Effect of PSK on the maturation of dendritic cells derived from human peripheral blood monocytes

Dendritic cells (DCs) are powerful antigen-presenting cells (APCs) that have attracted attention in recent years from the viewpoint of DC vaccine therapy against cancer. However, the existence of a strongly immunosuppressed state in cancer-bearing individuals inhibits DC maturation, which is one of the problems facing anti-cancer DC vaccine therapy. Protein-bound polysaccharide K (PSK), which is extracted from the cultured mycelium of Coriolus versicolor (Fr.) Quél, is used as an anti-cancer agent in Japan. PSK is reported to improve the immunosuppressed state and might be associated with DC maturation directly. We examined the effect of PSK on the maturation of DC derived from CD14-positive cells obtained from human peripheral blood monocytes using a negative selection method. CD14-positive cells cultured in the presence of PSK significantly increased the expression of HLA class II antigen and CD40; significantly increased the number and expression of CD80-, CD86- and CD83-positive cells; decreased Fluorescein isothiocyanate (FITC)-dextran uptake, augmented IL-12 production; augmented the allogeneic mixed lymphocyte reaction; and induced antigen-specific cytotoxicity. These results indicate that PSK promotes both the phenotypic and functional maturation of DC derived from human CD14-positive mononuclear cells. The clinical significance of the combined use of PSK in DC vaccine therapy remains for study.     

Generation and characterization of ovine dendritic cells derived from peripheral blood monocytes

Dendritic cells (DCs) are professional antigen‐presenting cells with a highly immunostimulatory function and the capacity to activate naïve T cells. In recent years the rapid progress in mouse and human DC research can be mainly attributed to the generation of DCs from precursor cells in vitro, although a lack of reagents has hampered DC research in many large animal models. Here we describe the generation and characterization of ovine monocyte‐derived DCs in vitro. In addition to the characteristic morphology and non‐adherence of DCs, peripheral blood mononuclear cell monocytes cultured with ovine granulocyte–macrophage colony‐stimulating factor (GM–CSF) and interleukin‐4 (IL‐4) expressed CD11c and major histocompatibility complex (MHC) class II, but did not express CD14. High levels of endocytosis and an ability to stimulate antigen‐specific proliferation of CD4 T lymphocytes were also demonstrated.     

Generation of feline dendritic cells derived from peripheral blood monocytes for in vivo use

Dendritic cells (DCs) are professional antigen-presenting cells that can prime T cells and polarize the cellular immune response. Because Th1-type immune responses have been connected to success in combating viral infection, a promising therapeutic application of DCs would be their differentiation in vitro and injection back into the host to boost an immune response in infected animals. This study was aimed both at developing a protocol to cultivate feline DCs in the absence of exogenous proteins for their use in vivo and at investigating what might be the most appropriate stimulus to induce their maturation in vitro and finding correlates of maturation. We generated DCs from peripheral blood monocytes in the presence of feline interleukin-4 and granulocyte-macrophage colony stimulating factor, and after 5 days their maturation was induced with either lipopolysaccharide, human recombinant tumor necrosis factor alpha, poly(I:C), or activated feline platelets. After 48 h, their CD14, CD1a, major histocompatibility complex class II, and B7.1 surface expression was analyzed in parallel with their ability to uptake antigen or prime a mixed leukocyte reaction. The results presented show that feline DCs cultured in autologous plasma differentiate and are able to mature in the presence of stimuli similar to the ones currently used for other species. The present work sets the grounds for future use of DCs obtained by the protocol described for in vivo vaccination and immunotherapy of feline immunodeficiency virus-infected cats.     

Functional and phenotypic characterization of distinct porcine dendritic cells derived from peripheral blood monocytes

Dendritic cells (DCs) are bone marrow-derived antigen-presenting cells that have an exquisite capacity to interact with T cells and modulate their responses. Little is known about porcine DCs despite the fact that they represent an important target in strategies that are aimed at modulating resistance to infection in pigs and may be of major importance in transplantation biology. We generated immature monocyte-derived porcine dendritic cells (MoDCs) directly from adherent peripheral blood cells treated with porcine granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). The cells were observed via electron microscopy and their phenotype was characterized using monoclonal antibodies. The functionality of the porcine MoDCs was demonstrated showing that the cells were capable of different specialized functions relevant to antigen capture and were potent stimulators in a primary allo-mixed leucocyte reaction. Treatment of the MoDCs with porcine cell line-derived necrotic factors resulted in the phenotypic and functional maturation of MoDCs. We confirmed also that monocyte-derived DCs were differentially regulated by cytokines, showing that transforming growth factor-beta1 (TGF-beta1) is able to redirect monocytic precursors into the differentiation pathway of Langerhans' cells presenting typical Birbeck granules. Interestingly, and in contrast to the human and murine model, we showed that the monocyte-derived porcine Langerhans'-type cells (MoLCs) were much more potent activators of allogeneic T cells than MoDCs obtained without TGF-beta1.     

TGFbeta-dependent gene expression profile during maturation of dendritic cells

Primary immune response to pathogens involves the maturation of antigen-presenting dendritic cells (DC). Bacterial lipopolysacharride (LPS) is a potent inducer of DC maturation, whereas the transforming growth factor beta (TGFbeta) attenuates much of this process. Here, we analyzed the global gene expression pattern in LPS-treated bone marrow derived DC during inhibition of their maturation process by TGFbeta. Exposure of DC to LPS induces a pronounced cell response, manifested in altered expression of a large number of genes. Interestingly, TGFbeta did not affect most of the LPS responding genes. Nevertheless, analysis identified a subset of genes that did respond to TGFbeta, among them the two inflammatory cytokines interleukin (IL)-12 and IL-18. Expression of IL-12, the major proinflammatory cytokine secreted by mature DC, was downregulated by TGFbeta, whereas the expression level of the proinflammatory cytokine IL-18, known to potentiate the IL-12 effect, was upregulated. Expression of the peroxisome proliferator-activated receptor gamma (PPARgamma) increased in response to TGFbeta, concomitantly with reduced expression of chemokine receptor 7 (CCR7). This finding supports the possibility that TGFbeta-dependent inhibition of CCR7 expression in DC is mediated by PPARgamma.     

Analysis of methods for the generation of dendritic cells from human peripheral blood monocytes

Dendritic cells (DC) are highly efficient antigen-presenting cells that initiate the primary immune response. Several laboratories have developed culture systems for human DC from peripheral blood monocytes. Most of these studies have used fetal calf serum (FCS) containing culture conditions that are inappropriate for human application. GM-CSF and IL-4 were used to make immature DC. The monocyte-conditioned medium (MCM) was used to induce the final maturation of DC. Using the previously described methods, the quality of MCM has unpredictable variations. Therefore using a defined cocktail of growth factors for the generation of mature DC would be advantageous for experimental as well as clinical purposes. In this study, it is suggested that combinations of both GM-CSF/IL-4 or GM-CSF/IL-13 could be used as the first-step culture to produce immature DC, and that cytokine cocktail (GM-CSF, IL-4, IL-1beta, TNF-alpha, IL-6, PGE2) was as efficient as MCM for the second step-culture to produce fully maturated DC. Here, we have generated an easily reproducible culture system for DC that allows for the generation of large amounts of immature and mature DC, and we also now have established the method in a FCS-free system that is suitable for clinical use.     

Mechanism of NK cell activation induced by coculture with dendritic cells derived from peripheral blood monocytes.

Dendritic cells (DCs) have been regarded as one of the effective antigen-presenting cells, but the relationship between DCs and lymphocytes, in particular natural killer (NK) cells, remains unclear. In this study, we evaluated how DCs interact with both lymphocytes and NK cells using a coculture system. The number of lymphocytes increased significantly when cocultured with DCs (1.8-fold increase). In particular, the proliferation of NK cells was prominent. Furthermore, the coculture of DCs with lymphocytes induced a marked increase in IL-12 and IFN-gamma secretion. When contact between the DCs and lymphocytes was prevented, the secretion of both IL-12 and IFN-gamma was markedly reduced. IFN-gamma production was completely blocked by an anti-IL-12 antibody, indicating that IFN-gamma secretion was dependent on IL-12 secretion. The stimulating effect of the DCs on the proliferation of the lymphocytes was partially suppressed by anti-IL-12 antibodies, and was completely attenuated when cellular contact was prevented. Furthermore, the NK cell proliferation induced by coculture with DCs was significantly blocked by the inhibition of the interaction of either CD40-CD40L or CD28-B7 molecule. The coculture with DCs enhanced NK activity by 40%, and this was partially suppressed by anti-IL-12 antibodies and was completely blocked by the inhibition of cell-to-cell contact. These results indicate that the activation of NK cells by DCs is partially mediated by IL-12 secretion, and that direct contact between DCs and NK cells play a major role in this response.     

Differential MHC class II expression on human peripheral blood monocytes and dendritic cells

Both monocytes (MO) and dendritic cells (DC) in human peripheral blood are of a plastic-adherent nature. The expression of the MHC class II sublocus products HLA-DP, -DQ and -DR on human peripheral blood transiently adherent cells (TA) was examined by an immunocytochemical staining technique. While most TA showed strong expression of molecules of the HLA-DR subtype, only a small proportion of cells (2-6%) showed strong HLA-DP or -DQ positivity. This strong expression of the HLA-DP and HLA-DQ sublocus products by a subset of TA was seen only after short-term culture; freshly isolated cells expressed comparatively low levels of these molecules. Enrichment for Fc receptor-negative or low-density cells from TA produced populations with strong HLA-DQ and -DP expression. Such co-enrichment of the strongly HLA-DQ+ and strongly HLA-DP+ cells suggests that the same cells express high levels of both types of MHC class II molecule. Immunocytochemical analysis of TA indicated that the strongly HLA-DQ+ cells, at least, were only weakly or non-reactive with the MO-specific monoclonal antibodies OKM1, UCHM1, MO2 and EB11. In addition, strongly HLA-DQ- or -DP-positive cells were poorly phagocytic in comparison with the majority of adherent cells. The apparent FcR-negative, low-density and weakly phagocytic nature of the strongly HLA-DQ/DP+ cells, combined with their lack of reactivity with several MO-specific antibodies, suggests that they may represent the DC component of TA. Such strong HLA-DQ/DP expression by DC may aid their positive identification in human peripheral blood and may be of relevance to DC function in antigen presentation.     

Interferon-alpha disables dendritic cell precursors: dendritic cells derived from interferon-alpha-treated monocytes are defective in maturation and T-cell stimulation

Dendritic cells (DC) can be derived from monocytes in vitro by culture with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). It is unknown whether this regimen reflects DC differentiation from blood precursors under physiological conditions. Induction of DC development from monocytes by interferon-alpha (IFN-alpha) may occur in vivo during infection or inflammation and thus may represent a more physiological approach to DC differentiation in vitro. Here, we show that incubation of GM-CSF-cultured monocytes with IFN-alpha does not induce DC differentiation: cells maintain their original phenotype and cytokine secretion pattern. Even after stimulation with pro-inflammatory or T-cell-derived activation signals, IFN-alpha-treated monocytes do not develop DC characteristics. Addition of IL-4 during stimulation of IFN-alpha-treated monocytes results in the rapid development of DC-like cells expressing co-stimulatory molecules, CD83 and chemokine receptor CCR7, indicating that some degree of developmental plasticity is preserved. However, DC pre-activated with IFN-alpha are less effective in inducing allogeneic or antigen-specific autologous T-cell proliferation, produce less IL-12 and express lower levels of CCR7 compared to DC generated by culture with GM-CSF and IL-4. Incubating GM-CSF-cultured monocytes simultaneously with IFN-alpha and IL-4 does not affect phenotypic maturation of DC, but reduces IL-12 production upon pro-inflammatory activation. We conclude that: (1) IFN-alpha fails to induce DC differentiation and thus cannot replace IL-4 in generating DC from monocytes in vitro; and (2) the presence of IFN-alpha prior to or during differentiation of DC from monocyte precursors alters their response to maturation stimuli and may affect their capacity to stimulate T helper type 1 immune responses in vivo.     

Phenotype and function of myeloid dendritic cells derived from African green monkey blood monocytes

Myeloid dendritic cells probably play an important role in the immune response against HIV and SIV, and in the enhancement of CD4+ T cell infection. Here, we have investigated phenotypic and functional features of myeloid monocyte-derived DC (MDDC) from African green monkeys (AGMs). AGMs are natural hosts of SIV and exhibit no signs of abnormal T cell activation despite high SIV plasma viremia. We identified mAbs that cross-react specifically with homologous molecules expressed on AGM DC. We adapted a protocol to derive AGM MDDC by culture in the presence of GM-CSF and IL-4. The differentiated cells possessed a typical dendritic morphology and the majority were CD11c+ DC-SIGN+. AGM MDDC displayed a high expression of typical maturation markers, such as CD83, CD86 and DC-LAMP, and moderate immunostimulatory capacity, suggesting that the cells were in a semi-mature state. Stimulation resulted in further maturation, as shown by up-regulation of CD80 and decrease of endocytosis ability. However, neither increase of HLA-DR or CD40 expression nor enhanced immunostimulatory capacity was observed. The latter was associated with a low pro-inflammatory cytokine production during mixed lymphocyte reactions and a cytokine balance in favour of IL-10 in contrast to human MDDC. This is the first characterization of AGM MDDC. The tools described here are a crucial step for future studies in vivo or in vitro on the function of myeloid DC using the AGM animal model.     

人外周血单核细胞源性朗格汉斯细胞和表皮炎症样树突状细胞的诱导及表型分析

目的利用人外周血单核细胞体外诱导培养朗格罕氏细胞(Mo-LC)和炎症性树突状表皮细胞(Mo-IDEC)并观察其表型特点。方法联合应用LymphoPrepTM梯度离心试剂和CD14+磁珠分离和筛选外周血CD14+单核细胞;在重组人粒细胞-巨噬细胞集落刺激因子(GM-CSF)和重组人白介素4(IL-4)的基础上分别于第0、2、4天加入人天然TGF-β1或β-巯基乙醇(β-ME)。培养第6天时收集细胞,通过相差显微镜观察其形态,并利用单克隆抗体和流式细胞术对诱导细胞亚群检测细胞表面分子的表达水平。结果 CD14+单核细胞体外诱导培养6 d后可形成具有树突状外观的Mo-LC和Mo-IDEC,2种细胞均不同程度表达CD1a、FcεRI、FcεRII、TLR1、TLR2;Mo-LC表达CD207,Mo-IDEC表达CD206。特应性皮炎患者来源的Mo-IDEC表面CD1a表达高于Mo-LC,且CD23、TLR2、FcεRI的表达水平显著高于健康对照组。结论利用外周血单核细胞可在体外成功诱导Mo-LC和Mo-IDEC,这2种细胞表型特点与体内分离的细胞在形态和表型上类似,为体外进一步研究这2类细胞的功能打下基础。     

Morphological characteristics and immunophenotype of dendritic cells generated from monocytes of human peripheral blood

Morphological features and immunophenotype of mature dendritic cells (DC) generated from the monocytes of healthy donor blood after culture with GM-CSF and IL-4 with the addition of TNF, were studied using light and electron microscopy, as well as flow-cytometry. It was shown that DC were characterized by a number of morphological features such as: large size, eccentrically located nucleus, highly developed system of extensions, large vacuolated cytoplasm, prominent and activated Golgi complex and ribosomal apparatus. Mature DC are characterized by active surface expression of MHC and co-stimulatory molecules (MHC I, MHC II, CD40, CD80, CD86).     

钙离子载体对外周血单核细胞来源的树突状细胞的影响

目的：探讨钙离子载体（calcium ionophore,CI)对外周血单核细胞来源的树突状细胞（DC）的影响。方法：分离分离献血者外周血单核细胞。分别加入重组人粒/单集落刺激因子（rhGM-CSF)100μg/L，rhGM-CSF100μg/L CI10μg/L及rhGM-CSF CI各100μg/L，体外培养40h后，于光镜及电镜下观察细胞的形态，流式细胞仪检测细胞的表面标志，MTT比色法检测上述分子对自体T细胞的刺激增殖作用。结果：外周血单核细胞在GM-CSF CI各100μg/L的条件下培养40h，就可看到典型的DC形态，其表面CD14分子表达减少。HLA-DR，CD40，CD83及CD86分子的表达明显增高，且具有明显刺激自体T细胞增殖的能力。结论：CI有显著加速GM-CSF诱导的外周血单核细胞向DC转化的作用。     

Thymosin-alpha1 modulates dendritic cell differentiation and functional maturation from human peripheral blood CD14+ monocytes

Although thymosins have been demonstrated to have immunomodulatory effects, it is still not clear whether they could affect dendritic cells (DCs), the most professional antigen-presenting cells. The objective of this study was to determine the effect and potential mechanisms of thymosin-alpha1 (Talpha1) on DC differentiation and functional maturation. Human peripheral blood CD14(+) monocytes were purified by using a magnetic separation column and cultured with GM-CSF and IL-4 to differentiate into immature DCs (iDCs). In the presence of Talpha1, iDC surface markers CD40, CD80, MHC class I and class II molecules were significantly upregulated as measured by flow cytemotry analysis. However, Tbeta4 or Tbeta10 did not show these effects on iDCs. There was an approximately 30% reduction in antigen (FITC-conjugated dextran)-uptake by Talpha1-treated iDCs as compared with non-Talpha1-treated iDCs. In addition, Talpha1-treated matured DCs (mDCs) showed an increased stimulation of allogeneic CD3(+) T-cell proliferation as measured by a mixed-lymphocyte reaction assay. Talpha1-treated mDCs also increased the production of several Th1- and Th2-type cytokines as measured by a Bio-Plex cytokine assay. Furthermore, rapid activation of p38 MAPK and NFkappaB was seen in Talpha1-treated iDCs as measured by a Bio-Plex phosphoprotein assay. Thus, Talpha1 significantly enhances DC differentiation, activation, and functions from human peripheral blood CD14(+) monocytes possibly through a mechanism of the activation of p38 MAPK and NFkappaB pathways. This study provides a basis to further evaluate Talpha1 as a possible adjuvant for a DC-directed vaccine or therapy.     

慢性乙型肝炎患者树突状细胞表型的研究

目的探讨慢性乙型肝炎患者外周血来源树突状细胞（Dendritic cell，DC）数量及表型的改变，并对其与肝功能、乙肝病毒复制水平的关系进行研究。方法检测37例慢性乙肝患者和21例健康人肝功能及血清HBV DNA水平，并提取外周血单个核细胞（Peripheral blood mononuclear cell，PBMC）进行体外诱导培养，促使其发育成DC，计数其数量并检测膜表面分子的变化。分析DC数量及表型与肝功能、乙肝病毒复制水平的关系。结果与正常对照组比较，慢性乙肝患者的树突状细胞数量明显减少（P〈0．05），且其膜表面分子CD83、CD86的表达均明显降低（P〈0．05）。在慢性乙肝患者中，DC数量、DC膜表面分子CD83和CD86与血清HBV DNA之间呈负相关关系，而与肝功能之间无明显相关关系。结论慢性乙肝患者体内存在DC数量减少及成熟障碍，这种改变与肝内炎症反应程度不相关，但与乙肝病毒（Hepatitis Bvirus，HBV）的复制水平呈负相关，提示DC参与慢性乙肝患者体内HBV的清除。     

Enrichment of dendritic cells from human peripheral blood

A simplified method is described for purification of dendritic cells from human peripheral blood. The method is based on depletion of phagocytes with carbonyl iron and magnet, followed by centrifugation of nonphagocytic cells on Percoll and elimination of contaminating T lymphocytes, B lymphocytes, natural killer cells, and monocytes from the low-density cell fraction by treatment with monoclonal antibodies and complement. The purity of enriched dendritic cells was about 80% and these cells represented 0.2% of the starting mononuclear cell population. Dendritic cells were potent autologous and allogeneic stimulators in mixed leukocyte cultures.     

Nicotinic environment affects the differentiation and functional maturation of monocytes derived dendritic cells (DCs)

Differentiation of tissue monocytes into DCs is a critical phase in the development of a competent immune system. We show that in a nicotinic environment, while human monocytes differentiate into DCs (henceforth called nicDCs) with a typical morphology, they display unique phenotype and cytokine profile that adversely affect their function. Despite an increased capacity for receptor-dependent antigen uptake, nicDCs do not express CD1a and fail to fully up-regulate MHCs, molecules essential for their antigen-presenting function. Additionally, in response to bacterial antigen LPS, maturing nicDCs hardly express the chemotactic cytokine receptor 7 required for their entry into lymphatic vessels. Furthermore, in parallel with their differential expression of costimulatory molecules CD80 and CD86 and lack of IL-12, nicDCs display profoundly reduced Th1 promoting capacity. These findings thus indicate that nicotine impedes the development of cell-mediated immunity by skewing DC differentiation. These effects of nicotinic environment on DC differentiation may contribute to the increased risks of respiratory tract infection and various cancers in smokers.     

孕酮对人树突状细胞成熟和免疫功能的影响

目的：研究孕酮（P₄）对人外周血来源树突状细胞（DCs）成熟和免疫学功能的影响。方法：在人外周血来源DCs体外培养时加入两种浓度的P₄ (10-7 mol/L和10-6 mol/L)处理，光镜和电镜下观察DCs的生成情况及形态变化，以流式细胞仪分析各组细胞的免疫表型，用ELISA方法测定其分泌的IL-10和IL-12水平，［3H］-TdR掺入法检测体外混合淋巴细胞反应中DCs刺激同种反应性T细胞的增殖能力。结果：加入P4培养后, DCs树突状和膜面状伪足减少，表达低水平MHC-II分子和共刺激分子CD40、CD80和CD86，其分泌的IL-10水平升高，IL-12水平明显下降，DCs刺激同种反应性T细胞的功能显著下降。结论：P₄抑制人外周血来源DCs的成熟，对其免疫学功能具有负性调节作用。     

树突状细胞诱导的CTL抗乙型肝炎病毒效应

目的　研究乙肝表面抗原 (HBsAg)负载的树突状细胞疫苗在抗乙肝病毒中的作用。方法　从健康人外周血中分离出单核细胞 ,在GM CSF和IL 4的作用下培养 7d诱导出DC ,然后以DC为刺激细胞在体外诱导出HBsAg特异性CTL ;将携有HBV S基因的pLXSN S重组质粒 ,电击导入肝癌细胞系 (HepG2 ) ,建立表达HBsAg的靶细胞模型HepG2 S ;用DC激活的HBsAg特异性CTL与HepG2 S细胞同时接种于BALB c裸鼠或用HBsAg特异性CTL治疗HepG2 S荷瘤裸鼠 ,观察肿瘤的发生和生长情况。结果　在接种后的 38d内 ,治疗组肿瘤明显比对照组小 ,差异有显著性 (P <0 .0 5 ) ,而且治疗组有 3只荷瘤鼠肿瘤消退 (6 0 % )。结论　DC激活的HBsAg特异性CTL细胞对HepG2 S移植瘤有治疗作用。