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Myeloid Dendritic Cells (myeloid + dendritic_cell)
Selected AbstractsDevelopmental biology of the dendritic cell systemACTA PAEDIATRICA, Issue 2002KR Schibler Aim: To determine whether an imbalance of dendritic cell subsets might contribute to diminished adaptive host responses observed in newborn infants. It was hypothesized that the proportion of lymphoid dendritic cells would be greater than that of myeloid dendritic cells in cord blood. Methods: To investigate this, dendritic cell subsets were evaluated in whole cord blood by flow cytometry. Circulating dendritic cells were also isolated from cord blood based on CD1c and BDCA-2 expression. Myeloid dendritic cells were also obtained by culturing cord and adult blood monocytes. Surface phenotypes of these cells were determined by flow cytometry using monoclonal antibodies directed against lineage, major histocompatibility, adhesion, co-stimulation and cytokine receptor molecules. Antigen-presenting functions of dendritic cell subsets were determined by mixed leukocyte reactions. Results: Circulating myeloid dendritic cells were higher in cord blood than previously reported in adult blood, whereas lymphoid dendritic cell numbers were similar between cord and adult blood. Expression of CD11c, CD45RA and CD45RO did not accurately differentiate between dendritic cell subsets circulating in cord blood. Fresh and culture-derived cord blood myeloid dendritic cells stimulated adult allogeneic leukocyte proliferation, while lymphoid dendritic cells were less effective inducers of an adult allogeneic leukocyte response. Culture-derived dendritic cells induced modest autologous cord blood leukocyte proliferation, but freshly isolated myeloid and lymphoid dendritic cells did not stimulated autologous leukocytes. Conclusion: Contrary to the hypothesis, an imbalance in the ratio of circulating myeloid to lymphoid dendritic cell subsets does not exist and, therefore, does not contribute to diminished adaptive immune responses in newborn infants. [source] Favorable effect of adefovir on the number and functionality of myeloid dendritic cells of patients with chronic HBV,HEPATOLOGY, Issue 4 2006Renate G. van der Molen In patients with chronic hepatitis B virus (HBV), 2 predominant precursor dendritic cell (DC) subtypes, the myeloid dendritic cell (mDC) and the plasmacytoid dendritic cell (pDC), were recently found to be functionally impaired. HBV DNA was found to be present in the DC subtypes, but no viral replication could be detected. The question remains whether simply the presence of the virus and viral proteins causes this dysfunction of DCs. To address this issue, the effect of viral load reduction resulting from treatment with the nucleotide analogue adefovir dipivoxil on the number and functionality of circulating DCs was studied during 6 months of treatment. Treatment resulted in a mean 5 log10 decrease in the viral load and normalization of alanine aminotransferase within 3 months. The number of mDCs, but not of pDCs, increased significantly over 6 months of treatment to a level comparable to that of uninfected healthy controls. The allostimulatory capacity of isolated and in vitro matured mDCs increased significantly after 3 months of treatment. Accordingly, mDCs exhibited an increased capacity to produce tumor necrosis factor alpha and interleukin-12 after 3-6 months of treatment. There was no change in interferon alpha production by pDCs during treatment. In conclusion, adefovir treatment results in an improvement in the number and functionality of mDCs, but not of pDCs. Our findings provide clues for the reasons why current antiviral therapy does not lead to consistently sustained viral eradication. (HEPATOLOGY 2006;44:907,914.) [source] Ratio of myeloid and plasmacytoid dendritic cells and TH2 skew in CRS with nasal polypsALLERGY, Issue 1 2010H. Kirsche Abstract Background:, The role of myeloid and plasmacytoid dendritic cells and its consequences for the TH2 skew in chronic rhinosinusitis (CRS) with nasal polyps (CRSNP+) should be detailed. Methods:, In 18 CRS patients without nasal polyps (CRSNP,), 35 CRSNP+ patients and 22 patients with nasal structural abnormalities without rhinosinusitis (controls), dendritic cells (DC) were differentiated into myeloid (mDC) and plasmacytoid (pDC) subtypes using an antibody cocktail including CD1c (BDCA-1) and CD303 (BDCA-2) in peripheral blood mononuclear cells (PBMC) and single cell preparations of sinonasal mucosa by flow cytometry. Moreover, cells were analysed for expression of CD45, CD3, CD4, CXCR3 (TH1) and CCR4 (TH2) and IFN-,, IL-5, TGF-,1, TGF-,2, ECP and total IgE in nasal secretions were determined. As a possible confounder, Staphylococcus aureus in nasal lavages was detected. Results:, The tissue mDC/pDC-ratio was 1.7 (1.0,2.4) in controls, 3.0 (1.8,4.0) in CRSNP, and 0.8 (0.6,1.0) in CRSNP+ (P < 0.01). In tissue samples, the TH1/TH2 ratio was 12.6 (6.4,16.0) in controls, 12.5 (6.9,21.2) in CRSNP, and 1.8 (1.3,3.6) in CRSNP+ (median and interquartile range, P < 0.001). Less pronounced differences were found in PBMC. S. aureus detection rates or TGF-, levels did not differ between patient groups and S. aureus detection had no influence on the parameters investigated. Conclusion:, A significant TH2 skew in CRSNP+ could be confirmed on the cellular level. It was driven by low myeloid dendritic cell numbers. The TH2 skew did not correlate with S. aureus detection. The data support the concept that CRSNP+ and CRSNP, are pathophysiologically distinct. [source] Cytologic features and frequency of plasmacytoid dendritic cells in the lymph nodes of patients with histiocytic necrotizing lymphadenitis (Kikuchi-Fujimoto disease)DIAGNOSTIC CYTOPATHOLOGY, Issue 7 2010I.A.C., Koji Kishimoto C.T., Ph.D. Abstract Histiocytic necrotizing lymphadenitis (HNL), also known as Kikuchi-Fujimoto disease, is a benign and self-limiting disease. It is histologically characterized by nodal lesions that show the infiltration of histiocytes, lymphoid cells, myeloid dendritic cells (mDCs), and plasmacytoid dendritic cells (pDCs), along with either apoptotic or karyorrhexic nuclear debris. pDCs have been proposed to be lymphoid early-committed immature DCs which are positive for CD123, CD303, CD68, and HLA-DR but negative for fascin, a mature DC marker, as well as CD13 and CD33,which are mDC markers. In the present study, we analyzed the cytomorphologic features and frequency of pDCs in the lymph nodes of HNL patients. Because the cytologic apprearance of pDCs with Papanicolau staining was quite similar to that of large lymphocytes, immunocytochemistry against CD123 was necessary for the distinction of pDCs. Counting the number of CD123-positive pDCs in the HNL lymph nodes revealed that pDCs more frequently infiltrated the lymph nodes in the setting of HNL than in either reactive lymphadenitis or T and B cell lymphoma. In addition, interestingly, the numberof pDCs did not depend on the age of the HNL lesion, thus suggesting that pDCs are excellent indicators for the cytologic diagnosis of HNL. Diagn. Cytopathol. 2010. © 2009 Wiley-Liss, Inc. [source] B7-H1 up-regulation impairs myeloid DC and correlates with disease progression in chronic HIV-1 infectionEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 11 2008Xicheng Wang Abstract Impaired myeloid dendritic cells (mDC) fail to elicit host antiviral immune responses, leading to disease progression in HIV-1 infection. However, mechanisms underlying mDC suppression remain elusive. In this study, we found that the T-cell co-stimulatory molecule programmed death-1 ligand-1 (B7-H1) is significantly up-regulated on peripheral mDC in HIV-1-infected typical progressors and AIDS patients, but is maintained at a relatively low level in long-term non-progressors. Successful immune reconstitution after highly active antiretroviral therapy, indicated by full suppression of HIV-1 replication and substantial increases of CD4 T-cell counts, correlated with a decrease in B7-H1 expression. Importantly, we also found that X4 HIV-1 isolates directly induced B7-H1 expression on mDC in vitro, while adding antiviral agents hampered this B7-H1 up-regulation. Blockade of B7-H1 in vitro strongly enhanced mDC-mediated allostimulatory capacity and IL-12 production. In contrast, B7-H1 ligation with soluble programmed death-1 (PD-1) reduced mDC maturation and IL-12 production but increased mDC apoptosis and IL-10 production. Thus, B7-H1 up-regulation may inhibit mDC-mediated immune response, thereby facilitating viral persistence and disease progression in HIV-1-infected patients. This study provides new evidence that B7-H1 inhibitory signaling may reversely mediate functional impairment of mDC in HIV-1 infection, which further supports the notion that B7-H1 blockade represents a novel therapeutic approach to this disease. [source] DiC14-amidine cationic liposomes stimulate myeloid dendritic cells through Toll-like receptor 4EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 5 2008Tetsuya Tanaka Abstract DiC14-amidine cationic liposomes were recently shown to promote Th1 responses when mixed with allergen. To further define the mode of action of diC14-amidine as potential vaccine adjuvant, we characterized its effects on mouse and human myeloid dendritic cells (DC). First, we observed that, as compared with two other cationic liposomes, only diC14-amidine liposomes induced the production of IL-12p40 and TNF-, by mouse bone marrow-derived DC. DiC14-amidine liposomes also activated human DC, as shown by synthesis of IL-12p40 and TNF-,, accumulation of IL-6, IFN-, and CXCL10 mRNA, and up-regulation of membrane expression of CD80 and CD86. DC stimulation by diC14-amidine liposomes was associated with activation of NF-,B, ERK1/2, JNK and p38 MAP kinases. Finally, we demonstrated in mouse and human cells that diC14-amidine liposomes use Toll-like receptor 4 to elicit both MyD88-dependent and Toll/IL-1R-containing adaptor inducing interferon IFN-, (TRIF)-dependent responses. Supporting Information for this article is available at www.wiley-vch.de/contents/jc_2040/2008/37998_s.pdf [source] CpG ODN enhance antigen-specific NKT cell activation via plasmacytoid dendritic cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 8 2005Anja Marschner Abstract Human V,24+ V,11+ natural killer T cells (NKT cells) are "natural memory" T cells that detect glycolipid antigens such as ,-galactosylceramide (,-GalCer) presented on CD1d. In the present study we found that highly purified V,24+ NKT cells lack TLR9 mRNA, and thus are not sensitive towards stimulation with CpG oligodeoxynucleotides (ODN). Within PBMC, however, CpG ODN synergistically activated NKT cells stimulated with their cognate antigen ,-GalCer. Depletion of plasmacytoid dendritic cells (PDC) or myeloid dendritic cells (MDC) revealed that both DC subsets were necessary for the synergistic activation of NKT cells by ,-GalCer and CpG ODN. While PDC were responsible for the stimulation of NKT cells with CpG ODN, MDC but not PDC presented ,-GalCer via CD1d. Partial activation of NKT cells was mediated by PDC-derived IFN-,, whereas full activation of NKT cells as indicated by IFN,, production required cell-to-cell contact of PDC and NKT cells in addition to IFN-,; OX40 was involved in this interaction. We conclude that CpG-activated PDC enhance ,-GalCer-specific NKT cell activation, and bias activated NKT cells towards a Th1 phenotype. Our results lead to a novel concept of PDC function: to regulate effector activity of antigen-stimulated T cells in a cell contact-dependent manner without the need of simultaneous presentation of the cognate T cell antigen. [source] Favorable effect of adefovir on the number and functionality of myeloid dendritic cells of patients with chronic HBV,HEPATOLOGY, Issue 4 2006Renate G. van der Molen In patients with chronic hepatitis B virus (HBV), 2 predominant precursor dendritic cell (DC) subtypes, the myeloid dendritic cell (mDC) and the plasmacytoid dendritic cell (pDC), were recently found to be functionally impaired. HBV DNA was found to be present in the DC subtypes, but no viral replication could be detected. The question remains whether simply the presence of the virus and viral proteins causes this dysfunction of DCs. To address this issue, the effect of viral load reduction resulting from treatment with the nucleotide analogue adefovir dipivoxil on the number and functionality of circulating DCs was studied during 6 months of treatment. Treatment resulted in a mean 5 log10 decrease in the viral load and normalization of alanine aminotransferase within 3 months. The number of mDCs, but not of pDCs, increased significantly over 6 months of treatment to a level comparable to that of uninfected healthy controls. The allostimulatory capacity of isolated and in vitro matured mDCs increased significantly after 3 months of treatment. Accordingly, mDCs exhibited an increased capacity to produce tumor necrosis factor alpha and interleukin-12 after 3-6 months of treatment. There was no change in interferon alpha production by pDCs during treatment. In conclusion, adefovir treatment results in an improvement in the number and functionality of mDCs, but not of pDCs. Our findings provide clues for the reasons why current antiviral therapy does not lead to consistently sustained viral eradication. (HEPATOLOGY 2006;44:907,914.) [source] THIS ARTICLE HAS BEEN RETRACTED STEALTH matters: a novel paradigm of durable primate allograft toleranceIMMUNOLOGICAL REVIEWS, Issue 1 2001J. M. Thomas Summary: We review a novel strategy for tolerance induction developed in rhesus macaques and termed STEALTH. We summarize the evolution of the STEALTH model, the results of successful trials in inducing long-term, stable transplant tolerance in rhesus kidney and diabetic islet recipients and discuss information related to the mechanism by which durable tolerance is induced. STEALTH tolerance is induced by a 3-day treatment course of CD3, immunotoxin (IT) combined with a 14-day treatment with deoxyspergualin (DSG). IT causes profound depletion of sessile lymph node T cells as well as the more accessible circulating T cells. DSG, an inhibitor of HSC 70-mediated NF-,B nuclear translocation, arrests maturation of myeloid dendritic cells, blocks production of proinflammatory cytokines induced by IT administration, and promotes systemic production of Th2 type cytokines that persist indefinitely. Such Th2 cytokine deviation has not been reported in NHP transplant recipients. These studies provide proof of principle in a preclinical model that prevention of both acute and chronic allograft rejection, for at least 2.2,4.9 years of follow-up, can be achieved in NHP in the absence of chronic immunosuppressive drugs or other interventions. This strategy for inducing NHP tolerance is discussed in relation to current tolerance paradigms. [source] Impact of class A, B and C CpG-oligodeoxynucleotides on in vitro activation of innate immune cells in human immunodeficiency virus-1 infected individualsIMMUNOLOGY, Issue 4 2007Jeffrey A. Martinson Summary Oligodeoxynucleotides (ODN) with unmethylated deoxycytidyl-deoxyguanosine dinucleotides (CpG-ODNs) stimulate Toll-like receptor 9 (TLR9) in plasmacytoid dendritic cells (pDC) and B cells and activate innate and adaptive immunity. Three classes of synthetic CpG-ODNs, class A, B and C, activate cells through TLR9; our goal was to evaluate their effect on cells from human immunodeficiency virus (HIV)-1+ individuals. We compared the frequencies and the unstimulated activation status of immune effector cells in HIV-1+ and HIV-1, individuals. Fewer pDC, myeloid dendritic cells (mDC), B cells, natural killer (NK) cells and invariant natural killer T cells (iNKT) were present in HIV-1+ peripheral blood mononuclear cells (PBMC) and their baseline activation status was higher than HIV-1, PBMC. Exposure of HIV-1+ PBMC to all classes of CpG-ODNs led to activation and maturation of pDC based on CD86, CD80, and CD83 expression similar to that of cells from HIV-1, individuals. The percentage of CpG-ODN stimulated pDC that express CD40 was dramatically higher when cells were obtained from HIV-1+ than from HIV-1, individuals. B-lymphocytes were activated similarly in HIV-1+ and HIV-1, individuals. mDC, NK and iNKT cell, which lack TLR9, were indirectly activated. Interferon-, (IFN-,) and interferon inducible protein 10 (IP-10) secretion was induced by class A or C but not class B CpG-ODN, but the concentrations were less than those produced by HIV-1, PBMC. HIV-1 infected individuals have fewer innate effector cells that are chronically activated, but these cells can be further activated by CpG-ODN, which suggests that synthetic CpG-ODNs could be used to enhance the immune system in HIV-1 infected individuals. [source] Prostaglandin E2 is a negative regulator on human plasmacytoid dendritic cellsIMMUNOLOGY, Issue 1 2006Yonsu Son Summary Prostaglandin E2 (PGE2), a major lipid derived from the metabolism of arachidonic acid, is an environmentally bioactive substance produced by inflammatory processes and acts as a cAMP up-regulator that plays an important role in immune responses. It has been reported that PGE2 has the ability to inhibit the production of interleukin-12 by myeloid dendritic cells (MDCs) and macrophages, and then induce preferential T helper type 2 (Th2) cell responses. However, little is known of the function of PGE2 for plasmacytoid dendritic cells (PDCs), which may contribute to the innate and adaptive immune response to viral infection, allergy and autoimmune diseases. In the present study, we compared the biological effect of PGE2 on human PDCs and MDCs. PGE2 caused the death of PDCs but MDCs survived. Furthermore, we found that, whereas PGE2 inhibited interferon-, production by PDCs in response to virus or cytosine,phosphate,guanosine, it inhibited interelukin-12 production by MDCs in response to lipopolysaccharide (LPS) or poly(I:C). Although both virus-stimulated PDCs and LPS-stimulated MDCs preferentially induced the development of interferon-,-producing Th1 cells, pretreatment with PGE2 led both DC subsets to attenuate their Th1-inducing capacity. These findings suggest that PGE2 represents a negative regulator on not only MDCs but also PDCs. [source] Paradoxical effects of interleukin-10 on the maturation of murine myeloid dendritic cellsIMMUNOLOGY, Issue 2 2003Dianne L. Commeren Summary The immunoregulatory cytokine, interleukin-10 (IL-10), has been shown to inhibit the maturation of human myeloid dendritic cells (DC). In the present study, we demonstrate that IL-10 has paradoxical effects on the maturation of murine myeloid bone marrow-derived DC. On the one hand, IL-10 inhibits the maturation of murine myeloid DC. The addition of IL-10 to granulocyte,macrophage colony-stimulating factor (GM-CSF)-supported murine BM-derived DC cultures reduced the frequency of major histocompatibility complex (MHC) class IIbright cells. These IL-10-pretreated DC have a reduced capacity to stimulate T cells in an allogeneic mixed leucocyte reaction. On the other hand, however, and in contrast to the effects of IL-10 on human DC, we found that the addition of IL-10 from the initiation of the culture onwards induced an up-regulation of the expression of the costimulatory molecules CD40, CD80 and CD86 on murine myeloid DC, as compared to DC generated with GM-CSF only. Moreover, a subpopulation of IL-10-pretreated MHC class IIdim DC lacked the capacity to take up dextran-fluorescein isothiocyanate (FITC), a feature of DC maturation. Taken together, our data demonstrate that the generation of murine myeloid DC in the presence of IL-10 results in a population of incompletely matured MHC class IIdim CD80+ CD86+ DC. These DC lack T-cell stimulatory capacity, suggesting a role for IL-10 in conferring tolerogenic properties on murine myeloid DC. [source] Characterization of colonic and mesenteric lymph node dendritic cell subpopulations in a murine adoptive transfer model of inflammatory bowel diseaseINFLAMMATORY BOWEL DISEASES, Issue 6 2004John Karlis BScHons Abstract Ulcerative colitis and Crohn's disease, collectively termed inflammatory bowel diseases (IBD), are chronic inflammatory diseases of the intestine that afflict more than 4 million people worldwide. Intestinal inflammation is characterized by an abnormal mucosal immune response to normally harmless antigens in the gut flora. In Crohn's disease, the pathogenic mucosal immune response is a typical T helper (TH1) type cell response, whereas ulcerative colitis is predominantly associated with a TH2 response. We are interested in the role of dendritic cells in early immunologic events leading to T cell activation and chronic intestinal inflammation. Using a murine adoptive transfer model of IBD, we found an accumulation of dendritic cells in colon and mesenteric lymph nodes during the early stage of IBD before the appearance of epithelial lesions and tissue degradation. In situ immunostaining and flow-cytometric analysis revealed that approximately 50% of colonic dendritic cells were CD11b+ B220, myeloid dendritic cells and 50% expressed the CD11b, B220+ plasmacytoid phenotype. In corresponding mesenteric lymph nodes, approximately 16% were plasmacytoid dendritic cells. Colonic myeloid dendritic cells were shown to express the co-stimulatory molecule CD40. Both, colonic myeloid and plasmacytoid dendritic cells released interferon-, in situ and stimulated T cell proliferation ex vivo. Our results show that dendritic cells can mature in the intestine without migrating to mesenteric lymph nodes. Mature intestinal dendritic cells may form a nucleation site for a local T cell response and play an important role in the pathogenesis of IBD. [source] Additive Inhibition of Dendritic Cell Allostimulatory Capacity by Alcohol and Hepatitis C Is Not Restored by DC Maturation and Involves Abnormal IL-10 and IL-2 InductionALCOHOLISM, Issue 6 2003Angela Dolganiuc Background: Excessive alcohol use results in impaired immunity, and it is associated with increased incidence and progression of chronic hepatitis C virus (HCV) infection. Here we investigated the effects of HCV infection and alcohol on myeloid dendritic cells (DC) that are critical in antiviral immunity. Methods: Immature and mature DCs were generated from monocytes of chronic HCV infected patients (HCV-DC) and controls (N-DC) with IL-4 plus granulocyte-macrophage colony stimulating factor (GM-CSF) in the presence or absence of alcohol (25 mM). DC allostimulatory capacity was tested in mixed lymphocyte reaction (MLR) and cytokine production by ELISA. Results: Allostimulatory capacity of HCV-DCs was reduced compared to N-DCs and it was further inhibited by alcohol treatment (p < 0.01). MLR was also decreased with alcohol-treated N-DCs. DC phenotypic markers and apoptosis were comparable between HCV-DCs and N-DCs irrespective of alcohol treatment. However, HCV-DCs and alcohol-treated N-DCs exhibited elevated IL-10 and reduced IL-12 production. Reduced MLR with HCV-DCs and its further inhibition by alcohol coexisted with decreasing IL-2 levels (p < 0.017). DC maturation partially improved but failed to fully restore the reduced allostimulatory function of either alcohol-treated or alcohol-naïve HCV-DCs (p < 0.018). Conclusions: Alcohol and HCV independently and together inhibit DC allostimulatory capacity, increase IL-10, reduce IL-12 and IL-2 production that cannot be normalized by DC maturation. HCV and alcohol interact to modulate innate and adaptive immune responses via dendritic cells. [source] Characterization of human liver dendritic cells in liver grafts and perfusatesLIVER TRANSPLANTATION, Issue 3 2006Brenda M. Bosma It is generally accepted that donor myeloid dendritic cells (MDC) are the main instigators of acute rejection after organ transplantation. The aim of the present study was to characterize MDC in human donor livers using liver grafts and perfusates as a source. Perfusates were collected during ex vivo vascular perfusion of liver grafts pretransplantation. MDC, visualized in wedge biopsies by immunohistochemistry with anti-BDCA-1 monoclonal antibody (mAb), were predominantly observed in the portal fields. Liver MDC, isolated from liver wedge biopsies, had an immature phenotype with a low expression of CD80 and CD83. Perfusates were collected from 20 grafts; perfusate mononuclear cells (MNC) contained 1.5% (range, 0.3-6.6%) MDC with a viability of 97 ± 2%. Perfusates were a rich source of hepatic MDC since 0.9 × 106 (range, 0.11-4.5 × 106) MDC detached from donor livers during vascular perfusion pretransplantation. Perfusate MDC were used to further characterize hepatic MDC. Perfusate MDC expressed less DC-LAMP (P = 0.000), CD80 (P = 0.000), CD86 (P = 0.003), and CCR7 (P = 0.014) than mature hepatic lymph node (LN) MDC, and similar CD86 (P = 0.140) and CCR7 (P = 0.262) as and more DC-LAMP (P = 0.007) and CD80 (P = 0.002) than immature blood MDC. Perfusate MDC differed from blood MDC in producing significantly higher amounts of interleukin (IL)-10 in response to lipopolysaccharide (LPS), and in being able to stimulate allogeneic T-cell proliferation. In conclusion, human donor livers contain exclusively immature MDC that detach in high numbers from the liver graft during pretransplantation perfusion. These viable MDC have the capacity to stimulate allogeneic T-cells, and thus may represent a major player in the induction of acute rejection. Liver Transpl 12: 384,393, 2006. © 2006 AASLD. [source] Candida albicans cell surface superoxide dismutases degrade host-derived reactive oxygen species to escape innate immune surveillanceMOLECULAR MICROBIOLOGY, Issue 1 2009Ingrid E. Frohner Summary Mammalian innate immune cells produce reactive oxygen species (ROS) in the oxidative burst reaction to destroy invading microbial pathogens. Using quantitative real-time ROS assays, we show here that both yeast and filamentous forms of the opportunistic human fungal pathogen Candida albicans trigger ROS production in primary innate immune cells such as macrophages and dendritic cells. Through a reverse genetic approach, we demonstrate that coculture of macrophages or myeloid dendritic cells with C. albicans cells lacking the superoxide dismutase (SOD) Sod5 leads to massive extracellular ROS accumulation in vitro. ROS accumulation was further increased in coculture with fungal cells devoid of both Sod4 and Sod5. Survival experiments show that C. albicans mutants lacking Sod5 and Sod4 exhibit a severe loss of viability in the presence of macrophages in vitro. The reduced viability of sod5,/, and sod4,/,sod5,/, mutants relative to wild type is not evident with macrophages from gp91phox,/, mice defective in the oxidative burst activity, demonstrating a ROS-dependent killing activity of macrophages targeting fungal pathogens. These data show a physiological role for cell surface SODs in detoxifying ROS, and suggest a mechanism whereby C. albicans, and perhaps many other microbial pathogens, can evade host immune surveillance in vivo. [source] Lower levels of plasmacytoid dendritic cells in peripheral blood are associated with a diagnosis of asthma 6 yr after severe respiratory syncytial virus bronchiolitisPEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 5 2009Eli Silver Plasmacytoid dendritic cells (pDC) play a crucial role in antiviral immunity and promoting Th1 polarization, possibly protecting against development of allergic disease. Examination of the relationship between peripheral blood plasmacytoid DC levels and manifestations of asthma and atopy early in life. We have isolated peripheral blood mononuclear cells (PBMC) from 73 children (mean age ± SD: 6.6 ± 0.5 yr old) participating in the RSV Bronchiolitis in Early Life (RBEL) study. Flow cytometry was performed on PBMC detecting DC surface-markers: Blood Dendritic Cell Antigens (BDCA) 1, 3, and 2 which identify myeloid type 1, type 2, and plasmacytoid cells, respectively. Total serum IgE, peripheral eosinophil count, and allergy skin tests were documented. About 45% (n = 33) of study participants had physician-diagnosed asthma by 6 yr of age. These children had significantly lower quantities (mean ± SD) of plasmacytoid DC than their non-asthmatic counterparts (1020 ± 921 vs. 1952 ± 1170 cells per 106 PBMC, p = 0.003). We found significantly lower numbers of myeloid dendritic cells in children with asthma (3836 ± 2472 cells per 106 PBMC) compared with those without asthma (4768 ± 2224 cells per 106 PBMC, p = 0.02); however, this divergence was not significant after adjusting for covariates of age, gender, race, skin test reactivity, smoke exposure, and daycare attendance. We did not identify any direct association between DC levels and markers of atopy: skin test reactivity, peripheral eosinophilia, and IgE level. Children who are diagnosed with asthma after severe RSV bronchiolitis appear to have a relative deficiency of plasmacytoid DC in peripheral blood. [source] A new inducible adenoviral expression system that responds to inflammatory stimuli in vivoTHE JOURNAL OF GENE MEDICINE, Issue 12 2006Gang Cai Abstract Background Gene transfer using inducible promoters, which control expression of transgenic proteins in response to physiological conditions, may have significant advantages. In this study, we tried to achieve an inducible adenoviral expression system for physiologically responsive gene therapy of autoimmune or inflammatory diseases. Methods A luciferase reporter vector with a hybrid promoter containing the human IL-1, enhancer region (,3690 to , 2720) and the human CIITA promoter IV (,399 to + 2) was constructed. A replication-deficient adenovirus was engineered with luciferase controlled by the IL1,/CIITApIV promoter (Ad-IL1,/CIITApIV-Luc). The reporter vector or adenovirus was transfected to C57Bl/6 myeloid dendritic cells (DCs), RAW264.7, and Hep G2 to study the in vitro characteristics of this hybrid promoter. An inflammation model was prepared by injecting lipopolysaccharide (LPS) into Balb/c mice intraperitoneally (i.p.), and infected with Ad-IL1,/CIITApIV-Luc or Ad-CMV-Luc to study the in vivo characteristics of the IL1,/CIITApIV promoter. Results The IL1,/CIITApIV hybrid promoter has pronounced promoter activity, broad-range responsiveness to cytokines or LPS, and can be rechallenged after first induction. In the inflammation model, IL1,/CIITApIV could drive hepatic luciferase expression increasedly rapidly after LPS challenge and in a LPS dose-dependent manner. Conclusions Using the IL1,/CIITApIV hybrid promoter in gene transfer vectors may make it possible to produce transgenic proteins in vivo in direct relationship with the intensity and duration of an individual's status. By providing endogenously controlled production of transgenic proteins, this approach might limit the severity of autoimmune or inflammatory response without interfering with the beneficial components of host defense and immunity. Copyright © 2006 John Wiley & Sons, Ltd. [source] Porcine Antigen Presenting Cells Produce Soluble Adjuvants That Stimulate B cells Within and Across the SpeciesAMERICAN JOURNAL OF TRANSPLANTATION, Issue 4 2003Nada Kanaan Interactions between porcine antigen presenting cells (pAPCs) and host lymphocytes may be important in cellular and humoral rejection of porcine organ xenografts. To investigate the role of pAPCs in the activation of xenogeneic lymphocytes, porcine bone marrow cells were stimulated using porcine GM-CSF with or without porcine IL-4 to generate populations of pAPCs that had phenotypic characteristics of myeloid dendritic cells. These bone marrow-derived pAPCs were weak stimulators of xenogeneic (mouse and human) T cells in vitro but induced primary B-cell proliferation and augmented CD40-induced B-cell proliferation. Inoculation of mice with small numbers of pAPCs resulted in localized expansion of lymph node B cells. The mitogenic effect on xenogeneic B cells could be reproduced by medium in which pAPCs had been cultured, implicating one or more soluble products. In blocking experiments IL-12, IL-6, and IL-10 were found not to contribute to the mitogenic effect of pAPC medium. In contrast, pIFN was found to be capable of augmenting CD40-induced proliferation of xenogeneic B-cell proliferation but did not act as a B-cell mitogen. We conclude that myeloid APCs from the pig produce soluble factors that are capable of acting as primary mitogens for xenogeneic B cells as well as augmenting additional B-cell activating stimuli. This direct interaction between porcine APCs and xenogeneic B cells may serve as an important adjuvant for the stimulation of humoral immunity to porcine xenografts. [source] Contribution of myeloid dendritic cells to type I interferon,induced cytokines and chemokines: Comment on the article by Bilgic et alARTHRITIS & RHEUMATISM, Issue 7 2010Mohan S. Maddur DVM No abstract is available for this article. [source] Mediation of nonerosive arthritis in a mouse model of lupus by interferon-,,stimulated monocyte differentiation that is nonpermissive of osteoclastogenesisARTHRITIS & RHEUMATISM, Issue 4 2010Kofi A. Mensah Objective In contrast to rheumatoid arthritis (RA), the joint inflammation referred to as Jaccoud's arthritis that occurs in systemic lupus erythematosus (SLE) is nonerosive. Although the mechanism responsible is unknown, the antiosteoclastogenic cytokine interferon-, (IFN,), whose transcriptome is present in SLE monocytes, may be responsible. This study was undertaken to examine the effects of IFN, and lupus on osteoclasts and erosion in the (NZB × NZW)F1 mouse model of SLE with K/BxN serum,induced arthritis. Methods Systemic IFN, levels in (NZB × NZW)F1 mice were elevated by administration of AdIFN,. SLE disease was marked by anti,double-stranded DNA (anti-dsDNA) antibody titer and proteinuria, and Ifi202 and Mx1 expression represented the IFN, transcriptome. Microfocal computed tomography was used to evaluate bone erosions. Flow cytometry for CD11b and CD11c was used to evaluate the frequency of circulating osteoclast precursors (OCPs) and myeloid dendritic cells (DCs) in blood. Results Administration of AdIFN, to (NZB × NZW)F1 mice induced osteopetrosis. (NZB × NZW)F1 mice without autoimmune disease were fully susceptible to focal erosions in the setting of serum-induced arthritis. However, (NZB × NZW)F1 mice with high anti-dsDNA antibody titers and the IFN, transcriptome were protected against bone erosions. AdIFN, pretreatment of NZW mice before K/BxN serum administration also resulted in protection against bone erosion (r2 = 0.4720, P < 0.01), which was associated with a decrease in the frequency of circulating CD11b+CD11c, OCPs and a concomitant increase in the percentage of CD11b+CD11c+ cells (r2 = 0.6330, P < 0.05), which are phenotypic of myeloid DCs. Conclusion These findings suggest that IFN, in SLE shifts monocyte development toward myeloid DCs at the expense of osteoclastogenesis, thereby resulting in decreased bone erosion. [source] Amphoteric liposomes enable systemic antigen-presenting cell,directed delivery of CD40 antisense and are therapeutically effective in experimental arthritisARTHRITIS & RHEUMATISM, Issue 4 2009Evangelos Andreakos Objective Mediation of RNA interference by oligonucleotides constitutes a powerful approach for the silencing of genes involved in the pathogenesis of inflammatory disease, but in vivo application of this technique requires effective delivery to immune cells and/or sites of inflammation. The aim of the present study was to develop a new carrier system to mediate systemic administration of oligonucleotides to rheumatoid arthritis (RA) joints, and to develop an antisense oligonucleotide (ASO),based approach to interfere with CD40,CD154 interactions in an experimental model of RA. Methods A novel liposomal carrier with amphoteric properties, termed Nov038, was developed and assessed for its ability to systemically deliver an ASO directed against CD40 (CD40-ASO). Male DBA/1 mice with collagen-induced arthritis were treated with Nov038-encapsulated CD40-ASO, and the effects of treatment on various parameters of disease activity, including clinical score, paw swelling, lymph node responses, and inflammatory cytokine production in the joints, were assessed. Results Nov038 was well tolerated, devoid of immune-stimulatory effects, and efficacious in mediating systemic oligonucleotide delivery to sites of inflammation. In mice with collagen-induced arthritis, Nov038 enabled the therapeutic administration of CD40-ASO and improved established disease, while unassisted CD40-ASO was ineffective, and anti,tumor necrosis factor , (anti-TNF,) treatment was less effective in this model. Nov038/CD40-ASO efficacy was attributed to its tropism for monocyte/macrophages and myeloid dendritic cells (DCs), resulting in rapid down-regulation of CD40, inhibition of DC antigen presentation, and reduction in collagen-specific T cell responses, as well as decreased levels of TNF,, interleukin-6 (IL-6), and IL-17 in arthritic joints. Conclusion Amphoteric liposomes represent a novel carrier concept for systemic and antigen-presenting cell,targeted oligonucleotide delivery with clinical applicability and numerous potential applications, including target validation in vivo and inflammatory disease therapeutics. Moreover, Nov038/CD40-ASO constitutes a potent alternative to monoclonal antibody,based approaches for interfering with CD40,CD40L interactions. [source] Tissue targeting of anti-RNP autoimmunity: Effects of T cells and myeloid dendritic cells in a murine modelARTHRITIS & RHEUMATISM, Issue 2 2009Eric L. Greidinger Objective To explore the role of immune cells in anti-RNP autoimmunity in a murine model of pneumonitis or glomerulonephritis, using adoptive transfer techniques. Methods Donor mice were immunized with 50 ,g of U1,70-kd small nuclear RNP fusion protein and 50 ,g of U1 RNA adjuvant. Whole splenocytes as well as CD4+ cell and dendritic cell (DC) subsets from the immunized mice were infused into naive syngeneic recipients. Anti-RNP and T cell responses were assessed by immunoblotting, enzyme-linked immunosorbent assay, and flow cytometry. Development of renal or lung disease was assessed by histology and urinalysis. Results Unfractionated splenocytes from donor mice without proteinuria induced predominantly lung disease in recipients (8 [57%] of 14 versus 2 [14%] of 14 developing renal disease; P = 0.046). However, infusion of CD4+ cells from donors without proteinuria induced renal disease more frequently than lung disease (7 [70%] of 10 versus 2 [20%] of 10; P = 0.01); adoptive transfer of RNP+CD4+ T cells from short-term culture yielded similar results (renal disease in 8 [73%] of 11 recipients versus lung disease in 3 [27%] of 11). Cotransfer of splenic myeloid DCs and CD4+ T cells from immunized donors prevented induction of renal disease in all 5 recipients (P = 0.026 versus recipients of fresh CD4+ cells alone), although lung disease was still observed in 1 of 5 mice. Transfer of myeloid DCs alone from immunized donors induced lung disease in 3 (60%) of 5 recipients, without evidence of nephritis. Cotransfer of splenocytes from mice with and those without nephritis led to renal disease in 4 of 5 recipients, without evidence of lung disease. Conclusion These findings indicate that RNP+CD4+ T cells are sufficient to induce anti-RNP autoimmunity, tissue targeting in anti-RNP autoimmunity can be deviated to either a renal or pulmonary phenotype depending on the presence of accessory cells such as myeloid DCs, and DC subsets can play a role in both propagation of autoimmunity and end-organ targeting. [source] Developmental biology of the dendritic cell systemACTA PAEDIATRICA, Issue 2002KR Schibler Aim: To determine whether an imbalance of dendritic cell subsets might contribute to diminished adaptive host responses observed in newborn infants. It was hypothesized that the proportion of lymphoid dendritic cells would be greater than that of myeloid dendritic cells in cord blood. Methods: To investigate this, dendritic cell subsets were evaluated in whole cord blood by flow cytometry. Circulating dendritic cells were also isolated from cord blood based on CD1c and BDCA-2 expression. Myeloid dendritic cells were also obtained by culturing cord and adult blood monocytes. Surface phenotypes of these cells were determined by flow cytometry using monoclonal antibodies directed against lineage, major histocompatibility, adhesion, co-stimulation and cytokine receptor molecules. Antigen-presenting functions of dendritic cell subsets were determined by mixed leukocyte reactions. Results: Circulating myeloid dendritic cells were higher in cord blood than previously reported in adult blood, whereas lymphoid dendritic cell numbers were similar between cord and adult blood. Expression of CD11c, CD45RA and CD45RO did not accurately differentiate between dendritic cell subsets circulating in cord blood. Fresh and culture-derived cord blood myeloid dendritic cells stimulated adult allogeneic leukocyte proliferation, while lymphoid dendritic cells were less effective inducers of an adult allogeneic leukocyte response. Culture-derived dendritic cells induced modest autologous cord blood leukocyte proliferation, but freshly isolated myeloid and lymphoid dendritic cells did not stimulated autologous leukocytes. Conclusion: Contrary to the hypothesis, an imbalance in the ratio of circulating myeloid to lymphoid dendritic cell subsets does not exist and, therefore, does not contribute to diminished adaptive immune responses in newborn infants. [source] | |||||||||||||||||||||||||