“树枝状”运输系统在大型露天煤矿开采中的运用

对"树枝状"开拓运输系统的概念、布置方式和适应条件进行了总结,介绍了在安太堡露天煤矿的运用"树枝状"分叉运输系统,利用采场坡道将剥离物集中于一个运输水平运往排土场,减少主运输水平,可加速工作帮开拓运输系统建设,为大型露天矿的开拓运输系统积累经验。

“树枝状”运输系统在安家岭矿排土场的应用

单斗-卡车开采工艺的露天矿,采用端帮双环运输,实现了物料流的优化,但在特定条件下,受到地形条件、爬坡距离、复垦规划等条件限制,必须寻求新的运输系统。本文将"树枝状"状运输系统引入内排土场,充分发挥了其在运距减少、土场长远规划的特点,产生良好的效果。

具有“树枝状”结构的短氟碳链含氟聚合物的制备及性能

基于溶液聚合的方法,将合成的具有"树枝状"结构含氟单体与其他丙烯酸类单体进行共聚反应,制备出了一种具有"树枝状"结构的短氟碳链含氟聚合物。考察了含氟单体用量及含氟单体的氟含量对水接触角的影响;系统探究了"树枝状"结构对聚合物材料表面接触角的影响。结果表明,与"伞形"和线型短氟碳链含氟聚合物相比,"树枝状"结构的含氟聚合物的表面接触角有明显提高,可高达111.3°,X射线光电子能谱测试表明其表面的含氟量亦从18.4%增加到了26.9%;同时材料表面拒水性能得到有效提高。

基于“树枝状”信号放大的电化学DNA生物传感器研究

发展了一种基于"树枝状"信号放大的电化学生物传感器用于DNA的检测。该传感器利用两种DNA功能化的纳米金颗粒,通过两次"三明治"杂交,在电极表面形成"树枝"状结构,从而实现DNA的定量检测。首先通过共价交联方法获得巯基DNA1和DNA2修饰的两种纳米金颗粒,其中DNA1和DNA2与目标cDNA部分互补。然后,修饰在金电极上的捕获探针DNA1与目标cDNA分子及巯基DNA2修饰的纳米金颗粒(DNA2-AuNPs)形成第一个"三明治"杂交结构,实现一次放大检测。接着,DNA2-AuNPs又可与cDNA、巯基DNA1修饰的纳米金颗粒(DNA1-AuNPs)形成第二个"三明治"杂交结构,实现二次放大检测。这种"树枝状"放大信号的方法的检测限是0.13pmol/L,相对仅利用纳米金颗粒放大的方法而言,其检测限降低了4倍。并且,该传感器具有较好的识别碱基错配的能力。

Effect of energy density on microstructure and mechanical properties of Ta−33Ti alloy prepared via laser powder bed fusion

The influence of laser process parameters on the densification,phase composition,microstructure,and mechanical properties of Ta−33wt.%Ti alloy prepared via laser powder bed fusion(LPBF)was investigated.The results show that fully dense and homogeneous Ta−Ti parts can be obtained from LPBF with appropriate energy input.The cellular and dendritic structures were formed due to constitutional undercooling.Transmission electron microscopy(TEM)analysis showed that the lamellarα″phase within the cellular structures preferred to concentrate at the cellular boundaries owing to the elemental micro-segregation in the solidification front.The samples fabricated under the energy density of 166.7 J/mm^(3) had a favorable ultimate tensile strength of 806 MPa and an excellent Young’s modulus of 36.7 GPa.

Controllable Electrochemical Synthesis of Silver Dendritic Nanostructures and Their SERS Properties

Ag dendritic nanostructures were synthesized on fluorine-doped tin oxide covered glass sub- strates by the electrodeposition method. Results demonstrate that the size, diameter, crys- tallinity, and branch density of the Ag dendrites can be controlled by the applied potential, the surfactants and the concentration of AgNO3. Three kinds of typical silver dendrites were applied as substrates of the surface enhanced Raman scattering （SERS） and one of them was able to clearly detect rhodamine 6G concentrations up to 0.1 nmol/L. The differences of the SERS spectra at these Ag dendrites confirmed that the shapes and interparticle spacings have great effect on Raman enhancement, especially the interparticle spacings.

Synthesis of an Amphiphilic Dendrimer-Like Block Copolymer and Its Application on Drug Delivery

Dendrimer-like amphiphilic copolymer is a kind of three-dimensional spherical structure polymer. An amphiphilic dendrimer-like diblock copolymer, PEEGE-G2-b-PEO（OH）12, constituted of a hydrophobic poly（ethoxyethyl glycidol ether） inner core and a hydrophilic poly（ethylene oxide） outer layer, has been successfully synthesized by the living anionic ring-opening polymerization method. The intermediates and targeted products were charac-terized with 1H NMR spectroscopy and gel permeation chromatography. The application on drug delivery of dendrimer-like diblock copolymer PEEGE-G2-b-PEO（OH）12 using DOX as a model drug was also studied. The drug loading content and encapsulation e ciency were found at 13.07% and 45.75%, respectively. In vitro release experiment results indicated that the drug-loaded micelles exhibited a sustained release behavior under acidic media.

Potentially probiotic bacteria induce efficient maturation but differential cytokine production in human monocyte-derived dendritic cells

AIM： To analyze the ability of nine different potentially probiotic bacteria to induce maturation and cytokine production in human monocyte-derived dendritic cells （moDCs）. METHODS： Cytokine production and maturation of moDCs in response to bacterial stimulation was analyzed with enzyme-linked immunosorbent assay （ELISA） and flow cytometric analysis （FACS）, respectively. The kinetics of mRNA expression of cytokine genes was determined by Northern blotting. The involvement of different signaling pathways in cytokine gene expression was studied using specific pharmacological signaling inhibitors. RESULTS： All studied bacteria induced the maturation of moDCs in a dose-dependent manner. More detailed analysis with S. thermophilus THS, B. breve Bb99, and L. lactis subsp, cremoris ARH74 indicated that these bacteria induced the expression of moDC maturation markers HLA class Ⅱ and CD86 as efficiently as pathogenic bacteria. However, these bacteria differed in their ability to induce moDC cytokine gene expression. S. thermophilus induced the expression of pro-inflammatory （TNF-α, IL-12, IL-6, and CCL20） and Thl type （IL-12 and IFN-γ） cytokines, while B. breve and L. lactis were also potent inducers of antiinflammatory IL-10. Mitogen-activated protein kinase （MAPK） p38, phosphatidylinositol 3 （PI3） kinase, and nuclear factor-kappa B （NF-κB） signaling pathways were shown to be involved in bacteria-induced cytokine production. CONCLUSION： Our results indicate that potentially probiotic bacteria are able to induce moDC maturation, but their ability to induce cytokine gene expression varies significantly from one bacterial strain to another,

Indoleamine 2,3-dioxygenase (IDO) is essential for dendritic cell activation and chemotactic responsiveness to chemokines

Indoleamine 2, 3-dioxygenase (IDO) is a rate-limiting enzyme for the tryptophan catabolism. In human and murine cells, IDO inhibits antigen-specific T cell proliferation in vitro and suppresses T cell responses to fetal alloantigens during murine pregnancy. In mice, IDO expression is an inducible feature of specific subsets of dendritic cells (DCs), and is important for T cell regulatory properties. However, the effect of IDO and tryptophan deprivation on DC func- tions remains unknown. We report here that when tryptophan utilization was prevented by a pharmacological inhibitor of IDO, 1-methyl tryptophan (1MT), DC activation induced by pathogenic stimulus lipopolysaccharide (LPS) or inflam- matory cytokine TNF-α was inhibited both phenotypically and functionally. Such an effect was less remarkable when DC was stimulated by a physiological stimulus, CD40 ligand. Tryptophan deprivation during DC activation also regu- lated the expression of CCR5 and CXCR4, as well as DC responsiveness to chemokines. These results suggest that tryptophan usage in the microenvironment is essential for DC maturation, and may also play a role in the regulation of DC migratory behaviors.

Dendritic cells engineered to secrete anti-Dc R3 antibody augment cytotoxic T lymphocyte response against pancreatic cancer in vitro

AIM To investigate the enhanced cytotoxic T lymphocyte responses against pancreatic cancer (PC) in vitro induced by dendritic cells (DCs) engineered to secrete anti-DcR3 monoclonal antibody (mAb). METHODS DCs, T lymphocytes and primary PC cells were obtained from PC patients. DCs were transfected with a designed humanized anti-DcR3 monoclonal antibody heavy and light chain mRNA and/or total tumor RNA (DC-tumor-anti-DcR3 RNA or DC-total tumor RNA) by using electroporation technology. The identification, concentration and function of anti-DcR3 mAb secreted by DC-tumor-anti-DcR3 RNA were determined by western blotting and enzyme-linked immunosorbent assay. After co-culturing of autologous isolated PC cells with target DCs, the effects of secreting anti-DcR3 mAb on RNA-DCs' viability and apoptosis were assessed by MTT assay and flow cytometry. Analysis of enhanced antigen-specific immune response against PC induced by anti-DcR3 mAb secreting DCs was performed using a Cr-51 releasing test. T cell responses induced by RNAloaded DCs were analyzed by measuring cytokine levels, including IFN-gamma, IL-10, IL4, TNF-alpha and IL-12. RESULTS The anti-DcR3 mAb secreted by DCs reacted with recombinant human DcR3 protein and generated a band with 35 kDa molecular weight. The secreting mAb was transient, peaking at 24 h and becoming undetectable after 72 h. After co-incubation with DCtumor- anti-DcR3 RNA for designated times, the DcR3 level in the supernatant of autologous PC cells was significantly down-regulated (P < 0.05). DCs secreting anti-DcR3 mAb could improve cell viability and slow down the apoptosis of RNA-loaded DCs, compared with DC-total tumor RNA (P < 0.01). The anti-DcR3 mAb secreted by DC-tumor-anti-DcR3 RNA could enhance the induction of cytotoxic T lymphocytes (CTLs) activity toward RNA-transfected DCs, primary tumor cells, and PC cell lines, compared with CTLs stimulated by DC-total tumor RNA or control group (P < 0.05). Meanwhile, the antigen-specific CTL responses were MHC class I-restricted. The CD4+ T cells and CD8+ T cells incubated with anti-DcR3 mAb secreting DCs could produce extremely higher level IFN-gamma and lower level IL4 than those incubated with DC-total tumor RNA or controls (P < 0.01). CONCLUSION DCs engineered to secrete anti-DcR3 antibody can augment CTL responses against PC in vitro, and the immune-enhancing effects may be partly due to their capability of down-regulating DC apoptosis and adjusting the Th1/Th2 cytokine network.

Entecavir up-regulates dendritic cell function in patients with chronic hepatitis B

AIM: To investigate the in vitro effect of entecavir (ETV on the function of dendritic cells (DCs) derived from chronic hepatitis B (CHB) patients. METHODS: Mononuclear cells were isolated from peripheral blood of patients with CHB. DCs wer incubated with RPMI-1640 medium supplemented wit fetal bovine serum, IL-4, granulocyte-macrophag colony-stimulating factor (GM-CSF). DCs were treate with or without ETV on the fourth day. Cell surfac molecules, including CD1a, CD80, CD83 and HLA-DR were assessed by flow cytometry. Concentrations of IL- and IL-12 in the supernatant were assayed by enzyme linked immunosorbent assay (ELISA). The ability of th generated DCs to stimulate lymphocyte proliferation wa observed. RESULTS: Compared with CHB control group, th expression levels of CD1a (29.07 ± 3.20 vs 26.85 ± 2.80 CD83 (25.66 ± 3.19 vs 23.21 ± 3.10), CD80 (28.00 ± 2.7 vs 25.75 ± 2.51) and HLA-DR (41.96 ± 3.81 vs 32.20 ± 3.04) in ETV-treated group were higher (P < 0.05). ETV treated group secreted significantly more IL-12 (157.6 ± 26.85 pg/mL vs 132.60 ± 22.00 pg/mL (P < 0.05) an had a lower level of IL-6 in the culture supernatant (83.0 ± 13.88 pg/mL vs 93.60 ± 13.61 pg/mL, P < 0.05) tha CHB control group. The ability of DCs to stimulate th proliferation of allogeneic lymphocytes was increase in ETV-treated group compared with CHB control grou (1.53 ± 0.09 vs 1.42 ± 0.08, P < 0.05).CONCLUSION: Entecavir can enhance the biological activity of DCs derived from CHB patients.

Heparanase expression,degradation of basement membrane and low degree of infi ltration by immunocytes correlate with invasion and progression of human gastric cancer

AIM： To disclose the mechanisms that accelerate or limit tumor invasion and metastasis in gastric cancer patients. METHODS： The heparanase expression, continuity of basement, degree of infiltration by dendritic cells and lymphocytes in gastric cancer tissues from 33 the early and late stage patients were examined by immunohistochemistry, in situ hybridization and transmission electron microscopy. RESULTS： Heparanase mRNA expression in the late stage patients with gastric cancer was stronger than that in the early stage gastric cancer patients. In the early stage gastric cancer tissues, basement membrane （BM） appeared intact, whereas in the late stage, discontinuous BM was often present. The density of Sl00 protein positive tumor infiltrating dendritic cells （TIDC） in the early stage gastric cancer tissues was higher than that in the late stage. The infiltrating degree of tumor infiltrating lymphocytes （TIL） in the early stage patients whose tumor tissues contained a high density of TIDC was significantly higher than that in the late stage gastric cancer tissues patients with a low density of TIDC. There were few cancer cells penetrated through the continuous BM of cancer nests in the early stage gastric cancers, but many cancer cells were found outside of the defective BM of cancer nests in the late stage. CONCLUSION： Our results suggest that strongheparanase expression is related with the degradation of BM which allows or accelerates tumor invasion and metastasis. However, high density of TIDC and degree of infiltration by TIL are associated with tumor progression in human gastric cancers.

Gastric cancer-derived heat shock protein-gp96 peptide complex enhances dendritic cell activation

AIM To investigate the role of heat shock protein (HSP)glycoprotein (gp) 96 in dendritic cells (DCs) and lymphocytes induction in gastric cancer (GC). METHODS Human GC cell lines KATOIII, MKN-28 and SGC-7901 were infected with adenovirus gp96 at a multiplicity of infection of 100. gp96-GC antigen peptide complexes were purified. MTT (3-(4,5-dimethylthiazol-2-yl)2,5- diphenyltetrazolium bromide) assay, lactate dehydrogenase (LDH) release assay and enzyme-linked immunosorbent assay were used to determine allo-reactive T cell stimulation, natural killer (NK) cell activity and expression of cytokines (such as interleukin (IL)-10, IL-12, interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha), respectively. Effect of cytotoxic T lymphocyte (CTL) on DCs incubated with HSP-gp96 was also evaluated by LDH release. All assays were performed in triplicate and the average values were reported. Comparison between groups was conducted using Student's t test. RESULTS T cells incubated with HSP-gp96 exhibited a marked increase in proliferation in a dose-dependent manner (P < 0.05). NK cell activity after gp96-GC peptide complex treatment was significantly higher than that after antigen peptide treatment (P < 0.05). The activity of CTLs incubated with DCs from three GC cells lines was obviously higher than that stimulated by GC antigen at ratios of 50: 1, 25: 1, 10: 1, and 5: 1 (P < 0.05). Furthermore, the secretion of TNF-alpha, IL-10, IL-12 (P70) and IFN-alpha markedly increased after incubation with HSP-gp96 (P < 0.05). CONCLUSION HSP-gp96 promotes T cell response, enhances DC antigen presentation and induces cytokine secretion, as well. HSP-gp96 has potential as immunotherapy for elimination of residual GC cells.

Hepatitis B virus upregulates host expression of α-1,2-mannosidases via the PPARα pathway

AIM To assess the effects of hepatitis B virus(HBV) on the expression of host α-1,2-mannosidases and determine the underlying mechanisms.METHODS We measured the expression levels of MAN1A1, MAN1A2, MAN1B1, and MAN1C1 in cell lines HepG 2.2.15, HepN 10, HepA D38 and Hep G2 by Western blot. Viral antigens(HBs Ag and HBe Ag) in the culture medium were measured using the chemiluminescence method. HBV DNA quantification assays were performed using a commercial real-time PCR kit. Protein levels of human liver tissue α-1,2-mannosidases were also evaluated by Western blot. Plasmids containing seven individual viral genes of HBV(PTT22-HBx, PTT22-HBs, PTT22-pre S2, PTT22-pre S1, PTT22-HBc, PTT22-HBe, and PTT22-HBp) or control plasmids(PTT22-vector) were transfected into Hep G2 cells. MK886(PPARα) and GW9662(PPARγ) inhibitors were used to explore the effects of HBV on α-1,2-mannosidase expression after the PPARα and PPARγ pathways were blocked.RESULTS We showed that the expression of α-1,2-mannosidases was higher in stably transfected HBV cells than in controls. The expression levels of α-1,2-mannosidase were higher in AD38 cells than those in ND10 cells, which were in turn greater than those in G2.2.15 cells, and positively correlated with the expression of HBsA gin all the cell lines. Levels of α-1,2-mannosidase in nontumorous liver tissues of HBV-related HCC patients were also higher than in the tissues from non-HBVrelated HCC patients. Moreover, transfecting Hep G2 cells with a component of the HBV viral envelope also increased the expression of α-1,2-mannosidases. However, this envelope protein component could not induce MAN1C1 expression in the presence of a PPARα inhibitor, MK886. We also found that MK886 did not affect the expression of MAN1C1 in AD38 cells without tetracycline in the culture medium. This phenomenon was not observed in the case of GW9662.CONCLUSION Our results indicate that HBV increases the expression of α-mannosidases both in vitro and in vivo via activation of the PPARα pathway by its envelope protein.

Induction of hepatitis C virus-specific cytotoxic T and B cell responses by dendritic cells expressing a modified antigen targeting receptor

AIM: To find a novel antigen (Ag) presentation strategy to improve the immune responses induced by dendritic cell (DC)vaccine expressing hepatitis C virus (HCV) core antigen (pcDNA3HCV C-Fc) in Balb/c mice (H-2d).METHODS: pcDNA3HCV C-Fc plasmid and eukaryotic expression vector pcDNA3 were injected into mice sc. Immune responses to pcDNA3HCV C-Fc were studied. Meanwhile the effect of pcDNA3HCV C-Fc on anti-translated subcutaneous tumor of SP2/0 cells stably expressing HCV C Ag (SP2/0-HCV C-FC) was also studied. Anti-HCV C in serum was detected by enzyme-linked immunoadsordent assay (ELISA) and HCV specific cytotoxic T lymphocyte (CTL) activity was measured by LDH release assay. After 3 wk of DNA immunization,the cells of SP2/0-HCV C-FC were inoculated into mice subcutaneously and tumor growth was measured every 5 d.The survival rate and living time of mice were also calculated.RESULTS: After 4 wk of DC immunization, the A450 nm values of sera in mice immunized with pcDNA3HCV C-Fc-DC and pcDNA3-DC were 0.56±0.17 and 0.12±0.03 respectively. The antibody titres in mice codeliveried with pcDNA3HCV C-Fc with DC were significantly higher than those of mice injected with pcDNA3-DC. The HCV specific CTL activities in mice coinjected with DC and pcDNA3HCV C-Fc or empty expression vectors were(73.2±3.1) % and (24.4±8.8) %, which were significantly higher than those of mice injected with water.The DC vaccine could evidently inhibit tumor growth, prolong the survival time of mice and improve the survival rate of mice and these effects could be improved by HCV C-Fc (pcDNA3HCV C-Fc) gene codelivered.CONCLUSION: DC vaccine has a strong antigenicity in humoral and cellular immunities, which can be promoted by transduced pcDNA3HCV C-Fc expressing HCV C or Fc.Thus, pcDNA3HCV C-Fc-transduced DCs may be a promising candidate for a CTL-based vaccine against HCV.

Preparation of dendritic bismuth film electrodes and their application for detection of trace Pb(Ⅱ)and Cd(Ⅱ)

In this paper,dendritic Bi film electrodes with porous structure had successfully been prepared on glassy carbon electrode using a constant current electrolysis method based on hydrogen bubble dynamic templates.The electrode prepared using a large applied current density showed an increased internal electroactive area and a significantly improved electrochemical performance.The analytical utility of the prepared dendritic Bi film electrodes for the determination of Pb(Ⅱ)and Cd(Ⅱ)in the range of 5–50 μg·L^(-1)were presented in combination with square wave stripping voltammetry in model solution.Compared with non-porous Bi film electrode,the dendritic Bi film electrode exhibited higher sensitivity and lower detection limit.The prepared Bi film electrode with dendritic structure was also successfully applied to real water sample analysis.

Interaction Mechanism of Nano-silicon Dioxide Modified by Poly（amidoamine） Dendrimers

To gain insight into the attachment of =Si^＋ （SC） ion （regarded as guest） to the lowest generation, NH2-terminated poly（amidoamine） （PAMAM） dendrimers （regarded as host） in the liquid phase, density functional theory is used to investigate the structures and energetics of the host-guest complex. The effect of solvent on the structures and energetics is also investigated. Various initial configurations of the ion bound to PAMAM are tested, and two stable conformers are found, i.e, types A （=Si^＋ is bound to the amine site） and C （=Si^＋ is bound to the amide site）. Types A and C are the most stable due to the chemical bond formations of Si-N° （amine nitrogen atoms） and Si-O, respectively. The IR spectra for the lowest energy conformers are thoroughly analyzed and compared with the available experimental data.

Synthesis and Properties of Dendritic Long-Chain Esters as Crude Oil Flow Improver Additives

The efficiencies of 6 kinds of macromolecules with dendritic structure in improving the flow properties of crude oil were investigated. The dendritic additives were synthesized using low-generation dendritic poly(amidoamine) and alkyl longchain acrylic esters as starting materials, and their structures were characterized by the Fourier transform infrared spectroscopy, 1H-nuclear magnetic resonance and elemental analysis. The effects on the pour point and rheological properties of crude oil samples were studied. Efficiencies of dendritic long-chain esters were not only influenced by the alky chain length, but also by the generation of dendrimer. The longer the alkyl chain of dendritic long-chain ester was, the better the effect in the reduction of pour point and apparent viscosity was. Efficiencies of 1.5 generation dendritic long-chain ester with 8 branched chains for the reduction of pour point and apparent viscosity were superior to those of 0.5 generation dendritic long-chain ester with 4 branched chains. Under the same conditions, efficiencies of 1.5 generation dendritic eighteen ester were superior to those of other 1.5 generation dendritic long-chain esters for the reduction of pour point and viscosity of crude oil.

Highly soluble dendritic fullerene derivatives as electron transport material for perovskite solar cells

A series of shape-persistent polyphenylene dendritic C_(60)derivatives as the electron transport materials were designed and synthesized via a catalyst-free Diels-Alder[4+2]cycloaddition reaction.These increasing hyperbranched scaffolds could effectively enhance the solubility;notably,both first and second generation dendrimers,C_(60)-G1 and C_(60)-G2,demonstrated more than 5 times higher solubilities than pristine C_(60).Furthermore,both simulated and experimental data proved their promising solution-processabilities as electron-transporting layers(ETLs)for perovskite solar cells.As a result,the planar p-i-n structural perovskite solar cell could achieve a maximum power conversion efficiency of 14.7%with C_(60)-G2.

Acute myeloid leukemia cells inhibit the differentiation and maturation of dendritic cells and induce the generation of regulatory T cells

Objective： To investigate the effects of soluble factors secreted by acute myeloid leukemia （AML） cells on the phenotypical and functional properties of DCs derived from normal mononuclear cells. Methods： Mononuclear cells were cultured with interleukin-4 （IL-4） and granulocyte-macrophage colony-stimulating factor （GM-CSF）, in the presence or absence of 24 h culture supematants from fresh pdmary AML cells, to generate immature DCs. The maturation of DCs was induced by cytokines IL-lbeta, IL-6, tumor necrosis factor-alpha （TNF-alpha）, and prostaglandin-2 （PGE-2）. The phenotypic alterations of DCs and DCs-primed CD4＋ T cells were evaluated using flow cytometry. Precursor frequency （PF） was calculated to monitor the allostimulatory effects of DCs on CD4^＋ and CD8^＋ T cells. Results：AML cell supernatant-treated DCs showed significantly lower expression of co-stimulatory molecules CDS0 and CD86, and reduced response to cytokines IL-1beta, IL-6, TNF-alpha, and PGE-2. The allostimulatory effects of AML cell supematant-treated DCs on CD4^＋ and CD8^＋ T cells were significantly lower than those of normal mature DCs [PF： （1.8 ±0.5）% vs. （5.2 ± 1.6）% for CD4^＋ T cells, （2.1 ±0.6）% vs. （6.5 ± 2.0）% for CD8^＋ T cells, P 〈 0.01]. These AML supernatantoinduced DCs could also induce allogeneic CD4^＋ T cells to differentiate into CD4^＋CD25high T cells, which had immunophenotyping characteristics of regulatory T cells, i.e. they expressed Foxp3 but not active maker CD69. Conclusion： This study demonstrates that soluble factors secreted by AML cells can inhibit development and functions of DCs. In addition, AML supernatant-induced DCs can induce the generation of CD4^＋CD25^high T cells from CD4^＋ T cells, which may be a mechanism of increased prevalence of CD4^＋CD25^high regulatory T cells and immune dysfunction in AML patients.