Altered cytokine production by dendritic cells from infants with atopic dermatitis

Dendritic cells (DC) are potent initiators of immune responses, compared to other professional antigen-presenting cells, based on their ability to capture antigen, express high amounts of MHC and co-stimulatory molecules, and to secrete immunostimulatory cytokines. Altered functions of DC in atopic individuals have been observed, though it is not clear if this is a cause or a result of the development of allergic disease. In this report we demonstrate altered cytokine production by DC isolated from infants with atopic dermatitis but without a diagnosis of asthma, compared to infants with non-atopic dermatitis. Increased production of IL-6, IL-10 and IFNα from DC isolated from atopic infants is less apparent when DC from infants were examined 1 year later. An increase in the same cytokines was observed in neonatal mice that are genetically predisposed towards allergic inflammation. These results suggest that an atopic environment promotes altered cytokine production by DC from infants.     

TLR-mediated stimulation of APC: Distinct cytokine responses of B cells and dendritic cells

In addition to their role in humoral immunity, B lymphocytes are important antigen-presenting cells (APC). In the same way as other APC, B cells make cytokines upon activation and have the potential to modulate T cell responses. In this study, we investigated which mouse B cell subsets are the most potent cytokine producers, and examined the role of Toll-like receptors (TLR) in the control of secretion of IL-6, IL-10, IL-12 and IFN-gamma by B cells. Production of some cytokines was restricted to particular subsets. Marginal zone and B1 cells were the predominant source of B cell IL-10 in the spleen. Conversely, follicular B cells were found to express IFN-gamma mRNA directly ex vivo. The nature of the activating stimulus dramatically influenced the cytokine made by B cells. Thus, in response to combined TLR stimulation, or via phorbol esters, IFN-gamma was secreted. IL-10 was elicited by T-dependent activation or stimulation through TLR2, 4 or 9. This pattern of cytokine expression contrasts with that elicited from dendritic cells. QRT-PCR array data indicate that this may be due to differential expression of TLR signalling molecules, effectors and adaptors. Our data highlight the potentially unique nature of immune modulation when B cells act as APC.     

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。     

Selective synergy in anti-inflammatory cytokine production upon cooperated signaling via TLR4 and TLR2 in murine conventional dendritic cells

Toll-like receptor (TLR) ligands, i.e. lipopolysaccharide (LPS), induce dendritic cell (DC) production of both inflammatory and anti-inflammatory cytokines including interleukin (IL)-12, tumor necrosis factor (TNF)-, and IL-10. The balance of inflammatory versus anti-inflammatory cytokines appears to be crucial to control immune homeostasis. In the present study, we investigated TLR-mediated regulation of inflammatory versus anti-inflammatory cytokine production using murine bone marrow derived conventional DCs. Standard LPS (sLPS) that contains lipoprotein, a TLR2 ligand, induced vigorous production of both IL-10 and IL-12 p40 by DCs. Highly purified LPS (ultra-pure LPS, upLPS) also induced vigorous production of IL-12 p40, but markedly low IL-10 production. Thus, signal deficiency through TLR2 appeared to result in marked reduction in DC production of IL-10 but not IL-12 p40 upon stimulation with upLPS. To examine this possibility, DCs were stimulated with Pam3CSK4, a synthetic ligand of TLR2, in addition to stimulation with upLPS. It was shown that Pam3CSK4 alone failed to induce IL-10 production. However, Pam3CSK4 synergistically enhanced upLPS-induced DC production of IL-10 but neither IL-12 p40 nor TNF-. Extracellular signal-regulated kinase (ERK)1/2, p38 mitogen-activated protein kinase (MAPK), and c-jun N-terminal kinase (JNK)1/2 in DCs were significantly activated by upLPS stimulation. The upLPS-induced activities of these MAPKs were considerably enhanced by additional stimulation with Pam3CSK4. Blocking either p38 MAPK or JNK1/2 pathway completely inhibited the synergistic enhancement of the IL-10 production by DCs upon upLPS and Pam3CSK4 stimulation. Thus, cooperated stimulation of these MAPKs via TLR4 and TLR2 appeared to induce selective synergy in anti-inflammatory cytokine production by murine conventional DCs.     

4种细胞因子组合方式对小鼠树突状细胞分化发育的影响

目的观察在体外培养时4种细胞因子(CK)组合方式对小鼠骨髓源树突状细胞(DC)分化、增殖、发育的影响.方法用不同的CK定向诱导小鼠骨髓细胞分化为DC,通过流式细胞仪(荧光抗体双标记法)测定CD11c+细胞比例、MHC-Ⅱ类分子的表达及在脂多糖(LPS)刺激后CD86表达的变化.结果GM-CSF+IL-3+SCF促进DC分化、增殖的能力明显高于其他3组(P＜0.05).该组CK所诱导的DC在LPS刺激后,CD86表达增加的幅度明显低于GM-CSF+IL-4组(P＜0.01).结论GM-CSF、IL-3和SCF对于促进小鼠骨髓细胞向DC定向分化、增殖有协同作用,分化后的DC多数处于发育早期,DC前体所占的比例较大.     

Maturation and cytokine production potential of dendritic cells isolated from rheumatoid arthritis patients peripheral blood and induced in vitro

BackgroundSince dendritic cells (DC) are involved in the development of autoimmune inflammation, researchers consider DC both as target cells for specific therapy of rheumatoid arthritis (RA) and as candidate cells for the development of cell-based methods to treat autoimmune diseases. The development of treatment strategies requires comprehensive research into the quantitative and qualitative characteristics of DC subtypes both ex vivo from RA patients and in vitro, to determine the possibility of inducing functionally mature DC in RA.ObjectiveTo study the phenotypic and functional properties of myeloid (mDC) and plasmacytoid (pDC) DC isolated from the peripheral blood of patients with RA and induced in vitro.Materials and methodsBlood samples were obtained from RA patients and healthy donors. Immature DC in the whole blood and in vitro induced DC were characterized by the positive expression of CD80, CD83, CCR7, IL-10, IL-4, IL-12 and IFN-α. R848 and lipopolysaccharide were used to determine DC maturation ability. From PBMCs of RA patients and health donors DCs with myeloid (imDC) and plasmacytoid (ipDC) phenotype were induced.ResultsThe relative count of mDC in the peripheral blood between studied groups did not differ. pDC count was significantly lower for RA patients. DC from RA patients were characterized by low expression levels of CD80 and CD83 on both populations cells and high expression of CCR7 only on pDC. An increase in pDC producing IL-12 and IFN-α and a decrease in mDC and pDC producing IL-4 and IL-10 were shown in RA. imDC and ipDC obtained from RA patients according to their phenotype and cytokine profile did not differ from those obtained from healthy donors.ConclusionsThere is an imbalance between subpopulations of DC in the peripheral blood of RA patients. DC of RA patients are less mature. The data suggest the involvement of DC in RA pathogenesis and confirm DC participation in balance shift towards Th1-type immune responses. At the same time, in vitro induced RA DC are phenotypically and functionally competent.     

ICOS-mediated signaling regulates cytokine production by human T cells and provides a unique signal to selectively control the clonal expansion of Th2 helper cells

The CD28 homologue inducible costimulator (ICOS) has been demonstrated to regulate a number of T cell-dependent immune responses in vivo. However, the expression and functional importance of ICOS during APC-Th cell interaction in the human is not fully understood. Here, we demonstrate that ICOS-mediated signaling plays an important role in the production of selective cytokines during both primary and subsequent Th cell responses upon allospecific or superantigen activation. In contrast, ICOS does not play a role in the differentiation of naive cells into Th1 or Th2 effector cells, nor does it determine the type of effector function of memory cells upon subsequent allogeneic challenge. In addition, our data demonstrate that ICOS provides a novel and unique role in regulating DC-mediated Th2, but not Th1 cell clonal expansion. These data suggest that ICOS-mediated signaling plays a discrete role in the regulation of human T helper cell responses.     

Sphingosine-1-phosphate differently regulates the cytokine production of IL-12, IL-23 and IL-27 in activated murine bone marrow derived dendritic cells

Sphingosine-1-phosphate (S1P) modulates many cell functions such as lymphocyte trafficking and signaling as well as keratinocyte proliferation. However, less is known about the specific effects of S1P on cytokine production, particularly on the interaction between dendritic cells (DCs) and keratinocytes, cell types which are crucial for the initiation and maintenance of chronic inflammatory skin diseases like atopic dermatitis or psoriasis. Especially the cytokines of the IL-12 family play a dominant role in many inflammatory diseases as they have a significant impact on T-helper cell function. In the present study we show that S1P decreased the production of the pro-inflammatory cytokines IL-12 and IL-23 in LPS-stimulated DCs via the common subunit p40 as well as in the crosstalk with activated keratinocytes. By using specific S1P receptor agonists (SEW2871, FTY720-P) and antagonist (JTE013) we identified an important role for S1P receptor 1 in the modulation of the cytokine profile. While diminishing IL-12 and IL-23 secretion, S1P enhanced IL-27 production in DCs. To elucidate the mechanism of the different impact on the IL-12 family cytokine production, we investigated the mitogen-activated protein kinase (MAPK) and phosphatidylinositide 3-kinase (PI3K) pathways in DCs. By using specific MAPK-Inhibitors (U0126, SB202190, SP600125) we demonstrated that ERK, p38 and JNK differently regulate each pathway of each cytokine. While p38 and JNK did not seem to play a role in the modulation properties of S1P on cytokine production, ERK is at least partially involved in the S1P mediated modulation of IL-12 and IL-27. The PI3K-Inhibitor abrogated the S1P-induced decrease of IL-12 and IL-23 secretion, while it had no influence on the S1P-induced increase of IL-27 production. These data implicate, that S1P has an anti-inflammatory impact on the production of IL-12 family cytokines, indicating therapeutic potential for S1P treatment of several inflammatory diseases like psoriasis.     

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.     

Adipose tissue-derived mesenchymal stem cells are more potent suppressors of dendritic cells differentiation compared to bone marrow-derived mesenchymal stem cells

Both mesenchymal stem cells (MSCs) and dendritic cells (DCs) are engaged in the regulation of the immune response parallel to their numerous functions.The main objective of this study was to compare the effects of mesenchymal stem cells isolated from human adipose tissue or human bone marrow on the expression of specific cell surface markers as well as the secretion of some cytokines by monocyte-derived dendritic cells. The set of methods used includes cell cultures, magnetic beads isolation of cells, flow cytometry, ELISA and proteome profiler kit assays. The results obtained show that MSCs isolated from human adipose tissue are more potent immunomodulators of differentiation of human DCs in comparison to the bone marrow-derived MSCs. In both cases the percentages of CD14+ cells were increased in co-cultures of MSCs and DCs and at the same time down-regulated the expression of CD80, CD86 and CD83 as in all experiments the effect of adipose tissue MSCs was stronger. Similarly, the secretion of IL-10 by dendritic cells was up-regulated in co-cultures of MSCs and dendritic cells and the effect was stronger when adipose tissue-derived MSCs were used.Taken together all results presented reveal the higher potential of the adipose tissue-derived MSCs to inhibit the differentiation and expression of functionally important co-stimulatory molecules on the surface of monocyte-derived dendritic cells than the bone marrow-derived MSCs.     

Monomethylfumarate affects polarization of monocyte-derived dendritic cells resulting in down-regulated Th1 lymphocyte responses

Psoriasis vulgaris, a type-1 cytokine-mediated chronic skin disease, can be treated successfully with fumaric acid esters (FAE). Beneficial effects of this medication coincided with decreased production of IFN-gamma. Since dendritic cells (DC) regulate the differentiation of T helper (Th) cells, this study focussed on effects of monomethylfumarate (MMF, bioactive metabolite of FAE) on polarization of monocyte-derived DC. MMF-incubated, lipo-polysaccharide-stimulated DC (MMF-DC) produced dramatically (p<0.05) reduced levels of IL-12p70 and IL-10 (8+/-4% and 20+/-4%, respectively) compared to control DC. MMF-DC were mature. MMF affected polarization of DC irrespective of polarization factor(s) and ligands for the various Toll-like receptors used. Coculture of MMF-DC with naive and primed allogenous Th cells resulted in lymphocytes producing less IFN-gamma, i.e. 59% and 54% of that by the respective Th cells cocultured with control DC. IL-4 production by primed, but not naive Th cells cocultured with MMF-DC was decreased as compared to cocultures with control DC. IL-10 production by naive and primed Th cells cocultured with MMF-DC and control DC did not differ. In addition, MMF inhibited LPS-induced NF-kappaB activation in DC. Together, beneficial effects of FAE in psoriasis involve modulation of DC polarization by MMF such that these cells down-regulate IFN-gamma production by Th cells.     

带有IL-24的腺病毒扩增及其在小鼠树突状细胞中的表达

目的：在293细胞中扩增带有IL-24的腺病毒,感染小鼠树突状细胞,观察IL-24在树突状细胞中的表达。方法：将构建的重组腺病毒表达载体IL-24转染到293细胞中包装、扩增,感染分离培养的小鼠树突状细胞,RT-PCR、Westernblot、荧光显微镜检测IL-24的表达。结果：获得了大量的带有IL-24的腺病毒,成功的感染小鼠树突状细胞,RT-PCR和Westernblot检测结果显示,IL-24在树突状细胞中高表达。结论：带有IL-24的腺病毒可以高效的感染小鼠树突状细胞。     

p38MAPK通路调控树突状细胞表达PD-L1的实验研究

目的探讨脂多糖刺激单核细胞源树突状细胞表达程序性死亡因子配体1(PD-L1)与p38MAPK信号通路的关系。方法体外培养树突状细胞,用p38抑制剂SB203580阻断p38MAPK通路后再用LPS刺激树突状细胞。光学显微镜观察各组细胞的形态变化;流式细胞术测定CD86和PD-L1表达的平均荧光强度;Western blot测定PD-L1蛋白表达。结果光镜下观察LPS刺激组细胞先经历梭型贴壁后逐渐恢复圆形,树突较多;SB203580和LPS共同刺激组细胞树突退化,未刺激组细胞成团悬浮,树突较多。SB203580和LPS共同刺激组细胞CD86、PD-L1较LPS刺激组的明显降低(P<0.05或P<0.01),与未刺激组的相比CD86差异无统计学意义,但PD-L1降低(P<0.05)。SB203580和LPS共同刺激组细胞PD-L1的蛋白表达量较其它两组的均明显减少(P<0.01或P<0.01)。结论 LPS通过p38MAPK信号通路调控树突状细胞表达PD-L1。     

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.     

抗原致敏DC与CIK共培养体外抗肾癌效应的研究

目的： 探讨肾癌(RCC)抗原致敏树突状细胞(DC)与同源细胞因子诱导杀伤细胞(CIK)共培养后的DC-CIK细胞对RCC的杀伤活性。 方法： 将健康成人外周血单个核细胞（PBMC）来源的DC经RCC(786-0细胞株)抗原致敏后与同源CIK细胞共培养，实验分3组：RCC抗原致敏DC与CIK共培养组（A组），未致敏DC与CIK共培养组（B组），单纯CIK组（C组）。流式细胞仪检测DC及CIK免疫表型。MTT法检测3组效应细胞对786-0细胞杀伤活性。 结果： 效靶比 20∶1 时，A、B、C组对786-0细胞杀伤活性分别为（70.64±8.26）%、（53.40±7.33）%、（46.64±6.01）%，各组比较差异显著（P<0.05）；以前列腺癌PC3细胞作靶细胞对照，A组对786-0及PC3细胞的杀伤活性有显著差异（P<0.05）。 结论： RCC抗原致敏DC与CIK共培养后的DC-CIK细胞可明显提高CIK细胞对RCC的杀伤特异性和杀伤活性。     

Antigen delivery by dendritic cells

Dendritic cells (DC) link the innate and adaptive arms of the immune system and thus orchestrate the immune response to pathogens. A novel immune intervention strategy to control infectious diseases is based on the use of the potent immunostimulatory properties of DC for vaccination and immunotherapy. Recent advances in our understanding of DC biology and the molecular mechanisms by which DC instruct the development of an appropriate immune response to microorganisms provide means for DC-based approaches to manipulate the immune system. In experimental systems, DC vaccination has been documented to mediate protection against a wide spectrum of infectious diseases caused by viral, bacterial, parasitic and fungal pathogens. The protocols for the generation, stimulation and antigen loading of DC are being optimized, and methods for DC targeting in situ are likely to become available soon, thus paving the way for clinical applications of DC-based vaccines.     

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.     

Complement protein C1q induces maturation of human dendritic cells

Maturation of dendritic cells (DCs) is known to be induced by several stimuli, including microbial products, inflammatory cytokines and immobilized IgG, as demonstrated recently. Since immune complexes formed in vivo also contain C1q, moreover apoptotic cells and several pathogens fix C1q in the absence of antibodies, we undertook to investigate whether this complement protein has an impact on various functions of human DCs. Maturation of monocyte-derived immature DCs (imMDCs) cultured on immobilized C1q was followed by monitoring expression of CD80, CD83, CD86, MHCII and CCR7. The functional activity of the cells was assessed by measuring cytokine secretion and their ability to activate allogeneic T lymphocytes. Cytokine production by T cells co-cultured with C1q-matured DCs was also investigated. C1q, but not the structurally related mannose-binding lectin was found to bind to imMDC in a dose-dependent manner and induced NF-kappaB translocation to the nucleus. Immobilized C1q induced maturation of MDCs and enhanced secretion of IL-12 and TNF-alpha, moreover, elevated their T-cell stimulating capacity. As IFN-gamma levels were increased in supernatants of MDC-T cell co-cultures, our data suggest that C1q-induced DC maturation generates a Th1-type response. Interestingly, IL-10 levels were elevated by C1q-treated MDCs but not in the supernatant of their co-cultures with allogeneic T cells. Taken together, these results indicate that C1q-opsonized antigens may play a role in the induction and regulation of immune response. Moreover our data are relevant in view of the role of C1q in removal of apoptotic cells and the association between C1q-deficiency and autoimmunity.     

A role for plasmacytoid dendritic cells in the rapid IL-18-dependent activation of NK cells following HSV-1 infection

Natural killer (NK) cells play a crucial role in the initial response to viral infections but the mechanisms controlling their activation are unclear. We show a rapid and transient activation of NK cells that results in the production of IFN-gamma immediately following infection with herpes simplex virus type 1 (HSV-1). Activation of NK cells leading to synthesis of IFN-gamma was not mediated by a direct interaction with virus but required the presence of additional cell types and was largely dependent on the cytokine IL-18, but not IL-12. HSV-1-induced IFN-gamma expression by NK cells in vitro was impaired in spleen cultures depleted of CD11c(+) cells. Conversely, coculture of NK cells with virus-exposed conventional DC or plasmacytoid (p)DC restored the production of IFN-gamma, indicating that multiple DC subsets could mediate NK cell activation. While conventional DC populations stimulated NK cells independently of IL-18, they were less effective than pDC in promoting NK cell IFN-gamma expression. In contrast, the potent stimulation of NK cells by pDC was dependent on IL-18 as pDC from IL-18-deficient mice only activated a similar proportion of NK cells as conventional DC. These data identify IL-18 as a crucial factor for pDC-mediated NK cell regulation.     

骨髓来源的原代树突状细胞对细菌颗粒抗原交叉呈递的动力学研究

目的研究小鼠骨髓细胞来源的树突状细胞对细菌颗粒抗原交叉递呈的动力学特点。方法取小鼠骨髓细胞,采用GM-CSF诱导培养。用倒置显微镜观察培养过程中细胞形态,用流式细胞仪进行细胞纯度和表型测定。采用第7天未成熟的DC细胞进行细菌抗原的交叉递呈能力检测和动力学分析。结果小鼠骨髓细胞经GM-CSF诱导培养,第7天获得大量具有典型形态和免疫表型的树突状细胞,并且在细菌脂多糖刺激后,其表型也发生特征性变化表现在共刺激分子CD80由刺激前的27.7%上调到71.6%,CD86从刺激前的36.0%上调到80.3%,DEC205从刺激前的6.5%上调到26.2%。同时该细胞吞噬低剂量的细菌抗原即可有效活化T细胞,其动力学曲线为:1～3h,该细胞抗原递呈能力呈对数增加,3～8hDC抗原递呈能力进入一个平台期,10～12h,抗原递呈能力又迅速增强。结论采用GM-CSF可以从小鼠骨髓中获得大量纯度高并且具有典型免疫表型的DC,该DC细胞能有效的递呈外源性细菌抗原,并具有特殊的抗原递呈动力学曲线。