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。     

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。     

TGF-β1对单核细胞来源的树突状细胞表型和功能的影响

目的:研究 TGF-β1对树突状细胞(DC)的分化、成熟及功能影响.方法:应用100万U/L粒-巨噬细胞集落刺激因子(GM-CSF)和白细胞介素-4(IL-4)7 d诱导单核细胞分化为不成熟DC,加入终浓度20万U/L的肿瘤坏死因子-α(TNF-α)48 h后获得成熟DC的体外模型,将TGF-β1加入该模型中,用流式细胞术分别检测DC分化,成熟阶段细胞表型的变化,应用ELISA检测DC IL-12的分泌水平,应用MTT法检测DC刺激同种异体T细胞增殖的能力.结果:TGF-β1对不成熟DC的特征性分子 CD1a的表达无明显影响,但在诱导DC的成熟阶段,TGF-β1明显抑制CD40、CD86及CD83上调.此外,TGF-β1显著减少DC IL-12的分泌,显著抑制DC刺激同种异体T 细胞增殖的能力.结论:DC是TGF-β1免疫抑制活性的靶细胞.TGF-β1不影响DC的分化,但抑制DC的成熟和细胞因子的分泌,降低DC刺激同种异体反应T细胞增殖的能力.     

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.     

IL-27促进外周血单个核细胞来源树突状细胞分化成熟

目的:研究IL-27体外对人外周血单个核细胞(PBMC)的来源树突状细胞(DC)分化、成熟及其免疫活性的影响。方法:采集健康成人外周血,密度梯度离心法获得PB-MC,给予GM-CSF、IL-4诱导DC,第5天后根据不同处理因素将DC分为3组:IL-27组、TNF-α组和阴性对照组。倒置显微镜和透射电镜下观察DC形态;流式细胞术(FCM)检测DC表面分子CD1a、CD80、CD83和CD86的表达情况;MTT法检测DC刺激T细胞增殖的能力。结果:IL-27刺激后PB-MC来源DC呈现典型的成熟DC形态学特征。IL-27组DC表面CD1a、CD80、CD83和CD86表达水平较对阴性对照组均明显上调(P<0.05),与TNF-α组DC相比无显著差异。IL-27组DC诱导T细胞增殖的能力较对照组DC明显增高(P<0.05)。结论:IL-27可刺激PBMC来源DC的成熟。     

香加皮羽扇豆烷乙酸酯(CPLA)对树突状细胞分化成熟的影响

目的：探讨香加皮羽扇豆烷乙酸酯（CPLA）对人外周血单个核细胞（PBMC）来源的树突状细胞（DC）在体外分化成熟及免疫活性的影响。方法：从人外周血分离单个核细胞，与细胞因子GM—CSF、IL-4共培养，于第5天加入DC的促成熟刺激剂TNF-α（阳性对照组）或CPLA。倒置显微镜和透射电镜下观察DC的形态；应用流式细胞术检测成熟DC的表面标志CD1a、CD83、CD80和CD86的表达情况；用ELISA检测DC培养上清中IL-12和IFN-γ的含量；用MTT法测定DC刺激T细胞增殖的能力。结果：培养10d后，经CPLA刺激的PBMC呈现出典型DC的形态学特征；成熟DC的特征性表面分子CD1a、CD83、CD80和CD86表达水平均明显上调（P〈0．05）；细胞培养上清中IL-12和IFN-γ含量明显增高（P〈0．05）；刺激T细胞增殖的能力明显增强（P〈0．05）。结论：CPLA可诱导PBMC来源的DC分化成熟，并可促进其细胞因子的分泌，增强DC的免疫调节活性。     

红树林淡紫拟青霉胞外多糖对小鼠DCs 表型成熟的影响

目的:探讨红树林来源的淡紫拟青霉胞外多糖对小鼠骨髓源性树突状细胞(DCs)表型成熟的影响。方法:从小鼠骨髓腔中分离获得单核细胞,加入细胞因子rmGM-CSF、rmIL-4 诱导分化为未成熟DCs 并用不同浓度淡紫拟青霉胞外多糖干预,流式细胞术检测成熟DCs 的表面标志CD11c、MHC 、CD80、CD86 分子的表达及吞噬FITC-dextran 的能力,ELISA 检测该多糖对DCs 分泌IL-12 的影响;MTT 法检测该多糖对DCs 刺激T 细胞增殖的影响。结果:经400 μg/ ml 多糖作用48 h 后DCs 表面分子CD11c、MHC 、CD80、CD86 的表达显著上调,与空白对照组相比P<0.01,与LPS 组相比P>0.05;经该多糖作用后DCs 吞噬FITC-dextran 的能力下降,尤其300 μg/ ml 、400 μg/ ml 的多糖作用效果最明显,与空白对照组相比P<0.05;该多糖还可刺激DCs 分泌IL-12,尤其100 ~400 μg/ ml 的多糖刺激作用较强,与空白对照组相比P<0.05;另外,经该多糖处理的DCs 还可刺激T 细胞增殖,将不同比例刺激细胞与T 作用后均可见T 细胞增殖,与空白对照组相比P<0.05。结论:淡紫拟青霉胞外多糖可上调DCs 表面CD11c、MHCⅡ、CD80 和CD86 分子表达,降低其吞噬能力,促进其分泌IL-12,还可刺激T 细胞增殖,初步表明该多糖可刺激DCs 分化成熟。     

人重组白细胞介素-13在毕氏酵母中的表达及其体外诱导DC分化作用的研究

目的：在毕氏酵母中表达重组人IL-13并探讨其对DC的诱导作用。方法：用基因工程的方法人工合成IL-13的全长片段，并转化至毕氏酵母菌株GS115中，筛选后获得表达量相对较高且分泌稳定的rhIL-l3基因工程菌株，用rhIL-l3来替代IL-4体外诱导DC。结果：得到表达量达25mg/L且分泌稳定的rhIL-l3基因工程菌株；rhIL-l3具有rhIL-4同样的体外诱导外周血单核细胞向比增殖分化的作用,MHCII、CDlα、CD80、CD80、CD86等DC表型分析和混合淋巴细胞反应刺激T细胞增殖的作用与IL-4诱导得到的成熟DC并无显著差别，其所诱导的末成熟DC具有很强的摄取抗原能力。结论：获得表达量相对较高且分泌稳定的rhIL-l3基因工程菌株，rhIL-l3在体外可有效地诱导外周血单核细胞向DC分化。     

IL-10对单核来源的DC体外分化发育及功能的抑制效应

目的：研究IL-10对单核细胞来源的DC体外发育分化和功能的影响及TNF-a和sCD40L对IL-10抑制DC生物学功能的阻断或逆转效应。方法：检测经IL-10抑制及添加上述干预因素后DC的表型、刺激T细胞增殖和分泌IL-12的能力。结果：IL-10能够抑制幼稚DC的成熟，促进其向巨噬细胞分化，并伴随有DC激发T细胞增殖和分泌IL-12能力明显下降，这种抑制效应与IL-10浓度存在相关性；IL-10对由sCD40L诱导成熟的DC无抑制作用，但能抑制TNF-a诱导成熟DC分泌IL-12的能力；在IL-10作用后加入TNF-a或sCD40L均不能逆转IL-10对DC抑制作用；在IL-10作用的同时加入sCD40L而不是TNF-a能完全阻断IL-10抑制DC刺激T细胞增殖和分泌IL-12的作用。结论：IL-10是肿瘤细胞逃脱免疫攻击的重要因子，能够抑制DC的成熟、抗原提呈以及削弱其刺激T细胞增殖的能力等多重负性作用，其对由TNF-a或sCD40L途径诱导成熟的DC的抑制作用不一致，CD40信号干预对制备肿瘤免疫治疗运用的DC具有重要的价值。     

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.     

Dexamethasone and cyclosporin A affect the maturation of monocyte-derived dendritic cells differently

In contrast to the confirmed effects of glucocorticoids (GCs) and cyclosporin A (CyA) on T cells, the effects of both agents on antigen-presenting cells (APCs), especially on dendritic cells (DCs), are still poorly understood. In this study, we cultured monocyte-derived DCs (MoDCs) under a variety of stimulations in the presence or absence of these immunosuppressants and compared their effects on the activation of MoDCs by these stimulations. The stimulations used were the following: three bacterial toxins, including lipopolysaccharide (LPS), staphylococcal enterotoxin A (SEA) and streptococcal pyrogenic exotoxin A (SPEA), the combination of IL-1beta and TNF-alpha, and an agonistic anti-CD40 antibody. All of these stimulations increased the expression of CD54, CD83, CD86, and HLA-DR antigen, and the production of TNF-alpha in MoDCs. When MoDCs were treated with dexamethasone (Dex) during the stimulation, Dex significantly suppressed the augmentation of CD86 expression and TNF-alpha production induced by all of these stimulations. In contrast, when MoDCs were treated with CyA, it inhibited only the effects induced by the superantigens, SEA and SPEA, but not that induced by LPS, the combination of cytokines, or anti-CD40 antibody. The augmentation of CD54 or HLA-DR antigen expression was not significantly suppressed by either Dex or by CyA. When we used MoDCs pretreated with each of these stimulations + Dex or + CyA as APCs, however, significant suppression of T cell proliferation was observed only in the case of the pretreatment with IL-1beta/TNF-alpha + Dex. The allogeneic T cell stimulation by MoDCs pretreated with the other combinations did not significantly differ from that treated with the stimulation alone. Our present study succeeded in demonstrating a clear difference between Dex and CyA in the activation of MoDCs. These differences may induce a significant difference in their final immunological responses.     

Effects of mesenchymal stem cells on differentiation, maturation, and function of human monocyte-derived dendritic cells

Mesenchymal stem cells (MSCs) reportedly inhibit the mixed lymphocyte reaction. Whether this effect is mediated by dendritic cells (DCs) is still unknown. In this study, we used an in vitro model to observe the effects of MSCs and their supernatants on the development of monocyte-derived DCs. Phenotypes and the endocytosic ability of harvested DCs were determined by flow cytometry; interleukin 12 (IL-12) secreted by DCs was evaluated by enzyme-linked immunosorbent assay (ELISA); and the antigen-presenting function of DCs was evaluated by MLR. Our results show that MSCs inhibit the up-regulation of CD1a, CD40, CD80, CD86, and HLA-DR during DC differentiation and prevent an increase of CD40, CD86, and CD83 expression during DC maturation. MSCs supernatants had no effect on DCs differentiation, but they inhibited the up-regulation of CD83 during maturation. Both MSCs and their supernatants interfered with endocytosis of DCs, decreased their capacity to secret IL-12 and activate alloreactive T cells. Thus, effects of MSCs on DCs contribute to immunoregulation and development.     

Airway epithelial IL-15 transforms monocytes into dendritic cells

IL-15 has recently been shown to induce the differentiation of functional dendritic cells (DCs) from human peripheral blood monocytes. Since DCs lay in close proximity to epithelial cells in the airway mucosa, we investigated whether airway epithelial cells release IL-15 in response to inflammatory stimuli and thereby induce differentiation and maturation of DCs. Alveolar (A549) and bronchial (BEAS-2B) epithelial cells produced IL-15 spontaneously and in a time- and dose-dependent manner after stimulation with IL-1beta, IFN-gamma, or TNF-alpha. Airway epithelial cell supernatants induced an increase of IL-15Ralpha gene expression in ex vivo monocytes, and stimulated DCs enhanced their IL-15Ralpha gene expression up to 300-fold. Airway epithelial cell-conditioned media induced the differentiation of ex vivo monocytes into partially mature DCs (HLA-DR+, DC-SIGN+, CD14+, CD80-, CD83+, CD86+, CCR3+, CCR6(+), CCR7-). Based on their phenotypic (CD123+, BDCA2+, BDCA4+, BDCA1(-), CD1a-) and functional properties (limited maturation upon stimulation with LPS and limited capacity to induce T cell proliferation), these DCs resembled plasmacytoid DCs. The effects of airway epithelial cell supernatants were largely blocked by a neutralizing monoclonal antibody to IL-15. Thus, our results demonstrate that airway epithelial cell-conditioned media have the capacity to differentiate monocytes into functional DCs, a process substantially mediated by epithelial-derived IL-15.     

固相MHC Ⅰ类相关抗原A刺激的NK细胞对树突状细胞活性的影响

目的:观察固相MHC I类相关抗原A(iMICA)刺激的NK细胞对树突状细胞(DCs)活性的影响。方法:首先取新鲜分离及受固相MICA刺激的异体NK细胞,或IL-2、及IL-2联合iMICA刺激的自体NK细胞与未成熟DCs(iDCs)按5∶1比例孵育24 h后,用流式细胞术(FCM)分析HLA-DR+或CD86+频率的DCs。然后取自体NK细胞以iMICA刺激后,按1∶5的比例与iDCs孵育24 h后,FCM检测DCs上HLA-DR、CD86的表达。最后在NK细胞与DCs的共培养体系中加入抗IFN-γ抗体,观察DCs上HLA-DR、CD86表达的变化。结果:当NK细胞与iDCs孵育比例为5∶1时,异体新鲜分离的与自体活化的NK细胞均能杀伤iDCs;而iMICA无协同作用。当NK细胞与iDCs孵育的比例为1∶5时,iMICA刺激的NK细胞可促进DCs表达HLA-DR和CD86;而加入抗IFN-γ抗体可抑制NK细胞诱导DCs表面HLA-DR和CD86表达的上调。结论:异体新鲜分离的或自体活化的NK细胞杀伤iDCs时,无需iMICA的刺激;但当NK细胞的数目明显低于iDCs时,iMICA可刺激NK细胞分泌IFN-γ促进DCs成熟。     

The sesquiterpene lactone parthenolide inhibits LPS- but not TNF-alpha-induced maturation of human monocyte-derived dendritic cells by inhibition of the p38 mitogen-activated protein kinase pathway

BACKGROUND: Dendritic cells (DCs) are the most potent antigen-presenting cells, and the manipulation of DC maturation provides a strategy for the treatment of allergic and inflammatory diseases. OBJECTIVE: In this study we examined the effect of the anti-inflammatory sesquiterpene lactone parthenolide (PTL) on DC maturation induced by LPS or TNF-alpha. METHODS: Human monocyte-derived DCs generated by means of culture with GM-CSF and IL-4 were pretreated with PTL and subsequently stimulated with LPS or TNF-alpha. RESULTS: PTL inhibited the upregulation of CD80, CD83, CD86, CD40, and MHC class II; the allostimulatory function; the production of TNF-alpha and IL-12; and the downregulation of FITC-labeled dextran uptake in human monocyte-derived DCs stimulated with LPS but not with TNF-alpha. The inhibitory effect of PTL on DC maturation was preceded by inhibition of the phosphorylation of p38 mitogen-activated protein kinase but not the nuclear translocation of NF-kappaB. CONCLUSION: These results might offer PTL not only as a promising compound for the treatment of LPS-induced disorders, including sepsis or septic shock, by inhibition of excessive DC maturation but also as a tool to further dissect the signaling pathways involved in DC maturation.     

The anti-microbial peptide LL-37 inhibits the activation of dendritic cells by TLR ligands

The endogenous anti-microbial peptide LL-37/hCAP-18 is an effector molecule of the innate host defense system at surfaces of the body. Besides its direct anti-microbial activity, the peptide interacts with different cell types. Dendritic cells (DCs) play a central role in mucosal host defense. It was the aim of the study to determine whether LL-37 modulates the response of DCs to pathogen-associated molecular patterns. Monocyte-derived DCs were stimulated with the Toll-like receptors (TLRs) ligands LPS, lipoteichoic acid and flagellin. We measured classical markers of DC maturation and assayed the ability of the DCs to activate T cell responses. Co-incubation with LL-37 resulted in suppressed activation of DCs. Levels of released IL-6, IL-12p70 and TNF-alpha and surface expression of HLA-DR, CD80, CD83, CD86 and the chemokine receptor CCR7 were decreased. Exposure of DCs to LL-37 during LPS exposure induced co-cultured naive T cells to produce less IL-2 and IFN-gamma and decreased their proliferation. The response of memory T cells to a recall antigen was also decreased. In conclusion, we demonstrate that the anti-microbial peptide LL-37 inhibits the activation of DCs by TLR ligands. We propose that LL-37 is a regulator of host defense responses at the intersection of innate and adaptive immune systems.     

Adjuvant activity of pollen grains

Background: The induction of an immune response to a biologically inert soluble protein requires an adjuvant. Here we have examined whether intact grains of pollen display such adjuvant effect, accounting for the immunogenic activity of pollen protein allergens that are devoid of intrinsic pro-inflammatory/adjuvant property. Methods: Human monocyte-derived dendritic cells (DCs) were cultured with intact grains of grass or ragweed pollen for 48 h. The state of DCs maturation was analyzed by FACS and their cytokine production by ELISA. T cell priming activity of DCs was examined in co-cultures with naïve cord blood-derived CD4⁺ T cells. Results: Contact with grains of pollen induced a distinct maturation program in immature DCs. Pollen up-regulated the expression of CD54, CD80, CD83, CD86, HLA-DR, CCR7, and CD40 on DCs. Moreover, CCR5 expression was up-regulated by pollen but suppressed by LPS. In sharp contrast to LPS-stimulated DCs, pollen-treated DCs did not produce cytokines [interleukin (IL)-10, IL-12, tumor necrosis factor (TNF)-α] but retained the ability to secrete high levels of these cytokines upon simulation with soluble CD40 ligand and interferon (IFN)-γ. Pollen-primed DCs strongly stimulated the proliferation of allogeneic naïve CD4⁺ T cells and promoted their development into effector cells producing high levels of IL-5 and IL-13 together with moderate levels of IFN-γ and IL-4. Conclusion: Intact grains of pollen induce activation and maturation of DCs in vitro. Similar mechanisms may be effective in vivo, suggesting that pollen grain is not only an allergen carrier but also acts as an adjuvant in the induction phase of the allergic immune response.     

CCK-8对LPS诱导树突状细胞成熟的影响

目的: 观察八肽胆囊收缩素(CCK-8)对脂多糖(LPS)诱导树突状细胞(DCs)成熟的影响。方法: 采用粒-巨噬细胞集落刺激因子(GM-CSF)诱导法培养小鼠骨髓来源DCs,在LPS诱导其成熟过程中用不同浓度的CCK-8进行干预,采用流式细胞分析技术检测DCs表面主要组织相容性复合物II(MHC II)、分化群80(CD80)和分化群86(CD86)的表达;ELISA法检测DCs培养上清中白细胞介素1β(IL-1β)、白细胞介素6(IL-6)和肿瘤坏死因子α(TNF-α)的含量;MTT法检测CCK-8处理DCs对同种异体T细胞增殖反应的影响。结果: CCK-8剂量依赖性地抑制LPS诱导DCs表面CD80、CD86和MHC II表达(P<0.01, P<0.05 );CCK-8抑制LPS诱导DCs分泌IL-1β、IL-6和TNF-α(P<0.01);并且,CCK-8降低LPS诱导DCs刺激同种异体T淋巴细胞增殖的活性(P<0.05,P<0.01)。结论: CCK-8对LPS诱导DCs成熟过程中的细胞表型、细胞因子分泌和抗原提呈功能有抑制作用,提示CCK-8有可能在抗感染和抵抗自身免疫性疾病过程中发挥重要调节作用。     

Induction of suppressive phenotype in monocyte-derived dendritic cells by leukemic cell products and IL-1β

Professional antigen-presenting cells, dendritic cells (DCs) play an important role in controlling tumors. It is known that solid tumor cell products inhibit DC differentiation. Recently a similar effect produced by leukemic cell products has been demonstrated. In this case, leukemic cell products induced the secretion of IL-1β by monocytes undergoing differentiation. The aim of the present work was to characterize and to compare the development of monocyte-derived DCs under the influence of leukemic cell products (K562 supernatant) or exogenous IL-1β. It became clear that leukemic cell products and IL-1β differentially modulate some of the parameters studied on monocytes stimulated to differentiate into DCs. In the presence of K562 supernatant, the expression of the macrophage markers CD16 and CD68 were higher than in immature DCs control. Contrasting with IL-1β, leukemic cell products possibly favor the development of cells with macrophage markers. In addition, CD80 and CD83 expressions were also higher in the presence of tumor supernatant whereas HLA-DR was lower. In the presence of IL-1β, only CD80 was increased. Furthermore, it was observed that when monocytes were induced to differentiate into DCs in the presence of tumor supernatant and then activated, they expressed less CD80 and CD83 than activated DCs control. A reduced expression of CD83 following activation was also seen in cells differentiated with IL-1β. TGF-β and VEGF were found in the tumor supernatants. Moreover, the exposure to tumor supernatant or IL-1β stimulated IL-10 production while decreased IL-12 production by activated DCs. Finally, these results suggest that the addition of products released by leukemic cells or, more discreetly, the addition of IL-1β affects DC differentiation, inducing a suppressive phenotype.