     

Evaluation of the Immunomodulatory Effect of Curdlan on Maturation and Function of Mouse Spleen-Derived Dendritic Cells

Background: T helper 1 and T helper 17 cells play important roles in immunity against foreign invaders. Differentiation of these Th subsets is affected by state of maturation and cytokines that are produced by dendritic cells (DCs). Curdlan is a linear (1→3)-β- glucan and has shown activity against tumors and infectious agents. Objective: This study aims to investigate whether curdlan plays its role through affecting the maturation and cytokine production by DCs. Methods: DCs were isolated from the spleen of BALB/c mice by MACS method. After an overnight culture of DCs in the presence of curdlan, the expression levels of CD40, CD86, and MHC-II molecules were determined by flow cytometry. The production of cytokines involved in Th1 and Th17 cell differentiation (IL-12 and IL-6, respectively) was also evaluated by ELISA. Lipopolysaccharide (LPS) treated and untreated cells were considered as positive and negative controls, respectively. Results: The results of this study did not show a significant difference in the levels of surface expression of CD40 (p=0.82), CD86 (p=0.79), and MHC class II (p=0.84) molecules upon exposure to curdlan. However, LPS increased the intensity of CD40 expression on dendritic cells (p=0.04). In addition, it was revealed that curdlan-exposed DCs are not able to produce a significant amount of IL-6 and IL-12 cytokines. Conversely, LPS-treated DCs were able to make a significant amount of IL-12 (p=0.005). Conclusion: The results of the present study suggest that curdlan has no effect on Th1 or Th17 differentiation while LPS may induce Th1 deviation by induction of CD40 expression and IL-12 production.     

骨髓间充质干细胞的免疫学特性

目的 研究骨髓间充质干细胞(MSC)的免疫学特性,为临床应用提供实验依据.方法 培养鉴定MSC,检测其生长动力学、细胞周期.检测单纯和200 U/ml干扰素(IFN)γ干预后MSC的程序性死亡配体(PDL)-1、CD54、CD40、CD80、CD86、主要组织相容性复合物(MHC)-Ⅰ、MHC-Ⅱ的表达情况,并以此为调节细胞进行混合淋巴细胞反应.封闭PDL-1、CD54,观察它们在MSC免疫调节中的作用.检测培养上清液中IFN γ、白细胞介素(IL)-2,IL-4、IL-10的水平.将MSC移植于体内观察肝脏归巢和诱导微嵌合体情况.结果 分离、培养的MSC纯度较高;生长曲线显示第1、2天为潜伏期,第3、4、5天为对数生长期,第6、7天为平台期.细胞周期显示G0/G1期为76.0%±2.0%,S期为13.0%±2.0%,(G2+M)期为10.0%±1.7%.IFN γ上调CD54、PDL-1、MHC-Ⅰ、MHC-Ⅱ的表达,CD40、CD80、CD86为阴性表达.MSC呈剂量依赖性地抑制T淋巴细胞增殖,IFN γ增强其抑制作用.封闭PDL-1、CD54后能减弱MSC对T淋巴细胞增殖的抑制作用.培养上清液中IFN γ、IL-10水平较高,IL-4较低,IL-2未检测到.MSC在肝实质内有多处定居,并能诱导肝移植术后微嵌合体形成.结论 IFN γ能增强MSC对淋巴细胞增殖的抑制作用,PDL-1和CD54可能发挥关键作用;MSC移植后能在体内存活并诱导微嵌合体形成.     

来氟米特对狼疮患者树突状细胞作用机制的初探

目的　探讨来氟米特(LEF)处理前后系统性红斑狼疮(SLE)患者树突状细胞(DC)表面标志及功能的改变,揭示LEF治疗SLE的作用机制,为开展“抑制性DCs”治疗SLE奠定实验基础。方法　(1)分离SLE患者外周血单核细胞,用细胞因子诱导DC成熟, LEF组再加入A7717262(来氟米特的活性代谢产物)培养。第9天收集DC细胞,流式细胞仪检测CD80、CD83、CD86和HLA DR的表达。(2)分别将A771726处理或不处理的第9天DC和T细胞进行培养, 72h后用MTT法检测DC刺激淋巴细胞增殖的能力,FACS检测T细胞亚群和ELISA检测培养上清中IL 10和IFNγ水平。结果A771726处理后虽DC形态无改变,但DC表达CD83、CD86和HLA DR百分数较对照组均明显降低(72 70±1 77vs 79 36±4 80, 63 50±14 06vs. 83 91±9 81, 80 44±12 56vs. 90 51±8 63,P值均<0 01)。A771726处理后的DC,其刺激T细胞增殖相应的吸光度值明显降低,混合培养的上清液中IL 10水平较无A771726处理的DC与T细胞的混合培养上清液明显降低,而IFNγ两者间无显著差异;但见CD 4 CD 25CTLA 4 T细胞百分比增高。结论　LEF在体外可抑制SLE患者外周血DC的成熟;未成熟DC能抑制T细胞增殖及T细胞向Th2 细胞转化,诱导CD 4 CD 25CTLA 4 T细胞产生,从而纠正SLE患者的部分免疫紊乱。     

In Vivo Effects of Calcitriol on Phenotypic and Functional Properties of Dendritic Cells

Background: Dendritic cells (DCs) play a central role in the initiation and expansion of T cell mediated immune responses with potential immunotherapy application. The compounds which have the ability to induce immunomodulatory effects on DCs may be employed for the treatment of immunopathologic conditions such as autoimmune diseases. Objective: The aim of this study was to investigate the in vivo effects of calcitriol (active form of vitamin D3) on DCs. Methods: 0.1 microgram calcitriol was injected intra-peritoneally into C57BL/6 mice every other day within 3 weeks, and spleen DCs were extracted by magnetic beads. The phenotypic and functional properties of DCs were studied by flow cytometry and mixed lymphocyte reaction (MLR), respectively. Results: The expression of CD86 and MHC II, as maturation markers and costimulatory molecules were significantly decreased (p=0.028 and p=0.047, respectively) while CD11b expression, as a marker of mice myeloid DCs which mostly induces Th2 cytokine profile, was significantly increased (p=0.011). Allogeneic T cell stimulation in MLR was also significantly inhibited in comparison with the control groups (p<0.05). Conclusion: Our data indicate that in vivo calcitriol administration inhibits maturation and activation of DCs in the same manner as in vitro conditions.     

Prolongation of liver allograft survival by dendritic cells modified with NF-κB decoy oligodeoxynucleotides

AIM: To induce the tolerance of rat liver allograft by dendritic cells (DCs) modified with NF-κB decoy oligodeoxynucleotides (ODNs).METHODS: Bone marrow (BM)-derived DCs from SD rats were propagated in the presence of GM-CSF or GM-CSF+IL-4to obtain immature DCs or mature DCs. GM-CSF+IL-4-propagated DCs were treated with double-strand NF-κB decoy ODNs containing two NF-κB binding sites or scrambled ODNs to ascertain whether NF-κB decoy ODNs might prevent DC maturation. GM-CSF-propagated DCs, GMCSF+NF-κB decoy ODNs or scrambled ODNs-propagated DCs were treated with LPS for 18 h to determine whether NF-κB decoy ODNs could prevent LPS-induced IL-12production in DCs. NF-κB binding activities, costimulatory molecule (CD40, CD80, CD86) surface expression, IL-12protein expression and allostimulatory capacity of DCs were measured with electrophoretic mobility shift assay (EMSA),flow cytometry, Western blotting, and mixed lymphocyte reaction (MLR), respectively. GM-CSF-propagated DCs, GMCSF+IL-4 -propagated DCs, and GM-CSF+NF-κB decoy ODNs or scrambled ODNs-propagated DCs were injected intravenously into recipient LEW rats 7 d prior to liver transplantation and immediately after liver transplantation.Histological grading of liver graft rejection was determined 7 d after liver transplantation. Expression of IL-2, IL-4 and IFN-γ mRNA in liver graft and in recipient spleen was analyzed by semiquantitative RT-PCR. Apoptosis of liver allograft-infiltrating cells was measured with TUNEL staining.RESULTS: GM-CSF-propagated DCs, GM-CSF+NF-κB decoy ODNs-propagated DCs and GM-CSF+ scrambled ODNspropagated DCs exhibited features of immature DCs, with similar low level of costimulatory molecule(CD40, CD80,CD86) surface expression, absence of NF-κB activation,and few allocostimulatory activities. GM-CSF+IL-4-propagated DCs displayed features of mature DCs, with high levels of costimulatory molecule (CD40, CD80, CD86) surface expression, marked NF-κB activation, and significant allocostimulatory activity. NF-κB decoy ODNs completely abrogated IL-4-induced DC maturation and allocostimulatory activity as well as LPS-induced NF-κB activation and IL-12protein expression in DCs. GM-CSF+NF-κB decoy ODNspropagated DCs promoted apoptosis of liver allograftinfiltrating cells within portal areas, and significantly decreased the expression of IL-2 and IFN-γ mRNA but markedly elevated IL-4 mRNA expression both in liver allograft and in recipient spleen, and consequently suppressed liver allograft rejection, and promoted liver allograft survival.CONCLUSION: NF-κB decoy ODNs-modified DCs can prolong liver allograft survival by promoting apoptosis of graft-infiltrating cells within portal areas as well as downregulating IL-2 and IFN-γ mRNA and up-regulating IL-4 mRNA expression both in liver graft and in recipient spleen.     

Enhancement of CTLs induced by DCs loaded with ubiquitinated hepatitis B virus core antigen

AIM: To investigate whether hepatitis B virus (HBV) could induce a hepatitis B virus core antigen (HBcAg)-specific cytotoxic T lymphocyte (CTL) response in vitro by dendritic cells (DCs) transduced with lentiviral vector-encoding ubiquitinated hepatitis B virus core antigen (LV-Ub-HBcAg).METHODS: Recombinant LV-Ub-HBcAg were transfected into highly susceptible 293 T cells to obtain high virus titres. Bone marrow-derived DCs isolated from BALB/c mice were cultured with recombinant granulocyte-macrophage colony-stimulating factor and recombinant interleukin (IL)-4. LV-Ub-HBcAg, lentiviral vector-encoding hepatitis B virus core antigen (LV-HBcAg), lentiviral vector (LV) or lipopolysaccharide were added to induce DC maturation, and the DC phenotypes were analyzed by flow cytometry. The level of IL-12 in the supernatant was detected by enzyme-linked immunosorbent assay (ELISA). T lymphocytes were proliferated using Cell Counting Kit-8. DCs were cultured and induced to mature using different LVs, and co-cultured with allogeneic T cells to detect the secretion levels of IL-2, IL-4, IL-10 and interferon-γ in the supernatants of T cells by ELISA. Intracellular cytokines of proliferative T cells were analyzed by flow cytometry, and specific CTL activity was measured by a lactate dehydrogenase release assay.RESULTS: LV-Ub-HBcAg-induced DCs secreted more IL-12 and upregulated the expression of CD80, CD86 and major histocompatibility class II. DCs sensitised by different LVs effectively promoted cytokine secretion; the levels of IL-2 and interferon-γ induced by LV-Ub-HBcAg were higher than those induced by LV-HBcAg. Compared with LV-HBcAg-transduced DCs, LV-Ub-HBcAg-transduced DCs more efficiently stimulated the proliferation of T lymphocytes and generated HBcAg-specific cytotoxic T lymphocytes.CONCLUSION: LV-Ub-HBcAg effectively induced DC maturation. The mature DCs efficiently induced T cell polarisation to Th1 and generated HBcAg-specific CTLs.     

ADMA对单核细胞来源的树突状细胞成熟和免疫的影响

目的:通过观察非对称性二甲基精氨酸(ADMA)对树突状细胞(dendritic cells,DCs)成熟及免疫的影响来探讨AS形成的可能机制。方法:贴壁法分离人外周血单核细胞,在含重组人粒-巨噬细胞集落刺激因子(rhGM-CSF 20ng/ml)和重组人白细胞介素-4(rhIL-4,10ng/ml)的完全培养基中培养,五天后收集imDC,用1、8、16umol/L的ADMA干预未成熟DC 24h。用流式细胞术检测DC细胞表面分子的表达、吞噬能力及DC的凋亡,用混合淋巴细胞反应检测成熟DC刺激T淋巴细胞增殖的能力,用ELISA检测DC细胞因子的分泌。结果:生理浓度ADMA并不刺激DC成熟及分化;但病理浓度ADMA抑制DC成熟;抑制DC诱导的T淋巴细胞增殖;诱导DC凋亡:抑制DC分泌IL-12细胞因子、TNF-α及IL-10细胞因子。结论:生理浓度ADMA并不刺激DC成熟及分化;但病理浓度AD-MA抑制DC成熟和免疫。     

脂多糖对人外周血树突状细胞成熟的影响

目的 通过研究内毒素的不同作用方式,模拟慢性乙型肝炎肠源性内毒素血症,探讨脂多糖(LPS)对人外周血树突状细胞(DC)成熟的影响.方法 用重组人粒细胞集落刺激因子、重组人白细胞介素-4、酪氨酸激酶受体3配体和肿瘤坏死因子α体外诱导、培养人外周血单个核细胞.分为持续刺激组:于1、4、7、9 d加入LPS 1 μg/ml;短期刺激组:于7、8 d加入LPS 1 μg/ml;对照组:不加LPS.观察细胞形态,用流式细胞仪检测细胞表型,混合淋巴细胞反应检测DC刺激T淋巴细胞的能力,用酶联免疫吸附法检测DC分泌细胞因子的水平.组间比较采用SPSS10.0统计学软件进行单因素方差分析,进一步两两比较用SNK法.结果 DC表达人白细胞-DR抗原、CD86、CD80、CD83分子水平,持续刺激组分别为65.81%±10.96%、48.81%±18.13%、13.56%±5.48%、11.52%±5.09%,对照组分别为78.43%±20.34%、51.29%±15.75%、15.22%±5.53%、15.64%±5.26%,短期刺激组分别为89.83%±16.99%、69.90%±24.05%、25.97%±10.81%、25.96%±10.59%,持续刺激组DC表面分子表达水平低于短期刺激组和对照组,各组比较,F值分别为3.376、3.823、4.535、5.320,P值均＜0.05,差异均有统计学意义.3组DC诱导同种异体混合T淋巴细胞的增殖指数分别为1.593±0.303、1.949±0.240、1.548±0.365,各组比较,F=3.572,P=0.049,差异有统计学意义.3组DC表达干扰素γ水平短期刺激组为(40.52±11.38)pg/ml,高于对照组和持续刺激组[分别为(21.57±7.68)pg/ml、(15.6±5.83)pg/ml],各组比较,F=3.403,P=0.019,差异有统计学意义.3组DC表达白细胞介素12水平短期刺激组为(84.45±31.28)pg/ml,高于对照组和持续刺激组[分别为(54.42±20.34)pg/ml、(51.77±11.02)pg/ml],各组比较,F=2.212,P=0.088,差异有统计学意义.结论 LPS持续刺激可抑制DC的发育成熟,可能是肠源性内毒素血症患者细胞免疫功能低下的原因所在.     

Aging affects AO rat splenic conventional dendritic cell subset composition, cytokine synthesis and T-helper polarizing capacity

It is well-established that almost all cellular components of innate and adaptive immunity undergo age-related remodelling. The findings on age-related changes in both human and mouse dendritic cells (DCs) are conflicting, whereas there are no data on the influence of aging on rat DCs. In an attempt to fill this gap, freshly isolated splenic DCs expressing CD103 (α_OX-62 integrin), a DC specific marker recognized by MRC OX62 monoclonal antibody, from 3- (young) and 26-month-old (aged) Albino Oxford rats were examined for subset composition, expression of activation/differentiation markers (CD80, CD86 and CD40 and MHC II molecules) and endocytic capacity using flow cytometric analysis (FCA). In addition, splenic OX62+ DCs cultured in the presence or absence of LPS were analysed for the activation marker and TNF-α, IL-6, IL-12, IL-23, TGF-β1, IL-10 expression using FCA, RT-PCR and ELISA, respectively. Moreover, the allostimulatory capacity of OX62+ DCs and IFN-γ, IL-4 and IL-17 production by CD4+ T cells in mixed leukocyte reaction was quantified using FCA and ELISA, respectively. It was found that aging: i) shifts the CD4+:CD4? subset ratio in the OX62+ DCs population towards the CD4? subset and ii) influences DCs maturation (judging by activation marker expression and efficiency of endocytosis) by affecting the expression of intrinsic (TNF-α and IL-10) and extrinsic maturation regulators. Furthermore, in LPS-matured OX62+ DCs from aged rats expression of TNF-α, IL-12, IL-23 and IL-6 was increased, whereas that of IL-10 was diminished compared with the corresponding cells from young rats. Moreover, in MLR, OX62+ DCs from aged rats exhibited enhanced Th1/Th17 driving force and diminished allostimulatory capacity compared with those from young rats.     

Human mesenchymal stem cells inhibit differentiation and function of monocyte-derived dendritic cells

Mesenchymal stem cells (MSCs), in addition to their multilineage differentiation, have a direct immunosuppressive effect on T-cell proliferation in vitro. However, it is unclear whether they also modulate the immune system by acting on the very first step. In this investigation, we addressed the effects of human MSCs on the differentiation, maturation, and function of dendritic cells (DCs) derived from CD14+ monocytes in vitro. Upon induction with granulocyte-macrophage colony-stimulating factor (GM-CSF) plus interleukin-4 (IL-4), MSC coculture could strongly inhibit the initial differentiation of monocytes to DCs, but this effect is reversible. In particular, such suppression could be recapitulated with no intercellular contact at a higher MSC/monocyte ratio (1:10). Furthermore, mature DCs treated with MSCs were significantly reduced in the expression of CD83, suggesting their skew to immature status. Meanwhile, decreased expression of presentation molecules (HLA-DR and CD1a) and costimulatory molecules (CD80 and CD86) and down-regulated IL-12 secretion were also observed. In consistence, the allostimulatory ability of MSC-treated mature DCs on allogeneic T cells was impaired. In conclusion, our data suggested for the first time that human MSCs could suppress monocyte differentiation into DCs, the most potent antigen-presenting cells (APCs), thus indicating the versatile regulation of MSCs on the ultimate specific immune response.     

The roles of IFN-γ versus IL-17 in pathogenic effects of human Th17 cells on synovial fibroblasts

Objectives

Th17 cells, while indispensable in host defense, may play pathogenic roles in many autoimmune diseases, including rheumatoid arthritis (RA). However, the mechanisms by which human Th17 cells drive autoimmunity have not been fully defined. We assessed the potential of the human Th17 CD4 T cell subset to induce expression of cell–cell interaction molecules and inflammatory mediators by fibroblast-like synoviocytes (FLS), and the roles of IFN-γ and IL-17 in these interactions.

Methods

Th1 or Th17 cells were induced from healthy adult donor CD4 T cells and were co-cultured with FLS for 48 h with/without neutralization of IFN-γ, IL-17A, or both. Alternatively, FLS were treated only with IFN-γ or IL-17 for 48 h. FLS expression of CD40, CD54, and MHC-II, as well as IL-6 and IL-8 secretion, were assessed by surface staining followed by flow cytometry and ELISA, respectively.

Results

Both Th1 and Th17 cells secreted IL-17 as well as IFN-γ, although IFN-γ production was much greater from Th1 cells. FLS expression of CD40, CD54, and MHC-II significantly increased upon co-culture with Th1 cells, while Th17 cells increased only the percentage of FLS that were CD54+. Both T cell subsets induced IL-6 and IL-8 secretion by RA FLS. Neutralization of IL-17A did not reduce FLS expression of CD40, MHC-II, or CD54, but did inhibit IL-6 and IL-8 secretion. Although IFN-γ was a weak inducer of IL-6 secretion and significantly inhibited IL-8 secretion from FLS when used as a single stimulus, neutralization of IFN-γ inhibited the secretion of both cytokines in Th17/FLS co-cultures with RA but not OA FLS.

Conclusion

FLS cell–cell interaction molecules and soluble inflammatory mediators are differentially regulated by IFN-γ and IL-17. The effects of IFN-γ may depend in part on the particular milieu of other co-existing cytokines and its potential to induce cell–cell interactions. The potential benefit of therapeutic neutralization of either IL-17 or IFN-γ could depend on the relative proportions of these cytokines in the synovial compartment of an RA patient.     

Long-Term Effects of Low-Dose Naltrexone on Immunomodulatory Properties of Human Adipose-Derived Mesenchymal Stem Cells

Background: Low-dose naltrexone (LDN) is involved in the treatment of inflammatory and immune system diseases and can affect immune cells. Mesenchymal stem cells (MSCs) are known for their immunomodulatory effects and the potential for the treatment of certain types of autoimmune diseases.Objective: To investigate the long-term effects of LDN on human adipose-derived mesenchymal stem cells (ASCs) to see how their immunomodulatory properties are affected and also how LDN-treated ASCs interact with other immune cells present in peripheral blood mononuclear cells (PBMCs).Methods: After 14 days of treatment, the ability of LDN-treated ASCs to modulate PBMC proliferation in a two-way mixed lymphocyte reaction (MLR) model was assessed using XTT. The relative expression of IDO, PD-L1, COX-2, HGF genes, and the level of IL-6 and TGF-β cytokines were measured in IFN-γ stimulated and unstimulated ASCs (treated and not treated cells) using real-time PCR and ELISA respectively.Results: Unstimulated ASCs treated with 10-8 M Naltrexone (10-8 M NTX) showed higher levels of TGF-β, compared with the controls (P<0.05). Stimulated ASCs treated with 10-6 M NTX showed elevated expression of IDO, PD-L1 genes, and IL-6 level (P<0.05).Conclusion: Our results demonstrated that various LDN concentrations have dissimilar effects on ASCs’ immunomodulatory properties. A higher LDN concentration induced an alteration in the immunomodulatory features of ASCs.     

细粒棘球绦虫Eg10诱导树突状细胞产生Th2免疫反应

目的 研究细粒棘球绦虫蛋白10(antigen 10 of Echinococcus granulosus Eg10)对小鼠感染细粒棘球绦虫免疫机制的影响。方法 通过体外培养骨髓来源的小鼠树突状细胞(Bone marrow dendritic cell, BMDC),用不同的抗原包囊囊液(hydatid fluid HF)、 Eg10、脂多糖(lipopolysaccharide LPS)单独或联合作用DC,共6组。通过扫描电镜和透射电镜观察各组DC形态学的变化;通过流式细胞仪检测DC的吞噬能力、迁移能力的变化、刺激T细胞增殖能力的变化及DC表面分子的表达情况;利用ELISA检测DC分泌各种细胞因子的变化。结果 Eg10抑制DC向成熟状态发展,与囊液对照组相比,DC表面仅增多了褶皱,两者均可提高DC吞噬能力;刺激T细胞的增殖能力很弱,但是能够提高Treg细胞的含量;同时发现Eg10组DC表面分子MHCII 和CD86的表达量高于空白组,分泌高含量的IL-10, IL-6。通过给予LPS联合刺激DC形态趋于半成熟状态,细胞表面树突增加,表面分子MHCII、CD80、CD40的表达增高,CD86的表达量降低;IL-10和IL-6的含量也相应的下降。结论 Eg10诱导DC产生Th2反应。     

三氧化二砷对炎症细胞的影响及其分子机制

目的观察三氧化二砷(As2O3)对人T淋巴细胞和人树突状细胞(DCs)凋亡以及对树突状细胞表型、细胞因子分泌的影响,探索As2O3洗脱支架局部抗炎作用的有关机制。方法分离培养人T淋巴细胞,用rhGM-CSF和rhIL-4诱导单个核细胞分化为树突状细胞,流式细胞仪检测As2O3对T淋巴细胞和树突状细胞凋亡的影响;用LPS诱导树突状细胞分化成熟,流式细胞仪检测As2O3干预对树突状细胞成熟表型的影响,ELISA检测As2O3对树突状细胞分泌细胞因子的影响。结果 As2O3在1umol/L浓度时即可明显诱导人T淋巴细胞凋亡,在5umol/L浓度时可诱导树突状细胞凋亡,且均呈剂量依赖性;As2O3在低于凋亡诱导剂量时即可抑制LPS诱导的树突状细胞成熟,下调树突状细胞表面分子CD83和CD86的表达率,并减少树突状细胞IL-10、IL-12和IFN-γ等细胞因子的释放。结论 As2O3具有诱导T淋巴细胞、树突状细胞凋亡以及抑制树突状细胞的免疫成熟的作用,As2O3洗脱支架的局部抗炎作用和As2O3的上述作用有关。     

Dominance of CD86, transforming growth factor- beta 1, and interleukin-10 in Mycobacterium tuberculosis secretory antigen-activated dendritic cells regulates T helper 1 responses to mycobacterial antigens

We report that stimulation of Mycobacterium tuberculosis (M. tuberculosis) secretory antigen (MTSA)-differentiated dendritic cells (DCs) and MTSA-matured DCs with M. tuberculosis cell extract (CE) down-regulated proinflammatory responses to CE-primed T (CE-T) cells by increasing surface expression of CD86 after CE stimulation. CE stimulation also decreased interleukin (IL)-12p40 and interferon (IFN)- gamma levels and increased IL-10 and transforming growth factor- beta 1 (TGF- beta 1) levels from these DCs. Blocking either CD86, IL-10, or TGF- beta with monoclonal antibodies before CE stimulation restored the attenuated T helper 1 (Th1) responses of CE-T cells. Conversely, treatment of these DCs with IL-12p70 and/or IFN- gamma completely restored Th1 responses from CE-T cells. These results indicate that M. tuberculosis secretory antigens down-regulate proinflammatory Th1 responses to mycobacteria by differentially modulating the cytokine profiles and surface densities of costimulatory molecules on DCs. Of importance, this down-regulation is independent of the maturation status of MTSA-activated DCs and can be rescued after treatment of DCs with IFN- gamma or IL-12.     

Tolerance Induction by CD40 Blocking through Specific Antibody in Dendritic Cells

Blocking antibodies are valuable tools for inhibiting the specific receptor- ligand interactions. The interaction of co-stimulatory molecules on the antigen presenting cells with their ligands on T cells is an essential step for T cell activation. In the present study, the effect of blocking antibody against CD40 on its T cell stimulatory potential is investigated.The DCs (dendritic cells) were collected from the mice spleens and then cultured in vitro. We used purified rat anti-mice CD40 (Clone HM40-3) (BD USA) as a blocking antibody and the appropriate titer of the blocking antibody was determined by flow cytometry. The DCs were then treated by antibody and used in MLR assay. The results of these experiments showed that CD40 blockade were associated with the increase in the of IL-4 secretion, shifting the DCs to stimulate Th2 cytokine production by the allogenic T cells, while the secretion of IL-12 by DCs decreased. Similarly, the DCs with reduced CD40 expression poorly responded to alloantigen stimulation in the MLR. Collectively, these results emphasize the importance of CD40 pathway in tolerogenic DCs generation and also support the idea that downregulation of CD40 is effective in inhibiting the allostimulatory function.