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Maturation Markers (maturation + marker)
Selected AbstractsDifferential toxicity on monocytes and monocyte-derived dendritic Cells: a new tool to differentiate allergens from irritants?INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 5 2007Laetitia Furio Phenotypic activation of monocyte-derived dendritic cells has been proposed as an in vitro alternative assay to discriminate potential sensitizers from irritants, but the sensitivity of the assay remains controversial. In this study, we first determined the dynamic range of expression of activation/maturation markers on human monocyte-derived dendritic cells cultured in the presence or absence of transforming growth factor ß (TGF,)? On day three of culture, most monocytes had already differentiated into dendritic cells that expressed low levels of costimulatory molecules especially in the presence TGF,-treatment of 3-day-old TGF,-treated monocyte-derived dendritic cells with several chemicals at sub-toxic concentrations induced significant phenotypic changes for all the strong and mild sensitizers tested, whereas the irritant sodium lauryl sulfate had no effect. However, a very large variability was observed among the experiments. Most interestingly, we could show here for the first time that at concentrations sub-toxic for monocyte-derived dendritic cells all the allergens tested induced monocyte apoptosis within 2 days of culture. In contrast, sodium lauryl sulfate displayed similar toxicity on monocytes and monocyte-derived dendritic cells and these results were confirmed with other irritants such as benzoic acid or methylsalicylate. Although testing of far more chemicals is required, these results indicate that differential toxicity of chemicals to monocytes and monocyte-derived dendritic cells could be a rapid, simple and valuable tool to differentiate sensitizers from irritants. [source] Enhanced differentiation of embryonic stem cells using co-cultivation with hepatocytesBIOTECHNOLOGY & BIOENGINEERING, Issue 6 2008Rebecca N. Moore Abstract We examined the effects of co-cultivated hepatocytes on the hepatospecific differentiation of murine embryonic stem (ES) cells. Utilizing an established mouse ES cell line expressing high or low levels of E-cadherin, that we have previously shown to be responsive to hepatotrophic growth factor stimulation (Dasgupta et al., 2005. Biotechnol Bioeng 92(3):257,266), we compared co-cultures of cadherin-expressing ES (CE-ES) cells with cultured rat hepatocytes, allowing for either paracrine interactions (indirect co-cultures) or both juxtacrine and paracrine interactions (direct co-cultures, random and patterned). Hepatospecific differentiation of ES cells was evaluated in terms of hepatic-like cuboidal morphology, heightened gene expression of late maturation marker, glucose-6-phosphatase in relation to early marker, alpha-fetoprotein (AFP), and the intracellular localization of albumin. Hepatocytes co-cultured with growth factor primed CE-ES cells markedly enhanced ES cell differentiation toward the hepatic lineage, an effect that was reversed through E-cadherin blockage and inhibited in control ES cells with reduced cadherin expression. Comparison of single ES cell cultures versus co-cultures show that direct contact co-cultures of hepatocytes and CE-ES cells maximally promoted ES cell commitment towards hepatodifferentiation, suggesting cooperative effects of cadherin-based juxtacrine and paracrine interactions. In contrast, E-cadherin deficient mouse ES (CD-ES) cells co-cultured with hepatocytes failed to show increased G6P expression, confirming the role of E-cadherin expression. To establish whether albumin expression in CE-ES cells was spatially regulated by co-cultured hepatocytes, we co-cultivated CE-ES cells around micropatterned, pre-differentiated rat hepatocytes. Albumin localization was enhanced "globally" within CE-ES cell colonies and was inhibited through E-cadherin antibody blockage in all but an interfacial band of ES cells. Thus, stem cell based cadherin presentation may be an effective tool to induce hepatotrophic differentiation by leveraging both distal/paracrine and contact/juxtacrine interactions with primary cells of the liver. Biotechnol. Bioeng. © 2008 Wiley Periodicals, Inc. [source] Hepatitis C virus,infected hepatocytes extrinsically modulate dendritic cell maturation to activate T cells and natural killer cells,HEPATOLOGY, Issue 1 2008Takashi Ebihara Dendritic cell maturation critically modulates antiviral immune responses, and facilitates viral clearance. Hepatitis C virus (HCV) is characterized by its high predisposition to persistent infection. Here, we examined the immune response of human monocyte-derived dendritic cells (MoDCs) to the JFH1 strain of HCV, which can efficiently replicate in cell culture. However, neither HCV RNA replication nor antigen production was detected in MoDCs inoculated with JFH1. None of the indicators of HCV interacting with MoDCs we evaluated were affected, including expression of maturation markers (CD80, 83, 86), cytokines (interleukin-6 and interferon-beta), the mixed lymphocyte reaction, and natural killer (NK) cell cytotoxicity. Strikingly, MoDCs matured by phagocytosing extrinsically-infected vesicles containing HCV-derived double-stranded RNA (dsRNA). When MoDCs were cocultured with HCV-infected apoptotic Huh7.5.1 hepatic cells, there was increased CD86 expression and interleukin-6 and interferon-beta production in MoDCs, which were characterized by the potential to activate NK cells and induce CD4+ T cells into the T helper 1 type. Lipid raft-dependent phagocytosis of HCV-infected apoptotic vesicles containing dsRNA was indispensable to MoDC maturation. Colocalization of dsRNA with Toll-like receptor 3 (TLR3) in phagosomes suggested the importance of TLR3 signaling in the MoDC response against HCV. Conclusion: The JFH1 strain does not directly stimulate MoDCs to activate T cells and NK cells, but phagocytosing HCV-infected apoptotic cells and their interaction with the TLR3 pathway in MoDCs plays a critical role in MoDC maturation and reciprocal activation of T and NK cells. (HEPATOLOGY 2008.) [source] Hericium erinaceum induces maturation of dendritic cells derived from human peripheral blood monocytesPHYTOTHERAPY RESEARCH, Issue 1 2010Sun Kyung Kim Abstract Hericium erinaceum, a medicinal mushroom, has long been used as a therapeutic due to its immuno-regulating potentials eliciting anticarcinogenic and antimicrobial efficacies. Since maturation of dendritic cells (DC) is an important process in the initiation and regulation of immune responses, the ability of water-soluble components from H. erinaceum (WEHE) to regulate DC maturation was investigated. Immature DC were prepared by differentiating human peripheral blood CD14-positive cells with GM-CSF and IL-4. DC were stimulated with WEHE at 2,20 µg/mL for 48 h and subjected to flow cytometric analysis to determine the expression of indicative maturation markers. The endocytic capacity of WEHE-stimulated DC was examined by a Dextran-FITC uptake assay. An enzyme-linked immunosorbent assay was performed to examine the secretion of TNF- , and IL-12p40. DC stimulated with WEHE showed representative features upon DC maturation: enhanced expression of CD80, CD83 and CD86, and both MHC class I and II molecules, decreased endocytic capacity of DC, increased expression of CD205, and decreased expression of CD206. However, interestingly, WEHE could not induce the production of TNF- , and IL-12p40, whereas lipopolysaccharide substantially increased the production of both cytokines. Collectively, these results suggest that H. erinaceum induces the maturation of human DC, which might reinforce the host innate immune system. Copyright © 2009 John Wiley & Sons, Ltd. [source] Induction of dendritic cell migration upon Toxoplasma gondii infection potentiates parasite disseminationCELLULAR MICROBIOLOGY, Issue 10 2006Henrik Lambert Summary The processes leading to systemic dissemination of the obligate intracellular parasite Toxoplasma gondii remain unelucidated. In vitro studies on human and murine dendritic cells (DC) revealed that active invasion of DC by Toxoplasma induces a state of hypermotility in DC, enabling transmigration of infected DC across endothelial cell monolayers in the absence of chemotactic stimuli. Infected DC exhibited upregulation of maturation markers and co-stimulatory molecules. While modulation of cell adhesion molecules CD11/CD18 was similar for Toxoplasma -infected DC and lipopolysaccharide (LPS)-matured DC, Toxoplasma -infected DC did not exhibit upregulation of CD54/ICAM-1. Induction of host cell migration in vitro required live intracellular parasite(s) and was inhibited by uncoupling the Gi -protein signalling pathway with pertussis toxin, but did not depend on CCR5, CCR7 or Toll/interleukin-1 receptor signalling. When migration of Toxoplasma -infected DC was compared with migration of LPS-stimulated DC in vivo, similar or higher numbers of Toxoplasma -infected DC reached the mesenteric lymph nodes and spleen respectively. Adoptive transfer of Toxoplasma -infected DC resulted in more rapid dissemination of parasites to distant organs and in exacerbation of infection compared with inoculation with free parasites. Altogether, these findings show that Toxoplasma is able to subvert the regulation of host cell motility and likely exploits the host's natural pathways of cellular migration for parasite dissemination. [source] Inhaled allergen-driven CD1c up-regulation and enhanced antigen uptake by activated human respiratory-tract dendritic cells in atopic asthmaCLINICAL & EXPERIMENTAL ALLERGY, Issue 1 2007N. E. McCarthy Summary Background Dendritic cells (DC) mediate inflammation in rodent models of allergic airway disease, but the role played by human respiratory-tract DC (hRTDC) in atopic asthma remains poorly defined. Recent data suggest that CD1 antigen presentation by hRTDC may contribute to asthma pathogenesis. Objective To investigate the influence of hRTDC on the balance between atopy and allergic asthma in human subjects and to determine whether CD1 expression by hRTDC is modulated during asthmatic inflammation. Methods Sputum cells were induced from steroid-naïve, allergen-challenged and allergen-naïve subjects (atopic asthmatics, atopic non-asthmatics and non-atopic controls). hRTDC were identified using monoclonal antibody labelling and analysis by flow cytometry. Results hRTDC stained HLA-DR+ (negative for markers of other cell lineages) were predominantly myeloid and comprised ,0.5% of viable sputum cells. Sputum cells were potent stimulators of allogeneic CD4+ naïve T cells and enrichment/depletion experiments correlated stimulatory potency with DC numbers. Sputum contained cells that exhibited typical dendritic morphology when analysed by electron microscopy. Myeloid hRTDC were endocytically active, but uptake of FITC-dextran was enhanced in cells from asthmatics (P<0.001). Despite their increased endocytic capacity, asthmatic myeloid hRTDC appeared mature and expressed increased levels of maturation markers (P<0.05,P<0.001), CD1c, CD1d and langerin (P<0.05). CD1c expression by asthmatic myeloid hRTDC was enhanced upon in vivo allergen challenge (three to ninefold within 24 h; P<0.05). CD11c,CD123high hRTDC were only detected in asthmatic sputum and were increased in number following allergen challenge. Conclusion Despite limited cell numbers, it proved possible to analyse human RTDC in induced sputum, providing evidence that increased antigen uptake and enhanced CD1 presentation by activated hRTDC may contribute to allergic airway disease. CD1 presentation by hRTDC in atopic asthma may therefore constitute a novel target for future intervention strategies. [source] | |||||||||||||