Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human natural killer (NK) cells can induce cell death in autologous dendritic cells (DCs), though an interaction between these two cell types can also lead to a reciprocal activation. We have recently shown cell contact between NK cells and DCs in vivo, in Malassezia-induced lesional skin of patients with atopic eczema, where the yeast acts as an allergen although it is part of the normal skin microflora. Here we characterize the interaction of human NK cells and monocyte-derived DCs (MDDCs) by using an in vitro system where short-term activated polyclonal NK cells are cocultured with autologous, immature, Malassezia-stimulated or lipopolysaccharide-matured MDDCs. We found that the number of CD83(+) MDDCs increased in the immature and Malassezia-stimulated MDDCs upon coculture with NK cells, while an increased number of CD86(+) cells was detected in the Malassezia-stimulated MDDCs. NK cell-MDDC interaction induced the production of interleukin-8 (IL-8). In conclusion, our results imply that NK cells provide maturation signals and may play a role in inducing IL-8 production in DCs. Furthermore, the increased expression of CD86 on Malassezia-stimulated MDDCs might have a function in subsequent T-cell activation by DCs, and indicate a role for NK cell-DC interaction in modulating the immune responses to microbial stimuli.
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PMID:Malassezia enhances natural killer cell-induced dendritic cell maturation. 1514 62

Langerhans cells (LCs) represent an immature population of myeloid dendritic cells (DCs). As a result of their unique Birbeck granules (BGs), langerin expression, and heterogeneous maturation process, they differ from other immature DCs. Monocyte-derived LCs (MoLCs) mimic epidermal LCs. MoLCs with characteristic BGs are generated by culturing blood-derived monocytes with granulocyte macrophage-colony stimulating factor, interleukin (IL)-4, and transforming growth factor-beta1. Here, we compare maturation-induced antigen expression and cytokine release of LCs with MoLCs. To achieve comparable cell populations, LCs and MoLCs were isolated by CD1c cell sorting, resulting in high purity. In unstimulated cells, CD40 was expressed at equal levels. After stimulation with CD40 ligand (CD40L), LCs and MoLCs acquired CD83 and increased CD86. High CD80 expression was exclusively detected in CD1c-sorted MoLCs. Human leukocyte antigen-DR and CD54 expression was found in all cell populations, however, at different intensities. CD40 triggering increased the potency of LCs and MoLCs to stimulate CD4+ T cell proliferation. Activated MoLCs released IL-12p70 and simultaneously, anti-inflammatory IL-10. The application of the Toll-like receptor ligands peptidoglycan, flagellin, and in particular, lipopolysaccharide (LPS) increased the corelease of these cytokines. LCs secreted IL-10 at a comparable level with MoLCs but failed to produce high amounts of IL-12p70 after application of danger signals. These data indicate that MoLCs as well as LCs display no maturation arrest concerning CD83 and CD86 expression. In difference to MoLCs, LCs resisted activation by CD40L and LPS in terms of IL-12 production. This shows that natural and generated LCs share similar features but differ in relevant functions.
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PMID:Human epidermal Langerhans cells differ from monocyte-derived Langerhans cells in CD80 expression and in secretion of IL-12 after CD40 cross-linking. 1517 2

Adenosine 5'-triphosphate (ATP), which is released from necrotic cells, induces a semimaturation state of dendritic cells (DC), characterized by the up-regulation of costimulatory molecules and the inhibition of proinflammatory cytokines. This action is mediated by cyclic adenosine monophosphate (cAMP) and involves the P2Y11 receptor. As DC express the ecto-enzyme CD39, which converts ATP into adenosine 5'-diphosphate (ADP), the effects of adenine nucleotides diphosphates on molecular signaling [intracellular calcium ([Ca2+]i), cAMP, extracellular signal-regulated kinase 1 (ERK1)], costimulatory molecule expression (CD83), and cytokine production [interleukin (IL)-12, tumor necrosis factor alpha (TNF-alpha), IL-10] were investigated in human monocyte-derived DC. ADP, 2-methylthio-ADP, and ADPbetaS had no effect on cAMP, increased [Ca2+]i, and stimulated the phosphorylation of ERK1. The effect on ERK1 was inhibited by AR-C69931MX, a P2Y12 and P2Y13 antagonist. On the contrary the effect on [Ca2+]i was neither inhibited by AR-C69931MX or by the P2Y1 antagonist MRS-2179. Both effects were inhibited by pertussis toxin. ADPbetaS alone was less potent for up-regulation of CD83 than ATPgammaS and did not increase the CD83 expression by DC stimulated with lipopolysaccharide (LPS). Similar to ATPgammaS, ADPbetaS inhibited the release of IL-12p40, IL-12p70, and TNF-alpha stimulated by LPS (1-100 ng/ml). The inhibitory effect of ADPbetaS on IL-12 release was neither reversed by AR-C69931MX or by MRS-2179. The two nucleotides had opposite effects on IL-10 production: inhibition by ADPbetaS and potentiation by ATPgammaS. In conclusion, ATP can modulate the function of DC, directly via a cAMP increase mediated by the P2Y11 receptor and indirectly via its degradation into ADP, which acts via Gi-coupled receptors coupled to ERK activation and calcium mobilization. These distinct mechanisms converge on the inhibition of inflammatory cytokine production, particularly IL-12, but have a differential effect on IL-10.
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PMID:Involvement of multiple P2Y receptors and signaling pathways in the action of adenine nucleotides diphosphates on human monocyte-derived dendritic cells. 1524 Jul 47

Biological response modifiers (BRMs) augment the cytotoxic activity of various effector cells by the induction of multiple cytokines and suppression of immunosuppressive factors. BRMs are used extensively in adjuvant therapy for gastric cancer in Japan. In dendritic cell (DC)-based vaccine therapy, the quality of DCs is important in inducing strong antitumor immunity. A good manufacturing practice (GMP) grade agent for DCs maturation is desirable for safety. Here we report the effects of two BRMs, OK432 and PSK, which are GMP grade agents for the functional maturation of DCs. OK432 and PSK were examined in vitro, and compared with lipopolysaccharide (LPS) and a cytokine cocktail (IL-1beta, TNF-alpha, IL-6 and PGE2). In the immunophenotypical analysis, the expression of CD80 and CD83 of DCs stimulated with OK-432 increased significantly compared with PSK and medium, and this up-regulation was the same as levels of DCs stimulated with cytokine cocktail. DCs stimulated with OK-432 showed significantly higher production of IL-12 and Th1-type cytokines (IL-2 and IFN-gamma) compared with DCs stimulated with LPS or cytokine cocktail. OK-432 stimulated DCs could induce the significantly high level of cytotoxic T cell activity compared with PSK-stimulated or unstimulated DCs. These results suggest that OK432 is a GMP-grade reagent that promotes functional maturation of DCs and could be applied in DC-based vaccinations.
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PMID:Usefulness of immunomodulators for maturation of dendritic cells. 1525 44

Dendrimers are hyperbranched macromolecules that can be chemically synthesized to have precise structural characteristics. We used anionic, polyamidoamine, generation 3.5 dendrimers to make novel water-soluble conjugates of D(+)-glucosamine and D(+)-glucosamine 6-sulfate with immuno-modulatory and antiangiogenic properties respectively. Dendrimer glucosamine inhibited Toll-like receptor 4-mediated lipopolysaccharide induced synthesis of pro-inflammatory chemokines (MIP-1 alpha, MIP-1 beta, IL-8) and cytokines (TNF-alpha, IL-1 beta, IL-6) from human dendritic cells and macrophages but allowed upregulation of the costimulatory molecules CD25, CD80, CD83 and CD86. Dendrimer glucosamine 6-sulfate blocked fibroblast growth factor-2 mediated endothelial cell proliferation and neoangiogenesis in human Matrigel and placental angiogenesis assays. When dendrimer glucosamine and dendrimer glucosamine 6-sulfate were used together in a validated and clinically relevant rabbit model of scar tissue formation after glaucoma filtration surgery, they increased the long-term success of the surgery from 30% to 80% (P = 0.029). We conclude that synthetically engineered macromolecules such as the dendrimers described here can be tailored to have defined immuno-modulatory and antiangiogenic properties, and they can be used synergistically to prevent scar tissue formation.
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PMID:Polyvalent dendrimer glucosamine conjugates prevent scar tissue formation. 1525 95

Human DCs (dendritic cells) express surface CD83 upon activation. Comparing the surface induction of CD83 with the upregulation of CD40, CD80 and CD86 during LPS (lipopolysaccharide)-induced DC maturation showed that CD83 induction occurred more rapidly. Despite the lack of CD83 on immature DCs, it was detected in these cells by Western blotting and flow cytometry. Indirect immunofluorescence revealed CD83 inside immature DCs in perinuclear regions. CD83 was absent on monocytes and macrophages, but it was detected inside these cells and found to be rapidly surface-expressed upon LPS-induced activation. Whereas CD83 expression on activated DCs was sustainable, its expression on monocytes and macrophages was transient. Optimal interleukin-4 co-stimulation during DC generation from monocytes was found to be essential for stable CD83 surface expression. CD83 was detected as 37 and 50 kDa forms in transfected 293T cells. Macrophages and immature DCs expressed the 37 kDa form, whereas mature DCs predominantly expressed the 50 kDa form. In monocytes, CD83 was detected as a 22 kDa detergent-insoluble form. The rapid CD83 surface induction on DCs and macrophages was blocked by brefeldin A, but not by cycloheximide, showing that fresh CD83 synthesis was not essential. Tunicamycin inhibited the expression of the 50 and 37 kDa CD83 forms, and also blocked CD83 surface expression on DCs and macrophages. PNGase F (peptide N-glycosidase F) digestion reduced the 37 and 50 kDa CD83 forms to 28 kDa. In summary, monocytes, macrophages and immature DCs contain preformed intracellular CD83, and its rapid surface expression upon activation is post-translationally regulated in a process involving glycosylation.
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PMID:CD83 is preformed inside monocytes, macrophages and dendritic cells, but it is only stably expressed on activated dendritic cells. 1532 Aug 71

Dendritic cells (DCs) are potent antigen-presenting cells that play a pivotal role in the initiation of T cell-dependent immune responses. Immature DCs obtained from peripheral blood CD14+ monocytes by culture with granulocyte macrophage-colony stimulating factor (GM-CSF) and interleukin-4 (IL-4) differentiate into mature DCs upon stimulation with lipopolysaccharide (LPS). At least three families of mitogen-activated protein kinases (MAPKs), that is, extracellular signal-regulated kinases (ERK), c-Jun N-terminal kinases (JNK) and p38 MAPK, are involved in the DC maturation process. We report investigations of the role of JNK in the maturation of human monocyte-derived DCs. SP600125, a specific inhibitor of JNK, inhibited the LPS-induced up-regulation of CD80, CD83, CD86 and CD54, but augmented the up-regulation of HLA-DR. SP600125 slightly inhibited the down-regulation of FITC-dextran uptake during DC maturation. However, SP600125 did not affect the LPS induced up-regulation of allostimulatory capacity of DCs. SP600125 inhibited the release of IL-12 p70 and TNF-alpha from mature DCs. Although autologous T cells primed by the ovalbumin (OVA)-pulsed mature DCs produced IFN-gamma, but not IL-4, OVA-pulsed SP600125-treated mature DCs could initiate IL-4 production from autologous T cells. In contrast, a p38 MAPK inhibitor, SB203580, profoundly inhibited the phenotypic and functional maturation of DCs, while an ERK inhibitor, PD98059, had little or no effect. Taken together, the JNK signaling pathway appears to have a role that is distinct from the p38 MAPK and ERK cascades in the maturation process of DCs, and may be involved in the augmentation of Th2-prone T cell responses when it is suppressed.
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PMID:Role of c-Jun N-terminal kinase on lipopolysaccharide induced maturation of human monocyte-derived dendritic cells. 1547 28

There is growing interest in the in vitro generation of dendritic cells (DC) from peripheral blood monocytes, but the effect of the method chosen to isolate CD14+ monocytes for subsequent DC generation is poorly documented. The method used to isolate monocytes may have an impact on the subsequent function of DC by affecting their ability to express costimulatory molecules (CD80/86), maturation marker (CD83) and/or to produce important immunomodulatory cytokines. In this study, we show that the positive selection of monocytes by anti-CD14-coated microbeads inhibits the lipopolysaccharide (LPS)-induced production of interleukin (IL)-12, IL-10 and tumour necrosis factor-alpha (TNF-alpha) from human DC. However, when DC were grown from monocytes isolated by plastic adherence, LPS induced the production of much higher levels of these cytokines. DC derived from adherence-isolated monocytes induced the development of potent cytotoxic T lymphocytes of the Tc1 subset specific for influenza matrix protein, as confirmed by interferon-gamma (IFN-gamma) enzyme-linked immunosorbent spot-forming cell assay (ELISPOT), cytotoxicity assay, major histocompatibility complex (MHC)-peptide tetrameric complexes and T helper 1/T helper 2 (Th1/Th2) cytokine production assays.
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PMID:Human monocyte isolation methods influence cytokine production from in vitro generated dendritic cells. 1566 65

Polymyxin B is a lipopolysaccharide binding antibiotic used to inactivate potential lipopolysaccharide contaminations when evaluating the activity of different agents on innate immune cells. We report that polymyxin B is able to induce directly in monocyte-derived human dendritic cells (DCs) several functional and molecular modifications characteristic of DCs undergoing a maturation process. DCs incubated with polymyxin B up-regulate the expression of HLA class I and II, the co-stimulatory CD86 molecule, and show an increase in the fraction of adherent cells at short time, which persist at 48 h of incubation. Adhesion to the plate was required for the polymyxin B-induced DCs maturation. A transient activation of IkappaB-alpha/NF-kappaB and ERK1/2 pathways at short time and a further ERK1/2 activation at long term were also detected. Neither up-regulation of the maturation marker CD83 nor activation of p38 nor induction of cytokines secretion was observed in DCs treated with polymyxin B. We demonstrated that inhibition of IkappaB-alpha/NF-kappaB pathway abolishes polymyxin B effects. ERK1/2 inhibition instead allowed DCs treated with polymyxin B to progress in their maturation process as revealed by the increased up-regulation of the CD83 co-stimulatory molecules, the activation of p38, and the reduced adhesion to culture plates at 48 h of incubation. Our results indicate that polymyxin B induces a partial maturation of human DCs through increased adhesion to a substrate and activation of the IkappaB-alpha/NF-kappaB pathway. The increased ERK1/2 activation observed, even though correlating with the initial phases of the maturation process, actually inhibits the occurrence of full maturation.
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PMID:Direct effects of polymyxin B on human dendritic cells maturation. The role of IkappaB-alpha/NF-kappaB and ERK1/2 pathways and adhesion. 1567 Oct 28

Dendritic cells (DCs) are derived from CD34+ progenitors and play a central role in the development of immune responses and in tolerance. Their therapeutic potential underscores the need for in vivo models that accurately recapitulate human DC development and function to provide a better understanding of DC biology in health and disease. Using nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice transplanted with human CD34+ cells as a model of human hematopoiesis, we examined DC ontogeny. Progenitors of both myeloid (m) and plasmacytoid (p) DCs were identified in the bone marrow of mice up to 24 weeks after transplant, indicating ongoing and sustained production of DCs after initial engraftment. To determine whether human DCs derived from transplanted stem cells were functional, their response to acute inflammation using lipopolysaccharide (LPS) was examined. Eighteen hours after LPS administration, a dramatic increase in the plasma levels of the human inflammatory cytokines interleukin (IL)-8, IL-10, tumor necrosis factor-alpha, and IL-12p70 was observed. Only mDCs and not pDCs responded in vivo to LPS by upregulating CD86 and CD83. In vivo activation of human mDCs resulted in a substantial increase in the ability of mDCs to induce the proliferation of naive human T cells. Taken together, these data indicate that human CD34+ cells seem to have differentiated appropriately within the NOD/SCID microenvironment into DCs that are developmentally, phenotypically, and functionally similar to the DC subsets found in humans.
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PMID:Development and activation of human dendritic cells in vivo in a xenograft model of human hematopoiesis. 1567 Nov 49


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