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Sample records for dendritic cells activated

  1. Immune activation: death, danger and dendritic cells.

    PubMed

    Pulendran, Bali

    2004-01-06

    Dendritic cells are critical for host immunity, and sense microbes with pathogen recognition receptors. New evidence indicates that these cells also sense uric acid crystals in dead cells, suggesting that the immune system is conscious not only of pathogens, but also of death and danger.

  2. Mannoproteins from Cryptococcus neoformans promote dendritic cell maturation and activation.

    PubMed

    Pietrella, Donatella; Corbucci, Cristina; Perito, Stefano; Bistoni, Giovanni; Vecchiarelli, Anna

    2005-02-01

    Our previous data show that mannoproteins (MPs) from Cryptococcus neoformans are able to induce protective responses against both C. neoformans and Candida albicans. Here we provide evidence that MPs foster maturation and activation of human dendritic cells (DCs). Maturation was evaluated by the ability of MPs to facilitate expression of costimulatory molecules such as CD40, CD86, CD83, and major histocompatibility complex classes I and II and to inhibit receptors such as CD14, CD16, and CD32. Activation of DCs was measured by the capacity of MPs to promote interleukin-12 and tumor necrosis factor alpha secretion. DC-induced maturation and interleukin-12 induction are largely mediated by engagement of mannose receptors and presume MP internalization and degradation. DC activation leads to IkappaBalpha phosphorylation, which is necessary for nuclear factor kappaB transmigration into the nucleus. MP-loaded DCs are efficient stimulators of T cells and show a remarkable capacity to promote CD4 and CD8 proliferation. In conclusion, we have evidenced a novel regulatory role of MPs that promotes their candidacy as a vaccine against fungi.

  3. Mannoproteins from Cryptococcus neoformans Promote Dendritic Cell Maturation and Activation

    PubMed Central

    Pietrella, Donatella; Corbucci, Cristina; Perito, Stefano; Bistoni, Giovanni; Vecchiarelli, Anna

    2005-01-01

    Our previous data show that mannoproteins (MPs) from Cryptococcus neoformans are able to induce protective responses against both C. neoformans and Candida albicans. Here we provide evidence that MPs foster maturation and activation of human dendritic cells (DCs). Maturation was evaluated by the ability of MPs to facilitate expression of costimulatory molecules such as CD40, CD86, CD83, and major histocompatibility complex classes I and II and to inhibit receptors such as CD14, CD16, and CD32. Activation of DCs was measured by the capacity of MPs to promote interleukin-12 and tumor necrosis factor alpha secretion. DC-induced maturation and interleukin-12 induction are largely mediated by engagement of mannose receptors and presume MP internalization and degradation. DC activation leads to IκBα phosphorylation, which is necessary for nuclear factor κB transmigration into the nucleus. MP-loaded DCs are efficient stimulators of T cells and show a remarkable capacity to promote CD4 and CD8 proliferation. In conclusion, we have evidenced a novel regulatory role of MPs that promotes their candidacy as a vaccine against fungi. PMID:15664921

  4. Rotavirus activates dendritic cells derived from umbilical cord blood monocytes.

    PubMed

    Rosales-Martinez, D; Gutierrez-Xicotencatl, L; Badillo-Godinez, O; Lopez-Guerrero, D; Santana-Calderon, A; Cortez-Gomez, R; Ramirez-Pliego, O; Esquivel-Guadarrama, F

    2016-10-01

    Rotavirus is the most common cause of acute infectious diarrhea in human neonates and infants. However, the studies aimed at dissecting the anti-virus immune response have been mainly performed in adults. Dendritic cells (DCs) play a crucial role in innate and acquired immune responses. Therefore, it is very important to determine the response of neonatal and infant DCs to rotavirus and to compare it to the response of adult DCs. Thus, we determined the response of monocyte-derived DCs from umbilical cord blood (UCB) and adult peripheral blood (PB) to rotavirus in vitro. It was found that the rotavirus and its genome, composed of segmented doubled stranded RNA (dsRNA), induced the activation of neonatal DCs, as these cells up-regulated the levels of CD40, CD86, MHC II, TLR-3 and TLR-4, the production of cytokines IL-6, IL-12/23p40, IL-10, TGF-β (but not of IL-12p70), and the message for TNF-α and IFN-β. This activation enabled the neonatal DCs to induce a strong proliferation of allogeneic CD4(+) T cells and the production of IFN-γ. Moreover, neonatal DCs could be infected by rotavirus and sustain its replication. Neonatal DCs had a similar response as adult DCs towards rotavirus and its genome. However, adult DCs had a biased pro-inflammatory response compared to neonatal DCs, which showed a biased regulatory profile, as they produced higher levels of IL-10 and TGF-β, and were less efficient in inducing a Th1 type response. So it can be concluded that rotavirus and its genome can induce the activation of neonatal DCs in spite of their tolerogenic bias.

  5. An Engineered Herpesvirus Activates Dendritic Cells and Induces Protective Immunity

    PubMed Central

    Ma, Yijie; Chen, Min; Jin, Huali; Prabhakar, Bellur S.; Valyi-Nagy, Tibor; He, Bin

    2017-01-01

    Herpes simplex viruses (HSV) are human pathogens that switch between lytic and latent infection. While attenuated HSV is explored for vaccine, the underlying event remains poorly defined. Here we report that recombinant HSV-1 with a mutation in the γ134.5 protein, a virulence factor, stimulates dendritic cell (DC) maturation which is dependent on TANK-binding kinase 1 (TBK1). When exposed to CD11+ DCs, the mutant virus that lacks the amino terminus of γ134.5 undergoes temporal replication without production of infectious virus. Mechanistically, this leads to sequential phosphorylation of interferon regulatory factor 3 (IRF3) and p65/RelA. In correlation, DCs up-regulate the expression of co-stimulatory molecules and cytokines. However, selective inhibition of TBK1 precludes phosphorylation of IRF3 and subsequent DC activation by the γ134.5 mutant. Herein, the γ134.5 mutant is immune-stimulatory and non-destructive to DCs. Remarkably, upon immunization the γ134.5 mutant induces protection against lethal challenge by the wild type virus, indicative of its vaccine potential. Furthermore, CD11+ DCs primed by the γ134.5 mutant in vivo mediate protection upon adoptive transfer. These results suggest that activation of TBK1 by engineered HSV is crucial for DC maturation, which may contribute to protective immunity. PMID:28150813

  6. Haemophilus ducreyi partially activates human myeloid dendritic cells.

    PubMed

    Banks, Keith E; Humphreys, Tricia L; Li, Wei; Katz, Barry P; Wilkes, David S; Spinola, Stanley M

    2007-12-01

    Dendritic cells (DC) orchestrate innate and adaptive immune responses to bacteria. How Haemophilus ducreyi, which causes genital ulcers and regional lymphadenitis, interacts with DC is unknown. H. ducreyi evades uptake by polymorphonuclear leukocyte and macrophage-like cell lines by secreting LspA1 and LspA2. Many H. ducreyi strains express cytolethal distending toxin (CDT), and recombinant CDT causes apoptosis of DC in vitro. Here, we examined interactions between DC and H. ducreyi 35000HP, which produces LspA1, LspA2, and CDT. In human volunteers infected with 35000HP, the ratio of myeloid DC to plasmacytoid DC was 2.8:1 in lesions, compared to a ratio of 1:1 in peripheral blood. Using myeloid DC derived from monocytes as surrogates for lesional DC, we found that DC infected with 35000HP remained as viable as uninfected DC for up to 48 h. Gentamicin protection and confocal microscopy assays demonstrated that DC ingested and killed 35000HP, but killing was incomplete at 48 h. The expression of LspA1 and LspA2 did not inhibit the uptake of H. ducreyi, despite inactivating Src kinases. Infection of DC with live 35000HP caused less cell surface marker activation than infection with heat-killed 35000HP and lipopolysaccharide (LPS) and inhibited maturation by LPS. However, infection of DC with live bacteria caused the secretion of significantly higher levels of interleukin-6 and tumor necrosis factor alpha than infection with heat-killed bacteria and LPS. The survival of H. ducreyi in DC may provide a mechanism by which the organism traffics to lymph nodes. Partial activation of DC may abrogate the establishment of a full Th1 response and an environment that promotes phagocytosis.

  7. Adipose Recruitment and Activation of Plasmacytoid Dendritic Cells Fuel Metaflammation.

    PubMed

    Ghosh, Amrit Raj; Bhattacharya, Roopkatha; Bhattacharya, Shamik; Nargis, Titli; Rahaman, Oindrila; Duttagupta, Pritam; Raychaudhuri, Deblina; Liu, Chinky Shiu Chen; Roy, Shounak; Ghosh, Parasar; Khanna, Shashi; Chaudhuri, Tamonas; Tantia, Om; Haak, Stefan; Bandyopadhyay, Santu; Mukhopadhyay, Satinath; Chakrabarti, Partha; Ganguly, Dipyaman

    2016-11-01

    In obese individuals, visceral adipose tissue (VAT) is the seat of chronic low-grade inflammation (metaflammation), but the mechanistic link between increased adiposity and metaflammation largely remains unclear. In obese individuals, deregulation of a specific adipokine, chemerin, contributes to innate initiation of metaflammation by recruiting circulating plasmacytoid dendritic cells (pDCs) into VAT through chemokine-like receptor 1 (CMKLR1). Adipose tissue-derived high-mobility group B1 (HMGB1) protein activates Toll-like receptor 9 (TLR9) in the adipose-recruited pDCs by transporting extracellular DNA through receptor for advanced glycation end products (RAGE) and induces production of type I interferons (IFNs). Type I IFNs in turn help in proinflammatory polarization of adipose-resident macrophages. IFN signature gene expression in VAT correlates with both adipose tissue and systemic insulin resistance (IR) in obese individuals, which is represented by ADIPO-IR and HOMA2-IR, respectively, and defines two subgroups with different susceptibility to IR. Thus, this study reveals a pathway that drives adipose tissue inflammation and consequent IR in obesity.

  8. Controlling T-Cell Activation with Synthetic Dendritic Cells Using the Multivalency Effect

    PubMed Central

    2017-01-01

    Artificial antigen-presenting cells (aAPCs) have recently gained a lot of attention. They efficiently activate T cells and serve as powerful replacements for dendritic cells in cancer immunotherapy. Focusing on a specific class of polymer-based aAPCs, so-called synthetic dendritic cells (sDCs), we have investigated the importance of multivalent binding on T-cell activation. Using antibody-functionalized sDCs, we have tested the influence of polymer length and antibody density. Increasing the multivalent character of the antibody-functionalized polymer lowered the effective concentration required for T-cell activation. This was evidenced for both early and late stages of activation. The most important effect observed was the significantly prolonged activation of the stimulated T cells, indicating that multivalent sDCs sustain T-cell signaling. Our results highlight the importance of multivalency for the design of aAPCs and will ultimately allow for better mimics of natural dendritic cells that can be used as vaccines in cancer treatment. PMID:28393131

  9. Constitutive activation of neuronal Src causes aberrant dendritic morphogenesis in mouse cerebellar Purkinje cells.

    PubMed

    Kotani, Takenori; Morone, Nobuhiro; Yuasa, Shigeki; Nada, Shigeyuki; Okada, Masato

    2007-02-01

    Src family tyrosine kinases are essential for neural development, but their in vivo functions remain elusive because of functional compensation among family members. To elucidate the roles of individual Src family members in vivo, we generated transgenic mice expressing the neuronal form of c-Src (n-Src), Fyn, and their constitutively active forms in cerebellar Purkinje cells using the L7 promoter. The expression of the constitutively active n-Src retarded the postnatal development of Purkinje cells and disrupted dendritic morphogenesis, whereas the wild-type n-Src had only moderate effects. Neither wild-type nor constitutively active Fyn over-expression significantly affected Purkinje-cell morphology. The aberrant Purkinje cells in n-Src transgenic mice retained multiple dendritic shafts extending in non-polarized directions and were located heterotopically in the molecular layer. Ultrastructural observation of the dendritic shafts revealed that the microtubules of n-Src transgenic mice were more densely and irregularly arranged, and had structural deformities. In primary culture, Purkinje cells from n-Src transgenic mice developed abnormally thick dendritic shafts and large growth-cone-like structures with poorly extended dendrites, which could be rescued by treatment with a selective inhibitor of Src family kinases, PP2. These results suggest that n-Src activity regulates the dendritic morphogenesis of Purkinje cells through affecting microtubule organization.

  10. Activation of antitumor cytotoxic T lymphocytes by fusions of human dendritic cells and breast carcinoma cells

    PubMed Central

    Gong, Jianlin; Avigan, David; Chen, Dongshu; Wu, Zekui; Koido, Shigeo; Kashiwaba, Masahiro; Kufe, Donald

    2000-01-01

    We have reported that fusions of murine dendritic cells (DCs) and murine carcinoma cells reverse unresponsiveness to tumor-associated antigens and induce the rejection of established metastases. In the present study, fusions were generated with primary human breast carcinoma cells and autologous DCs. Fusion cells coexpressed tumor-associated antigens and DC-derived costimulatory molecules. The fusion cells also retained the functional potency of DCs and stimulated autologous T cell proliferation. Significantly, the results show that autologous T cells are primed by the fusion cells to induce MHC class I-dependent lysis of autologous breast tumor cells. These findings demonstrate that fusions of human breast cancer cells and DCs activate T cell responses against autologous tumors. PMID:10688917

  11. Human Liver Stem Cells Suppress T-Cell Proliferation, NK Activity, and Dendritic Cell Differentiation

    PubMed Central

    Bruno, Stefania; Grange, Cristina; Tapparo, Marta; Pasquino, Chiara; Romagnoli, Renato; Dametto, Ennia; Amoroso, Antonio; Tetta, Ciro; Camussi, Giovanni

    2016-01-01

    Human liver stem cells (HLSCs) are a mesenchymal stromal cell-like population resident in the adult liver. Preclinical studies indicate that HLSCs could be a good candidate for cell therapy. The aim of the present study was to evaluate the immunogenicity and the immunomodulatory properties of HLSCs on T-lymphocytes, natural killer cells (NKs), and dendritic cells (DCs) in allogeneic experimental settings. We found that HLSCs inhibited T-cell proliferation by a mechanism independent of cell contact and dependent on the release of prostaglandin E2 (PGE2) and on indoleamine 2,3-dioxygenase activity. When compared with mesenchymal stromal cells (MSCs), HLSCs were more efficient in inhibiting T-cell proliferation. At variance with MSCs, HLSCs did not elicit NK degranulation. Moreover, HLSCs inhibited NK degranulation against K562, a NK-sensitive target, by a mechanism dependent on HLA-G release. When tested on DC generation from monocytes, HLSCs were found to impair DC differentiation and DCs ability to induce T-cell proliferation through PGE2. This study shows that HLSCs have immunomodulatory properties similar to MSCs, but, at variance with MSCs, they do not elicit a NK response. PMID:27127520

  12. Active Dendrites and Differential Distribution of Calcium Channels Enable Functional Compartmentalization of Golgi Cells

    PubMed Central

    Rudolph, Stephanie; Hull, Court

    2015-01-01

    Interneurons are essential to controlling excitability, timing, and synaptic integration in neuronal networks. Golgi cells (GoCs) serve these roles at the input layer of the cerebellar cortex by releasing GABA to inhibit granule cells (grcs). GoCs are excited by mossy fibers (MFs) and grcs and provide feedforward and feedback inhibition to grcs. Here we investigate two important aspects of GoC physiology: the properties of GoC dendrites and the role of calcium signaling in regulating GoC spontaneous activity. Although GoC dendrites are extensive, previous studies concluded they are devoid of voltage-gated ion channels. Hence, the current view holds that somatic voltage signals decay passively within GoC dendrites, and grc synapses onto distal dendrites are not amplified and are therefore ineffective at firing GoCs because of strong passive attenuation. Using whole-cell recording and calcium imaging in rat slices, we find that dendritic voltage-gated sodium channels allow somatic action potentials to activate voltage-gated calcium channels (VGCCs) along the entire dendritic length, with R-type and T-type VGCCs preferentially located distally. We show that R- and T-type VGCCs located in the dendrites can boost distal synaptic inputs and promote burst firing. Active dendrites are thus critical to the regulation of GoC activity, and consequently, to the processing of input to the cerebellar cortex. In contrast, we find that N-type channels are preferentially located near the soma, and control the frequency and pattern of spontaneous firing through their close association with calcium-activated potassium (KCa) channels. Thus, VGCC types are differentially distributed and serve specialized functions within GoCs. SIGNIFICANCE STATEMENT Interneurons are essential to neural processing because they modulate excitability, timing, and synaptic integration within circuits. At the input layer of the cerebellar cortex, a single type of interneuron, the Golgi cell (GoC), carries

  13. In vivo blockade of neural activity alters dendritic development of neonatal CA1 pyramidal cells.

    PubMed

    Groc, Laurent; Petanjek, Zdravko; Gustafsson, Bengt; Ben-Ari, Yehezkel; Hanse, Eric; Khazipov, Roustem

    2002-11-01

    During development, neural activity has been proposed to promote neuronal growth. During the first postnatal week, the hippocampus is characterized by an oscillating neural network activity and a rapid neuronal growth. In the present study we tested in vivo, by injecting tetanus toxin into the hippocampus of P1 rats, whether this neural activity indeed promotes growth of pyramidal cells. We have previously shown that tetanus toxin injection leads to a strong reduction in the frequency of spontaneous GABA and glutamatergic synaptic currents, and to a complete blockade of the early neural network activity during the first postnatal week. Morphology of neurobiotin-filled CA1 pyramidal cells was analyzed at the end of the first postnatal week (P6-10). In activity-reduced neurons, the total length of basal dendritic tree was three times less than control. The number, but not the length, of basal dendritic branches was affected. The growth impairment was restricted to the basal dendrites. The apical dendrite, the axons, or the soma grew normally during activity deprivation. Thus, the in vivo neural activity in the neonate hippocampus seems to promote neuronal growth by initiating novel branches.

  14. Comparative analysis of signature genes in PRRSV-infected porcine monocyte-derived dendritic cells at differential activation statuses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Activation statuses of monocytic cells including monocytes, macrophages and dendritic cells (DCs) are critically important for antiviral immunity. In particular, some devastating viruses, including porcine reproductive and respiratory syndrome virus (PRRSV), are capable of directly infecting these c...

  15. Efficient Killing of High Risk Neuroblastoma Using Natural Killer Cells Activated by Plasmacytoid Dendritic Cells

    PubMed Central

    Cordeau, Martine; Belounis, Assila; Lelaidier, Martin; Cordeiro, Paulo; Sartelet, Hervé; Duval, Michel

    2016-01-01

    High-risk neuroblastoma (NB) remains a major therapeutic challenge despite the recent advent of disialoganglioside (GD2)-antibody treatment combined with interleukin (IL)-2 and granulocyte monocyte-colony stimulating factor (GM-CSF). Indeed, more than one third of the patients still die from this disease. Here, we developed a novel approach to improve the current anti-GD2 immunotherapy based on NK cell stimulation using toll-like receptor (TLR)-activated plasmacytoid dendritic cells (pDCs). We demonstrated that this strategy led to the efficient killing of NB cells. When the expression of GD2 was heterogeneous on NB cells, the combination of pDC-mediated NK-cell activation and anti-GD2 treatment significantly increased the cytotoxicity of NK cells against NB cells. Activation by pDCs led to a unique NK-cell phenotype characterized by increased surface expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), with increased expression of CD69 on CD56dim cytotoxic cells, and strong interferon-γ production. Additionally, NB-cell killing was mediated by the TRAIL death-receptor pathway, as well as by the release of cytolytic granules via the DNAX accessory molecule 1 pathway. NK-cell activation and lytic activity against NB was independent of cell contact, depended upon type I IFN produced by TLR-9-activated pDCs, but was not reproduced by IFN-α stimulation alone. Collectively, these results highlighted the therapeutic potential of activated pDCs for patients with high-risk NB. PMID:27716850

  16. T lymphocytes and dendritic cells are activated by the deletion of peroxiredoxin II (Prx II) gene.

    PubMed

    Moon, Eun-Yi; Noh, Young-Wook; Han, Ying-Hao; Kim, Sun-Uk; Kim, Jin-Man; Yu, Dae-Yeul; Lim, Jong-Seok

    2006-02-15

    Peroxiredoxin II (Prx II) is a member of antioxidant enzyme family and it plays a protective role against oxidative damage. Constitutive production of endogenous reactive oxygen species was detected in spleen and bone marrow cells lacking Prx II. Here, we investigated the role of Prx II in immune responses. The total number of splenocytes (especially, the population of S-phase cells and CD3(+) T cells) was significantly higher in Prx II(-/-) mice than in wild type. Number of peripheral blood mononuclear cells (PBMCs) in Prx II(-/-) mice was also higher than wild type. Differentiation of Prx II(-/-) mouse bone marrow cells into CD11c-positive dendritic cells was greater than that of wild type. Transplantation of Prx II(-/-) bone marrow cells into wild type mice increased PBMCs in blood and bone marrow-derived dendritic cells. Prx II deletion enhances concanavalin A (ConA)-induced splenocyte proliferation and mixed lymphocyte reaction (MLR) activity of bone marrow-derived CD11c-positive dendritic cells to stimulate recipient splenocytes. Collectively, these data suggest that Prx II inhibits the immune cell responsiveness, which may be regulated by scavenging the low amount of reactive oxygen species (ROS).

  17. IL-32γ induces chemotaxis of activated T cells via dendritic cell-derived CCL5.

    PubMed

    Son, Mi Hye; Jung, Mi Young; Choi, Seulah; Cho, Daeho; Kim, Tae Sung

    2014-07-18

    Interleukin (IL)-32 has been associated with a variety of inflammatory diseases including rheumatoid arthritis, vasculitis and Crohn's disease. We have previously reported that IL-32γ, the IL-32 isoform with the highest biological activity, could act as an immune modulator through regulation of dendritic cell (DC) functions in immune responses. Cell locomotion is crucial for induction of an effective immune response. In this study, we investigated the effect and underlying mechanisms of IL-32γ on recruitment of T cells. IL-32γ upregulated the expression of several chemokines including CCL2, CCL4, and CCL5 in the DCs. In particular, IL-32γ significantly increased CCL5 expression in a dose-dependent manner. Treatment with JNK and NF-κB inhibitors suppressed IL-32γ-induced CCL5 expression in DCs, indicating that IL-32γ induced CCL5 production through the JNK and NF-κB pathways. Furthermore, supernatants from IL-32γ-treated DCs showed chemotactic activities controlling migration of activated CD4(+) and CD8(+) T cells, and these activities were suppressed by addition of neutralizing anti-CCL5 antibody. These results show that IL-32γ effectively promotes migration of activated T cells via CCL5 production in DCs. The chemotactic potential of IL-32γ may explain the pro-inflammatory effects of IL-32 and the pathologic role of IL-32 in immune disorders such as rheumatoid arthritis.

  18. Targeting dendritic cells to accelerate T-cell activation overcomes a bottleneck in tuberculosis vaccine efficacy

    PubMed Central

    Griffiths, Kristin L.; Ahmed, Mushtaq; Das, Shibali; Gopal, Radha; Horne, William; Connell, Terry D.; Moynihan, Kelly D.; Kolls, Jay K.; Irvine, Darrell J.; Artyomov, Maxim N.; Rangel-Moreno, Javier; Khader, Shabaana A.

    2016-01-01

    The development of a tuberculosis (TB) vaccine that induces sterilizing immunity to Mycobacterium tuberculosis infection has been elusive. Absence of sterilizing immunity induced by TB vaccines may be due to delayed activation of mucosal dendritic cells (DCs), and subsequent delay in antigen presentation and activation of vaccine-induced CD4+ T-cell responses. Here we show that pulmonary delivery of activated M. tuberculosis antigen-primed DCs into vaccinated mice, at the time of M. tuberculosis exposure, can overcome the delay in accumulation of vaccine-induced CD4+ T-cell responses. In addition, activating endogenous host CD103+ DCs and the CD40–CD40L pathway can similarly induce rapid accumulation of vaccine-induced lung CD4+ T-cell responses and limit early M. tuberculosis growth. Thus, our study provides proof of concept that targeting mucosal DCs can accelerate vaccine-induced T-cell responses on M. tuberculosis infection, and provide insights to overcome bottlenecks in TB vaccine efficacy. PMID:28004802

  19. Leptin deficiency in vivo enhances the ability of splenic dendritic cells to activate T cells

    PubMed Central

    Ramirez, Oscar

    2014-01-01

    Leptin is a pleiotropic adipokine that is critical for regulating food intake and energy expenditure and also participates in functions of the immune system, including those of antigen-presenting cells. Here, we assess the effect of leptin deficiency on the function splenic dendritic cells (sDC). sDC from leptin-deficient mice (Lepob) were evaluated ex vivo for phenotype, ability to respond to inflammatory stimuli, to acquire and process antigens and to activate T cells. The data show that Lepob sDC express activation markers similar to controls and respond similarly to LPS activation or anti-CD40 cross-linking. In addition, antigen acquisition and processing by Lepob sDC was similar to controls. However, Lepob sDC elicited higher production of IFN-γ in mixed lymphocyte reactions and increased production of IL-2 by antigen-specific T-cell hybridoma relative to controls. To assess Lepob sDC activation of T cells in vivo, Lepob and control mice were infected systemically with Mycobacterium avium. Lepob mice were significantly better at neutralizing the infection as measured by splenic bacterial load over time. This was mirrored with an increased percentage of activated T cells in M. avium-infected Lepob mice. Thus, although no changes were detected in sDC phenotype, activation, antigen processing or presentation, these DC surprisingly presented an enhanced ability to activate T cells ex vivo and in vivo. These data demonstrate that leptin can modulate DC function and suggest that leptin may dampen T-cell responsiveness in the physiological setting. PMID:24966213

  20. Assessment of genetic markers and glioblastoma stem-like cells in activation of dendritic cells.

    PubMed

    Yurtsever, Aysel; Haydaroglu, Ayfer; Biray Avci, Cigir; Gunduz, Cumhur; Oktar, Nezih; Dalbasti, Tayfun; Caglar, Hasan Onur; Attar, Rukset; Kitapcioglu, Gul

    2013-09-01

    Glioblastoma (GBM) is the most common and aggressive intraparenchymal primary brain tumor in adults. The principal reasons for the poor outcomes of GBM are the high rates of recurrence and resistance to chemotherapy. The aim of this study was to determine the role of tailored cellular therapy for GBM with a poor prognosis and compare the activity of dendritic cells (DCs) that have encountered GBM cells. Detecting the correlations between methylation and expression of MGMT and PTEN genes and GBM cancer stem cells (CSCs) markers after co-cultures with a mononuclear cell cocktail are also aims for this study. Allogenic umbilical cord blood (UCB)-derived DCs were labeled with the CD11a and CD123 for immature DCs, and CD80 and CD11c for mature DCs. CD34, CD45, and CD56 cells were isolated from allogenic UCB for using in DCs maturation. GBM CSCs were detected with CD133/1 and CD111 antibodies after co-culture studies. DC activation was carried out via GBM cells including CD133 and CD111 cells and a mononuclear cells cocktail including CD34, CD45, and CD56 natural killer cells. Real-time PCR was performed to detect the expression and promoter methylation status of PTEN and MGMT genes. The expression of CSCs markers was found in all GBM cases, and a statistically significant correlation was found among them after co-culture studies. The most pronounced affinity of DCs to GBM cells was observed at dilutions between 1/4 and 1/256 in co-cultures. There was a statistically significant correlation between cellularity and granularity ratios for CD123 and CD11c. PTEN and MGMT gene expression and methylation values were evaluated with respect to CSCs expression and no statistical significance was found. Activation of DCs might associate with CSCs and the mononuclear cells cocktail including CD34, CD45, and CD56 cells which were obtained from allogenic UCB.

  1. Isolation of dendritic cells from umbilical cord blood using magnetic activated cell sorting or adherence.

    PubMed

    Bie, Yachun; Xu, Qiuxiang; Zhang, Zhenyu

    2015-07-01

    Dendritic cells (DCs) are a highly specialized type of antigen-presenting cell. The present study describes and compares two methods for preparing DCs from umbilical cord blood. The first method involves the isolation of DCs by magnetic activated cell sorting (MACS). This technique isolates CD34(+) cells from cord blood and induces the formation of DCs by the addition of cytokines, granulocyte macrophage colony-stimulating factor and interleukin-4. The second method involves the generation of large numbers of DCs from cord blood using an adherent method, which isolates umbilical cord blood mononuclear cells and induces DCs in the same conditions as those used in MACS. The DCs were harvested following 7 days of incubation and observed with an inverted microscope. The phenotype of the cells was then analyzed by flow cytometry. The results revealed that, subsequent to 7 days of incubation, the differentiated DCs obtained using the adherent method were more mature than those isolated using MACS. However, these cells were unable to be maintained in culture for more than 9-10 days. By contrast, the DCs derived from CD34(+) cells by MACS were phenotypically stable and could be maintained for up to 3 weeks in culture. Either method produced DCs from cord blood. However, the DCs isolated using the MACS method demonstrated higher homogeneity, yield and viability than those obtained using the adherent method. Due to the various compositions of the monocyte subsets isolated, isolation methods affect the phenotypes and functions of the resultant DCs.

  2. Cross-dressed dendritic cells drive memory CD8+ T-cell activation after viral infection.

    PubMed

    Wakim, Linda M; Bevan, Michael J

    2011-03-31

    After an infection, cytotoxic T lymphocyte precursors proliferate and become effector cells by recognizing foreign peptides in the groove of major histocompatibility complex (MHC) class I molecules expressed by antigen-presenting cells (APCs). Professional APCs specialized for T-cell activation acquire viral antigen either by becoming infected themselves (direct presentation) or by phagocytosis of infected cells, followed by transfer of antigen to the cytosol, processing and MHC class I loading in a process referred to as cross-presentation. An alternative way, referred to as 'cross-dressing', by which an uninfected APC could present antigen was postulated to be by the transfer of preformed peptide-MHC complexes from the surface of an infected cell to the APC without the need of further processing. Here we show that this mechanism exists and boosts the antiviral response of mouse memory CD8(+) T cells. A number of publications have demonstrated sharing of peptide-loaded MHC molecules in vitro. Our in vitro experiments demonstrate that cross-dressing APCs do not acquire peptide-MHC complexes in the form of exosomes released by donor cells. Rather, the APCs and donor cells have to contact each other for the transfer to occur. After a viral infection, we could isolate cross-dressed APCs able to present viral antigen in vitro. Furthermore, using the diphtheria toxin system to selectively eliminate APCs that could only acquire viral peptide-MHC complexes by cross-dressing, we show that such presentation can promote the expansion of resting memory T cells. Notably, naive T cells were excluded from taking part in the response. Cross-dressing is a mechanism of antigen presentation used by dendritic cells that may have a significant role in activating previously primed CD8(+) T cells.

  3. Cytotoxic activity of interferon alpha induced dendritic cells as a biomarker of glioblastoma

    NASA Astrophysics Data System (ADS)

    Mishinov, S. V.; Stupak, V. V.; Tyrinova, T. V.; Leplina, O. Yu.; Ostanin, A. A.; Chernykh, E. R.

    2016-08-01

    Dendritic cells (DCs) are the most potent antigen presenting cells that can play direct role in anti-tumor immune response as killer cells. DC tumoricidal activity can be stimulated greatly by type I IFN (IFNα and IFNβ). In the present study, we examined cytostatic and cytotoxic activity of monocyte-derived IFNα-induced DCs generated from patients with brain glioma and evaluated the potential use of these parameters in diagnostics of high-grade gliomas. Herein, we demonstrated that patient DCs do not possess the ability to inhibit the growth of tumor HEp-2 cell line but low-grade and high-grade glioma patients do not differ significantly in DC cytostatic activity. However, glioma patient DCs are characterized by reduced cytotoxic activity against HEp-2 cells. The impairment of DC cytotoxic function is observed mainly in glioblastoma patients. The cytotoxic activity of DCs against HEp-2 cells below 9% is an informative marker for glioblastomas.

  4. Impaired NK Cell Activation and Chemotaxis toward Dendritic Cells Exposed to Complement-Opsonized HIV-1.

    PubMed

    Ellegård, Rada; Crisci, Elisa; Andersson, Jonas; Shankar, Esaki M; Nyström, Sofia; Hinkula, Jorma; Larsson, Marie

    2015-08-15

    Mucosa resident dendritic cells (DCs) may represent one of the first immune cells that HIV-1 encounters during sexual transmission. The virions in body fluids can be opsonized with complement factors because of HIV-mediated triggering of the complement cascade, and this appears to influence numerous aspects of the immune defense targeting the virus. One key attribute of host defense is the ability to attract immune cells to the site of infection. In this study, we investigated whether the opsonization of HIV with complement (C-HIV) or a mixture of complement and Abs (CI-HIV) affected the cytokine and chemokine responses generated by DCs, as well as their ability to attract other immune cells. We found that the expression levels of CXCL8, CXCL10, CCL3, and CCL17 were lowered after exposure to either C-HIV or CI-HIV relative to free HIV (F-HIV). DCs exposed to F-HIV induced higher cell migration, consisting mainly of NK cells, compared with opsonized virus, and the chemotaxis of NK cells was dependent on CCL3 and CXCL10. NK cell exposure to supernatants derived from HIV-exposed DCs showed that F-HIV induced phenotypic activation (e.g., increased levels of TIM3, CD69, and CD25) and effector function (e.g., production of IFNγ and killing of target cells) in NK cells, whereas C-HIV and CI-HIV did not. The impairment of NK cell recruitment by DCs exposed to complement-opsonized HIV and the lack of NK activation may contribute to the failure of innate immune responses to control HIV at the site of initial mucosa infection.

  5. Antitumor efficacy of radiation plus immunotherapy depends upon dendritic cell activation of effector CDS+ T cells

    PubMed Central

    Dovedi, Simon J.; Lipowska-Bhalla, Grazyna; Beers, Stephen A.; Cheadle, Eleanor J.; Mu, Lijun; Glennie, Martin J.

    2017-01-01

    Tumor cells dying after cytotoxic therapy are a potential source of antigen for T-cell priming. Antigen-presenting cells (APCs) can cross-present MHC I–restricted peptides after the uptake of dying cells. Depending on the nature of the surrounding environmental signals, APCs then orchestrate a spectrum of responses ranging from immune activation to inhibition. Previously, we had demonstrated that combining radiation with either agonistic monoclonal antibody (mAb) to CD40 or a systemically administered TLR7 agonist could enhance CD8 T-cell–dependent protection against syngeneic murine lymphoma models. However, it remains unknown how individual APC populations impact on this antitumor immune response. Using APC depletion models, we now show that dendritic cells (DCs), but not macrophages or B cells, were responsible for the generation of long-term immunological protection following combination therapy with radiotherapy and either agonistic CD40 mAb or systemic TLR7 agonist therapy. Novel immunotherapeutic approaches that augment antigen uptake and presentation by DCs may further enhance the generation of therapeutic antitumor immune responses, leading to improved outcomes after radiotherapy. PMID:27241845

  6. Brugia malayi infective larvae fail to activate Langerhans cells and dermal dendritic cells in human skin.

    PubMed

    Cotton, R N; McDonald-Fleming, R; Boyd, A; Spates, K; Nutman, T B; Tolouei Semnani, R

    2015-02-01

    Filarial infection in humans is initiated when a mosquito deposits third-stage parasite larvae (L3) in the skin. Langerhans cells (LCs) and dermal dendritic cells (DDCs) are the first cells that the parasite encounters, and L3s must evade these highly effective antigen-presenting cells to establish infection. To assess LC and DDC responses to L3 in human skin, we employed three models of increasing physiologic relevance: in vitro-generated LCs, epidermal blister explants and full-thickness human skin sections. In vitro-generated LCs expressed TLR1-10 and robustly produced IL-6 and TNF-α in response to PolyI:C, but pre-exposure to L3s did not alter inflammatory cytokine production or TLR expression. L3s did not modulate expression of LC markers CDH1, CD207, or CD1a, or the regulatory products TSLP or IDO in epidermal explants or in vitro-generated LC. LC, CD14+ DDC, CD1c+ DC and CD141+ DC from human skin sections were analysed by flow cytometry. While PolyI:C potently induced CCL22 production in LC, CD1c+ DC, and CD141+ DC, and IL-10 production in LC, L3s did not modulate the numbers of or cytokine production by any skin DC subset. L3s broadly failed to activate or modulate LCs or DDCs, suggesting filarial larvae expertly evade APC detection in human skin.

  7. Active immunotherapy for cancer patients using tumor lysate pulsed dendritic cell vaccine: a safety study.

    PubMed

    Ovali, E; Dikmen, T; Sonmez, M; Yilmaz, M; Unal, A; Dalbasti, T; Kuzeyli, K; Erturk, M; Omay, S B

    2007-06-01

    Cancer vaccine therapy represents a promising therapeutical option. Consistently, with these new treatment strategies, the use of dendritic cell vaccines is becoming increasingly widespread and currently in the forefront for cancer treatment. The purpose of this study was to evaluate the feasibility and safety of tumor lysate-pulsed dendritic cell (DC) vaccine in patients with advanced cancers. For this purpose, eighteen patients with relapsed or refractory cancer were vaccinated with peripheral monocyte-derived DCs generated with GM-CSF and IL-4, and pulsed consequently with 100 microg/ml of tumor lysate before maturation in culture in the presence of IL-1beta, PGE2 and TNF alpha for two days. The first two vaccinations were given intradermally every two weeks while further injections were given monthly. Tumor lysate-pulsed dendritic cell injections were well-tolerated in all patients with no more than grade 1 injection-related toxicity. Local inflammatory response was mainly erythematous which subsided in 48 hrs time. No end organ toxicity or autoimmune toxicity was identified. Clinical responses observed in our study were satisfactory for a phase I clinical study. We observed 4 (22%) objective clinical responses. These responses are significantly correlated with delayed type hypersensitivity testing (DTH) (p < 0.01). The results showed that this active immunotherapy is feasible, safe, and may be capable of eliciting immune responses against cancer.

  8. Suppression of Dendritic Cell Activation by Diabetes Autoantigens Linked to the Cholera Toxin B Subunit

    PubMed Central

    Odumosu, Oludare; Payne, Kimberly; Baez, Mavely; Jutzy, Jessica; Wall, Nathan; Langridge, William

    2010-01-01

    Antigen presenting cells, specifically dendritic cells (DCs) are a focal point in the delicate balance between T cell tolerance and immune responses contributing to the onset of type I diabetes (T1D). Weak adjuvant proteins like the cholera toxin B subunit when linked to autoantigens may sufficiently alter the balance of this initial immune response to suppress the development of autoimmunity. To assess adjuvant enhancement of autoantigen mediated immune suppression of Type 1 diabetes, we examined the cholera toxin B subunit (CTB)-proinsulin fusion protein (CTB-INS) activation of immature dendritic cells (iDC) at the earliest detectable stage of the human immune response. In this study, Incubation of human umbilical cord blood monocyte-derived immature DCs with CTB-INS autoantigen fusion protein increased the surface membrane expression of DC toll-like receptor (TLR-2) while no significant upregulation in TLR-4 expression was detected. Inoculation of iDCs with CTB stimulated the biosynthesis of both CD86 and CD83 co-stimulatory factors demonstrating an immunostimulatory role for CTB in both DC activation and maturation. In contrast, incubation of iDCs with proinsulin partially suppressed CD86 co-stimulatory factor mediated DC activation, while incubation of iDCs with CTB-INS fusion protein completely suppressed iDC biosynthesis of both CD86 and CD83 costimulatory factors. The incubation of iDCs with increasing amounts of insulin did not increase the level of immune suppression but rather activated DC maturation by stimulating increased biosynthesis of both CD86 and CD83 costimulatory factors. Inoculation of iDCs with CTB-INS fusion protein dramatically increased secretion of the immunosuppressive cytokine IL-10 and suppressed synthesis of the pro-inflammatory cytokine IL12/23 p40 subunit protein suggesting that linkage of CTB to insulin (INS) may play an important role in mediating DC guidance of cognate naïve Th0 cell development into immunosuppressive T

  9. Brucella β 1,2 Cyclic Glucan Is an Activator of Human and Mouse Dendritic Cells

    PubMed Central

    Martirosyan, Anna; Pérez-Gutierrez, Camino; Banchereau, Romain; Dutartre, Hélène; Lecine, Patrick; Dullaers, Melissa; Mello, Marielle; Pinto Salcedo, Suzana; Muller, Alexandre; Leserman, Lee; Levy, Yves; Zurawski, Gerard; Zurawski, Sandy; Moreno, Edgardo; Moriyón, Ignacio; Klechevsky, Eynav; Banchereau, Jacques; Oh, SangKon; Gorvel, Jean-Pierre

    2012-01-01

    Bacterial cyclic glucans are glucose polymers that concentrate within the periplasm of alpha-proteobacteria. These molecules are necessary to maintain the homeostasis of the cell envelope by contributing to the osmolarity of Gram negative bacteria. Here, we demonstrate that Brucella β 1,2 cyclic glucans are potent activators of human and mouse dendritic cells. Dendritic cells activation by Brucella β 1,2 cyclic glucans requires TLR4, MyD88 and TRIF, but not CD14. The Brucella cyclic glucans showed neither toxicity nor immunogenicity compared to LPS and triggered antigen-specific CD8+ T cell responses in vivo. These cyclic glucans also enhanced antigen-specific CD4+ and CD8+ T cell responses including cross-presentation by different human DC subsets. Brucella β 1,2 cyclic glucans increased the memory CD4+ T cell responses of blood mononuclear cells exposed to recombinant fusion proteins composed of anti-CD40 antibody and antigens from both hepatitis C virus and Mycobacterium tuberculosis. Thus cyclic glucans represent a new class of adjuvants, which might contribute to the development of effective antimicrobial therapies. PMID:23166489

  10. Brucella β 1,2 cyclic glucan is an activator of human and mouse dendritic cells.

    PubMed

    Martirosyan, Anna; Pérez-Gutierrez, Camino; Banchereau, Romain; Dutartre, Hélène; Lecine, Patrick; Dullaers, Melissa; Mello, Marielle; Salcedo, Suzana Pinto; Muller, Alexandre; Leserman, Lee; Levy, Yves; Zurawski, Gerard; Zurawski, Sandy; Moreno, Edgardo; Moriyón, Ignacio; Klechevsky, Eynav; Banchereau, Jacques; Oh, Sangkon; Gorvel, Jean-Pierre

    2012-01-01

    Bacterial cyclic glucans are glucose polymers that concentrate within the periplasm of alpha-proteobacteria. These molecules are necessary to maintain the homeostasis of the cell envelope by contributing to the osmolarity of Gram negative bacteria. Here, we demonstrate that Brucella β 1,2 cyclic glucans are potent activators of human and mouse dendritic cells. Dendritic cells activation by Brucella β 1,2 cyclic glucans requires TLR4, MyD88 and TRIF, but not CD14. The Brucella cyclic glucans showed neither toxicity nor immunogenicity compared to LPS and triggered antigen-specific CD8(+) T cell responses in vivo. These cyclic glucans also enhanced antigen-specific CD4(+) and CD8(+) T cell responses including cross-presentation by different human DC subsets. Brucella β 1,2 cyclic glucans increased the memory CD4(+) T cell responses of blood mononuclear cells exposed to recombinant fusion proteins composed of anti-CD40 antibody and antigens from both hepatitis C virus and Mycobacterium tuberculosis. Thus cyclic glucans represent a new class of adjuvants, which might contribute to the development of effective antimicrobial therapies.

  11. p38 Mitogen-Activated Protein Kinase in beryllium-induced dendritic cell activation.

    PubMed

    Li, L; Huang, Z; Gillespie, M; Mroz, P M; Maier, L A

    2014-12-01

    Dendritic cells (DC) play a role in the regulation of immune responses to haptens, which in turn impact DC maturation. Whether beryllium (Be) is able to induce DC maturation and if this occurs via the MAPK pathway is not known. Primary monocyte-derived DCs (moDCs) models were generated from Be non-exposed healthy volunteers as a non-sensitized cell model, while PBMCs from BeS (Be sensitized) and CBD (chronic beryllium disease) were used as disease models. The response of these cells to Be was evaluated. The expression of CD40 was increased significantly (p<0.05) on HLA-DP Glu69+ moDCs after 100 μM BeSO₄-stimulation. BeSO₄ induced p38MAPK phosphorylation, while IκB-α was degraded in Be-stimulated moDCs. The p38 MAPK inhibitor SB203580 blocked Be-induced NF-κB activation in moDCs, suggesting that p38MAPK and NF-κB are dependently activated by BeSO₄. Furthermore, in BeS and CBD subjects, SB203580 downregulated Be-stimulated proliferation in a dose-dependent manner, and decreased Be-stimulated TNF-α and IFNγ cytokine production. Taken together, this study suggests that Be-induces non-sensitized Glu69+ DCs maturation, and that p38MAPK signaling is important in the Be-stimulated DCs activation as well as subsequent T cell proliferation and cytokine production in BeS and CBD. In total, the MAPK pathway may serve as a potential therapeutic target for human granulomatous lung diseases.

  12. Irradiation enhances dendritic cell potential antitumor activity by inducing tumor cell expressing TNF-α.

    PubMed

    Chang, Lijia; Zhang, Zhengzheng; Chen, Fang; Zhang, Wen; Song, Shuang; Song, Shuxia

    2017-03-01

    Dendritic cells (DCs)-based tumor vaccines have shown to be the promising methods for inducing therapeutic antitumor response. However, DCs alone rarely carry curative antitumor activity, and the immunosuppressive microenvironment may contribute to this defect of DC vaccinal function. Irradiation in combination with DCs has been shown to promote immune-mediated tumor destruction in preclinical studies. However, little is known about how irradiation alters the tumor microenvironment, and what host pathways modulate the activity of administrated DCs. In this study, BALB/c mice and the 4T1 breast cancer cell line were used in a tumor-bearing model. The tumor-bearing mice were irradiated locally up to 10 Gy for 3 consecutive days or a single dose of 30 Gy using a cesium source. Studies of dynamic change of the tumor microenvironment in irradiated versus untreated tumors revealed that there was no obvious change on IL-10, IL-6 and TGF-β expression or production, whereas increased TNF-α level within the first 2 weeks of irradiation. The increased TNF-α level is exactly right timing window for DCs injection, corresponding to the significant elevation of intratumoral CD8(+) T infiltration and the regression of tumor size. With attention to scheduling, combination X-ray with DCs i.t. injection may offer a practical strategy to improve treatment outcomes.

  13. Lysosome-Dependent Activation of Human Dendritic Cells by the Vaccine Adjuvant QS-21

    PubMed Central

    Welsby, Iain; Detienne, Sophie; N’Kuli, Francisca; Thomas, Séverine; Wouters, Sandrine; Bechtold, Viviane; De Wit, Dominique; Gineste, Romain; Reinheckel, Thomas; Elouahabi, Abdelatif; Courtoy, Pierre J.; Didierlaurent, Arnaud M.; Goriely, Stanislas

    2017-01-01

    The adjuvant properties of the saponin QS-21 have been known for decades. It is a component of the Adjuvant System AS01 that is used in several vaccine candidates. QS-21 strongly potentiates both cellular and humoral immune responses to purified antigens, yet how it activates immune cells is largely unknown. Here, we report that QS-21 directly activated human monocyte-derived dendritic cells (moDCs) and promoted a pro-inflammatory transcriptional program. Cholesterol-dependent QS-21 endocytosis followed by lysosomal destabilization and Syk kinase activation were prerequisites for this response. Cathepsin B, a lysosomal cysteine protease, was essential for moDC activation in vitro and contributed to the adjuvant effects of QS-21 in vivo. Collectively, these findings provide new insights into the pathways involved in the direct activation of antigen-presenting cells by a clinically relevant QS-21 formulation. PMID:28105029

  14. Deletion of Wiskott–Aldrich syndrome protein triggers Rac2 activity and increased cross-presentation by dendritic cells

    PubMed Central

    Baptista, Marisa A. P.; Keszei, Marton; Oliveira, Mariana; Sunahara, Karen K. S.; Andersson, John; Dahlberg, Carin I. M.; Worth, Austen J.; Liedén, Agne; Kuo, I-Chun; Wallin, Robert P. A.; Snapper, Scott B.; Eidsmo, Liv; Scheynius, Annika; Karlsson, Mikael C. I.; Bouma, Gerben; Burns, Siobhan O.; Forsell, Mattias N. E.; Thrasher, Adrian J.; Nylén, Susanne; Westerberg, Lisa S.

    2016-01-01

    Wiskott–Aldrich syndrome (WAS) is caused by loss-of-function mutations in the WASp gene. Decreased cellular responses in WASp-deficient cells have been interpreted to mean that WASp directly regulates these responses in WASp-sufficient cells. Here, we identify an exception to this concept and show that WASp-deficient dendritic cells have increased activation of Rac2 that support cross-presentation to CD8+ T cells. Using two different skin pathology models, WASp-deficient mice show an accumulation of dendritic cells in the skin and increased expansion of IFNγ-producing CD8+ T cells in the draining lymph node and spleen. Specific deletion of WASp in dendritic cells leads to marked expansion of CD8+ T cells at the expense of CD4+ T cells. WASp-deficient dendritic cells induce increased cross-presentation to CD8+ T cells by activating Rac2 that maintains a near neutral pH of phagosomes. Our data reveals an intricate balance between activation of WASp and Rac2 signalling pathways in dendritic cells. PMID:27425374

  15. Active properties of neuronal dendrites.

    PubMed

    Johnston, D; Magee, J C; Colbert, C M; Cristie, B R

    1996-01-01

    Dendrites of neurons in the central nervous system are the principal sites for excitatory synaptic input. Although little is known about their function, two disparate perspectives have arisen to describe the activity patterns inherent to these diverse tree-like structures. Dendrites are thus considered either passive or active in their role in integrating synaptic inputs. This review follows the history of dendritic research from before the turn of the century to the present, with a primary focus on the hippocampus. A number of recent techniques, including high-speed fluorescence imaging and dendritic patch clamping, have provided new information and perspectives about the active properties of dendrites. The results support previous notions about the dendritic propagation of action potentials and also indicate which types of voltage-gated sodium and calcium channels are expressed and functionally active in dendrites. Possible roles for the active properties of dendrites in synaptic plasticity and integration are also discussed.

  16. Natural amines inhibit activation of human plasmacytoid dendritic cells through CXCR4 engagement

    PubMed Central

    Smith, Nikaïa; Pietrancosta, Nicolas; Davidson, Sophia; Dutrieux, Jacques; Chauveau, Lise; Cutolo, Pasquale; Dy, Michel; Scott-Algara, Daniel; Manoury, Bénédicte; Zirafi, Onofrio; McCort-Tranchepain, Isabelle; Durroux, Thierry; Bachelerie, Françoise; Schwartz, Olivier; Münch, Jan; Wack, Andreas; Nisole, Sébastien; Herbeuval, Jean-Philippe

    2017-01-01

    Plasmacytoid dendritic cells (pDC) are specialized in secretion of type I interferon in response to pathogens. Here we show that natural monoamines and synthetic amines inhibit pDC activation by RNA viruses. Furthermore, a synthetic analogue of histamine reduces type I interferon production in a mouse model of influenza infection. We identify CXC chemokine receptor 4 (CXCR4) as a receptor used by amines to inhibit pDC. Our study establishes a functional link between natural amines and the innate immune system and identifies CXCR4 as a potential ‘on-off' switch of pDC activity with therapeutic potential. PMID:28181493

  17. Dendritic cell-elicited B-cell activation fosters immune privilege via IL-10 signals in hepatocellular carcinoma

    PubMed Central

    Ouyang, Fang-Zhu; Wu, Rui-Qi; Wei, Yuan; Liu, Rui-Xian; Yang, Dong; Xiao, Xiao; Zheng, Limin; Li, Bo; Lao, Xiang-Ming; Kuang, Dong-Ming

    2016-01-01

    B cells are prominent components of human solid tumours, but activation status and functions of these cells in human cancers remain elusive. Here we establish that over 50% B cells in hepatocellular carcinoma (HCC) exhibit an FcγRIIlow/− activated phenotype, and high infiltration of these cells positively correlates with cancer progression. Environmental semimature dendritic cells, but not macrophages, can operate in a CD95L-dependent pathway to generate FcγRIIlow/− activated B cells. Early activation of monocytes in cancer environments is critical for the generation of semimature dendritic cells and subsequent FcγRIIlow/− activated B cells. More importantly, the activated FcγRIIlow/− B cells from HCC tumours, but not the resting FcγRIIhigh B cells, without external stimulation suppress autologous tumour-specific cytotoxic T-cell immunity via IL-10 signals. Collectively, generation of FcγRIIlow/− activated B cells may represent a mechanism by which the immune activation is linked to immune tolerance in the tumour milieu. PMID:27853178

  18. Residual endotoxin contaminations in recombinant proteins are sufficient to activate human CD1c+ dendritic cells.

    PubMed

    Schwarz, Harald; Schmittner, Maria; Duschl, Albert; Horejs-Hoeck, Jutta

    2014-01-01

    Many commercially available recombinant proteins are produced in Escherichia coli, and most suppliers guarantee contamination levels of less than 1 endotoxin unit (EU). When we analysed commercially available proteins for their endotoxin content, we found contamination levels in the same range as generally stated in the data sheets, but also some that were higher. To analyse whether these low levels of contamination have an effect on immune cells, we stimulated the monocytic cell line THP-1, primary human monocytes, in vitro differentiated human monocyte-derived dendritic cells, and primary human CD1c+ dendritic cells (DCs) with very low concentrations of lipopolysaccharide (LPS; ranging from 0.002-2 ng/ml). We show that CD1c+ DCs especially can be activated by minimal amounts of LPS, equivalent to the levels of endotoxin contamination we detected in some commercially available proteins. Notably, the enhanced endotoxin sensitivity of CD1c+ DCs was closely correlated with high CD14 expression levels observed in CD1c+ DCs that had been maintained in cell culture medium for 24 hours. When working with cells that are particularly sensitive to LPS, even low endotoxin contamination may generate erroneous data. We therefore recommend that recombinant proteins be thoroughly screened for endotoxin contamination using the limulus amebocyte lysate test, fluorescence-based assays, or a luciferase based NF-κB reporter assay involving highly LPS-sensitive cells overexpressing TLR4, MD-2 and CD14.

  19. Targeted antigen delivery and activation of dendritic cells in vivo: steps towards cost effective vaccines.

    PubMed

    Tacken, Paul J; Figdor, Carl G

    2011-02-01

    During the past decade, the immunotherapeutic potential of ex vivo generated professional antigen presenting dendritic cells (DCs) has been explored in the clinic. Albeit safe, clinical results have thus far been limited. A major disadvantage of current cell-based dendritic cell (DC) therapies, preventing universal implementation of this form of immunotherapy, is the requirement that vaccines need to be tailor made for each individual. Targeted delivery of antigens to DC surface receptors in vivo would circumvent this laborious and expensive ex vivo culturing steps involved with these cell-based therapies. In addition, the opportunity to target natural and often rare DC subsets in vivo might have advantages over loading more artificial ex vivo cultured DCs. Preclinical studies show targeting antigens to DCs effectively induces humoral responses, while cellular responses are induced provided a DC maturation or activation stimulus is co-administered. Here, we discuss strategies to target antigens to distinct DC subsets and to simultaneously employ adjuvants to activate these cells to induce immunity.

  20. Active Dendrites Enhance Neuronal Dynamic Range

    PubMed Central

    Gollo, Leonardo L.; Kinouchi, Osame; Copelli, Mauro

    2009-01-01

    Since the first experimental evidences of active conductances in dendrites, most neurons have been shown to exhibit dendritic excitability through the expression of a variety of voltage-gated ion channels. However, despite experimental and theoretical efforts undertaken in the past decades, the role of this excitability for some kind of dendritic computation has remained elusive. Here we show that, owing to very general properties of excitable media, the average output of a model of an active dendritic tree is a highly non-linear function of its afferent rate, attaining extremely large dynamic ranges (above 50 dB). Moreover, the model yields double-sigmoid response functions as experimentally observed in retinal ganglion cells. We claim that enhancement of dynamic range is the primary functional role of active dendritic conductances. We predict that neurons with larger dendritic trees should have larger dynamic range and that blocking of active conductances should lead to a decrease in dynamic range. PMID:19521531

  1. Central Muscarinic Cholinergic Activation Alters Interaction between Splenic Dendritic Cell and CD4+CD25- T Cells in Experimental Colitis

    PubMed Central

    Pavlov, Valentin A.; Tracey, Kevin J.; Khafipour, Ehsan; Ghia, Jean-Eric

    2014-01-01

    Background The cholinergic anti-inflammatory pathway (CAP) is based on vagus nerve (VN) activity that regulates macrophage and dendritic cell responses in the spleen through alpha-7 nicotinic acetylcholine receptor (a7nAChR) signaling. Inflammatory bowel disease (IBD) patients present dysautonomia with decreased vagus nerve activity, dendritic cell and T cell over-activation. The aim of this study was to investigate whether central activation of the CAP alters the function of dendritic cells (DCs) and sequential CD4+/CD25−T cell activation in the context of experimental colitis. Methods The dinitrobenzene sulfonic acid model of experimental colitis in C57BL/6 mice was used. Central, intracerebroventricular infusion of the M1 muscarinic acetylcholine receptor agonist McN-A-343 was used to activate CAP and vagus nerve and/or splenic nerve transection were performed. In addition, the role of α7nAChR signaling and the NF-kB pathway was studied. Serum amyloid protein (SAP)-A, colonic tissue cytokines, IL-12p70 and IL-23 in isolated splenic DCs, and cytokines levels in DC-CD4+CD25−T cell co-culture were determined. Results McN-A-343 treatment reduced colonic inflammation associated with decreased pro-inflammatory Th1/Th17 colonic and splenic cytokine secretion. Splenic DCs cytokine release was modulated through α7nAChR and the NF-kB signaling pathways. Cholinergic activation resulted in decreased CD4+CD25−T cell priming. The anti-inflammatory efficacy of central cholinergic activation was abolished in mice with vagotomy or splenic neurectomy. Conclusions Suppression of splenic immune cell activation and altered interaction between DCs and T cells are important aspects of the beneficial effect of brain activation of the CAP in experimental colitis. These findings may lead to improved therapeutic strategies in the treatment of IBD. PMID:25295619

  2. Dendritic cells in Graves' disease.

    PubMed

    Purnamasari, Dyah; Soewondo, Pradana; Djauzi, Samsuridjal

    2015-01-01

    Dendritic cells are major antigen-presenting cells (APC) that stimulate naive T cells, which induce adaptive immune responses. Graves' disease (GD) is an autoimmune disease characterized by the presence of autoantibodies against Thyroid Stimulating Hormone Receptor (TSHR). The autoantibodies bind with TSHR and stimulate thyroid hormone production. Dendritic cells are still the major APC in GD immune response although thyrocytes in GD can also express Major Histocompatibility Class (MHC) class II molecule. Studies about DC in GD have been conducted by isolating intra-thyroid DC or DC in peripheral circulation. Results of DC studies in GD are still controversial. Changes in number and profile of DC are found, which indicate altered immune response activity and defects of regulator T cell (Treg) in GD.

  3. Multistage T cell-dendritic cell interactions control optimal CD4 T cell activation through the ADAP-SKAP55-signaling module.

    PubMed

    Mitchell, Jason S; Burbach, Brandon J; Srivastava, Rupa; Fife, Brian T; Shimizu, Yoji

    2013-09-01

    The Ag-specific interactions between T cells and dendritic cells progress through dynamic contact stages in vivo consisting of early long-term stable contacts and later confined, yet motile, short-lived contacts. The signaling pathways that control in vivo interaction dynamics between T cells and dendritic cells during priming remain undefined. Adhesion and degranulation promoting adapter protein (ADAP) is a multifunctional adapter that regulates "inside-out" signaling from the TCR to integrins. Using two-photon microscopy, we demonstrate that, in the absence of ADAP, CD4 T cells make fewer early-stage stable contacts with Ag-laden dendritic cells, and the interactions are characterized by brief repetitive contacts. Furthermore, ADAP-deficient T cells show reduced contacts at the late motile contact phase and display less confinement around dendritic cells. The altered T cell interaction dynamics in the absence of ADAP are associated with defective early proliferation and attenuated TCR signaling in vivo. Regulation of multistage contact behaviors and optimal T cell signaling involves the interaction of ADAP with the adapter src kinase-associated phosphoprotein of 55 kDa (SKAP55). Thus, integrin activation by the ADAP-SKAP55-signaling module controls the stability and duration of T cell-dendritic cell contacts during the progressive phases necessary for optimal T cell activation.

  4. Dendritic Cell-Mediated Phagocytosis but Not Immune Activation Is Enhanced by Plasmin

    PubMed Central

    Borg, Rachael J.; Samson, Andre L.; Au, Amanda E.-L.; Scholzen, Anja; Fuchsberger, Martina; Kong, Ying Y.; Freeman, Roxann; Mifsud, Nicole A.; Plebanski, Magdalena; Medcalf, Robert L.

    2015-01-01

    Removal of dead cells in the absence of concomitant immune stimulation is essential for tissue homeostasis. We recently identified an injury-induced protein misfolding event that orchestrates the plasmin-dependent proteolytic degradation of necrotic cells. As impaired clearance of dead cells by the innate immune system predisposes to autoimmunity, we determined whether plasmin could influence endocytosis and immune cell stimulation by dendritic cells – a critical cell that links the innate and adaptive immune systems. We find that plasmin generated on the surface of necrotic cells enhances their phagocytic removal by human monocyte-derived dendritic cells. Plasmin also promoted phagocytosis of protease-resistant microparticles by diverse mouse dendritic cell sub-types both in vitro and in vivo. Together with an increased phagocytic capacity, plasmin-treated dendritic cells maintain an immature phenotype, exhibit reduced migration to lymph nodes, increase their expression/release of the immunosuppressive cytokine TGF-β, and lose their capacity to mount an allogeneic response. Collectively, our findings support a novel role for plasmin formed on dead cells and other phagocytic targets in maintaining tissue homeostasis by increasing the phagocytic function of dendritic cells while simultaneously decreasing their immunostimulatory capacity consistent with producing an immunosuppressive state. PMID:26132730

  5. Human dendritic cell activation induced by a permannosylated dendron containing an antigenic GM3-lactone mimetic

    PubMed Central

    Rojo, Javier; Ballerini, Clara; Comito, Giuseppina; Nativi, Cristina

    2014-01-01

    Summary Vaccination strategies based on dendritic cells (DCs) armed with specific tumor antigens have been widely exploited due the properties of these immune cells in coordinating an innate and adaptive response. Here, we describe the convergent synthesis of the bifunctional multivalent glycodendron 5, which contains nine residues of mannose for DC targeting and one residue of an immunogenic mimetic of a carbohydrate melanoma associated antigen. The immunological assays demonstrated that the glycodendron 5 is able to induce human immature DC activation in terms of a phenotype expression of co-stimulatory molecules expression and MHCII. Furthermore, DCs activated by the glycodendron 5 stimulate T lymphocytes to proliferate in a mixed lymphocytes reaction (MLR). PMID:24991284

  6. HPV vaccine stimulates cytotoxic activity of killer dendritic cells and natural killer cells against HPV-positive tumour cells.

    PubMed

    Van den Bergh, Johan M J; Guerti, Khadija; Willemen, Yannick; Lion, Eva; Cools, Nathalie; Goossens, Herman; Vorsters, Alex; Van Tendeloo, Viggo F I; Anguille, Sébastien; Van Damme, Pierre; Smits, Evelien L J M

    2014-07-01

    Cervarix™ is approved as a preventive vaccine against infection with the human papillomavirus (HPV) strains 16 and 18, which are causally related to the development of cervical cancer. We are the first to investigate in vitro the effects of this HPV vaccine on interleukin (IL)-15 dendritic cells (DC) as proxy of a naturally occurring subset of blood DC, and natural killer (NK) cells, two innate immune cell types that play an important role in antitumour immunity. Our results show that exposure of IL-15 DC to the HPV vaccine results in increased expression of phenotypic maturation markers, pro-inflammatory cytokine production and cytotoxic activity against HPV-positive tumour cells. These effects are mediated by the vaccine adjuvant, partly through Toll-like receptor 4 activation. Next, we demonstrate that vaccine-exposed IL-15 DC in turn induce phenotypic activation of NK cells, resulting in a synergistic cytotoxic action against HPV-infected tumour cells. Our study thus identifies a novel mode of action of the HPV vaccine in boosting innate immunity, including killing of HPV-infected cells by DC and NK cells.

  7. Complementary Dendritic Cell–activating Function of CD8+ and CD4+ T Cells

    PubMed Central

    Mailliard, Robbie B.; Egawa, Shinichi; Cai, Quan; Kalinska, Anna; Bykovskaya, Svetlana N.; Lotze, Michael T.; Kapsenberg, Martien L.; Storkus, Walter J.; Kalinski, Pawel

    2002-01-01

    Dendritic cells (DCs) activated by CD40L-expressing CD4+ T cells act as mediators of “T helper (Th)” signals for CD8+ T lymphocytes, inducing their cytotoxic function and supporting their long-term activity. Here, we show that the optimal activation of DCs, their ability to produce high levels of bioactive interleukin (IL)-12p70 and to induce Th1-type CD4+ T cells, is supported by the complementary DC-activating signals from both CD4+ and CD8+ T cells. Cord blood– or peripheral blood–isolated naive CD8+ T cells do not express CD40L, but, in contrast to naive CD4+ T cells, they are efficient producers of IFN-γ at the earliest stages of the interaction with DCs. Naive CD8+ T cells cooperate with CD40L-expressing naive CD4+ T cells in the induction of IL-12p70 in DCs, promoting the development of primary Th1-type CD4+ T cell responses. Moreover, the recognition of major histocompatibility complex class I–presented epitopes by antigen-specific CD8+ T cells results in the TNF-α– and IFN-γ–dependent increase in the activation level of DCs and in the induction of type-1 polarized mature DCs capable of producing high levels of IL-12p70 upon a subsequent CD40 ligation. The ability of class I–restricted CD8+ T cells to coactivate and polarize DCs may support the induction of Th1-type responses against class I–presented epitopes of intracellular pathogens and contact allergens, and may have therapeutical implications in cancer and chronic infections. PMID:11854360

  8. Inhibition of Protease-Activated Receptor 1 Does not Affect Dendritic Homeostasis of Cultured Mouse Dentate Granule Cells

    PubMed Central

    Schuldt, Gerlind; Galanis, Christos; Strehl, Andreas; Hick, Meike; Schiener, Sabine; Lenz, Maximilian; Deller, Thomas; Maggio, Nicola; Vlachos, Andreas

    2016-01-01

    Protease-activated receptors (PARs) are widely expressed in the central nervous system (CNS). While a firm link between PAR1-activation and functional synaptic and intrinsic neuronal properties exists, studies on the role of PAR1 in neural structural plasticity are scarce. The physiological function of PAR1 in the brain remains not well understood. We here sought to determine whether prolonged pharmacologic PAR1-inhibition affects dendritic morphologies of hippocampal neurons. To address this question we employed live-cell microscopy of mouse dentate granule cell dendrites in 3-week old entorhino-hippocampal slice cultures prepared from Thy1-GFP mice. A subset of cultures were treated with the PAR1-inhibitor SCH79797 (1 μM; up to 3 weeks). No major effects of PAR1-inhibition on static and dynamic parameters of dentate granule cell dendrites were detected under control conditions. Granule cells of PAR1-deficient slice cultures showed unaltered dendritic morphologies, dendritic spine densities and excitatory synaptic strength. Furthermore, we report that PAR1-inhibition does not prevent dendritic retraction following partial deafferentation in vitro. Consistent with this finding, no major changes in PAR1-mRNA levels were detected in the denervated dentate gyrus (DG). We conclude that neural PAR1 is not involved in regulating the steady-state dynamics or deafferentation-induced adaptive changes of cultured dentate granule cell dendrites. These results indicate that drugs targeting neural PAR1-signals may not affect the stability and structural integrity of neuronal networks in healthy brain regions. PMID:27378862

  9. Proteomics analysis of dendritic cell activation by contact allergens reveals possible biomarkers regulated by Nrf2.

    PubMed

    Mussotter, Franz; Tomm, Janina Melanie; El Ali, Zeina; Pallardy, Marc; Kerdine-Römer, Saadia; Götz, Mario; von Bergen, Martin; Haase, Andrea; Luch, Andreas

    2016-12-15

    Allergic contact dermatitis is a widespread disease with high clinical relevance affecting approximately 20% of the general population. Typically, contact allergens are low molecular weight electrophilic compounds which can activate the Keap1/Nrf2 pathway. We performed a proteomics study to reveal possible biomarkers for dendritic cell (DC) activation by contact allergens and to further elucidate the role of Keap1/Nrf2 signaling in this process. We used bone marrow derived dendritic cells (BMDCs) of wild-type (nrf2(+/+)) and Nrf2 knockout (nrf2(-/-)) mice and studied their response against the model contact sensitizers 2,4-dinitrochlorobenzene (DNCB), cinnamaldehyde (CA) and nickel(II) sulfate by 2-dimensional polyacrylamide gel electrophoresis (2D-PAGE) in combination with electrospray ionization tandem mass spectrometry (ESI-MS/MS). Sodium dodecyl sulfate (SDS, 100μM) served as irritant control. While treatment with nickel(II) sulfate and SDS had only little effects, CA and DNCB led to significant changes in protein expression. We found 18 and 30 protein spots up-regulated in wild-type cells treated with 50 and 100μM CA, respectively. For 5 and 10μM DNCB, 32 and 37 spots were up-regulated, respectively. Almost all of these proteins were not differentially expressed in nrf2(-/-) BMDCs, indicating an Nrf2-dependent regulation. Among them proteins were detected which are involved in oxidative stress and heat shock responses, as well as in signal transduction or basic cellular pathways. The applied approach allowed us to differentiate between Nrf2-dependent and Nrf2-independent cellular biomarkers differentially regulated upon allergen-induced DC activation. The data presented might contribute to the further development of suitable in vitro testing methods for chemical-mediated sensitization.

  10. Tetherin/BST-2 promotes dendritic cell activation and function during acute retrovirus infection

    PubMed Central

    Li, Sam X.; Barrett, Bradley S.; Guo, Kejun; Kassiotis, George; Hasenkrug, Kim J.; Dittmer, Ulf; Gibbert, Kathrin; Santiago, Mario L.

    2016-01-01

    Tetherin/BST-2 is a host restriction factor that inhibits retrovirus release from infected cells in vitro by tethering nascent virions to the plasma membrane. However, contradictory data exists on whether Tetherin inhibits acute retrovirus infection in vivo. Previously, we reported that Tetherin-mediated inhibition of Friend retrovirus (FV) replication at 2 weeks post-infection correlated with stronger natural killer, CD4+ T and CD8+ T cell responses. Here, we further investigated the role of Tetherin in counteracting retrovirus replication in vivo. FV infection levels were similar between wild-type (WT) and Tetherin KO mice at 3 to 7 days post-infection despite removal of a potent restriction factor, Apobec3/Rfv3. However, during this phase of acute infection, Tetherin enhanced myeloid dendritic cell (DC) function. DCs from infected, but not uninfected, WT mice expressed significantly higher MHC class II and the co-stimulatory molecule CD80 compared to Tetherin KO DCs. Tetherin-associated DC activation during acute FV infection correlated with stronger NK cell responses. Furthermore, Tetherin+ DCs from FV-infected mice more strongly stimulated FV-specific CD4+ T cells ex vivo compared to Tetherin KO DCs. The results link the antiretroviral and immunomodulatory activity of Tetherin in vivo to improved DC activation and MHC class II antigen presentation. PMID:26846717

  11. Triggering through NOD-2 Differentiates Bone Marrow Precursors to Dendritic Cells with Potent Bactericidal activity

    PubMed Central

    Khan, Nargis; Aqdas, Mohammad; Vidyarthi, Aurobind; Negi, Shikha; Pahari, Susanta; Agnihotri, Tapan; Agrewala, Javed N.

    2016-01-01

    Dendritic cells (DCs) play a crucial role in bridging innate and adaptive immunity by activating naïve T cells. The role of pattern recognition receptors like Toll-Like Receptors and Nod-Like Receptors expressed on DCs is well-defined in the recognition of the pathogens. However, nothing is precisely studied regarding the impact of NOD-2 signaling during the differentiation of DCs. Consequently, we explored the role of NOD-2 signaling in the differentiation of DCs and therefore their capability to activate innate and adaptive immunity. Intriguingly, we observed that NOD-2 stimulated DCs (nDCs) acquired highly activated and matured phenotype and exhibited substantially greater bactericidal activity by robust production of nitric oxide. The mechanism involved in improving the functionality of nDCs was dependent on IFN-αβ signaling, leading to the activation of STAT pathways. Furthermore, we also observed that STAT-1 and STAT-4 dependent maturation and activation of DCs was under the feedback mechanism of SOCS-1 and SOCS-3 proteins. nDCs acquired enhanced potential to activate chiefly Th1 and Th17 immunity. Taken together, these results suggest that nDCs can be exploited as an immunotherapeutic agent in bolstering host immunity and imparting protection against the pathogens. PMID:27265209

  12. Gene expression analysis during acute hepatitis C virus infection associates dendritic cell activation with viral clearance.

    PubMed

    Zabaleta, Aintzane; Riezu-Boj, Jose-Ignacio; Larrea, Esther; Villanueva, Lorea; Lasarte, Juan Jose; Guruceaga, Elizabeth; Fisicaro, Paola; Ezzikouri, Sayeh; Missale, Gabriele; Ferrari, Carlo; Benjelloun, Soumaya; Prieto, Jesús; Sarobe, Pablo

    2016-05-01

    Viral clearance during acute hepatitis C virus (HCV) infection is associated with the induction of potent antiviral T-cell responses. Since dendritic cells (DC) are essential in the activation of primary T-cell responses, gene expression was analyzed in DC from patients during acute HCV infection. By using microarrays, gene expression was compared in resting and activated peripheral blood plasmacytoid (pDC) and myeloid (mDC) DC from acute HCV resolving patients (AR) and from patients who become chronically infected (ANR), as well as in healthy individuals (CTRL) and chronically-infected patients (CHR). For pDC, a high number of upregulated genes was found in AR patients, irrespective of DC stimulation. However, for mDC, most evident differences were detected after DC stimulation, again corresponding to upregulated genes in AR patients. Divergent behavior of ANR was also observed when analyzing DC from CTRL and CHR, with ANR patients clustering again apart from these groups. These differences corresponded to metabolism-associated genes and genes belonging to pathways relevant for DC activation and cytokine responses. Thus, upregulation of relevant genes in DC during acute HCV infection may determine viral clearance, suggesting that dysfunctional DC may be responsible for the lack of efficient T-cell responses which lead to chronic HCV infection.

  13. Investigations on the immunosuppressive activity of derivatives of mycophenolic acid in immature dendritic cells.

    PubMed

    Iwaszkiewicz-Grzes, Dorota; Cholewinski, Grzegorz; Kot-Wasik, Agata; Trzonkowski, Piotr; Dzierzbicka, Krystyna

    2017-03-01

    The main activity of mycophenolic acid 1 (MPA) and its analogs is the inhibition of proliferation of T cells. Here, we hypothesized that MPA and its conjugates inhibits also the activity of antigen-presenting cells (APC) including dendritic cells (DCs). We tested the effect of novel amino acid derivatives of MPA and conjugates of MPA with acridines/acridones on DCs by flow cytometry, ELISA and MLR assay. Both acridines/acridone derivatives could inhibit the maturation of DC, as shown by the decreased expression of B7 family receptors. It was confirmed in the mixed leucocyte reaction (MLR), in which T cells challenged with DCs pretreated with the analogs showed decreased proliferation and reduced cytokine secretion. The most interesting activity in this series of studies, that is, the suppression of CD86 receptor expression, decreased cytokine production and suppressed mixed leucocyte reaction, exhibited (mycophenoyl-N-3-propyl)-9-acridone-4-carboxamide ester 5a and (mycophenoyl-N-5-pentyl)-9-acridone-4-carboxamide ester 5b. These compounds reduced also the secretion of IL-2 and IL-15. In addition, they increased secretion of suppressive IL-10. Equally promising results were obtained for the N-mycophenoyl-D-glutamic acid 4b, which previously gave the highest value of selectivity. Acridone derivatives of MPA are therefore good immunosuppressive drug candidates for further testing.

  14. Relation of apical dendritic spikes to output decision in CA1 pyramidal cells during synchronous activation: a computational study.

    PubMed

    Ibarz, José M; Makarova, Ioulia; Herreras, Oscar

    2006-03-01

    Recent studies on the initiation and propagation of dendritic spikes have modified the classical view of postsynaptic integration. Earlier we reported that subthreshold currents and spikes recruited by synaptic currents play a critical role in defining outputs following synchronous activation. Experimental factors strongly condition these currents due to their nonlinear behaviour. Hence, we have performed a detailed parametric study in a CA1 pyramidal cell model to explore how different variables interact and initiate dendritic spiking, and how they influence cell output. The input pattern, the relative excitability of axon and dendrites, the presence/modulation of voltage-dependent channels, and inhibition were cross analysed. Subthreshold currents and spikes on synaptically excited branches fired spikes in other branches to jointly produce different modalities of apical shaft spiking with a variable impact on cell output. Synchronous activation initiated a varying number and temporal scatter of firing branches that produced in the apical shaft-soma axis nonpropagating spikes, pseudosaltatory or continuous forward conduction, or backpropagation. As few as 6-10 local spikes within a time window of 2 ms ensure cell output. However, the activation mode varied extremely when two or more variables were cross-analysed, becoming rather unpredictable when all the variables were considered. Spatially clustered inputs and upper modulation of dendritic Na(+) or Ca(2+) electrogenesis favour apical decision. In contrast, inhibition biased the output decision toward the axon and switched between dendritic firing modes. We propose that dendrites can discriminate input patterns and decide immediate cell output depending on the particular state of a variety of endogenous parameters.

  15. Activation and measurement of NLRP3 inflammasome activity using IL-1β in human monocyte-derived dendritic cells.

    PubMed

    Fernandez, Melissa V; Miller, Elizabeth A; Bhardwaj, Nina

    2014-05-22

    Inflammatory processes resulting from the secretion of Interleukin (IL)-1 family cytokines by immune cells lead to local or systemic inflammation, tissue remodeling and repair, and virologic control(1) (,) (2) . Interleukin-1β is an essential element of the innate immune response and contributes to eliminate invading pathogens while preventing the establishment of persistent infection(1-5). Inflammasomes are the key signaling platform for the activation of interleukin 1 converting enzyme (ICE or Caspase-1). The NLRP3 inflammasome requires at least two signals in DCs to cause IL-1β secretion(6). Pro-IL-1β protein expression is limited in resting cells; therefore a priming signal is required for IL-1β transcription and protein expression. A second signal sensed by NLRP3 results in the formation of the multi-protein NLRP3 inflammasome. The ability of dendritic cells to respond to the signals required for IL-1β secretion can be tested using a synthetic purine, R848, which is sensed by TLR8 in human monocyte derived dendritic cells (moDCs) to prime cells, followed by activation of the NLRP3 inflammasome with the bacterial toxin and potassium ionophore, nigericin. Monocyte derived DCs are easily produced in culture and provide significantly more cells than purified human myeloid DCs. The method presented here differs from other inflammasome assays in that it uses in vitro human, instead of mouse derived, DCs thus allowing for the study of the inflammasome in human disease and infection.

  16. Comparative analysis of signature genes in porcine reproductive and respiratory syndrome virus (PRRSV)-infected porcine monocyte-derived dendritic cells at differential activation statuses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Activation statuses of monocytic cells, e.g. monocytes, macrophages and dendritic cells (DCs), are critically important for antiviral immunity. In particular, some devastating viruses, including porcine reproductive and respiratory syndrome virus (PRRSV), are capable of directly infecting these cell...

  17. Vaccines, adjuvants and dendritic cell activators – Current Status and Future Challenges

    PubMed Central

    Obeid, Joseph M.; Hu, Yinin; Slingluff, Craig L.

    2015-01-01

    Cancer vaccines offer a low-toxicity approach to induce anticancer immune responses. They have shown promise for clinical benefit with one cancer vaccine approved in the U.S. for advanced prostate cancer. As other immune therapies are now clearly effective for treatment of advanced cancers of many histologies, there is renewed enthusiasm for optimizing cancer vaccines for use to prevent recurrence in early stage cancers and/or to combine with other immune therapies for therapy of advanced cancers. Future advancements in vaccine therapy will involve the identification and selection of effective antigen formulations, optimization of adjuvants, dendritic cell activation, and combination therapies. In this summary we present the current practice, the broad collection of challenges, and the promising future directions of vaccine therapy for cancer. PMID:26320060

  18. Nanoparticles, [Gd@C82(OH)22]n, induces dendritic cell maturation and activates Th1 immune responses

    PubMed Central

    Yang, De; Zhao, Yuliang; Guo, Hua; Li, Yana; Tewary, Poonam; Xing, Gengmei; Hou, Wei; Oppenheim, Joost J.; Zhang, Ning

    2010-01-01

    Dendritic cells play a pivotal role in host immune defense, such as elimination of foreign pathogen and inhibition of tumorigenesis. In this paper, we report that [Gd@C82(OH)22]n could induce phenotypic maturation of dendritic cells by stimulating DC production of cytokines including IL-12p70, upregulating DC costimulatory (CD80, CD83, and CD86) and MHC (HLA-A,B,C and HLA-DR) molecules, and switching DCs from a CCL5-responsive to a CCL19-responsive phenotype. We found that [Gd@C82(OH)22]n can induce dendritic cells to become functionally mature as illustrated by their capacity to activate allogeneic T cells. Mice immunized with ovalbumin in the presence of [Gd@C82(OH)22]n exhibit enhanced ovalbumin-specific Th1-polarized immune response as evidenced by the predominantly increased production of IFNγ, IL-1β, and IL-2. The [Gd@C82(OH)22]n nanoparticle is a potent activator of dendritic cells and Th1 immune responses. These new findings also provide a rational understanding of the potent anticancer activities of [Gd@C82(OH)22]n nanoparticles reported previously. PMID:20121217

  19. Activation and genetic modification of human monocyte-derived dendritic cells using attenuated Salmonella typhimurium.

    PubMed

    Michael, Agnieszka; John, Justin; Meyer, Brendan; Pandha, Hardev

    2010-03-05

    Live attenuated bacterial vectors, such as Salmonella typhimurium, have shown promise as delivery vehicles for DNA. We have examined two new strains of S. typhimurium and their impact on dendritic cell maturation (CD12-sifA/aroC mutant and WT05-ssaV/aroC, both in TML background). Strain WT05 matured dendritic cells in a more efficient way; caused higher release of cytokines TNF-alpha, IL-12, IL-1beta; and was efficient for gene transfer. These findings suggest that the genetic background of the attenuation can influence the pattern of inflammatory immune response to Salmonella infection.

  20. SATB1 OVEREXPRESSION DRIVES TUMOR-PROMOTING ACTIVITIES IN CANCER-ASSOCIATED DENDRITIC CELLS

    PubMed Central

    Tesone, Amelia J.; Rutkowski, Melanie R.; Brencicova, Eva; Svoronos, Nikolaos; Perales-Puchalt, Alfredo; Stephen, Tom L.; Allegrezza, Michael J.; Payne, Kyle K.; Nguyen, Jenny M.; Wickramasinghe, Jayamanna; Tchou, Julia; Borowsky, Mark E.; Rabinovich, Gabriel A.; Kossenkov, Andrew V.; Conejo-Garcia, Jose R.

    2016-01-01

    SUMMARY Special AT-rich sequence-binding protein-1 (Satb1) governs genome-wide transcriptional programs. Using a conditional knockout mouse, we find that Satb1 is required for normal differentiation of conventional dendritic cells (DCs). Furthermore, Satb1 governs the differentiation of inflammatory DCs by regulating MHC-II expression through Notch1 signaling. Mechanistically, Satb1 binds to the Notch1 promoter, activating Notch expression and driving RBPJ occupancy of the H2-Ab1 promoter, which activates MHC-II transcription. However, tumor-driven, unremitting expression of Satb1 in activated Zbtb46+ inflammatory DCs that infiltrate ovarian tumors results in an immunosuppressive phenotype characterized by increased secretion of tumor-promoting Galectin-1 and IL-6. In vivo silencing of Satb1 in tumor-associated DCs reverses their tumorigenic activity and boosts protective immunity. Therefore, dynamic fluctuations in Satb1 expression govern the generation and immunostimulatory activity of steady-state and inflammatory DCs, but continuous Satb1 overexpression in differentiated DCs converts them into tolerogenic/pro-inflammatory cells that contribute to malignant progression. PMID:26876172

  1. FOXO1 regulates dendritic cell activity through ICAM-1 and CCR7.

    PubMed

    Dong, Guangyu; Wang, Yu; Xiao, Wenmei; Pacios Pujado, Sandra; Xu, Fanxing; Tian, Chen; Xiao, E; Choi, Yongwon; Graves, Dana T

    2015-04-15

    The transcription factor FOXO1 regulates cell function and is expressed in dendritic cells (DCs). We investigated the role of FOXO1 in activating DCs to stimulate a lymphocyte response to bacteria. We show that bacteria induce FOXO1 nuclear localization through the MAPK pathway and demonstrate that FOXO1 is needed for DC activation of lymphocytes in vivo. This occurs through FOXO1 regulation of DC phagocytosis, chemotaxis, and DC-lymphocyte binding. FOXO1 induces DC activity by regulating ICAM-1 and CCR7. FOXO1 binds to the CCR7 and ICAM-1 promoters, stimulates CCR7 and ICAM-1 transcriptional activity, and regulates their expression. This is functionally important because transfection of DCs from FOXO1-deleted CD11c.Cre(+)FOXO1(L/L) mice with an ICAM-1-expressing plasmid rescues the negative effect of FOXO1 deletion on DC bacterial phagocytosis and chemotaxis. Rescue with both CCR7 and ICAM-1 reverses impaired DC homing to lymph nodes in vivo when FOXO1 is deleted. Moreover, Ab production following injection of bacteria is significantly reduced with lineage-specific FOXO1 ablation. Thus, FOXO1 coordinates upregulation of DC activity through key downstream target genes that are needed for DCs to stimulate T and B lymphocytes and generate an Ab defense to bacteria.

  2. Recruitment and endo-lysosomal activation of TLR9 in dendritic cells infected with Trypanosoma cruzi.

    PubMed

    Bartholomeu, Daniella C; Ropert, Catherine; Melo, Mariane B; Parroche, Peggy; Junqueira, Caroline F; Teixeira, Santuza M R; Sirois, Cherilyn; Kasperkovitz, Pia; Knetter, Cathrine F; Lien, Egil; Latz, Eicke; Golenbock, Douglas T; Gazzinelli, Ricardo T

    2008-07-15

    TLR9 is critical in parasite recognition and host resistance to experimental infection with Trypanosoma cruzi. However, no information is available regarding nucleotide sequences and cellular events involved on T. cruzi recognition by TLR9. In silico wide analysis associated with in vitro screening of synthetic oligonucleotides demonstrates that the retrotransposon VIPER elements and mucin-like glycoprotein (TcMUC) genes in the T. cruzi genome are highly enriched for CpG motifs that are immunostimulatory for mouse and human TLR9, respectively. Importantly, infection with T. cruzi triggers high levels of luciferase activity under NF-kappaB-dependent transcription in HEK cells cotransfected with human TLR9, but not in control (cotransfected with human MD2/TLR4) HEK cells. Further, we observed translocation of TLR9 to the lysosomes during invasion/uptake of T. cruzi parasites by dendritic cells. Consistently, potent proinflammatory activity was observed when highly unmethylated T. cruzi genomic DNA was delivered to the endo-lysosomal compartment of host cells expressing TLR9. Thus, together our results indicate that the unmethylated CpG motifs found in the T. cruzi genome are likely to be main parasite targets and probably become available to TLR9 when parasites are destroyed in the lysosome-fused vacuoles during parasite invasion/uptake by phagocytes.

  3. [Active immunotherapy of prostate cancer with a focus on dendritic cells].

    PubMed

    Thomas-Kaskel, A K; Veelken, H

    2007-06-01

    Recurrent or metastatic prostate cancer is generally considered an incurable disease. Given the transient benefit from hormone deprivation therapy and limited successes of systemic chemotherapy, alternative treatment modalities are needed both in the situation of PSA recurrence and in hormone-refractory disease. Prostate cancer cells express several tumor associated antigens which are currently being evaluated as targets for active and specific immunotherapy approaches. Dendritic cells (DC) are the most powerful antigen-presenting cells (APC), able to prime naive T cells and to break peripheral tolerance and thus induce tumor immune responses. Close to 1000 prostate cancer patients have been treated with DC-based or other forms of active immunotherapy to date. Vaccination-induced immune responses have been reported in two thirds of DC trials, and favorable changes in the clinical course of the disease in almost half of the patients treated. Most responses, however, were modest and transient. Therefore, mechanisms of treatment failure and possibilities to improve vaccination efficacy are being discussed.

  4. Influence of autologous dendritic cells on cytokine-induced killer cell proliferation, cell phenotype and antitumor activity in vitro.

    PubMed

    Cao, Jingsong; Chen, Cong; Wang, Yuhuan; Chen, Xuecheng; Chen, Zeying; Luo, Xiaoling

    2016-09-01

    Dendritic cell (DCs) are essential antigen processing and presentation cells that play a key role in the immune response. In this study, DCs were co-cultured with cytokine-induced killer cells (DC-CIKs) in vitro to detect changes in cell proliferation, cell phenotype and cell cytotoxicity. The results revealed that the DCs were suitable for co-culture with CIKs at day 7, and that cell quantity of DC-CIKs was lower than that of CIKs until day 11, but it was significantly improved to 1.17-fold that of CIKs at day 13. Flow cytometry was used to detect the cell phenotype of CIKs and DC-CIKs. Compared with CIKs at day 13, the percentage of CD3(+), CD3(+)CD4(+), CD3(+)CD8(+) and CD3(+)CD56(+) T cells in DC-CIKs was significantly improved 1.02, 1.79, 1.26 and 2.44-fold, respectively. In addition, trypan blue staining analysis demonstrated that the cell viability of CIKs and DC-CIKs was 96% and 98%, respectively. Furthermore, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) analysis verified that CIK and DC-CIK cytotoxicity in Hela cells was 58% and 80%, respectively, with a significant difference. Taken together, our results indicate that the cell proliferation, cell phenotype and antitumor activity of CIKs were all enhanced following co-culture with DCs in vitro. These results are likely to be useful for DC-CIK application in antitumor therapies.

  5. Pancreatic adenocarcinoma upregulated factor serves as adjuvant by activating dendritic cells through stimulation of TLR4

    PubMed Central

    Yang, Benjamin; Lee, Je-Jung; Lee, Hyun-Ju; Lee, Jaemin; Jung, In Duk; Han, Hee Dong; Lee, Seung-Hyun; Koh, Sang Seok; Wu, T.-C.; Park, Yeong-Min

    2015-01-01

    Dendritic cell (DC) based cancer vaccines represent a promising immunotherapeutic strategy against cancer. To enhance the modest immunogenicity of DC vaccines, various adjuvants are often incorporated. Particularly, most of the common adjuvants are derived from bacteria. In the current study, we evaluate the use of a human pancreatic cancer derived protein, pancreatic adenocarcinoma upregulated factor (PAUF), as a novel DC vaccine adjuvant. We show that PAUF can induce activation and maturation of DCs and activate NFkB by stimulating the Toll-like receptor signaling pathway. Furthermore, vaccination with PAUF treated DCs pulsed with E7 or OVA peptides leads to generation of E7 or OVA-specific CD8+ T cells and memory T cells, which correlate with long term tumor protection and antitumor effects against TC-1 and EG.7 tumors in mice. Finally, we demonstrated that PAUF mediated DC activation and immune stimulation are dependent on TLR4. Our data provides evidence supporting PAUF as a promising adjuvant for DC based therapies, which can be applied in conjunction with other cancer therapies. Most importantly, our results serve as a reference for future investigation of human based adjuvants. PMID:26336989

  6. Podosomes of dendritic cells facilitate antigen sampling

    PubMed Central

    Reinieren-Beeren, Inge; Cambi, Alessandra; Figdor, Carl G.; van den Bogaart, Geert

    2014-01-01

    Summary Dendritic cells sample the environment for antigens and play an important role in establishing the link between innate and acquired immunity. Dendritic cells contain mechanosensitive adhesive structures called podosomes that consist of an actin-rich core surrounded by integrins, adaptor proteins and actin network filaments. They facilitate cell migration via localized degradation of extracellular matrix. Here we show that podosomes of human dendritic cells locate to spots of low physical resistance in the substrate (soft spots) where they can evolve into protrusive structures. Pathogen recognition receptors locate to these protrusive structures where they can trigger localized antigen uptake, processing and presentation to activate T-cells. Our data demonstrate a novel role in antigen sampling for podosomes of dendritic cells. PMID:24424029

  7. Podosomes of dendritic cells facilitate antigen sampling.

    PubMed

    Baranov, Maksim V; Ter Beest, Martin; Reinieren-Beeren, Inge; Cambi, Alessandra; Figdor, Carl G; van den Bogaart, Geert

    2014-03-01

    Dendritic cells sample the environment for antigens and play an important role in establishing the link between innate and acquired immunity. Dendritic cells contain mechanosensitive adhesive structures called podosomes that consist of an actin-rich core surrounded by integrins, adaptor proteins and actin network filaments. They facilitate cell migration via localized degradation of extracellular matrix. Here, we show that podosomes of human dendritic cells locate to spots of low physical resistance in the substrate (soft spots) where they can evolve into protrusive structures. Pathogen recognition receptors locate to these protrusive structures where they can trigger localized antigen uptake, processing and presentation to activate T-cells. Our data demonstrate a novel role in antigen sampling for the podosomes of dendritic cells.

  8. Signalling pathways involved in the activation of dendritic cells by layered double hydroxide nanoparticles.

    PubMed

    Li, Ang; Qin, Lili; Zhu, Di; Zhu, Rongrong; Sun, Jing; Wang, Shilong

    2010-02-01

    Layered double hydroxide (LDH) nanoparticles are attractive as potential drug vectors for the targeting not only of tissues, but also of intracellular organelles, and particularly the acidic endolysosomes created after cell endocytosis. The purpose of this study was to investigate the ability of LDH nanoparticles designed as vectors to activate dendritic cells (DCs), as measured by various cellular functions. The study also explored the possible signaling pathway through which the LDH nanoparticles exerted their effects on the cellular functions of DCs. First, LDH nanoparticles with different ratios of Mg(OH)(2) to Al(OH)(3) (1:1, 2:1 and 3:1, called R1, R2 and R3 respectively) were optimized and had a hydrodynamic diameter of 57 nm with a zeta potential of +35 mV. Then, the efficient endocytosis of the optimized LDH nanoparticles by bone marrow-derived dendritic cells (MDDCs) was monitored by fluorescence-activated cell sorting. The effect of R1, R2 and R3 on the expression of the pro- and anti-inflammatory cytokines (TNF-alpha, IL-6, and IL-12) and the co-stimulatory molecules (CD40, CD80, CD86, and MHC class II) in MDDCs was examined. The exposure of R1 caused a dose-dependent increase in the expression of TNF-alpha, IL-12, CD86 and CD40, while R2 and R3 did not up-regulate these cytokines and co-stimulatory molecules. Migration assays showed that R1 could increase the migration capacity of DCs to CCL21 and up-regulate the expression of CCR7. Furthermore, we found that R1 significantly increased the NF-kappaB expression in the nucleus (in a dose-dependent manner) and promoted the degradation of total IkappaBalpha levels, indicating that the NF-kappaB signaling pathway might involve in an R1-induced DC activation. Our results suggested that LDH nanoparticles, in the future, may function as a useful vector for ex vivo engineering to promote vaccine delivery in immune cells.

  9. The Combination of MBP and BCG-Induced Dendritic Cell Maturation through TLR2/TLR4 Promotes Th1 Activation In Vitro and Vivo

    PubMed Central

    Jiang, LiNa; Liu, GuoMu; Ni, WeiHua; Zhang, NanNan; Jie, Jing; Xie, Fei

    2017-01-01

    To explore whether TLR2/TLR4 could be involved in the maturation of dendritic cells and polarization of CD4+ T cells induced by dendritic cells stimulated with MBP and BCG, in vitro and in vivo experiments using TLR2−/− or TLR4−/− mice were employed. MBP and BCG elevated CD80, CD86 and MHC class II expressed on dendritic cells and increased IL-12 protein, induced DC maturation, and indirectly promoted Th1 activation. Moreover, MBP and BCG upregulated costimulatory molecules on DCs in a TLR2- and TLR4-dependent manner. The levels of IFN-γ, IL-4, and IL-10 in CD4+ T cells cocultured with dendritic cells from different types of mice were determined with ELISPOT or ELISA method. TLR2/TLR4 is important in the maturation and activation of dendritic cells and the activation of Th1 cells induced by stimulation with MBP and BCG. In conclusion, TLR2 and TLR4 play an important role in the upregulation of costimulatory molecules and MHC class II molecules on dendritic cells and the activation of Th1 cells induced by stimulation with MBP and BCG. The results above indicate that the combination of MBP and BCG induced the maturation and activation of dendritic cells and promoted Th1 activation via TLR2/TLR4. PMID:28293065

  10. Enveloped Viruses Disable Innate Immune Responses in Dendritic Cells by Direct Activation of TAM Receptors

    PubMed Central

    Bhattacharyya, Suchita; Zagórska, Anna; Lew, Erin D.; Shrestha, Bimmi; Rothlin, Carla V.; Naughton, John; Diamond, Michael S.; Lemke, Greg; Young, John A.T.

    2013-01-01

    SUMMARY Upon activation by the ligands Gas6 and Protein S, TAM receptor tyrosine kinases promote phagocytic clearance of apoptotic cells and downregulate immune responses initiated by Toll-like receptors and type I interferons (IFNs). Many enveloped viruses display the phospholipid phosphatidylserine on their membranes, through which they bind Gas6 and Protein S and engage TAM receptors. We find that ligand-coated viruses activate TAM receptors on dendritic cells (DCs), dampen type I IFN signaling, and thereby evade host immunity and promote infection. Upon virus challenge, TAM-deficient DCs display type I IFN responses that are elevated in comparison to wild-type cells. As a consequence, TAM-deficient DCs are relatively resistant to infection by flaviviruses and pseudotyped retroviruses, but infection can be restored with neutralizing type I IFN antibodies. Correspondingly, a TAM kinase inhibitor antagonizes the infection of wild-type DCs. Thus, TAM receptors are engaged by viruses in order to attenuate type I IFN signaling and represent potential therapeutic targets. PMID:23954153

  11. Immature human dendritic cells enhance their migration through KCa3.1 channel activation.

    PubMed

    Crottès, David; Félix, Romain; Meley, Daniel; Chadet, Stéphanie; Herr, Florence; Audiger, Cindy; Soriani, Olivier; Vandier, Christophe; Roger, Sébastien; Angoulvant, Denis; Velge-Roussel, Florence

    2016-04-01

    Migration capacity is essential for dendritic cells (DCs) to present antigen to T cells for the induction of immune response. The DC migration is supposed to be a calcium-dependent process, while not fully understood. Here, we report a role of the KCa3.1/IK1/SK4 channels in the migration capacity of both immature (iDC) and mature (mDC) human CD14(+)-derived DCs. KCa3.1 channels were shown to control the membrane potential of human DC and the Ca(2+) entry, which is directly related to migration capacities. The expression of migration marker such as CCR5 and CCR7 was modified in both types of DCs by TRAM-34 (100nM). But, only the migration of iDC was decreased by use of both TRAM-34 and KCa3.1 siRNA. Confocal analyses showed a close localization of CCR5 with KCa3.1 in the steady state of iDC. Finally, the implication of KCa3.1 seems to be limited to the migration capacities as T cell activation of DCs appeared unchanged. Altogether, these results demonstrated that KCa3.1 channels have a pro-migratory effect on iDC migration. Our findings suggest that KCa3.1 in human iDC play a major role in their migration and constitute an attractive target for the cell therapy optimization.

  12. Inhibition of human dendritic cell activation by hydroethanolic but not lipophilic extracts of turmeric (Curcuma longa).

    PubMed

    Krasovsky, Joseph; Chang, David H; Deng, Gary; Yeung, Simon; Lee, Mavis; Leung, Ping Chung; Cunningham-Rundles, Susanna; Cassileth, Barrie; Dhodapkar, Madhav V

    2009-03-01

    Turmeric has been extensively utilized in Indian and Chinese medicine for its immune-modulatory properties. Dendritic cells (DCs) are antigen-presenting cells specialized to initiate and regulate immunity. The ability of DCs to initiate immunity is linked to their activation status. The effects of turmeric on human DCs have not been studied. Here we show that hydroethanolic (HEE) but not lipophilic "supercritical" extraction (SCE) of turmeric inhibits the activation of human DCs in response to inflammatory cytokines. Treatment of DCs with HEE also inhibits the ability of DCs to stimulate the mixed lymphocyte reaction (MLR). Importantly, the lipophilic fraction does not synergize with the hydroethanolic fraction for the ability of inhibiting DC maturation. Rather, culturing of DCs with the combination of HEE and SCE leads to partial abrogation of the effects of HEE on the MLR initiated by DCs. These data provide a mechanism for the anti-inflammatory properties of turmeric. However, they suggest that these extracts are not synergistic and may contain components with mutually antagonistic effects on human DCs. Harnessing the immune effects of turmeric may benefit from specifically targeting the active fractions.

  13. Lentivirally engineered dendritic cells activate AFP-specific T cells which inhibit hepatocellular carcinoma growth in vitro and in vivo.

    PubMed

    Liu, Yang; Butterfield, Lisa H; Fu, Xiaohui; Song, Zhenshun; Zhang, Xiaoping; Lu, Chongde; Ding, Guanghui; Wu, Mengchao

    2011-07-01

    α-fetoprotein (AFP), a tumor-associated antigen for hepatocellular carcinoma (HCC), is an established biomarker for HCC. In this study, we created a lentivirus expressing the AFP antigen and investigated the anti-tumor activity of AFP-specific CD8+ T cells, with and without CD4+ T cells, which were activated by either AFP peptide-pulsed or Lenti-AFP-engineered Dendritic cells (DCs) in vitro and in vivo. AFP-specific T cells could efficiently kill HepG2 HCC cells, and produced IL-2, IFN-γ, TNF-α, perforin and granzyme B, with minimal production of IL-10 (a negative regulator of T cell activation). Both strategies activated AFP-specific T cells, but the lentiviral strategy was superior by several measures. Data also support an impact of CD4+ T cells in supporting anti-tumor activity. In vivo studies in a xenograft HCC tumor model also showed that AFP-specific T cells could markedly suppress HCC tumor formation and morbidity in tumor-bearing nude mice, as well as regulate serum levels of related cytokines and anti-tumor molecules. In parallel with human in vitro T cell cultures, the in vivo model demonstrated superior anti-tumor effects and Th1-skewing with Lenti-AFP-DCs. This study supports the superiority of a full-length antigen lentivirus-based DCs vaccine strategy over peptides, and provides new insight into the design of DCs-based vaccines.

  14. Dendritic cells and parasites: from recognition and activation to immune response instruction.

    PubMed

    Motran, Claudia Cristina; Ambrosio, Laura Fernanda; Volpini, Ximena; Celias, Daiana Pamela; Cervi, Laura

    2017-02-01

    The effective defense against parasite infections requires the ability to mount an appropriate and controlled specific immune response able to eradicate the invading pathogen while limiting the collateral damage to self-tissues. Dendritic cells are key elements for the development of immunity against parasites; they control the responses required to eliminate these pathogens while maintaining host homeostasis. Ligation of dendritic cell pattern recognition receptors by pathogen-associated molecular pattern present in the parasites initiates signaling pathways that lead to the production of surface and secreted proteins that are required, together with the antigen, to induce an appropriate and timely regulated immune response. There is evidence showing that parasites can influence and regulate dendritic cell functions in order to promote a more permissive environment for their survival. In this review, we will focus on new insights about the ability of protozoan and helminth parasites or their products to modify dendritic cell function and discuss how this interaction is crucial in shaping the host response.

  15. 3-bromopyruvate ameliorate autoimmune arthritis by modulating Th17/Treg cell differentiation and suppressing dendritic cell activation

    PubMed Central

    Okano, Takaichi; Saegusa, Jun; Nishimura, Keisuke; Takahashi, Soshi; Sendo, Sho; Ueda, Yo; Morinobu, Akio

    2017-01-01

    Recent studies have shown that cellular metabolism plays an important role in regulating immune cell functions. In immune cell differentiation, both interleukin-17-producing T (Th17) cells and dendritic cells (DCs) exhibit increased glycolysis through the upregulation of glycolytic enzymes, such as hexokinase-2 (HK2). Blocking glycolysis with 2-deoxyglucose was recently shown to inhibit Th17 cell differentiation while promoting regulatory T (Treg) cell generation. However, 2-DG inhibits all isoforms of HK. Thus, it is unclear which isoform has a critical role in Th17 cell differentiation and in rheumatoid arthritis (RA) pathogenesis. Here we demonstrated that 3-bromopyruvate (BrPA), a specific HK2 inhibitor, significantly decreased the arthritis scores and the histological scores in SKG mice, with a significant increase in Treg cells, decrease in Th17 cells, and decrease in activated DCs in the spleen. In vitro, BrPA facilitated the differentiation of Treg cells, suppressed Th17 cells, and inhibited the activation of DCs. These results suggested that BrPA may be a therapeutic target of murine arthritis. Although the role of IL-17 is not clarified in the treatment of RA, targeting cell metabolism to alter the immune cell functions might lead to a new therapeutic strategy for RA. PMID:28186160

  16. 3-bromopyruvate ameliorate autoimmune arthritis by modulating Th17/Treg cell differentiation and suppressing dendritic cell activation.

    PubMed

    Okano, Takaichi; Saegusa, Jun; Nishimura, Keisuke; Takahashi, Soshi; Sendo, Sho; Ueda, Yo; Morinobu, Akio

    2017-02-10

    Recent studies have shown that cellular metabolism plays an important role in regulating immune cell functions. In immune cell differentiation, both interleukin-17-producing T (Th17) cells and dendritic cells (DCs) exhibit increased glycolysis through the upregulation of glycolytic enzymes, such as hexokinase-2 (HK2). Blocking glycolysis with 2-deoxyglucose was recently shown to inhibit Th17 cell differentiation while promoting regulatory T (Treg) cell generation. However, 2-DG inhibits all isoforms of HK. Thus, it is unclear which isoform has a critical role in Th17 cell differentiation and in rheumatoid arthritis (RA) pathogenesis. Here we demonstrated that 3-bromopyruvate (BrPA), a specific HK2 inhibitor, significantly decreased the arthritis scores and the histological scores in SKG mice, with a significant increase in Treg cells, decrease in Th17 cells, and decrease in activated DCs in the spleen. In vitro, BrPA facilitated the differentiation of Treg cells, suppressed Th17 cells, and inhibited the activation of DCs. These results suggested that BrPA may be a therapeutic target of murine arthritis. Although the role of IL-17 is not clarified in the treatment of RA, targeting cell metabolism to alter the immune cell functions might lead to a new therapeutic strategy for RA.

  17. Rotavirus Infection Activates Dendritic Cells from Peyer's Patches in Adult Mice ▿ †

    PubMed Central

    Lopez-Guerrero, Delia V.; Meza-Perez, Selene; Ramirez-Pliego, Oscar; Santana-Calderon, Maria A.; Espino-Solis, Pavel; Gutierrez-Xicotencatl, Lourdes; Flores-Romo, Leopoldo; Esquivel-Guadarrama, Fernando R.

    2010-01-01

    This study used an in vivo mouse model to analyze the response of dendritic cells (DCs) in Peyer's patches (PPs) within the first 48 h of infection with the wild-type murine rotavirus EDIM (EDIMwt). After the infection, the absolute number of DCs was increased by 2-fold in the PPs without a modification of their relative percentage of the total cell number. Also, the DCs from PPs of infected mice showed a time-dependent migration to the subepithelial dome (SED) and an increase of the surface activation markers CD40, CD80, and CD86. This response was more evident at 48 h postinfection (p.i.) and depended on viral replication, since DCs from PPs of mice inoculated with UV-treated virus did not show this phenotype. As a result of the activation, the DCs showed an increase in the expression of mRNA for the proinflammatory cytokines interleukin-12/23p40 (IL-12/23p40), tumor necrosis factor alpha (TNF-α), and beta interferon (IFN-β), as well as for the regulatory cytokine IL-10. These results suggest that, a short time after rotavirus infection, the DCs from PPs play a critical role in controlling the infection and, at the same time, avoiding an excessive inflammatory immune response. PMID:20007263

  18. CD45R, CD44 and MHC class II are signaling molecules for the cytoskeleton-dependent induction of dendrites and motility in activated B cells.

    PubMed

    Partida-Sánchez, S; Garibay-Escobar, A; Frixione, E; Parkhouse, R M; Santos-Argumedo, L

    2000-09-01

    Anti-CD44 or anti-MHC II antibodies bound to tissue culture plates have previously been shown to induce a dramatic generation of dendritic processes in activated murine B cells. In this study, we demonstrate a similar generation of dendrites and cell motility in activated B cells through CD45R. The dynamic formation of dendritic processes and associated induction of cell motility were analyzed by video microscopy and were characterized by a rapid, and multidirectional emission of dendrites with retractile behavior. The addition of cytochalasin E totally blocked dendrites formation and motility induced through either CD45R, CD44 or MHC II, suggesting that the necessary cytoskeletal rearrangements require active polymerization of actin. Confocal microscopy showed an accumulation of F-actin in the dendrites, as long as cells were elongating. In contrast, G-actin was localized in the perinuclear area and also accumulated in sites where dendrites originated. Preincubation of B cells with staurosporine (a PKC inhibitor) or BAPTA-AM (a calcium chelator) prevented these morphological changes, indicating additionally a requirement for a PKC-calcium-dependent activity. Dendrite formation and cellular motility, therefore, seem to be two manifestations of the same phenomenon, and CD44, CD45R and MHC II appear to be signaling molecules for the observed cytoskeleton-dependent morphological changes.

  19. Gemcitabine-treated pancreatic cancer cell medium induces the specific CTL antitumor activity by stimulating the maturation of dendritic cells.

    PubMed

    Pei, Qingshan; Pan, Jianmei; Zhu, Hao; Ding, Xiwei; Liu, Wenjia; Lv, Ying; Zou, Xiaoping; Luo, Hesheng

    2014-03-01

    Gemcitabine (GEM) is a first line chemotherapeutic drug for advanced pancreatic cancer. Dendritic cell (DC) vaccine is a promising method of immunotherapy for malignant tumor. Recent research has indicated that gemcitabine can enhance the efficacy of DC vaccine, but precise mechanism is still unknown. Here, we aimed to investigate the effect of GEM on DCs. The results showed that GEM-treated pancreatic cancer cell medium stimulated maturation of DCs. When co-cultured with autologous T lymphocytes, the pulsed DCs promoted the proliferation of T cells, and exhibited specific cytotoxic T lymphocytes (CTLs) antitumor activity. Further research showed that stimulation of DC maturation may be related to the elevated level of Hsp70 induced by GEM. Our study indicates that GEM changes the immunogenicity of tumor cells, and enhances the efficacy of DC based immunotherapy for pancreatic cancer.

  20. Indirect activation of naïve CD4+ T cells by dendritic cell-derived exosomes.

    PubMed

    Théry, Clotilde; Duban, Livine; Segura, Elodie; Véron, Philippe; Lantz, Olivier; Amigorena, Sebastian

    2002-12-01

    Dendritic cells (DCs) secrete vesicles of endosomal origin, called exosomes, that bear major histocompatibility complex (MHC) and T cell costimulatory molecules. Here, we found that injection of antigen- or peptide-bearing exosomes induced antigen-specific naïve CD4+ T cell activation in vivo. In vitro, exosomes did not induce antigen-dependent T cell stimulation unless mature CD8alpha- DCs were also present in the cultures. These mature DCs could be MHC class II-negative, but had to bear CD80 and CD86. Therefore, in addition to carrying antigen, exosomes promote the exchange of functional peptide-MHC complexes between DCs. Such a mechanism may increase the number of DCs bearing a particular peptide, thus amplifying the initiation of primary adaptive immune responses.

  1. Expression of the RelB transcription factor correlates with the activation of human dendritic cells

    PubMed Central

    Clark, G J; Gunningham, S; Troy, A; Vuckovic, S; Hart, D N J

    1999-01-01

    The RelB gene product is a member of the nuclear factor (NF)-κB family of transcription factors. It has been identified recently within mouse antigen-presenting cells and human monocyte-derived dendritic cells (DC). Disruption of the mouse RelB gene is accompanied, amongst other phenotypes, by abnormalities in the antigen-presenting cell lineages. In order to define RelB expression during human DC differentiation, we have analysed RelB mRNA by reverse transcriptase–polymerase chain reaction and RelB protein by intracellular staining in CD34+ precursors and different types of DC preparations. RelB mRNA was not detected in CD34+ precursor populations. Fresh blood DC (lineage−human leucocyte antigen-DR+ (lin−HLA-DR+)) lacked RelB mRNA and cytoplasmic RelB protein but a period of in vitro culture induced RelB expression in blood DC. Purified Langerhans’ cells (LC) (CD1a+ HLA-DR+) failed to express RelB mRNA. Immunocytochemical staining identified RelB protein in human skin epithelium. RelB protein was expressed in a very few CD1a+, CD83+ or CMRF-44+ dermal DC but was not present in CD1a+ LC. Tonsil DC (lin−HLA-DR+ CMRF-44+) were positive for RelB mRNA and RelB protein. Intestinal DC (HLA-DR+) also lacked immunoreactive RelB protein. The majority of interdigitating CD83+, CMRF-44+, CMRF-56+ or p55+ DC located in paracortical T-lymphocyte areas of lymph node and tonsil contained RelB protein. The expression of RelB mRNA and RelB protein correlates with the activated phase of blood DC and the postmigration cell (activated) stage of tissue DC development. PMID:10540217

  2. Dendritic cell editing by activated natural killer cells results in a more protective cancer-specific immune response.

    PubMed

    Morandi, Barbara; Mortara, Lorenzo; Chiossone, Laura; Accolla, Roberto S; Mingari, Maria Cristina; Moretta, Lorenzo; Moretta, Alessandro; Ferlazzo, Guido

    2012-01-01

    Over the last decade, several studies have extensively reported that activated natural killer (NK) cells can kill autologous immature dendritic cells (DCs) in vitro, whereas they spare fully activated DCs. This led to the proposal that activated NK cells might select a more immunogenic subset of DCs during a protective immune response. However, there is no demonstration that autologous DC killing by NK cells is an event occurring in vivo and, consequently, the functional relevance of this killing remains elusive. Here we report that a significant decrease of CD11c(+) DCs was observed in draining lymph nodes of mice inoculated with MHC-devoid cells as NK cell targets able to induce NK cell activation. This in vivo DC editing by NK cells was perforin-dependent and it was functionally relevant, since residual lymph node DCs displayed an improved capability to induce T cell proliferation. In addition, in a model of anti-cancer vaccination, the administration of MHC-devoid cells together with tumor cells increased the number of tumor-specific CTLs and resulted in a significant increase in survival of mice upon challenge with a lethal dose of tumor cells. Depletion of NK cells or the use of perforin knockout mice strongly decreased the tumor-specific CTL expansion and its protective role against tumor cell challenge. As a whole, our data support the hypothesis that NK cell-mediated DC killing takes place in vivo and is able to promote expansion of cancer-specific CTLs. Our results also indicate that cancer vaccines could be improved by strategies aimed at activating NK cells.

  3. Aryl hydrocarbon receptor activation inhibits in vitro differentiation of human monocytes and Langerhans dendritic cells.

    PubMed

    Platzer, Barbara; Richter, Susanne; Kneidinger, Doris; Waltenberger, Darina; Woisetschläger, Maximilian; Strobl, Herbert

    2009-07-01

    The transcription factor aryl hydrocarbon receptor (AhR) represents a promising therapeutic target in allergy and autoimmunity. AhR signaling induced by the newly described ligand VAF347 inhibits allergic lung inflammation as well as suppresses pancreatic islet allograft rejection. These effects are likely mediated via alterations in dendritic cell (DC) function. Moreover, VAF347 induces tolerogenic DCs. Langerhans cells (LCs) are immediate targets of exogenous AhR ligands at epithelial surfaces; how they respond to AhR ligands remained undefined. We studied AhR expression and function in human LCs and myelopoietic cell subsets using a lineage differentiation and gene transduction model of human CD34(+) hematopoietic progenitors. We found that AhR is highly regulated during myeloid subset differentiation. LCs expressed highest AhR levels followed by monocytes. Conversely, neutrophil granulocytes lacked AhR expression. AhR ligands including VAF347 arrested the differentiation of monocytes and LCs at an early precursor cell stage, whereas progenitor cell expansion or granulopoiesis remained unimpaired. AhR expression was coregulated with the transcription factor PU.1 during myeloid subset differentiation. VAF347 inhibited PU.1 induction during initial monocytic differentiation, and ectopic PU.1 restored monocyte and LC generation in the presence of this compound. AhR ligands failed to interfere with cytokine receptor signaling during LC differentiation and failed to impair LC activation/maturation. VAF347-mediated antiproliferative effect on precursors undergoing LC lineage differentiation occurred in a clinically applicable serum-free culture model and was not accompanied by apoptosis induction. In conclusion, AhR agonist signaling interferes with transcriptional processes leading to monocyte/DC lineage commitment of human myeloid progenitor cells.

  4. Activation of Fc gamma RI on monocytes triggers differentiation into immature dendritic cells that induce autoreactive T cell responses.

    PubMed

    Tanaka, Motoyuki; Krutzik, Stephan R; Sieling, Peter A; Lee, Delphine J; Rea, Thomas H; Modlin, Robert L

    2009-08-15

    The formation of immune complexes results in activation of the innate immune system and subsequent induction of host inflammatory responses. In particular, the binding of IgG immune complexes to FcgammaR on monocytes triggers potent inflammatory responses leading to tissue injury in disease. We investigated whether activation of monocytes via FcgammaR induced cell differentiation, imparting specific inflammatory functions of the innate immune response. Human IgG alone induced monocytes to differentiate into cells with an immature dendritic cell (iDC) phenotype, including up-regulation of CD1b, CD80, CD86, and CD206. Differentiation into CD1b(+) iDC was dependent on activation via CD64 (FcgammaRI) and induction of GM-CSF. The human IgG-differentiated iDC were phenotypically different from GM-CSF-derived iDC at the same level of CD1b expression, with higher cell surface CD86, but lower MHC class II, CD32, CD206, and CD14. Finally, in comparison to GM-CSF-derived iDC, IgG-differentiated iDC were more efficient in activating T cells in both autologous and allogeneic mixed lymphocyte reactions but less efficient at presenting microbial Ag to T cells. Therefore, activation of FcgammaRI on monocytes triggers differentiation into specialized iDC with the capacity to expand autoreactive T cells that may contribute to the pathogenesis of immune complex-mediated tissue injury.

  5. Sirtuin 1 Regulates Dendritic Cell Activation and Autophagy during Respiratory Syncytial Virus-Induced Immune Responses.

    PubMed

    Owczarczyk, Anna B; Schaller, Matthew A; Reed, Michelle; Rasky, Andrew J; Lombard, David B; Lukacs, Nicholas W

    2015-08-15

    Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract infection in children worldwide. Sirtuin 1 (SIRT1), an NAD(+)-dependent deacetylase, has been associated with the induction of autophagy and the regulation of inflammatory mediators. We found that Sirt1 was upregulated in mouse lung after RSV infection. Infected animals that received EX-527, a selective SIRT1 inhibitor, displayed exacerbated lung pathology, with increased mucus production, elevated viral load, and enhanced Th2 cytokine production. Gene expression analysis of isolated cell populations revealed that Sirt1 was most highly upregulated in RSV-treated dendritic cells (DCs). Upon RSV infection, EX-527-treated DCs, Sirt1 small interfering RNA-treated DCs, or DCs from conditional knockout (Sirt1(f/f)-CD11c-Cre(+)) mice showed downregulated inflammatory cytokine gene expression and attenuated autophagy. Finally, RSV infection of Sirt1(f/f)-CD11c-Cre(+) mice resulted in altered lung and lymph node cytokine responses, leading to exacerbated pathology. These data indicate that SIRT1 promotes DC activation associated with autophagy-mediated processes during RSV infection, thereby directing efficient antiviral immune responses.

  6. Space exploration by dendritic cells requires maintenance of myosin II activity by IP3 receptor 1.

    PubMed

    Solanes, Paola; Heuzé, Mélina L; Maurin, Mathieu; Bretou, Marine; Lautenschlaeger, Franziska; Maiuri, Paolo; Terriac, Emmanuel; Thoulouze, Maria-Isabel; Launay, Pierre; Piel, Matthieu; Vargas, Pablo; Lennon-Duménil, Ana-Maria

    2015-03-12

    Dendritic cells (DCs) patrol the interstitial space of peripheral tissues. The mechanisms that regulate their migration in such constrained environment remain unknown. We here investigated the role of calcium in immature DCs migrating in confinement. We found that they displayed calcium oscillations that were independent of extracellular calcium and more frequently observed in DCs undergoing strong speed fluctuations. In these cells, calcium spikes were associated with fast motility phases. IP₃ receptors (IP₃Rs) channels, which allow calcium release from the endoplasmic reticulum, were identified as required for immature DCs to migrate at fast speed. The IP₃R1 isoform was further shown to specifically regulate the locomotion persistence of immature DCs, that is, their capacity to maintain directional migration. This function of IP₃R1 results from its ability to control the phosphorylation levels of myosin II regulatory light chain (MLC) and the back/front polarization of the motor protein. We propose that by upholding myosin II activity, constitutive calcium release from the ER through IP₃R1 maintains DC polarity during migration in confinement, facilitating the exploration of their environment.

  7. Clostridium difficile toxin B intoxicated mouse colonic epithelial CT26 cells stimulate the activation of dendritic cells

    PubMed Central

    Huang, Tuxiong; Perez-Cordon, Gregorio; Shi, Lianfa; Li, Guangchao; Sun, Xingmin; Wang, Xiaoning; Wang, Jufang; Feng, Hanping

    2015-01-01

    Clostridium difficile causes antibiotic-associated diarrhea and pseudomembranous colitis mainly through two exotoxins TcdA and TcdB that target intestinal epithelial cells. Dendritic cells (DCs) play an important role in regulating intestinal inflammatory responses. In the current study, we explored the interaction of TcdB-intoxicated epithelial cells with mouse bone marrow-derived DCs. TcdB induced cell death and heat shock protein translocation in mouse intestinal epithelial CT26 cells. The intoxicated epithelial cells promoted the phagocytosis and the TNF-α secretion by DCs. Incubation with TcdB-intoxicated CT26 cells stimulated DC maturation. Moreover, TcdB-treated CT26 cells induced DC immigration when they were injected into mice subcutaneously. Taken together, these data demonstrate that TcdB-intoxicated intestinal epithelial cells are able to stimulate DC activation in vitro and attract DCs in vivo, indicating that epithelial cells may be able to regulate DC activation under the exposure of TcdB during C. difficile infection. PMID:25743476

  8. Clostridium difficile toxin B intoxicated mouse colonic epithelial CT26 cells stimulate the activation of dendritic cells.

    PubMed

    Huang, Tuxiong; Perez-Cordon, Gregorio; Shi, Lianfa; Li, Guangchao; Sun, Xingmin; Wang, Xiaoning; Wang, Jufang; Feng, Hanping

    2015-04-01

    Clostridium difficile causes antibiotic-associated diarrhea and pseudomembranous colitis mainly through two exotoxins TcdA and TcdB that target intestinal epithelial cells. Dendritic cells (DCs) play an important role in regulating intestinal inflammatory responses. In the current study, we explored the interaction of TcdB-intoxicated epithelial cells with mouse bone marrow-derived DCs. TcdB induced cell death and heat shock protein translocation in mouse intestinal epithelial CT26 cells. The intoxicated epithelial cells promoted the phagocytosis and the TNF-α secretion by DCs. Incubation with TcdB-intoxicated CT26 cells stimulated DC maturation. Moreover, TcdB-treated CT26 cells induced DC immigration when they were injected into mice subcutaneously. Taken together, these data demonstrate that TcdB-intoxicated intestinal epithelial cells are able to stimulate DC activation in vitro and attract DCs in vivo, indicating that epithelial cells may be able to regulate DC activation under the exposure of TcdB during C. difficile infection.

  9. Comparison The Effects of Two Monocyte Isolation Methods, Plastic Adherence and Magnetic Activated Cell Sorting Methods, on Phagocytic Activity of Generated Dendritic Cells

    PubMed Central

    Delirezh, Nowruz; Shojaeefar, Ehsan; Parvin, Parva; Asadi, Behnaz

    2013-01-01

    Objective: It is believed that monocyte isolation methods and maturation factors affect the phenotypic and functional characteristics of resultant dendritic cells (DC). In the present study, we compared two monocyte isolation methods, including plastic adherence-dendritic cells (Adh-DC) and magnetic activated cell sorting- dendritic cells (MACS-DC), and their effects on phagocytic activity of differentiated immature DCs (immDCs). Materials and Methods: : In this experimental study, immDCs were generated from plastic adherence and MACS isolated monocytes in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin 4 (IL-4) in five days. The phagocytic activity of immDCs was analyzed by fluorescein isothiocyanate (FITC)-conjugated latex bead using flow cytometry. One way ANOVA test was used for statistical analysis of differences among experimental groups, including Adh-DC and MACS-DC groups. Results: We found that phagocytic activity of Adh-DC was higher than MACS-DC, whereas the mean fluorescence intensity (MFI) of phagocytic cells was higher in MACS-DC (p<0.05). Conclusion: : We concluded that it would be important to consider phagocytosis parameters of generated DCs before making any decision about monocyte isolation methods to have fully functional DCs. PMID:24027662

  10. Plasmacytoid dendritic cells alter the antitumor activity of CpG-oligodeoxynucleotides in a mouse model of lung carcinoma.

    PubMed

    Sorrentino, Rosalinda; Morello, Silvana; Luciano, Antonio; Crother, Timothy R; Maiolino, Piera; Bonavita, Eduardo; Arra, Claudio; Adcock, Ian M; Arditi, Moshe; Pinto, Aldo

    2010-10-15

    The effect of CpG-oligodeoxynucleotides (CpG) has been studied on a number of tumors. Although CpG may facilitate tumor regression in mouse models of melanoma, its activity in lung cancer is unclear. The aim of our study was to elucidate the effect of CpG (0.5-50 μg/mouse) in a mouse model of Lewis lung carcinoma cell-induced lung cancer. Lung tumor growth increased at 3 and 7 d after a single administration of CpG. This was associated with a greater influx of plasmacytoid dendritic cells (pDCs), immature myeloid dendritic cells, and greater recruitment of regulatory T cells. Depletion of pDCs using a specific Ab (m927) reversed the immune-suppressive environment and resulted in a decreased lung tumor burden, accompanied by a greater influx of active myeloid dendritic cells and CD8(+) T cells, and a higher production of Th1- and Th17-like cytokines. Furthermore, the rate of apoptosis in the lungs of mice treated with CpG increased following the depletion of pDCs. CpG treatment alone does not lead to tumor regression in the lung. However, ablation of pDCs renders CpG a good adjuvant for lung cancer chemotherapy in this experimental model.

  11. Monocyte-Derived Dendritic Cells Are Essential for CD8+ T Cell Activation and Antitumor Responses After Local Immunotherapy

    PubMed Central

    Kuhn, Sabine; Yang, Jianping; Ronchese, Franca

    2015-01-01

    Tumors harbor several populations of dendritic cells (DCs) with the ability to prime tumor-specific T cells. However, these T cells mostly fail to differentiate into armed effectors and are unable to control tumor growth. We have previously shown that treatment with immunostimulatory agents at the tumor site can activate antitumor immune responses and is associated with the appearance of a population of monocyte-derived DCs (moDCs) in the tumor and tumor-draining lymph node (dLN). Here, we use depletion of DCs or monocytes and monocyte transfer to show that these moDCs are critical to the activation of antitumor immune responses. Treatment with the immunostimulatory agents monosodium urate crystals and Mycobacterium smegmatis induced the accumulation of monocytes in the dLN, their upregulation of CD11c and MHCII, and expression of iNOS, TNFα, and IL12p40. Blocking monocyte entry into the lymph node and tumor through neutralization of the chemokine CCL2 or inhibition of colony-stimulating factor-1 receptor signaling prevented the generation of moDCs, the infiltration of tumor-specific T cells into the tumor, and antitumor responses. In a reciprocal fashion, monocytes transferred into mice depleted of CD11c+ cells were sufficient to rescue CD8+ T cell priming in lymph node and delay tumor growth. Thus, monocytes exposed to the appropriate conditions become powerful activators of tumor-specific CD8+ T cells and antitumor immunity. PMID:26635798

  12. Inducible expression of endomorphins in murine dendritic cells.

    PubMed

    Yang, Xiaohuai; Xia, Hui; Chen, Yong; Liu, Xiaofen; Zhou, Cheng; Gao, Qin; Li, Zhenghong

    2012-12-15

    Bone marrow precursor cells were extracted from C57BL/6J mice aged 7-8 weeks, and dendritic cells were purified using anti-CD11c (a specific marker for dendritic cells) antibody-coated magnetic beads. Immunofluorescence staining revealed that the expression levels of endomorphin-1 and endomorphin-2 were upregulated in dendritic cells activated by lipopolysaccharide. An enzyme immunoassay showed that lipopolysaccharide and other Toll-like receptor ligands promoted the secretion of endomorphin-1 and endomorphin-2 from activated dendritic cells. [(3)H]-thymidine incorporation demonstrated that endomorphin-1 and endomorphin-2 both inhibited the proliferation of T lymphocyte induced by activated dendritic cells. Furthermore, this immunosuppressive effect was blocked by CTOP, a specific antagonist of µ-opioid receptors. Our experimental findings indicate that activated dendritic cells can induce the expression and secretion of endomorphins, and that endomorphins suppress T lymphocyte proliferation through activation of µ-opioid receptors.

  13. The 40-year history of modeling active dendrites in cerebellar Purkinje cells: emergence of the first single cell “community model”

    PubMed Central

    Bower, James M.

    2015-01-01

    The subject of the effects of the active properties of the Purkinje cell dendrite on neuronal function has been an active subject of study for more than 40 years. Somewhat unusually, some of these investigations, from the outset have involved an interacting combination of experimental and model-based techniques. This article recounts that 40-year history, and the view of the functional significance of the active properties of the Purkinje cell dendrite that has emerged. It specifically considers the emergence from these efforts of what is arguably the first single cell “community” model in neuroscience. The article also considers the implications of the development of this model for future studies of the complex properties of neuronal dendrites. PMID:26539104

  14. Differential involvement of IFN-beta in Toll-like receptor-stimulated dendritic cell activation.

    PubMed

    Hoshino, Katsuaki; Kaisho, Tsuneyasu; Iwabe, Tomio; Takeuchi, Osamu; Akira, Shizuo

    2002-10-01

    Toll-like receptor (TLR) can activate dendritic cells (DC) through common signaling pathways requiring a cytoplasmic adapter, MyD88. However, the signaling is differentially regulated among TLR family members. TLR4 can activate MyD88-deficient bone marrow-derived DC (BMDC), and lead to induction of IFN-inducible genes and up-regulation of co-stimulatory molecules such as CD40, implying that the MyD88-independent signaling pathway functions downstream of TLR4. Because these effects can also be induced by type I IFN, we have analyzed whether type I IFN is involved in TLR4-induced responses. In response to lipopolysaccharide (LPS), IFN-beta gene expression was augmented in both wild-type and MyD88-deficient BMDC. Expression of all IFN-inducible genes except immune-responsive gene 1 (IRG1) was abolished and CD40 up-regulation was decreased in LPS-stimulated BMDC lacking either IFN-alpha/beta receptor (IFN-alpha/betaR) or signal transducer and activator of transcription 1 (STAT-1). Similar to the LPS response, TLR9 signaling can also induce expression of IFN-beta and IFN-inducible genes, and up-regulation of CD40. However, all these effects were MyD88 dependent. Thus, in TLR4 signaling, IFN-beta expression can be induced either by the MyD88-dependent or -independent pathway, whereas, in TLR9 signaling, it is dependent on MyD88. In CpG DNA-stimulated DC, expression of IFN-inducible genes except IRG1 was dependent on type I IFN signaling as in LPS-stimulated DC. However, in contrast to TLR4 signaling, TLR9 signaling requires type I IFN signaling for CD40 up-regulation. Taken together, this study demonstrates differential involvement of type I IFN in TLR4- and TLR9-induced effects on DC.

  15. Induction of Dendritic Cell Maturation and Activation by a Potential Adjuvant, 2-Hydroxypropyl-β-Cyclodextrin

    PubMed Central

    Kim, Sun Kyung; Yun, Cheol-Heui; Han, Seung Hyun

    2016-01-01

    2-Hydroxypropyl-β-cyclodextrin (HP-β-CD) is a chemically modified cyclic oligosaccharide produced from starch that is commonly used as an excipient. Although HP-β-CD has been suggested as a potential adjuvant for vaccines, its immunological properties and mechanism of action have yet to be characterized. In the present study, we investigated the maturation and activation of human dendritic cells (DCs) treated with HP-β-CD. We found that DCs stimulated with HP-β-CD exhibited a remarkable upregulation of costimulatory molecules, MHC proteins, and PD-L1/L2. In addition, the production of cytokines, such as TNF-α, IL-6, and IL-10, was modestly increased in DCs when treated with HP-β-CD. Furthermore, HP-β-CD-sensitized DCs markedly induced the proliferation and activation of autologous T lymphocytes. HP-β-CD also induced a lipid raft formation in DCs. In contrast, filipin, a lipid raft inhibitor, attenuated HP-β-CD-induced DC maturation, the cytokine expression, and the T lymphocyte-stimulating activities. To determine the in vivo relevance of the results, we investigated the adjuvanticity of HP-β-CD and the modulation of DCs in a mouse footpad immunization model. When mice were immunized with ovalbumin in the presence of HP-β-CD through a hind footpad, serum ovalbumin-specific antibodies were markedly elevated. Concomitantly, DC populations expressing CD11c and MHC class II were increased in the draining lymph nodes, and the expression of costimulatory molecules was upregulated. Collectively, our data suggest that HP-β-CD induces phenotypic and functional maturation of DCs mainly mediated through lipid raft formation, which might mediate the adjuvanticity of HP-β-CD. PMID:27812358

  16. Protein kinase CK2 controls T-cell polarization through dendritic cell activation in response to contact sensitizers.

    PubMed

    de Bourayne, Marie; Gallais, Yann; El Ali, Zeina; Rousseau, Philippe; Damiens, Marie-Hélène; Cochet, Claude; Filhol, Odile; Chollet-Martin, Sylvie; Pallardy, Marc; Kerdine-Römer, Saadia

    2017-03-01

    Allergic contact dermatitis (ACD) represents a severe health problem with increasing worldwide prevalence. It is a T-cell-mediated inflammatory skin disease caused by chemicals present in the daily or professional environment. NiSO4 and 2,4-dinitrochlorobenzene (DNCB) are 2 chemicals involved in ACD. These contact sensitizers are known to induce an up-regulation of phenotypic markers and cytokine secretion in dendritic cells (DCs; professional APCs), leading to the generation of CD8(+) Tc1/Tc17 and CD4(+) Th1/Th17 effector T cells. In the present study, using a peptide array approach, we identified protein kinase CK2 as a novel kinase involved in the activation of human monocyte-derived DCs (MoDCs) in response to NiSO4 and DNCB. Inhibition of CK2 activity in MoDCs led to an altered mature phenotype with lower expression of CD54, PDL-1, CD86, and CD40 in response to NiSO4 or DNCB. CK2 activity also regulated proinflammatory cytokine production, such as TNF-α, IL-1β, and IL-23 in MoDCs. Moreover, in a DC/T cell coculture model in an allogeneic setup, CK2 activity in MoDCs played a major role in Th1 polarization in response to NiSO4 and DNCB. CK2 inhibition in MoDCs led to an enhanced Th2 polarization in the absence of contact sensitizer stimulation.

  17. Shark cartilage 14 kDa protein as a dendritic cells activator.

    PubMed

    Safari, Elahe; Hassan, Zuhair M; Moazzeni, Seyed Mohammad

    2015-04-01

    Low molecular weight components of shark cartilage are reported to have anti-tumor as well as immuno-stimulating effects. Dendritic cells (DCs) are potent antigen-presenting cells (APCs) that have a key role in establishment of anti-cancer immune response. In this study, the effect of 14 kDa protein from shark cartilage was investigated on stimulation and maturation of dendritic cells. The isolated 14 kDa protein from shark cartilage extract was added to DCs medium during overnight culture and their maturation and T cells stimulation potential was investigated. The majority of shark-cartilage-treated DCs expressed higher levels of maturation markers and were more effective in stimulation of allogenic T cells compared with non-treated DCs (p < 0.05). Our results showed that shark cartilage 14 kDa protein can potentially be used in DC-mediated T-cells stimulation and induction of desirable immune responses in clinical trials such as cancer immunotherapy. However, further studies are required to examine this proposal.

  18. Salvianolic acid B suppresses maturation of human monocyte-derived dendritic cells by activating PPARγ

    PubMed Central

    Sun, Aijun; Liu, Hongying; Wang, Shijun; Shi, Dazhuo; Xu, Lei; Cheng, Yong; Wang, Keqiang; Chen, Keji; Zou, Yunzeng; Ge, Junbo

    2011-01-01

    BACKGROUND AND PURPOSE Salvianolic acid B (Sal B), a water-soluble antioxidant derived from a Chinese medicinal herb, is known to be effective in the prevention of atherosclerosis. Here, we tested the hypothesis that the anti-atherosclerotic effect of Sal B might be mediated by suppressing maturation of human monocyte-derived dendritic cells (h-monDC). EXPERIMENTAL APPROACH h-monDC were derived by incubating purified human monocytes with GM-CSF and IL-4. h-monDC were pre-incubated with or without Sal B and stimulated by oxidized low-density lipoprotein (ox-LDL) in the presence or absence of PPARγ siRNA. Expression of h-monDC membrane molecules (CD40, CD86, CD1a, HLA-DR) were analysed by FACS, cytokines were measured by elisa and the TLR4-associated signalling pathway was determined by Western blotting. KEY RESULTS Ox-LDL promoted h-monDC maturation, stimulated CD40, CD86, CD1a, HLA-DR expression and IL-12, IL-10, TNF-α production; and up-regulated TLR4 signalling. These effects were inhibited by Sal B. Sal B also triggered PPARγ activation and promoted PPARγ nuclear translocation, attenuated ox-LDL-induced up-regulation of TLR4 and myeloid differentiation primary-response protein 88 and inhibited the downstream p38-MAPK signalling cascade. Knocking down PPARγ with the corresponding siRNA blocked these effects of Sal B. CONCLUSIONS AND IMPLICATIONS Our data suggested that Sal B effectively suppressed maturation of h-monDC induced by ox-LDL through PPARγ activation. PMID:21649636

  19. Protein-bound polysaccharide activates dendritic cells and enhances OVA-specific T cell response as vaccine adjuvant

    PubMed Central

    Engel, Abbi L.; Sun, Guan-Cheng; Gad, Ekram; Rastetter, Lauren R.; Strobe, Katie; Yang, Yi; Dang, Yushe; Disis, Mary L; Lu, Hailing

    2013-01-01

    Protein-bound polysaccharide-K (PSK) is a hot water extract from Trametes versicolor mushroom. It has been used traditionally in Asian countries for its immune stimulating and anti-cancer effects. We have recently found that PSK can activate toll-like receptor 2 (TLR2). TLR2 is highly expressed on dendritic cells (DC), so the currently study was undertaken to evaluate the effect of PSK on DC activation and the potential of using PSK as a vaccine adjuvant. In vitro experiments using mouse bone marrow-derived DC (BMDC) demonstrated that PSK induces DC maturation as shown by dose-dependent increase in the expression of CD80, CD86, MHCII, and CD40. PSK also induces the production of multiple inflammatory cytokines by DC, including IL-12, TNF-α, and IL-6, at both mRNA and protein levels. In vivo experiments using PSK as an adjuvant to OVAp323-339 vaccine showed that PSK as adjuvant leads to enlarged draining lymph nodes with higher number of activated DC. PSK also stimulates proliferation of OVA-specific T cells, and induces T cells that produce multiple cytokines, IFN-γ, IL-2, and TNF-α. Altogether, these results demonstrate the ability of PSK to activate DC in vitro and in vivo and the potential of using PSK as a novel vaccine adjuvant. PMID:23735481

  20. Peroxisome proliferator-activated receptor gamma activators affect the maturation of human monocyte-derived dendritic cells.

    PubMed

    Gosset, P; Charbonnier, A S; Delerive, P; Fontaine, J; Staels, B; Pestel, J; Tonnel, A B; Trottein, F

    2001-10-01

    Peroxisome proliferator-activated receptor gamma (PPARgamma ), a member of the nuclear receptor superfamily, has recently been described as a modulator of macrophage functions and as an inhibitor of T cell proliferation. Here, we investigated the role of PPARgamma in dendritic cells (DC), the most potent antigen-presenting cells. We showed that PPARgamma is highly expressed in immature human monocyte-derived DC (MDDC) and that it may affect the immunostimulatory function of MDDC stimulated with lipopolysaccharide (LPS) or via CD40 ligand (CD40L). We found that the synthetic PPARgamma agonist rosiglitazone (as well as pioglitazone and troglitazone) significantly increases on LPS- and CD40L-activated MDDC, the surface expression of CD36 (by 184% and 104%, respectively) and CD86 (by 54% and 48%), whereas it reduces the synthesis of CD80 (by 42% and 42%). Moreover, activation of PPARgamma resulted in a dramatic decreased secretion of the Th1-promoting factor IL-12 in LPS- and CD40L-stimulated cells (by 47% and 62%), while the production of IL-1beta, TNF-alpha, IL-6 and IL-10 was unaffected. Finally, PPARgamma ligands down-modulate the synthesis of IFN-gamma -inducible protein-10 (recently termed as CXCL10) and RANTES (CCL5), both chemokines involved in the recruitment of Th1 lymphocytes (by 49% and 30%), but not the levels of the Th2 cell-attracting chemokines,macrophage-derived chemokine (CCL22) and thymus and activation regulated chemokine (CCL17), in mature MDDC. Taken together, our data suggest that activation of PPARgamma in human DC may have an impact in the orientation of primary and secondary immune responses by favoring type 2 responses.

  1. Epstein-Barr Virus–induced Molecule 1 Ligand Chemokine Is Expressed by Dendritic Cells in Lymphoid Tissues and Strongly Attracts Naive T Cells and Activated B Cells

    PubMed Central

    Ngo, Vu N.; Lucy Tang, H.; Cyster, Jason G.

    1998-01-01

    Movement of T and B lymphocytes through secondary lymphoid tissues is likely to involve multiple cues that help the cells navigate to appropriate compartments. Epstein-Barr virus– induced molecule 1 (EBI-1) ligand chemokine (ELC/MIP3β) is expressed constitutively within lymphoid tissues and may act as such a guidance cue. Here, we have isolated mouse ELC and characterized its expression pattern and chemotactic properties. ELC is expressed constitutively in dendritic cells within the T cell zone of secondary lymphoid tissues. Recombinant ELC was strongly chemotactic for naive (L-selectinhi) CD4 T cells and for CD8 T cells and weakly attractive for resting B cells and memory (L-selectinlo) CD4 T cells. After activation through the B cell receptor, the chemotactic response of B cells was enhanced. Like its human counterpart, murine ELC stimulated cells transfected with EBI-1/CC chemokine receptor 7 (CCR7). Our findings suggest a central role for ELC in promoting encounters between recirculating T cells and dendritic cells and in the migration of activated B cells into the T zone of secondary lymphoid tissues. PMID:9653094

  2. The Novel Toll-Like Receptor 2 Agonist SUP3 Enhances Antigen Presentation and T Cell Activation by Dendritic Cells

    PubMed Central

    Guo, Xueheng; Wu, Ning; Shang, Yingli; Liu, Xin; Wu, Tao; Zhou, Yifan; Liu, Xin; Huang, Jiaoyan; Liao, Xuebin; Wu, Li

    2017-01-01

    Dendritic cells (DCs) are highly specialized antigen-presenting cells that play crucial roles in innate and adaptive immunity. Previous studies suggested that Toll-like receptor (TLR) agonists could be used as potential adjuvants, as activation of TLRs can boost DC-induced immune responses. TLR2 agonists have been shown to enhance DC-mediated immune responses. However, classical TLR2 agonists such as Pam3CSK4 are not stable enough in vivo, which limits their clinical applications. In this study, a novel structurally stable TLR2 agonist named SUP3 was designed. Functional analysis showed that SUP3 induced much stronger antitumor response than Pam3CSK4 by promoting cytotoxic T lymphocytes activation in vivo. This effect was achieved through the following mechanisms: SUP3 strongly enhanced the ability of antigen cross-presentation by DCs and subsequent T cell activation. SUP3 upregulated the expression of costimulatory molecules on DCs and increased antigen deposition in draining lymph nodes. More interestingly, SUP3 induced less amount of pro-inflammatory cytokine production in vivo compared to other TLR agonists such as lipopolysaccharide. Taken together, SUP3 could serve as a novel promising immune adjuvant in vaccine development and immune modulations. PMID:28270814

  3. The active translation of MHCII mRNA during dendritic cells maturation supplies new molecules to the cell surface pool.

    PubMed

    Malanga, Donatella; Barba, Pasquale; Harris, Paul E; Maffei, Antonella; Del Pozzo, Giovanna

    2007-04-01

    The transition of human dendritic cells (DCs) from the immature to the mature phenotype is characterized by an increased density of MHC class II (MHCII) molecules on the plasma membrane, a key requirement of their competence as professional antigen presenting cells (APCs). MHCII molecules on the cell surface derive from newly synthesized as well as from preexisting proteins. So far, all the studies done on DCs during maturation, to establish the relative contribution of newly synthesized MHCII molecules to the cell surface pool did not produced a clear, unified scenario. We report that, in human DCs stimulated ex vivo with LPS, the changes in the RNA accumulation specific for at least two MHCII genes (HLA-DRA and HLA-DQA1) due to transcriptional upregulation, is associated with the active translation at high rate of these transcripts. Our finding reveals that, across the 24h of the maturation process in human DCs, newly synthesized MHCII proteins are supplied to the APCs cell surface pool.

  4. Bone marrow-derived dendritic cells.

    PubMed

    Roney, Kelly

    2013-01-01

    While much is understood about dendritic cells and their role in the immune system, the study of these cells is critical to gain a more complete understanding of their function. Dendritic cell isolation from mouse body tissues can be difficult and the number of cells isolated small. This protocol describes the growth of large number of dendritic cells from the culture of mouse bone marrow cells. The dendritic cells grown in culture facilitate experiments that may require large number of dendritic cells without great expense or use of large number of mice.

  5. Influenza Virus Hemagglutinin Glycoproteins with Different N-Glycan Patterns Activate Dendritic Cells In Vitro

    PubMed Central

    Liu, Wen-Chun; Lin, Yu-Li; Spearman, Maureen; Cheng, Pei-Yun; Butler, Michael

    2016-01-01

    ABSTRACT Influenza virus hemagglutinin (HA) N-glycans play important regulatory roles in the control of virus virulence, antigenicity, receptor-binding specificity, and viral escape from the immune response. Considered essential for controlling innate and adaptive immune responses against influenza virus infections, dendritic cells (DCs) trigger proinflammatory and adaptive immune responses in hosts. In this study, we engineered Chinese hamster ovary (CHO) cell lines expressing recombinant HA from pandemic H1, H5, and H7 influenza viruses. rH1HA, rH5HA, and rH7HA were obtained as wild-type proteins or in the presence of kifunensine (KIF) or further with endo-β-N-acetylglucosaminidase-treated KIF (KIF+E) to generate single-N-acetylglucosamine (GlcNAc) N-glycans consisting of (i) terminally sialylated complex-type N-glycans, (ii) high-mannose-type N-glycans, and (iii) single-GlcNAc-type N-glycans. Our results show that high-mannose-type and single-GlcNAc-type N-glycans, but not complex-type N-glycans, are capable of inducing more active hIL12 p40, hIL12 p70, and hIL-10 production in human DCs. Significantly higher HLA-DR, CD40, CD83, and CD86 expression levels, as well reduced endocytotic capacity in human DCs, were noted in the high-mannose-type rH1HA and single-GlcNAc-type rH1HA groups than in the complex-type N-glycan rH1HA group. Our data indicate that native avian rHA proteins (H5N1 and H7N9) are more immunostimulatory than human rHA protein (pH1N1). The high-mannose-type or single-GlcNAc-type N-glycans of both avian and human HA types are more stimulatory than the complex-type N-glycans. HA-stimulated DC activation was accomplished partially through a mannose receptor(s). These results provide more understanding of the contribution of glycosylation of viral proteins to the immune responses and may have implications for vaccine development. IMPORTANCE Influenza viruses trigger seasonal epidemics or pandemics with mild-to-severe consequences for human and

  6. Plasmacytoid dendritic cells and autoimmune inflammation.

    PubMed

    Galicia, Georgina; Gommerman, Jennifer L

    2014-03-01

    Plasmacytoid dendritic cells (pDC) are a sub-population of dendritic cells (DC) that produce large amounts of type I interferon (IFN) in response to nucleic acids that bind and activate toll-like-receptor (TLR)9 and TLR7. Type I IFN can regulate the function of B, T, DC, and natural killer (NK) cells and can also alter the residence time of leukocytes within lymph nodes. Activated pDC can also function as antigen presenting cells (APC) and have the potential to prime and differentiate T cells into regulatory or inflammatory effector cells, depending on the context. In this review we discuss pDC ontogeny, function, trafficking, and activation. We will also examine how pDC can potentially be involved in regulating immune responses in the periphery as well as within the central nervous system (CNS) during multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE).

  7. In vivo targeting of dendritic cells for activation of cellular immunity using vaccine carriers based on pH-responsive microparticles

    NASA Astrophysics Data System (ADS)

    Kwon, Young Jik; James, Edward; Shastri, Nilabh; Fréchet, Jean M. J.

    2005-12-01

    Activating the immune system to trigger a specific response is a major challenge in vaccine development. In particular, activating sufficient cytotoxic T lymphocyte-mediated cellular immunity, which is crucial for the treatment of many diseases including cancer and AIDS, has proven to be especially challenging. In this study, antigens were encapsulated in acid-degradable polymeric particle carriers to cascade cytotoxic T lymphocyte activation. To target dendritic cells, the most potent antigen-presenting cells, the particle carriers, were further conjugated with monoclonal antibodies. A series of ex vivo and in vivo studies have shown increased receptor-mediated uptake of antibody-conjugated particles by dendritic cells as well as migration of particle-carrying dendritic cells to lymph nodes and stimulation of naïve T cells leading to enhanced cellular immune response as confirmed by specific cell lysis and IFN- secretion. acid-degradable particle | drug delivery | targeted vaccine

  8. [Melanoma immunotherapy: dendritic cell vaccines].

    PubMed

    Lozada-Requena, Ivan; Núñez, César; Aguilar, José Luis

    2015-01-01

    This is a narrative review that shows accessible information to the scientific community about melanoma and immunotherapy. Dendritic cells have the ability to participate in innate and adaptive immunity, but are not unfamiliar to the immune evasion of tumors. Knowing the biology and role has led to generate in vitro several prospects of autologous cell vaccines against diverse types of cancer in humans and animal models. However, given the low efficiency they have shown, we must implement strategies to enhance their natural capacity either through the coexpression of key molecules to activate or reactivate the immune system, in combination with biosimilars or chemotherapeutic drugs. The action of natural products as alternative or adjuvant immunostimulant should not be ruled out. All types of immunotherapy should measure the impact of myeloid suppressor cells, which can attack the immune system and help tumor progression, respectively. This can reduce the activity of cellular vaccines and/or their combinations, that could be the difference between success or not of the immunotherapy. Although for melanoma there exist biosimilars approved by the Food and Drug Administration (FDA), not all have the expected success. Therefore it is necessary to evaluate other strategies including cellular vaccines loaded with tumor antigenic peptides expressed exclusively or antigens from tumor extracts and their respective adjuvants.

  9. Enhanced Follicular Dendritic Cell-B Cell Interaction in HIV and SIV Infections and its Potential Role in Polyclonal B Cell Activation

    PubMed Central

    Lewis, Mark. G.; Kosco-Vilbois, Marie H.

    1998-01-01

    Human immunodeficiency virus (HIV) infections have been characterized by both polyclonal Bcell activation and enhanced responsiveness to B-cell growth factors on one hand and the loss of specific antibody (Ab) responses and refractoriness to the normal signals for B-cell activation on the other. Histopathological studies of lymph node from HIV- and simian immunodeficiency virus (SIV)-infected individuals have indicated initial follicular hyperplasia and the appearance of large irregular germinal centers that undergo progressive involution concomitant with follicular dendritic-cell (FDC) disruption. During this process, follicular dendritic-cell -enriched lymph-node-cell cultures exhibit increased ability to induce cluster formation (“in vitro germinal centers”), lymphocyte proliferation and antibody production compared to uninfected controls. This paper discusses how enhanced FDC-B-cell interaction within SIV-infected germinal centers may result in a reduced ability to select high-affinity B cells and alter the dynamics of antibodyproducing- cell and memory-cell generation resulting in the observed hyperactivity. PMID:9716906

  10. Clinical grade OK432-activated dendritic cells: in vitro characterization and tracking during intralymphatic delivery.

    PubMed

    West, Emma; Morgan, Ruth; Scott, Karen; Merrick, Alison; Lubenko, Anatole; Pawson, David; Selby, Peter; Hatfield, Paul; Prestwich, Robin; Fraser, Sheila; Eves, David; Anthoney, Alan; Twelves, Chris; Beirne, Debbie; Patel, Poulam; O'Donnell, Dearbhaile; Watt, Suzanne; Waller, Michael; Dietz, Allan; Robinson, Philip; Melcher, Alan

    2009-01-01

    Dendritic cells (DC) are under intense preclinical and early clinical evaluation for the immunotherapy of cancer. However, the optimal culture conditions and route of delivery for DC vaccination have not been established. Here we describe the first human application of DC matured with the bacterial agent OK432 (OK-DC), using a short-term serum-free culture protocol, which generates mature DC from CD14+ precursors after 5 days. These cells were prepared within the framework of a National Blood Service facility, demonstrating that DC represent a product which is potentially deliverable alongside current standardized cell therapies within the UK National Health Service. In vitro analysis confirmed that OK-DC were mature, secreted tumor necrosis factor-alpha, interleukin-6, and interleukin-12, and stimulated both T cell and natural killer cell function. To explore effective delivery of OK-DC to lymph nodes, we performed an initial clinical tracking study of radioactively labeled, unpulsed OK-DC after intralymphatic injection into the dorsum of the foot. We showed that injected DC rapidly localized to ipsilateral pelvic lymph nodes, but did not disseminate to more distant nodes over a 48-hour period. There was no significant toxicity associated with OK-DC delivery. These results show that OK-DC are suitable for clinical use, and that intralymphatic delivery is feasible for localizing cells to sites where optimal priming of innate and adaptive antitumor immunity is likely to occur.

  11. Dendritic cells and immunotherapy for cancer.

    PubMed

    Chang, David H; Dhodapkar, Madhav V

    2003-06-01

    Dendritic cells, nature's adjuvant, are antigen-presenting cells specialized to initiate and regulate immunity. Their potent antigen-presenting function has encouraged targeting of dendritic cells (DCs) for harnessing the immune system against cancer. DCs are efficient at activating not only CD4+ helper T-cells and CD8+ killer T-cells but also B-cells and innate effectors such as natural killer and natural killer T-cells. Early studies of adoptive transfer of tumor antigen-loaded DCs have shown promise. However, DC vaccination is at an early stage, and several parameters still need to be established. The complexity of the DC system brings about the necessity for its rational manipulation for achieving protective and therapeutic immunity in patients.

  12. Rhamnogalacturonan II is a Toll-like receptor 4 agonist that inhibits tumor growth by activating dendritic cell-mediated CD8+ T cells.

    PubMed

    Park, Sung Nam; Noh, Kyung Tae; Jeong, Young-Il; Jung, In Duk; Kang, Hyun Kyu; Cha, Gil Sun; Lee, Su Jung; Seo, Jong Keun; Kang, Dae Hwan; Hwang, Tae-Ho; Lee, Eun Kyung; Kwon, Byungsuk; Park, Yeong-Min

    2013-02-08

    We evaluated the effectiveness of rhamnogalacturonan II (RG-II)-stimulated bone marrow-derived dendritic cells (BMDCs) vaccination on the induction of antitumor immunity in a mouse lymphoma model using EG7-lymphoma cells expressing ovalbumin (OVA). BMDCs treated with RG-II had an activated phenotype. RG-II induced interleukin (IL)-12, IL-1β, tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) production during dendritic cell (DC) maturation. BMDCs stimulated with RG-II facilitate the proliferation of CD8+ T cells. Using BMDCs from the mice deficient in Toll-like receptors (TLRs), we revealed that RG-II activity is dependent on TLR4. RG-II showed a preventive effect of immunization with OVA-pulsed BMDCs against EG7 lymphoma. These results suggested that RG-II expedites the DC-based immune response through the TLR4 signaling pathway.

  13. Synaptic activation of T-type Ca2+ channels via mGluR activation in the primary dendrite of mitral cells.

    PubMed

    Johnston, Jamie; Delaney, Kerry R

    2010-05-01

    Mitral cells are the primary output of the olfactory bulb, projecting to many higher brain areas. Understanding how mitral cells process and transmit information is key to understanding olfactory perception. Mitral dendrites possess high densities of voltage-gated channels, are able to initiate and propagate orthodromic and antidromic action potentials, and release neurotransmitter. We show that mitral cells also possess a low-voltage-activated T-type Ca(2+) current. Immunohistochemistry shows strong Cav3.3 labeling in the primary dendrite and apical tuft with weaker staining in basal dendrites and no staining in somata. A low-voltage-activated Ca(2+) current activates from -68 mV, is blocked by 500 microM Ni(2+) and 50 microM NNC 55-0396, but is insensitive to 50 microM Ni(2+) and 500 microM isradipine. 2-photon Ca(2+) imaging shows that T channels are functionally expressed in the primary dendrite where their activity determines the resting [Ca(2+)] and are responsible for subthreshold voltage-dependent Ca(2+) changes previously observed in vivo. Application of the group 1 mGluR agonist dihydroxyphenylglycine (DHPG) (50 microM) robustly upregulates T-channel current in the primary and apical tuft dendrite. Olfactory nerve stimulation generates a long-lasting depolarization, and we show that mGluRs recruit T channels to contribute approximately 36% of the voltage integral of this depolarization. The long-lasting depolarization results in sustained firing and block of T channels decreased action potential firing by 84.1 +/- 4.6%. Therefore upregulation of T channels by mGluRs is required for prolonged firing in response to olfactory nerve input.

  14. CCL-34, a synthetic toll-like receptor 4 activator, modulates differentiation and maturation of myeloid dendritic cells.

    PubMed

    Fu, Shu-Ling; Lin, Chun-Cheng; Hsu, Ming-Ling; Liu, Sheng-Hung; Huang, Yu-Chuen; Chen, Yu-Jen

    2016-03-08

    CCL-34, a synthetic α-galactosylceramide analog, has been reported as an activator of toll-like receptor 4 (TLR4) in macrophages. TLR4 is highly expressed in dendritic cell (DC) and several TLR4 agonists are known to trigger DC maturation. We herein evaluated the effect of CCL-34 on DC maturation. Human CD14+ monocyte-derived immature DC were treated with CCL-34, its inactive structural analog CCL-44, or LPS to assess the DC maturation. CCL-34 induced DC maturation according to their characteristically dendrite-forming morphology, CD83 expression and IL-12p70 production. The allostimulatory activity of DC on proliferation of naive CD4+CD45+RA+ T cells and their secretion of interferon-γ was increased by CCL-34. Phagocytosis, an important function of immature DC, was reduced after CCL-34 treatment. All these effects related to DC maturation were evidently induced by positive control LPS but not by CCL-44 treatment. TLR4 neutralization impaired human DC maturation triggered by CCL-34. The induction of IL-12, a hallmark of DC maturation, by CCL-34 and LPS was only evident in TLR4-competent C3H/HeN, but not in TLR4-defective C3H/HeJ mice. CCL-34 could further elicit the antigen presentation capability in mice inoculated with doxorubicin-treated colorectal cancer cells. In summary, CCL-34 triggers DC maturation via a TLR4-dependent manner, which supports its potential application as an immunostimulator.

  15. Molecular and Cellular Mechanisms of Antitumor Immune Response Activation by Dendritic Cells

    PubMed Central

    Markov, O. V.; Mironova, N. L.; Vlasov, V. V.; Zenkova, M. A.

    2016-01-01

    Dendritic cells (DCs) play a crucial role in the initiation and regulation of the antitumor immune response. Already , DC-based antitumor vaccines have been thoroughly explored both in animal tumor models and in clinical trials. DC-based vaccines are commonly produced from DC progenitors isolated from peripheral blood or bone marrow by culturing in the presence of cytokines, followed by loading the DCs with tumor-specific antigens, such as DNA, RNA, viral vectors, or a tumor cell lysate. However, the efficacy of DC-based vaccines remains low. Undoubtedly, a deeper understanding of the molecular mechanisms by which DCs function would allow us to enhance the antitumor efficacy of DC-based vaccines in clinical applications. This review describes the origin and major subsets of mouse and human DCs, as well as the differences between them. The cellular mechanisms of presentation and cross-presentation of exogenous antigens by DCs to T cells are described. We discuss intracellular antigen processing in DCs, cross-dressing, and the acquisition of the antigen cross-presentation function. A particular section in the review describes the mechanisms of tumor escape from immune surveillance through the suppression of DCs functions. PMID:27795841

  16. Schistosoma mansoni soluble egg antigens are internalized by human dendritic cells through multiple C-type lectins and suppress TLR-induced dendritic cell activation.

    PubMed

    van Liempt, Ellis; van Vliet, Sandra J; Engering, Anneke; García Vallejo, Juan Jesus; Bank, Christine M C; Sanchez-Hernandez, Marta; van Kooyk, Yvette; van Die, Irma

    2007-04-01

    In schistosomiasis, a parasitic disease caused by helminths, the parasite eggs induce a T helper 2 cell (T(H)2) response in the host. Here, the specific role of human monocyte-derived dendritic cells (DCs) in initiation and polarization of the egg-specific T cell responses was examined. We demonstrate that immature DCs (iDCs) pulsed with schistosome soluble egg antigens (SEA) do not show an increase in expression of co-stimulatory molecules or cytokines, indicating that no conventional maturation was induced. The ability of SEA to affect the Toll-like receptor (TLR) induced maturation of iDCs was examined by copulsing the DCs with SEA and TLR-ligands. SEA suppressed both the maturation of iDCs induced by poly-I:C and LPS, as indicated by a decrease in co-stimulatory molecule expression and production of IL-12, IL-6 and TNF-alpha. In addition, SEA suppressed T(H)1 responses induced by the poly-I:C-pulsed DCs, and skewed the LPS-induced mixed response towards a T(H)2 response. Immature DCs rapidly internalized SEA through the C-type lectins DC-SIGN, MGL and the mannose receptor and the antigens were targeted to MHC class II-positive lysosomal compartments. The internalization of SEA by multiple C-type lectins may be important to regulate the response of the iDCs to TLR-induced signals.

  17. Cell type-specific and activity-dependent dynamics of action potential-evoked Ca2+ signals in dendrites of hippocampal inhibitory interneurons

    PubMed Central

    Evstratova, Alesya; Chamberland, Simon; Topolnik, Lisa

    2011-01-01

    Abstract In most central neurons, action potentials (APs), generated in the initial axon segment, propagate back into dendrites and trigger considerable Ca2+ entry via activation of voltage-sensitive calcium channels (VSCCs). Despite the similarity in its underlying mechanisms, however, AP-evoked dendritic Ca2+ signalling often demonstrates a cell type-specific profile that is determined by the neuron dendritic properties. Using two-photon Ca2+ imaging in combination with patch-clamp whole-cell recordings, we found that in distinct types of hippocampal inhibitory interneurons Ca2+ transients evoked by backpropagating APs not only were shaped by the interneuron-specific properties of dendritic Ca2+ handling but also involved specific Ca2+ mechanisms that were regulated dynamically by distinct activity patterns. In dendrites of regularly spiking basket cells, AP-evoked Ca2+ rises were of large amplitude and fast kinetics; however, they decreased with membrane hyperpolarization or following high-frequency firing episodes. In contrast, AP-evoked Ca2+ elevations in dendrites of Schaffer collateral-associated cells exhibited significantly smaller amplitude and slower kinetics, but increased with membrane hyperpolarization. These cell type-specific properties of AP-evoked dendritic Ca2+ signalling were determined by distinct endogenous buffer capacities of the interneurons examined and by specific types of VSCCs recruited by APs during different patterns of activity. Furthermore, AP-evoked Ca2+ transients summated efficiently during theta-like bursting and were associated with the induction of long-term potentiation at inhibitory synapses onto both types of interneurons. Therefore, the cell type-specific profile of AP-evoked dendritic Ca2+ signalling is shaped in an activity-dependent manner, such that the same pattern of hippocampal activity can be differentially translated into dendritic Ca2+ signals in different cell types. However, Cell type-specific differences in Ca

  18. Dendritic cell analysis in primary immunodeficiency

    PubMed Central

    Bigley, Venetia; Barge, Dawn; Collin, Matthew

    2016-01-01

    Purpose of review Dendritic cells are specialized antigen-presenting cells which link innate and adaptive immunity, through recognition and presentation of antigen to T cells. Although the importance of dendritic cells has been demonstrated in many animal models, their contribution to human immunity remains relatively unexplored in vivo. Given their central role in infection, autoimmunity, and malignancy, dendritic cell deficiency or dysfunction would be expected to have clinical consequences. Recent findings Human dendritic cell deficiency disorders, related to GATA binding protein 2 (GATA2) and interferon regulatory factor 8 (IRF8) mutations, have highlighted the importance of dendritic cells and monocytes in primary immunodeficiency diseases and begun to shed light on their nonredundant roles in host defense and immune regulation in vivo. The contribution of dendritic cell and monocyte dysfunction to the pathogenesis of primary immunodeficiency disease phenotypes is becoming increasingly apparent. However, dendritic cell analysis is not yet a routine part of primary immunodeficiency disease workup. Summary Widespread uptake of dendritic cell/monocyte screening in clinical practice will facilitate the discovery of novel dendritic cell and monocyte disorders as well as advancing our understanding of human dendritic cell biology in health and disease. PMID:27755182

  19. Immunosuppressive effect of zhankuic acid C from Taiwanofungus camphoratus on dendritic cell activation and the contact hypersensitivity response.

    PubMed

    Lin, Ming-Kuem; Lee, Meng-Shiou; Chang, Wen-Te; Chen, Hsing-Yu; Chen, Jin-Fu; Li, Yi-Rong; Lin, Chi-Chen; Wu, Tian-Shung

    2015-10-15

    Some ergostane triterpenoids from Taiwanofungus camphoratus have been shown to exhibit anti-inflammatory activity in vitro. However, the effect of ergostane triterpenoids on the immune response remains unknown. In this study, we elucidated that ergostane triterpenoids significantly decreased the cytokines and chemokine release by dendritic cells (DC) and that, in the case of zhankuic acid C (ZAC), the decrease was dose-dependent and inhibited DC maturation. ZAC inhibited the contact hypersensitivity response and infiltrative T cells in the ears of DNFB-stimulated mice. Thus, we demonstrate for the first time that ZAC exhibits an immunosuppressive effect on DC activation and the contact hypersensitivity response. It is suggested that ZAC can potentially be used for treating chronic inflammation and autoimmune diseases.

  20. Tumor-derived α-fetoprotein impairs the differentiation and T cell stimulatory activity of human dendritic cells.

    PubMed

    Pardee, Angela D; Shi, Jian; Butterfield, Lisa H

    2014-12-01

    Several tumor-derived factors have been implicated in dendritic cell (DC) dysfunction in cancer patients. α-fetoprotein (AFP) is an oncofetal Ag that is highly expressed in abnormalities of prenatal development and several epithelial cancers, including hepatocellular carcinoma (HCC). In HCC patients exhibiting high levels of serum AFP, we observed a lower ratio of myeloid/plasmacytoid circulating DCs compared with patients with low serum AFP levels and healthy donors. To test the effect of AFP on DC differentiation in vitro, peripheral blood monocytes from healthy donors were cultured in the presence of cord blood-derived normal AFP (nAFP) or HCC tumor-derived AFP (tAFP), and DC phenotype and function were assessed. Although the nAFP and tAFP isoforms only differ at one carbohydrate group, low (physiological) levels of tAFP, but not nAFP, significantly inhibited DC differentiation. tAFP-conditioned DCs expressed diminished levels of DC maturation markers, retained a monocyte-like morphology, exhibited limited production of inflammatory mediators, and failed to induce robust T cell proliferative responses. Mechanistic studies revealed that the suppressive activity of tAFP is dependent on the presence of low molecular mass (LMM) species that copurify with tAFP and function equivalently to the LMM fractions of both tumor and nontumor cell lysates. These data reveal the unique ability of tAFP to serve as a chaperone protein for LMM molecules, both endogenous and ubiquitous in nature, which function cooperatively to impair DC differentiation and function. Therefore, novel therapeutic approaches that antagonize the regulatory properties of tAFP will be critical to enhance immunity and improve clinical outcomes.

  1. Leucine-Rich Repeat Kinase 2 (Lrrk2)-Sensitive Na(+)/K(+) ATPase Activity in Dendritic Cells.

    PubMed

    Hosseinzadeh, Zohreh; Singh, Yogesh; Shimshek, Derya R; van der Putten, Herman; Wagner, Carsten A; Lang, Florian

    2017-01-25

    Leucine-rich repeat kinase 2 (Lrrk2) has been implicated in the pathophysiology of Parkinson's disease. Lrrk2 is expressed in diverse cells including neurons and dendritic cells (DCs). In DCs Lrrk2 was shown to up-regulate Na(+)/Ca(2+)-exchanger activity. The elimination of Ca(2+) by Na(+)/Ca(2+) -exchangers requires maintenance of the Na(+) gradient by the Na(+)/K(+) -ATPase. The present study thus explored whether Lrrk2 impacts on Na(+)/K(+) -ATPase expression and function. To this end DCs were isolated from gene-targeted mice lacking Lrrk2 (Lrrk2(-/-)) and their wild-type littermates (Lrrk2(+/+)). Na(+)/K(+) -ATPase activity was estimated from K(+) induced, ouabain sensitive, current determined by whole cell patch clamp. Na(+)/K(+) -ATPase α1 subunit transcript and protein levels were determined by RT-qPCR and flow cytometry. As a result, the K(+) induced current was significantly smaller in Lrrk2(-/-) than in Lrrk2(+/+) DCs and was completely abolished by ouabain (100 μM) in both genotypes. The K(+) induced, ouabain sensitive, current in Lrrk2(+/+) DCs was significantly blunted by Lrrk2 inhibitor GSK2578215A (1 μM, 24 hours). The Na(+)/K(+) -ATPase α1 subunit transcript and protein levels were significantly lower in Lrrk2(-/-) than in Lrrk2(+/+) DCs and significantly decreased by Lrrk2 inhibitor GSK2578215A (1 μM, 24 hours). In conclusion, Lrrk2 is a powerful regulator of Na(+)/K(+) -ATPase expression and activity in dendritic cells.

  2. Leucine-Rich Repeat Kinase 2 (Lrrk2)-Sensitive Na+/K+ ATPase Activity in Dendritic Cells

    PubMed Central

    Hosseinzadeh, Zohreh; Singh, Yogesh; Shimshek, Derya R.; van der Putten, Herman; Wagner, Carsten A.; Lang, Florian

    2017-01-01

    Leucine-rich repeat kinase 2 (Lrrk2) has been implicated in the pathophysiology of Parkinson’s disease. Lrrk2 is expressed in diverse cells including neurons and dendritic cells (DCs). In DCs Lrrk2 was shown to up-regulate Na+/Ca2+-exchanger activity. The elimination of Ca2+ by Na+/Ca2+ -exchangers requires maintenance of the Na+ gradient by the Na+/K+ -ATPase. The present study thus explored whether Lrrk2 impacts on Na+/K+ -ATPase expression and function. To this end DCs were isolated from gene-targeted mice lacking Lrrk2 (Lrrk2−/−) and their wild-type littermates (Lrrk2+/+). Na+/K+ -ATPase activity was estimated from K+ induced, ouabain sensitive, current determined by whole cell patch clamp. Na+/K+ -ATPase α1 subunit transcript and protein levels were determined by RT-qPCR and flow cytometry. As a result, the K+ induced current was significantly smaller in Lrrk2−/− than in Lrrk2+/+ DCs and was completely abolished by ouabain (100 μM) in both genotypes. The K+ induced, ouabain sensitive, current in Lrrk2+/+ DCs was significantly blunted by Lrrk2 inhibitor GSK2578215A (1 μM, 24 hours). The Na+/K+ -ATPase α1 subunit transcript and protein levels were significantly lower in Lrrk2−/− than in Lrrk2+/+ DCs and significantly decreased by Lrrk2 inhibitor GSK2578215A (1 μM, 24 hours). In conclusion, Lrrk2 is a powerful regulator of Na+/K+ -ATPase expression and activity in dendritic cells. PMID:28120865

  3. Microbial Activation of Gut Dendritic Cells and the Control of Mucosal Immunity

    PubMed Central

    Owen, Jennifer L.

    2013-01-01

    Current data support a role for gut colonization in maintaining balanced mucosal and systemic immune responses and have suggested aberrant innate immune recognition of enteric bacteria as an initiator of the adaptive immune damage associated with inflammatory bowel disease (Crohn's disease and ulcerative colitis). In fact, data from human studies and experimental mouse models have implicated transformation of the gut microbiota from a beneficial symbiotic state to one of imbalance or “dysbiosis” in the pathogenesis of several autoinflammatory diseases, including allergic skin and respiratory disorders, rheumatoid arthritis, type I diabetes, and colorectal cancer. The host has evolved to co-exist and maintain a mutualistic relationship with the commensal microbes of the gut, and it is the function of the host innate immune system to initiate and maintain this homeostasis, while retaining the ability to respond appropriately to pathogenic organisms. In this review, we discuss the molecular and cellular interactions of the mucosal immune system that decide this delicate balance of mutualism. Furthermore, we will highlight the role of dendritic cells in preserving this precarious balance and how gene products of commensal microbes may play an integral role in re-establishing this balance once it has gone awry. PMID:23962004

  4. Lactobacilli Activate Human Dendritic Cells that Skew T Cells Toward T Helper 1 Polarization

    DTIC Science & Technology

    2005-01-06

    symbiotic bacteria to perform their critical functions in host nutrition, intestinal permeability, and protection against foreign, pathogenic microbes...memory T cells to Th1 responses, which are proinflammatory and lead to robust im- munity against infections and other diseases (27). Interestingly, IL-12...as safe when ad- ministered as probiotics . Because DCs can naturally or therapeu- tically encounter lactobacilli, we investigated the effects of

  5. Effect of thymoquinone on cytosolic pH and Na+/H+ exchanger activity in mouse dendritic cells.

    PubMed

    Yang, Wenting; Bhandaru, Madhuri; Pasham, Venkanna; Bobbala, Diwakar; Zelenak, Christine; Jilani, Kashif; Rotte, Anand; Lang, Florian

    2012-01-01

    The anti-inflammatory Nigella sativa component thymoquinone compromises the function of dendritic cells (DCs), key players in the regulation of innate and adaptive immunity. DC function is regulated by the Na(+)/H(+) exchanger (NHE), which is stimulated by lipopolysaccharides (LPS) and required for LPS-induced cell swelling, reactive oxygen species (ROS) production, TNF-α release and migration. Here we explored, whether thymoquinone influences NHE activity in DCs. To this end, bone marrow derived mouse DCs were treated with LPS in the absence and presence of thymoquinone (10 μM). Cytosolic pH (pH(i)) was determined from 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF) fluorescence, NHE activity from the Na(+)-dependent realkalinization following an ammonium pulse, cell volume from forward scatter in FACS analysis, ROS production from 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) fluorescence, TNF-α production utilizing ELISA and DC migration with transwell migration assays. As a result, exposure of DCs to LPS (1 μg/ml) led within 4 hours to transient increase of NHE activity. Thymoquinone did not significantly modify cytosolic pH or cellular NHE activity in the absence of LPS, but abrogated the effect of LPS on NHE activity. Accordingly, in the presence of thymoquinone LPS-treatment resulted in cytosolic acidification. LPS further increased forward scatter and ROS formation, effects similarly abrogated by thymoquinone. Again, in the absence of LPS, thymoquinone did not significantly modify ROS formation and cell volume. LPS further triggered TNF-α release and migration, effects again blunted in the presence of thymoquinone. NHE1 inhibitor cariporide (10 μM) blunted LPS induced TNF-α release and migration. The effects of thymoquinone on NHE activity and migration were reversed upon treatment of the cells with t-butyl hydroperoxide (TBOOH, 5 μM). In conclusion, thymoquinone blunts LPS induced NHE activity, cell swelling, oxidative burst

  6. Podoplanin-rich stromal networks induce dendritic cell motility via activation of the C-type lectin receptor CLEC-2.

    PubMed

    Acton, Sophie E; Astarita, Jillian L; Malhotra, Deepali; Lukacs-Kornek, Veronika; Franz, Bettina; Hess, Paul R; Jakus, Zoltan; Kuligowski, Michael; Fletcher, Anne L; Elpek, Kutlu G; Bellemare-Pelletier, Angelique; Sceats, Lindsay; Reynoso, Erika D; Gonzalez, Santiago F; Graham, Daniel B; Chang, Jonathan; Peters, Anneli; Woodruff, Matthew; Kim, Young-A; Swat, Wojciech; Morita, Takashi; Kuchroo, Vijay; Carroll, Michael C; Kahn, Mark L; Wucherpfennig, Kai W; Turley, Shannon J

    2012-08-24

    To initiate adaptive immunity, dendritic cells (DCs) move from parenchymal tissues to lymphoid organs by migrating along stromal scaffolds that display the glycoprotein podoplanin (PDPN). PDPN is expressed by lymphatic endothelial and fibroblastic reticular cells and promotes blood-lymph separation during development by activating the C-type lectin receptor, CLEC-2, on platelets. Here, we describe a role for CLEC-2 in the morphodynamic behavior and motility of DCs. CLEC-2 deficiency in DCs impaired their entry into lymphatics and trafficking to and within lymph nodes, thereby reducing T cell priming. CLEC-2 engagement of PDPN was necessary for DCs to spread and migrate along stromal surfaces and sufficient to induce membrane protrusions. CLEC-2 activation triggered cell spreading via downregulation of RhoA activity and myosin light-chain phosphorylation and triggered F-actin-rich protrusions via Vav signaling and Rac1 activation. Thus, activation of CLEC-2 by PDPN rearranges the actin cytoskeleton in DCs to promote efficient motility along stromal surfaces.

  7. Isolation and generation of human dendritic cells.

    PubMed

    Nair, Smita; Archer, Gerald E; Tedder, Thomas F

    2012-11-01

    Dendritic cells are highly specialized antigen-presenting cells (APC), which may be isolated or generated from human blood mononuclear cells. Although mature blood dendritic cells normally represent ∼0.2% of human blood mononuclear cells, their frequency can be greatly increased using the cell enrichment methods described in this unit. More highly purified dendritic cell preparations can be obtained from these populations by sorting of fluorescence-labeled cells. Alternatively, dendritic cells can be generated from monocytes by culture with the appropriate cytokines, as described here. In addition, a negative selection approach is provided that may be employed to generate cell preparations that have been depleted of dendritic cells to be used for comparison in functional studies.

  8. The renal microenvironment modifies dendritic cell phenotype.

    PubMed

    Chessa, Federica; Mathow, Daniel; Wang, Shijun; Hielscher, Thomas; Atzberger, Ann; Porubsky, Stefan; Gretz, Norbert; Burgdorf, Sven; Gröne, Hermann-Josef; Popovic, Zoran V

    2016-01-01

    Renal dendritic cells are a major component of the renal mononuclear phagocytic system. In the renal interstitium, these cells are exposed to an osmotic gradient, mainly sodium, whose concentration progressively increases towards inner medulla. Renal allograft rejection affects predominantly the cortex, suggesting a protective role of the renal medullary micromilieu. Whether osmolar variations can modulate the function of renal dendritic cells is currently undefined. Considering the central role of dendritic cells in promoting allorejection, we tested whether the biophysical micromilieu, particularly the interstitial osmotic gradient, influences their alloreactivity. There was a progressive depletion of leukocytes towards the medulla of homeostatic kidney. Only macrophages opposed this tendency. Flow cytometry of homeostatic and post-transplant medullary dendritic cells revealed a switch towards a macrophage-like phenotype. Similarly, bone marrow-derived dendritic cells developed ex vivo in sodium chloride-enriched medium acquired a M2-like signature. Microarray analysis of allotransplant dendritic cells posed a medullary downregulation of genes mainly involved in alloantigen recognition. Gene expression profiles of both medullary dendritic cells and bone marrow-derived dendritic cells matured in hyperosmolar medium had an overlap with the macrophage M2 signature. Thus, the medullary environment inhibits an alloimmune response by modulating the phenotype and function of dendritic cells.

  9. I kappa B kinase alpha (IKKα) activity is required for functional maturation of dendritic cells and acquired immunity to infection.

    PubMed

    Mancino, Alessandra; Habbeddine, Mohamed; Johnson, Ella; Luron, Lionel; Bebien, Magali; Memet, Sylvie; Fong, Carol; Bajenoff, Marc; Wu, Xuefeng; Karin, Michael; Caamano, Jorge; Chi, Hongbo; Seed, Michael; Lawrence, Toby

    2013-03-20

    Dendritic cells (DC) are required for priming antigen-specific T cells and acquired immunity to many important human pathogens, including Mycobacteriuim tuberculosis (TB) and influenza. However, inappropriate priming of auto-reactive T cells is linked with autoimmune disease. Understanding the molecular mechanisms that regulate the priming and activation of naïve T cells is critical for development of new improved vaccines and understanding the pathogenesis of autoimmune diseases. The serine/threonine kinase IKKα (CHUK) has previously been shown to have anti-inflammatory activity and inhibit innate immunity. Here, we show that IKKα is required in DC for priming antigen-specific T cells and acquired immunity to the human pathogen Listeria monocytogenes. We describe a new role for IKKα in regulation of IRF3 activity and the functional maturation of DC. This presents a unique role for IKKα in dampening inflammation while simultaneously promoting adaptive immunity that could have important implications for the development of new vaccine adjuvants and treatment of autoimmune diseases.

  10. CCL-34, a synthetic toll-like receptor 4 activator, modulates differentiation and maturation of myeloid dendritic cells

    PubMed Central

    Fu, Shu-Ling; Lin, Chun-Cheng; Hsu, Ming-Ling; Liu, Sheng-Hung; Huang, Yu-Chuen; Chen, Yu-Jen

    2016-01-01

    CCL-34, a synthetic α-galactosylceramide analog, has been reported as an activator of toll-like receptor 4 (TLR4) in macrophages. TLR4 is highly expressed in dendritic cell (DC) and several TLR4 agonists are known to trigger DC maturation. We herein evaluated the effect of CCL-34 on DC maturation. Human CD14+ monocyte-derived immature DC were treated with CCL-34, its inactive structural analog CCL-44, or LPS to assess the DC maturation. CCL-34 induced DC maturation according to their characteristically dendrite-forming morphology, CD83 expression and IL-12p70 production. The allostimulatory activity of DC on proliferation of naive CD4+CD45+RA+ T cells and their secretion of interferon-γ was increased by CCL-34. Phagocytosis, an important function of immature DC, was reduced after CCL-34 treatment. All these effects related to DC maturation were evidently induced by positive control LPS but not by CCL-44 treatment. TLR4 neutralization impaired human DC maturation triggered by CCL-34. The induction of IL-12, a hallmark of DC maturation, by CCL-34 and LPS was only evident in TLR4-competent C3H/HeN, but not in TLR4-defective C3H/HeJ mice. CCL-34 could further elicit the antigen presentation capability in mice inoculated with doxorubicin-treated colorectal cancer cells. In summary, CCL-34 triggers DC maturation via a TLR4-dependent manner, which supports its potential application as an immunostimulator. PMID:26883191

  11. Interferon-α-inducible Dendritic Cells Matured with OK-432 Exhibit TRAIL and Fas Ligand Pathway-mediated Killer Activity

    PubMed Central

    Koya, Terutsugu; Yanagisawa, Ryu; Higuchi, Yumiko; Sano, Kenji; Shimodaira, Shigetaka

    2017-01-01

    Active human dendritic cells (DCs), which efficiently induce immune responses through their functions as antigen-presenting cells, exhibit direct anti-tumour killing activity in response to some pathogens and cytokines. These antigen-presenting and tumour killing abilities may provide a breakthrough in cancer immunotherapy. However, the mechanisms underlying this killer DC activity have not been fully proven, despite the establishment of interferon-α (IFN-α)-generated killer DCs (IFN-DCs). Here mature IFN-DCs (mIFN-DCs), generated from IFN-DCs primed with OK-432 (streptococcal preparation), exhibited elevated expression of CD86 and human leukocyte antigen-DR (minimum criteria for DC vaccine clinical trials) as well as antigen-presenting abilities comparable with those of mature IL-4-DCs (mIL-4-DCs). Interestingly, the killing activity of mIFN-DCs, which correlated with the expression of CD56 (natural killer cell marker) and was activated via the tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) and Fas ligand pathway, was stronger than that of IFN-DCs and remarkably stronger than that of mIL-4-DCs. Therefore, mIFN-DCs exhibit great potential as an anti-cancer vaccine that would promote both acquired immunity and direct tumour killing. PMID:28191816

  12. Increased numbers of monocyte-derived dendritic cells during successful tumor immunotherapy with immune-activating agents.

    PubMed

    Kuhn, Sabine; Hyde, Evelyn J; Yang, Jianping; Rich, Fenella J; Harper, Jacquie L; Kirman, Joanna R; Ronchese, Franca

    2013-08-15

    Local treatment with selected TLR ligands or bacteria such as bacillus Calmette-Guérin increases antitumor immune responses and delays tumor growth. It is thought that these treatments may act by activating tumor-associated dendritic cells (DCs), thereby supporting the induction of antitumor immune responses. However, common parameters of successful immune activation have not been identified. We used mouse models to compare treatments with different immune-activating agents for the ability to delay tumor growth, improve priming of tumor-specific T cells, and induce early cytokine production and DC activation. Treatment with polyinosinic-polycytidylic acid or a combination of monosodium urate crystals and Mycobacterium smegmatis was effective at delaying the growth of s.c. B16 melanomas, orthotopic 4T1 mammary carcinomas, and reducing 4T1 lung metastases. In contrast, LPS, monosodium urate crystals, or M. smegmatis alone had no activity. Effective treatments required both NK1.1(+) and CD8(+) cells, and resulted in increased T cell priming and the infiltration of NK cells and CD8(+) T cells in tumors. Unexpectedly, both effective and ineffective treatments increased DC numbers and the expression of costimulatory molecules in the tumor-draining lymph node. However, only effective treatments induced the rapid appearance of a population of monocyte-derived DCs in the draining lymph node, early release of IL-12p70 and IFN-γ, and low IL-10 in the serum. These results suggest that the activation of existing DC subsets is not sufficient for the induction of antitumor immune responses, whereas early induction of Th1 cytokines and monocyte-derived DCs are features of successful activation of antitumor immunity.

  13. Cell-intrinsic drivers of dendrite morphogenesis.

    PubMed

    Puram, Sidharth V; Bonni, Azad

    2013-12-01

    The proper formation and morphogenesis of dendrites is fundamental to the establishment of neural circuits in the brain. Following cell cycle exit and migration, neurons undergo organized stages of dendrite morphogenesis, which include dendritic arbor growth and elaboration followed by retraction and pruning. Although these developmental stages were characterized over a century ago, molecular regulators of dendrite morphogenesis have only recently been defined. In particular, studies in Drosophila and mammalian neurons have identified numerous cell-intrinsic drivers of dendrite morphogenesis that include transcriptional regulators, cytoskeletal and motor proteins, secretory and endocytic pathways, cell cycle-regulated ubiquitin ligases, and components of other signaling cascades. Here, we review cell-intrinsic drivers of dendrite patterning and discuss how the characterization of such crucial regulators advances our understanding of normal brain development and pathogenesis of diverse cognitive disorders.

  14. Selective Activation of Human Dendritic Cells by OM-85 through a NF-kB and MAPK Dependent Pathway

    PubMed Central

    Scutera, Sara; Somma, Paolo; Salvi, Valentina; Musso, Tiziana; Tabbia, Giuseppe; Bardessono, Marco; Pasquali, Christian; Mantovani, Alberto; Sozzani, Silvano; Bosisio, Daniela

    2013-01-01

    OM-85 (Broncho-Vaxom®, Broncho-Munal®, Ommunal®, Paxoral®, Vaxoral®), a product made of the water soluble fractions of 21 inactivated bacterial strain patterns responsible for respiratory tract infections, is used for the prevention of recurrent upper respiratory tract infections and acute exacerbations in chronic obstructive pulmonary disease patients. OM-85 is able to potentiate both innate and adaptive immune responses. However, the molecular mechanisms responsible for OM-85 activation are still largely unknown. Purpose of this study was to investigate the impact of OM-85 stimulation on human dendritic cell functions. We show that OM-85 selectively induced NF-kB and MAPK activation in human DC with no detectable action on the interferon regulatory factor (IRF) pathway. As a consequence, chemokines (i.e. CXCL8, CXCL6, CCL3, CCL20, CCL22) and B-cell activating cytokines (i.e. IL-6, BAFF and IL-10) were strongly upregulated. OM-85 also synergized with the action of classical pro-inflammatory stimuli used at suboptimal concentrations. Peripheral blood mononuclear cells from patients with COPD, a pathological condition often associated with altered PRR expression pattern, fully retained the capability to respond to OM-85. These results provide new insights on the molecular mechanisms of OM-85 activation of the immune response and strengthen the rational for its use in clinical settings. PMID:24386121

  15. Immunostimulatory Effects Triggered by Enterococcus faecalis CECT7121 Probiotic Strain Involve Activation of Dendritic Cells and Interferon-Gamma Production.

    PubMed

    Molina, Matías Alejandro; Díaz, Ailén Magalí; Hesse, Christina; Ginter, Wiebke; Gentilini, María Virginia; Nuñez, Guillermo Gabriel; Canellada, Andrea Mercedes; Sparwasser, Tim; Berod, Luciana; Castro, Marisa Silvia; Manghi, Marcela Alejandra

    2015-01-01

    Probiotics can modulate the immune system, conferring beneficial effects on the host. Understanding how these microorganisms contribute to improve the health status is still a challenge. Previously, we have demonstrated that Enterococcus faecalis CECT7121 implants itself and persists in the murine gastrointestinal tract, and enhances and skews the profile of cytokines towards the Th1 phenotype in several biological models. Given the importance of dendritic cells (DCs) in the orchestration of immunity, the aim of this work was to elucidate the influence of E. faecalis CECT7121 on DCs and the outcome of the immune responses. In this work we show that E. faecalis CECT7121 induces a strong dose-dependent activation of DCs and secretion of high levels of IL-12, IL-6, TNFα, and IL-10. This stimulation is dependent on TLR signaling, and skews the activation of T cells towards the production of IFNγ. The influence of this activation in the establishment of Th responses in vivo shows the accumulation of specific IFNγ-producing cells. Our findings indicate that the activation exerted by E. faecalis CECT7121 on DCs and its consequence on the cellular adaptive immune response may have broad therapeutic implications in immunomodulation.

  16. Immunostimulatory Effects Triggered by Enterococcus faecalis CECT7121 Probiotic Strain Involve Activation of Dendritic Cells and Interferon-Gamma Production

    PubMed Central

    Molina, Matías Alejandro; Díaz, Ailén Magalí; Hesse, Christina; Ginter, Wiebke; Gentilini, María Virginia; Nuñez, Guillermo Gabriel; Canellada, Andrea Mercedes; Sparwasser, Tim; Berod, Luciana; Castro, Marisa Silvia; Manghi, Marcela Alejandra

    2015-01-01

    Probiotics can modulate the immune system, conferring beneficial effects on the host. Understanding how these microorganisms contribute to improve the health status is still a challenge. Previously, we have demonstrated that Enterococcus faecalis CECT7121 implants itself and persists in the murine gastrointestinal tract, and enhances and skews the profile of cytokines towards the Th1 phenotype in several biological models. Given the importance of dendritic cells (DCs) in the orchestration of immunity, the aim of this work was to elucidate the influence of E. faecalis CECT7121 on DCs and the outcome of the immune responses. In this work we show that E. faecalis CECT7121 induces a strong dose-dependent activation of DCs and secretion of high levels of IL-12, IL-6, TNFα, and IL-10. This stimulation is dependent on TLR signaling, and skews the activation of T cells towards the production of IFNγ. The influence of this activation in the establishment of Th responses in vivo shows the accumulation of specific IFNγ-producing cells. Our findings indicate that the activation exerted by E. faecalis CECT7121 on DCs and its consequence on the cellular adaptive immune response may have broad therapeutic implications in immunomodulation. PMID:25978357

  17. TLR2-dependent activation of β-catenin pathway in dendritic cells induces regulatory responses and attenuates autoimmune inflammation

    PubMed Central

    Manoharan, Indumathi; Hong, Yuan; Suryawanshi, Amol; Angus-Hill, Melinda L.; Sun, Zuoming; Mellor, Andrew L.; Munn, David H.; Manicassamy, Santhakumar

    2014-01-01

    Dendritic cells (DCs) sense microbes via multiple innate receptors. Signals from different innate receptors are coordinated and integrated by DCs to generate specific innate and adaptive immune responses against pathogens. Previously, we have shown that two pathogen recognition receptors, TLR2 and dectin-1 that recognize the same microbial stimulus (zymosan) on DCs, induce mutually antagonistic regulatory or inflammatory responses, respectively. How diametric signals from these two receptors are coordinated in DCs to regulate or incite immunity is not known. Here we show that TLR2-signaling via AKT activates the β-catenin/TCF4 pathway in DCs and programs them to drive T regulatory cell differentiation. Activation of β-catenin/TCF4 was critical to induce regulatory molecules interleukin-10 (Il-10) and vitamin A metabolizing enzyme retinaldehyde dehydrogenase 2 (Aldh1a2) and to suppress pro-inflammatory cytokines. Deletion of β-catenin in DCs programmed them to drive TH17/TH1 cell differentiation in response to zymosan. Consistent with these findings, activation of the β-catenin pathway in DCs suppressed chronic inflammation and protected mice from TH17/TH1-mediated autoimmune neuroinflammation. Thus activation of β-catenin in DCs via the TLR2 receptor is a novel mechanism in DCs that regulates autoimmune inflammation. PMID:25210120

  18. Dendritic cell-nerve clusters are sites of T cell proliferation in allergic airway inflammation.

    PubMed

    Veres, Tibor Z; Shevchenko, Marina; Krasteva, Gabriela; Spies, Emma; Prenzler, Frauke; Rochlitzer, Sabine; Tschernig, Thomas; Krug, Norbert; Kummer, Wolfgang; Braun, Armin

    2009-03-01

    Interactions between T cells and dendritic cells in the airway mucosa precede secondary immune responses to inhaled antigen. The purpose of this study was to identify the anatomical locations where dendritic cell-T cell interactions occur, resulting in T cells activation by dendritic cells. In a mouse model of allergic airway inflammation, we applied whole-mount immunohistology and confocal microscopy to visualize dendritic cells and T cells together with nerves, epithelium, and smooth muscle in three dimensions. Proliferating T cells were identified by the detection of the incorporation of the nucleotide analogue 5-ethynyl-2'-deoxyuridine into the DNA. We developed a novel quantification method that enabled the accurate determination of cell-cell contacts in a semi-automated fashion. Dendritic cell-T cell interactions occurred beneath the smooth muscle layer, but not in the epithelium. Approximately 10% of the dendritic cells were contacted by nerves, and up to 4% of T cells formed clusters with these dendritic cells. T cells that were clustered with nerve-contacting dendritic cells proliferated only in the airways of mice with allergic inflammation but not in the airways of negative controls. Taken together, these results suggest that during the secondary immune response, sensory nerves influence dendritic cell-driven T cell activation in the airway mucosa.

  19. Dendritic Cell-Targeted Vaccines

    PubMed Central

    Cohn, Lillian; Delamarre, Lélia

    2014-01-01

    Despite significant effort, the development of effective vaccines inducing strong and durable T-cell responses against intracellular pathogens and cancer cells has remained a challenge. The initiation of effector CD8+ T-cell responses requires the presentation of peptides derived from internalized antigen on class I major histocompatibility complex molecules by dendritic cells (DCs) in a process called cross-presentation. A current strategy to enhance the effectiveness of vaccination is to deliver antigens directly to DCs. This is done via selective targeting of antigen using monoclonal antibodies directed against endocytic receptors on the surface of the DCs. In this review, we will discuss considerations relevant to the design of such vaccines: the existence of DC subsets with specialized functions, the impact of the antigen intracellular trafficking on cross-presentation, and the influence of maturation signals received by DCs on the outcome of the immune response. PMID:24910635

  20. Protein-DNA complex is the exclusive malaria parasite component that activates dendritic cells and triggers innate immune responses.

    PubMed

    Wu, Xianzhu; Gowda, Nagaraj M; Kumar, Sanjeev; Gowda, D Channe

    2010-04-15

    Dendritic cells (DCs) play a crucial role in the development of protective immunity to malaria. However, it remains unclear how malaria parasites trigger immune responses in DCs. In this study, we purified merozoites, food vacuoles, and parasite membrane fragments released during the Plasmodium falciparum schizont burst to homogeneity and tested for the activation of bone marrow-derived DCs from wild-type and TLR2(-/-), TLR4(-/-), TLR9(-/-), and MyD88(-/-) C57BL/6J mice. The results demonstrate that a protein-DNA complex is the exclusive parasite component that activates DCs by a TLR9-dependent pathway to produce inflammatory cytokines. Complex formation with proteins is essential for the entry of parasite DNA into DCs for TLR9 recognition and, thus, proteins convert inactive DNA into a potent immunostimulatory molecule. Exogenous cationic polymers, polylysine and chitosan, can impart stimulatory activity to parasite DNA, indicating that complex formation involves ionic interactions. Merozoites and DNA-protein complex could also induce inflammatory cytokine responses in human blood DCs. Hemozoin is neither a TLR9 ligand for DCs nor functions as a carrier of DNA into cells. Additionally, although TLR9 is critical for DCs to induce the production of IFN-gamma by NK cells, this receptor is not required for NK cells to secret IFN-gamma, and cell-cell contact among myeloid DCs, plasmacytoid DCs, and NK cells is required for IFN-gamma production. Together, these results contribute substantially toward the understanding of malaria parasite-recognition mechanisms. More importantly, our finding that proteins and carbohydrate polymers are able to confer stimulatory activity to an otherwise inactive parasite DNA have important implications for the development of a vaccine against malaria.

  1. Transpresentation of interleukin-15 by IL-15/IL-15Rα mRNA-engineered human dendritic cells boosts antitumoral natural killer cell activity

    PubMed Central

    Van den Bergh, Johan; Willemen, Yannick; Lion, Eva; Van Acker, Heleen; De Reu, Hans; Anguille, Sébastien; Goossens, Herman; Berneman, Zwi

    2015-01-01

    In cancer immunotherapy, the use of dendritic cell (DC)-based vaccination strategies can improve overall survival, but until now durable clinical responses remain scarce. To date, DC vaccines are designed primarily to induce effective T-cell responses, ignoring the antitumor activity potential of natural killer (NK) cells. Aiming to further improve current DC vaccination outcome, we engineered monocyte-derived DC to produce interleukin (IL)-15 and/or IL-15 receptor alpha (IL-15Rα) using mRNA electroporation. The addition of IL-15Rα to the protocol, enabling IL-15 transpresentation to neighboring NK cells, resulted in significantly better NK-cell activation compared to IL-15 alone. Next to upregulation of NK-cell membrane activation markers, IL-15 transpresentation resulted in increased NK-cell secretion of IFN-γ, granzyme B and perforin. Moreover, IL-15-transpresenting DC/NK cell cocultures from both healthy donors and acute myeloid leukemia (AML) patients in remission showed markedly enhanced cytotoxic activity against NK cell sensitive and resistant tumor cells. Blocking IL-15 transpresentation abrogated NK cell-mediated cytotoxicity against tumor cells, pointing to a pivotal role of IL-15 transpresentation by IL-15Rα to exert its NK cell-activating effects. In conclusion, we report an attractive approach to improve antitumoral NK-cell activity in DC-based vaccine strategies through the use of IL-15/IL-15Rα mRNA-engineered designer DC. PMID:26675759

  2. Anti-inflammatory activity of Cymbopogon citratus leaf infusion in lipopolysaccharide-stimulated dendritic cells: contribution of the polyphenols.

    PubMed

    Figueirinha, Artur; Cruz, Maria Teresa; Francisco, Vera; Lopes, M Celeste; Batista, Maria Teresa

    2010-06-01

    Cymbopogon citratus, an herb known worldwide as lemongrass, is widely consumed as an aromatic drink, and its fresh and dried leaves are currently used in traditional cuisine. However, little is known about the mechanism of action of C. citratus, namely, the anti-inflammatory effects of its dietary components. Because nitric oxide (NO), produced in large quantities by activated inflammatory cells, has been demonstrated to be involved in the pathogenesis of acute and chronic inflammation, we evaluated the effects of the infusion of dried leaves from C. citratus, as well as its polyphenolic fractions--flavonoid-, tannin-, and phenolic acid-rich fractions (FF, TF, and PAF, respectively)--on the NO production induced by lipopolysaccharide (LPS) in a skin-derived dendritic cell line (FSDC). C. citratus infusion significantly inhibited the LPS-induced NO production and inducible NO synthase (iNOS) protein expression. All the polyphenolic fractions tested also reduced the iNOS protein levels and NO production stimulated by LPS in FSDC cells, without affecting cell viability, with the strongest effects being observed for the fractions with mono- and polymeric flavonoids (FF and TF, respectively). Our results also indicated that the anti-inflammatory properties of FF are mainly due to luteolin glycosides. In conclusion, C. citratus has NO scavenging activity and inhibits iNOS expression and should be explored for the treatment of inflammatory diseases, in particular of the gastrointestinal tract.

  3. Ascaris lumbricoides pseudocoelomic body fluid induces a partially activated dendritic cell phenotype with Th2 promoting ability in vivo.

    PubMed

    Dowling, David J; Noone, Cariosa M; Adams, Paul N; Vukman, Krisztina V; Molloy, Sile F; Forde, Jessica; Asaolu, Samuel; O'Neill, Sandra M

    2011-02-01

    Dendritic cells (DCs) matured with helminth-derived molecules that promote Th2 immune responses do not follow conventional definitions of DC maturation processes. While a number of models of DC maturation by Th2 stimuli are postulated, further studies are required if we are to clearly define DC maturation processes that lead to Th2 immune responses. In this study, we examine the interaction of Th2-inducing molecules from the parasitic helminth Ascaris lumbricoides with the maturation processes and function of DCs. Here we show that murine bone marrow-derived DCs are partially matured by A. lumbricoides pseudocoelomic body fluid (ABF) as characterised by the production of IL-6, IL-12p40 and macrophage inflammatory protein 2 (MIP-2) but no enhanced expression of cluster of differentiation (CD)-14, T-cell co-stimulatory markers CD80, CD86, CD40, OX40L and major histocompatibility complex class II was observed. Despite these phenotypic characteristics, ABF-stimulated DCs displayed the functional hallmarks of fully matured cells, enhancing DC phagocytosis and promoting Th2-type responses in skin-draining lymph node cells in vivo. ABF activated Th2-associated extracellular signal-regulated kinase-1 and nuclear factor-kB intracellular signalling pathways independently of toll-like receptor 4. Taken together, we believe this is the first paper to demonstrate A. lumbricoides murine DC-Th cell-driven responses shedding further light on DC maturation processes by helminth antigens.

  4. Ebola virus-like particles produced in insect cells exhibit dendritic cell stimulating activity and induce neutralizing antibodies

    SciTech Connect

    Ye Ling; Lin Jianguo; Sun Yuliang; Bennouna, Soumaya; Lo, Michael; Wu Qingyang; Bu Zhigao; Pulendran, Bali; Compans, Richard W. . E-mail: compans@microbio.emory.edu; Yang Chinglai . E-mail: chyang@emory.edu

    2006-08-01

    Recombinant baculoviruses (rBV) expressing Ebola virus VP40 (rBV-VP40) or GP (rBV-GP) proteins were generated. Infection of Sf9 insect cells by rBV-VP40 led to assembly and budding of filamentous particles from the cell surface as shown by electron microscopy. Ebola virus-like particles (VLPs) were produced by coinfection of Sf9 cells with rBV-VP40 and rBV-GP, and incorporation of Ebola GP into VLPs was demonstrated by SDS-PAGE and Western blot analysis. Recombinant baculovirus infection of insect cells yielded high levels of VLPs, which were shown to stimulate cytokine secretion from human dendritic cells similar to VLPs produced in mammalian cells. The immunogenicity of Ebola VLPs produced in insect cells was evaluated by immunization of mice. Analysis of antibody responses showed that most of the GP-specific antibodies were of the IgG2a subtype, while no significant level of IgG1 subtype antibodies specific for GP was induced, indicating the induction of a Th1-biased immune response. Furthermore, sera from Ebola VLP immunized mice were able to block infection by Ebola GP pseudotyped HIV virus in a single round infection assay, indicating that a neutralizing antibody against the Ebola GP protein was induced. These results show that production of Ebola VLPs in insect cells using recombinant baculoviruses represents a promising approach for vaccine development against Ebola virus infection.

  5. Generation of cellular immune responses to HCV NS5 protein through in vivo activation of dendritic cells

    PubMed Central

    Wintermeyer, P.; Gehring, S.; Eken, A.; Wands, J. R.

    2014-01-01

    SUMMARY Chronic hepatitis C (HCV) infection is a substantial medical problem that leads to progressive liver disease, cirrhosis, and hepatocellular carcinoma (HCC). The aim of this study was to achieve sustained cellular immune responses in vivo to a HCV nonstructural protein using dendritic cell (DC)-based immunization approach. We targeted the HCV NS5 protein to DCs in vivo by injecting microparticles loaded with this antigen. The DC population was expanded in BALB/C mice (H-2d) by hydrodynamic injection of a plasmid pUMVC3-hFLex expressing the secreted portion of the human Fms-like tyrosine kinase receptor-3 ligand (hFlt3). Mice were subsequently injected with microparticles coated with HCV NS5 protein via the tail vein. Cellular immune responses were determined with respect to secretion of INFγ and IL2 by CD4+ cells and cytotoxic T-lymphocyte (CTL) assays in vitro; inhibition of tumour cell growth was employed for the assessment of CD8+ generated activity in vivo. We found that Flt3L treatment expanded the DC population in the spleen to 43%, and such cells displayed a striking upregulation of CD86 as well as CD80 and CD40 co-stimulating molecules. Viral antigen-specific TH1 cytokine secretion by splenocytes was generated, and CTL activity against syngeneic NS5 expressing myeloma target cells was observed. In addition, these cells inhibited tumour growth indicating that NS5-specific robust CTL activity was operative in vivo. Thus, the capability of activating DCs in vivo using the methods described is valuable as a therapeutic vaccine strategy for chronic HCV infection. PMID:20002303

  6. [Exosomes derived from dendritic cells].

    PubMed

    Amigorena, S

    2001-01-01

    Dendritic cells (DC) are potent antigen presenting cells and the only ones capable of inducing primary cytotoxic immune responses both in vivo and vitro. DCs secrete a 60-80 nm membrane vesicle population of endocytic origin, called exosomes. The protein composition of exosomes was analyzed using a systematic proteomic approach. Besides MHC and costimulatory molecules, exosomes bear several adhesion proteins, probably involved in their specific targeting. Exosomes also accumulate several cytosolic factors, most likely involved in exoxome's biogenesis in late endosomes. Like DCs, exosomes induce potent anti tumor immune responses in vivo. Indeed, a single injection of DC-derived exosomes sensitized with tumor peptides induced the eradication of established mouse tumors. Tumor-specific cytotoxic T lymphocytes were found in the spleen of exosome treated mice, and depletion of CD8+ T cells in vivo inhibited the anti tumor effect of exosomes. These results strongly support the implementation of human DC-derived exosomes for cancer immunotherapy.

  7. A novel recombinant protein of ephrinA1-PE38/GM-CSF activate dendritic cells vaccine in rats with glioma.

    PubMed

    Li, Ming; Wang, Bin; Wu, Zhonghua; Zhang, Jiadong; Shi, Xiwen; Cheng, Wenlan; Han, Shuangyin

    2015-07-01

    Dendritic cells loaded with tumor-associated antigens can effectively stimulate the antitumor immune response of cytotoxic T lymphocytes in the body, which facilitates the development of novel and effective treatments for cancer. In this study, the adenovirus-mediated ephrinA1-PE38/GM-CSF was successfully constructed using the overlap extension method, and verified with sequencing analysis. HEK293 cells were infected with the adenovirus and the cellular expression of ephrinA1-PE38/GM-CSF was measured with an enzyme-linked immunosorbent assay. The recombinant adenovirus was then delivered into the tumor-bearing rats and the results showed that such treatment significantly reduced the volumes of gliomas and improved the survival of the transplanted rats. The results from immunohistochemistry and flow cytometry suggested that this immunomodulatory agent cause activation of dendritic cells. The findings that ephrinA1-PE38/GM-CSF had a high efficacy in the activation of the dendritic cells would facilitate the development of in vivo dendritic-cell vaccines for the treatment of gliomas in rats. Our new method of DC vaccine production induces not only a specific local antitumor immune response but also a systemic immunotherapeutic effect. In addition, this method completely circumvents the risk of contamination related to the in vitro culture of DCs, thus greatly improving the safety and feasibility of clinical application of the DC vaccines in glioma.

  8. Dendritic web silicon for solar cell application

    NASA Technical Reports Server (NTRS)

    Seidensticker, R. G.

    1977-01-01

    The dendritic web process for growing long thin ribbon crystals of silicon and other semiconductors is described. Growth is initiated from a thin wirelike dendrite seed which is brought into contact with the melt surface. Initially, the seed grows laterally to form a button at the melt surface; when the seed is withdrawn, needlelike dendrites propagate from each end of the button into the melt, and the web portion of the crystal is formed by the solidification of the liquid film supported by the button and the bounding dendrites. Apparatus used for dendritic web growth, material characteristics, and the two distinctly different mechanisms involved in the growth of a single crystal are examined. The performance of solar cells fabricated from dendritic web material is indistinguishable from the performance of cells fabricated from Czochralski grown material.

  9. The p50 Subunit of NF-κB Orchestrates Dendritic Cell Lifespan and Activation of Adaptive Immunity

    PubMed Central

    Larghi, Paola; Porta, Chiara; Riboldi, Elena; Totaro, Maria Grazia; Carraro, Lorenzo; Orabona, Ciriana; Sica, Antonio

    2012-01-01

    Dendritic cells play a central role in keeping the balance between immunity and immune tolerance. A key factor in this equilibrium is the lifespan of DC, as its reduction restrains antigen availability leading to termination of immune responses. Here we show that lipopolysaccharide-driven DC maturation is paralleled by increased nuclear levels of p50 NF-κB, an event associated with DC apoptosis. Lack of p50 in murine DC promoted increased lifespan, enhanced level of maturation associated with increased expression of the proinflammatory cytokines IL-1, IL-18 and IFN-β, enhanced capacity of activating and expanding CD4+ and CD8+ T cells in vivo and decreased ability to induce differentiation of FoxP3+ regulatory T cells. In agreement, vaccination of melanoma-bearing mice with antigen-pulsed LPS-treated p50−/− BM-DC boosted antitumor immunity and inhibition of tumor growth. We propose that nuclear accumulation of the p50 NF-κB subunit in DC, as occurring during lipopolysaccharide-driven maturation, is a homeostatic mechanism tuning the balance between uncontrolled activation of adaptive immunity and immune tolerance. PMID:23049782

  10. In vitro Models to Evaluate Drug-Induced Hypersensitivity: Potential Test Based on Activation of Dendritic Cells

    PubMed Central

    Galbiati, Valentina; Papale, Angela; Kummer, Elena; Corsini, Emanuela

    2016-01-01

    Hypersensitivity drug reactions (HDRs) are the adverse effect of pharmaceuticals that clinically resemble allergy. HDRs account for approximately 1/6 of drug-induced adverse effects, and include immune-mediated (“allergic”) and non-immune-mediated (“pseudo allergic”) reactions. In recent years, the severe and unpredicted drug adverse events clearly indicate that the immune system can be a critical target of drugs. Enhanced prediction in preclinical safety evaluation is, therefore, crucial. Nowadays, there are no validated in vitro or in vivo methods to screen the sensitizing potential of drugs in the pre-clinical phase. The problem of non-predictability of immunologically-based hypersensitivity reactions is related to the lack of appropriate experimental models rather than to the lack of -understanding of the adverse phenomenon. We recently established experimental conditions and markers to correctly identify drug associated with in vivo hypersensitivity reactions using THP-1 cells and IL-8 production, CD86 and CD54 expression. The proposed in vitro method benefits from a rationalistic approach with the idea that allergenic drugs share with chemical allergens common mechanisms of cell activation. This assay can be easily incorporated into drug development for hazard identification of drugs, which may have the potential to cause in vivo hypersensitivity reactions. The purpose of this review is to assess the state of the art of in vitro models to assess the allergenic potential of drugs based on the activation of dendritic cells. PMID:27462271

  11. The cystine/glutamate antiporter regulates indoleamine 2,3-dioxygenase protein levels and enzymatic activity in human dendritic cells.

    PubMed

    Mattox, Mildred L; D'Angelo, June A; Grimes, Zachary M; Fiebiger, Edda; Dickinson, Bonny L

    2012-11-30

    Indoleamine 2,3-dioxygenase (IDO) is the rate-limiting enzyme in the tryptophan-catabolizing pathway and a key regulator of peripheral immune tolerance. As the suppressive effects of IDO are predominantly mediated by dendritic cells (DCs) and IDO-competent DCs promote long-term immunologic tolerance, a detailed understanding of how IDO expression and activity is regulated in these cells is central to the rational design of therapies to induce robust immune tolerance. We previously reported that the cystine/glutamate antiporter modulates the functional expression of IDO in human monocyte-derived DCs. Specifically, we showed that blocking antiporter uptake of cystine significantly increased both IDO mRNA and IDO enzymatic activity and that this correlated with impaired DC presentation of exogenous antigen to T cells via MHC class II and the cross-presentation pathway. The antiporter regulates intracellular and extracellular redox by transporting cystine into the cell in exchange for glutamate. Intracellular cystine is reduced to cysteine to support biosynthesis of the major cellular antioxidant glutathione and cysteine is exported from the cell where it functions as an extracellular antioxidant. Here we show that antiporter control of IDO expression in DCs is reversible, independent of interferon-γ, regulated by redox, and requires active protein synthesis. These findings highlight a role for antiporter regulation of cellular redox as a critical control point for modulating IDO expression and activity in DCs. Thus, systemic disease and aging, processes that perturb redox homeostasis, may adversely affect immunity by promoting the generation of IDO-competent DCs.

  12. Borrelia burgdorferi Induces TLR2-Mediated Migration of Activated Dendritic Cells in an Ex Vivo Human Skin Model

    PubMed Central

    Wagemakers, Alex; van ‘t Veer, Cornelis; Oei, Anneke; van der Pot, Wouter J.; Ahmed, Kalam; van der Poll, Tom; Geijtenbeek, Teunis B. H.; Hovius, Joppe W. R.

    2016-01-01

    Borrelia burgdorferi is transmitted into the skin of the host where it encounters and interacts with two dendritic cell (DC) subsets; Langerhans cells (LCs) and dermal DCs (DDCs). These cells recognize pathogens via pattern recognition receptors, mature and migrate out of the skin into draining lymph nodes, where they orchestrate adaptive immune responses. In order to investigate the response of skin DCs during the early immunopathogenesis of Lyme borreliosis, we injected B. burgdorferi intradermally into full-thickness human skin and studied the migration of DCs out of the skin, the activation profile and phenotype of migrated cells. We found a significant increase in the migration of LCs and DDCs in response to B. burgdorferi. Notably, migration was prevented by blocking TLR2. DCs migrated from skin inoculated with higher numbers of spirochetes expressed significantly higher levels of CD83 and produced pro-inflammatory cytokines. No difference was observed in the expression of HLA-DR, CD86, CD38, or CCR7. To conclude, we have established an ex vivo human skin model to study DC-B. burgdorferi interactions. Using this model, we have demonstrated that B. burgdorferi-induced DC migration is mediated by TLR2. Our findings underscore the utility of this model as a valuable tool to study immunity to spirochetal infections. PMID:27695100

  13. Exceptional antineoplastic activity of a dendritic-cell-targeted vaccine loaded with a Listeria peptide proposed against metastatic melanoma

    PubMed Central

    Calderon-Gonzalez, Ricardo; Bronchalo-Vicente, Lucia; Freire, Javier; Frande-Cabanes, Elisabet; Alaez-Alvarez, Lidia; Gomez-Roman, Javier; Yañez-Diaz, Sonsóles; Alvarez-Dominguez, Carmen

    2016-01-01

    Vaccination with dendritic cells (DCs) is proposed to induce lasting responses against melanoma but its survival benefit in patients needs to be demonstrated. We propose a DC-targeted vaccine loaded with a Listeria peptide with exceptional anti-tumour activity to prevent metastasis of melanoma. Mice vaccinated with vaccines based on DCs loaded with listeriolysin O peptide (91–99) (LLO91–99) showed clear reduction of metastatic B16OVA melanoma size and adhesion, prevention of lung metastasis, enhanced survival, and reversion of immune tolerance. Robust innate and specific immune responses explained the efficiency of DC-LLO91–99 vaccines against B16OVA melanoma. The noTable features of this vaccine related to melanoma reduction were: expansion of immune-dominant LLO91–99-specific CD8 T cells that helped to expand melanoma-specific CD8+ T cells; high numbers of tumour-infiltrating lymphocytes with a cytotoxic phenotype; and a decrease in CD4+CD25high regulatory T cells. This vaccine might be a useful alternative treatment for advanced melanoma, alone or in combination with other therapies. PMID:26942874

  14. IL-2 phosphorylates STAT5 to drive IFN-γ production and activation of human dendritic cells.

    PubMed

    Herr, Florence; Lemoine, Roxane; Gouilleux, Fabrice; Meley, Daniel; Kazma, Ihab; Heraud, Audrey; Velge-Roussel, Florence; Baron, Christophe; Lebranchu, Yvon

    2014-06-15

    Human dendritic cells (hDCs) produce IL-2 and express IL-2R α-chain (CD25), but the role of IL-2 in DC functions is not well defined. A recent study suggested that the main function of CD25 on hDCs was to transpresent IL-2 to activate T lymphocytes. Our results demonstrate the expression of the three chains of the IL-2R on hDCs and that IL-2 induces STAT5 phosphorylation. Interestingly, use of inhibitors of p-STAT5 revealed that IL-2 increases LPS-induced IFN-γ through STAT5 phosphorylation. Finally, we report that IL-2 increases the ability of hDCs to activate helpless CD8(+) T cells, most likely because of IL-2-triggered IFN-γ synthesis, as we previously described. For the first time, to our knowledge, we disclose that IL-2 induces monocyte-derived hDC's functional maturation and activation through IL-2R binding. Interestingly, our study suggests a direct effect of anti-CD25 mAbs on hDCs that may contribute to their clinical efficacy.

  15. TRIF Is a Critical Negative Regulator of TLR Agonist Mediated Activation of Dendritic Cells In Vivo

    PubMed Central

    Appledorn, Daniel M.; Aylsworth, Charles F.; Godbehere, Sarah; Liu, Chyong-Jy Joyce; Quiroga, Dionisia; Amalfitano, Andrea

    2011-01-01

    Despite recent advances in developing and licensing adjuvants, there is a great need for more potent formulations to enhance immunogenicity of vaccines. An Eimeria tenella derived antigen (rEA) augments immune responses against several pathogens in animal models and recently was confirmed to be safe for human use. In this study, we have analyzed the molecular mechanisms underlying rEA activity in mice, and confirmed that rEA activates multiple immune cell types, including DCs, macrophages, NK, B, and T cells. The rEA adjuvant also elicits the induction of pleiotropic pro-inflammatory cytokines, responses that completely depend upon the presence of the TLR adaptor protein MyD88. Surprisingly, we also found that the TRIF adaptor protein acts as a potent negative regulator of TLR agonist-triggered immune responses. For example, IL12 production and the induction of co-stimulatory molecule expression by DCs and IFNγ production by NK cells in vivo were significantly increased in rEA-treated TRIF-KO mice. Importantly, however, TRIF suppressive effects were not restricted to rEA-mediated responses, but were apparent in LPS- or ODN2006-activated DCs as well. Taken together, our findings confirm that rEA is a potent adjuvant, triggering robust activation of the innate immune system, in a manner that is augmented by MyD88 and inhibited by TRIF; thereby unveiling the potential complexities of modulating TLR activity to augment vaccine efficacy. PMID:21760953

  16. Active specific T-cell-based immunotherapy for cancer: nucleic acids, peptides, whole native proteins, recombinant viruses, with dendritic cell adjuvants or whole tumor cell-based vaccines. Principles and future prospects.

    PubMed

    Fernandez, N; Duffour, M T; Perricaudet, M; Lotze, M T; Tursz, T; Zitvogel, L

    1998-03-01

    Whereas tumor cells are poor immunogens, recombinant tumor cells or dendritic cells as well as engineered viruses have been demonstrated to elicit specific antitumor immune responses leading to tumor growth suppression and long-lasting immunity in mouse tumor models. Single cytotoxic T lymphocyte-defined epitope-based strategies have proved useful for immunization in tumor-bearing mice. This strategy is under investigation in human melanoma, along with adjuvants such as cytokines or dendritic cells. Flt3L is an in vivo dendritic-cell growth factor that offers new prospects in the field of active specific immunotherapy. These immunotherapeutic approaches are being tested in clinical trials, and may open up novel avenues for disease-free patients with poor prognostic factors.

  17. TLR4 and DC-SIGN receptors recognized Mycobacterium scrofulaceum promoting semi-activated phenotype on bone marrow dendritic cells.

    PubMed

    Cruz-Aguilar, Marisa; Castillo-Rodal, Antonia I; Schcolnik-Cabrera, Alejandro; Bonifaz, Laura C; Molina, Gabriela; López-Vidal, Yolanda

    2016-07-01

    Nontuberculous mycobacteria (NTM) are recognized as emerging pathogens and their immune regulatory mechanisms are not well described yet. From them, Mycobacterium avium is known to be a weak activator of dendritic cells (DCs) that impairs the response induced by BCG vaccine. However, whether other NTM such as Mycobacterium scrofulaceum may modulate the activation of DCs, has not been extensively studied. Here, we exposed bone marrow-derived DCs (BMDCs) to M. scrofulaceum and we analyzed the effect on the activation of DCs. We found that M. scrofulaceum has a comparable ability to induce a semi-mature DC phenotype, which was produced by its interaction with DC-SIGN and TLR4 receptors in a synergic effect. BMDCs exposed to M. scrofulaceum showed high expression of PD-L2 and production of IL-10, as well as low levels of co-stimulatory molecules and pro-inflammatory cytokines. In addition to immunophenotype induced on DCs, changes in morphology, re-organization of cytoskeleton and decreased migratory capacity are consistent with a semi-mature phenotype. However, unlike other pathogenic mycobacteria, the DC-semi-mature phenotype induced by M. scrofulaceum was reversed after re-exposure to BCG, suggesting that modulation mechanisms of DC-activation used by M. scrofulaceum are different to other known pathogenic mycobacteria. This is the first report about the immunophenotypic characterization of DC stimulated by M. scrofulaceum.

  18. In vitro studies implicate an imbalanced activation of dendritic cells in the pathogenesis of murine autoimmune pancreatitis

    PubMed Central

    Borufka, Luise; Volmer, Erik; Müller, Sarah; Engelmann, Robby; Nizze, Horst; Ibrahim, Saleh; Jaster, Robert

    2016-01-01

    Objectives MRL/MpJ mice spontaneously develop an autoimmune pancreatitis (AIP) and are widely used as a model to study the genetic, molecular and immunological basis of the disease. Here, we have addressed the question whether distinctive features of their dendritic cells (DCs) may predispose MRL/MpJ mice to the chronic inflammation. Methods Pancreatic lesions were analyzed employing histological methods. Cohorts of young (healthy) MRL/MpJ mice, adult (sick) individuals, and AIP-resistant CAST/EiJ mice were used to establish cultures of bone marrow (BM)-derived conventional DCs (cDCs). The cells were subsequently characterized regarding the expression profile of CD markers and selected genes, proliferative activity as well as cytokine secretion. Results In pancreatic lesions, large numbers of cells expressing the murine DC marker CD11c were detected in close spatial proximity to CD3+ cells. A high percentage of BM-derived cDCs from adult MRL/MpJ mice expressed typical markers of DC maturation (such as CD83) already prior to a treatment with lipopolysaccharide (LPS). After LPS-stimulation, cDC cultures of both MRL/MpJ mouse cohorts contained more mature cells, proliferated at a higher rate and secreted less interleukin-10 (but also less pro-inflammatory cytokines) than cultures of CAST/EiJ mice. Compared with corresponding cultures of the control strain, LPS-free cultured cDCs from MRL/MpJ mice expressed less mRNA of the inhibitory receptor triggering receptor expressed on myeloid cells 2 (trem2). Conclusions BM-derived cDCs from AIP-prone MRL/MpJ mice display functional features that are compatible with the hypothesis of an imbalanced DC activation in the context of murine AIP. PMID:27356751

  19. Increased expression with differential subcellular location of cytidine deaminase APOBEC3G in human CD4(+) T-cell activation and dendritic cell maturation.

    PubMed

    Oliva, Harold; Pacheco, Rodrigo; Martinez-Navio, José M; Rodríguez-García, Marta; Naranjo-Gómez, Mar; Climent, Núria; Prado, Carolina; Gil, Cristina; Plana, Montserrat; García, Felipe; Miró, José M; Franco, Rafael; Borras, Francesc E; Navaratnam, Naveenan; Gatell, José M; Gallart, Teresa

    2016-08-01

    APOBEC3G (apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3G; A3G) is an innate defense protein showing activity against retroviruses and retrotransposons. Activated CD4(+) T cells are highly permissive for HIV-1 replication, whereas resting CD4(+) T cells are refractory. Dendritic cells (DCs), especially mature DCs, are also refractory. We investigated whether these differences could be related to a differential A3G expression and/or subcellular distribution. We found that A3G mRNA and protein expression is very low in resting CD4(+) T cells and immature DCs, but increases strongly following T-cell activation and DC maturation. The Apo-7 anti-A3G monoclonal antibody (mAb), which was specifically developed, confirmed these differences at the protein level and disclosed that A3G is mainly cytoplasmic in resting CD4(+) T cells and immature DCs. Nevertheless, A3G translocates to the nucleus in activated-proliferating CD4(+) T cells, yet remaining cytoplasmic in matured DCs, a finding confirmed by immunoblotting analysis of cytoplasmic and nuclear fractions. Apo-7 mAb was able to immunoprecipitate endogenous A3G allowing to detect complexes with numerous proteins in activated-proliferating but not in resting CD4(+) T cells. The results show for the first time the nuclear translocation of A3G in activated-proliferating CD4(+) T cells.

  20. DC-SCRIPT Regulates IL-10 Production in Human Dendritic Cells by Modulating NF-κBp65 Activation.

    PubMed

    Søndergaard, Jonas Nørskov; Poghosyan, Susanna; Hontelez, Saartje; Louche, Pauline; Looman, Maaike W G; Ansems, Marleen; Adema, Gosse J

    2015-08-15

    The balance between tolerance and immunity is important for the outcome of an infection or cancer, and dendritic cells (DCs) are key regulators of this balance. DC-specific transcript (DC-SCRIPT) is a protein expressed by DCs and has been demonstrated to suppress both TLR-mediated expression of IL-10 and glucocorticoid receptor-mediated transcription of glucocorticoid-induced leucine zipper (GILZ). Because GILZ is known to promote IL-10 production, we investigated whether these two processes are linked. Dual-knockdown and inhibition experiments demonstrated that neither GILZ nor glucocorticoid receptor play a role in TLR-induced IL-10 production after DC-SCRIPT knockdown. The NF-κB pathway is another route involved in IL-10 production after DC activation. Strikingly, inhibition of NF-κB led to a decreased TLR-mediated IL-10 production in DC-SCRIPT knockdown DCs. Moreover, DC-SCRIPT knockdown DCs showed enhanced phosphorylation, acetylation, and IL10 enhancer binding of the NF-κB subunit p65. These data demonstrate that besides nuclear receptor regulation, DC-SCRIPT also modulates activation of NF-κBp65 after TLR activation in human DCs.

  1. Activation and selective IL-17 response of human Vγ9Vδ2 T lymphocytes by TLR-activated plasmacytoid dendritic cells

    PubMed Central

    Presti, Elena Lo; Caccamo, Nadia; Orlando, Valentina; Dieli, Francesco; Meraviglia, Serena

    2016-01-01

    Vγ9Vδ2 T cells and plasmacytoid dendritic cells (pDCs) are two distinct cell types of innate immunity that participate in early phases of immune response. We investigated whether a close functional relationship exists between these two cell populations using an in vitro co-culture in a human system. pDCs that had been activated by IL-3 and the TLR9 ligand CpG induced substantial activation of Vγ9Vδ2 T cells upon co-culture, which was cell-to-cell contact dependent, as demonstrated in transwell experiments, but that did not involve any of the costimulatory molecules potentially expressed by pDCs or Vγ9V2 T cells, such as ICOS-L, OX40 and CD40L. Activated pDCs selectively induced IL-17, but not IFN-γ, responses of Vγ9Vδ2T cells, which was dominant over the antigen-induced response, and this was associated with the expansion of memory (both central and effector memory) subsets of Vγ9Vδ2 T cells. Overall, our results provide a further piece of information on the complex relationship between these two populations of cells with innate immunity features during inflammatory responses. PMID:27590513

  2. Natural killer cells expressing the KIR2DS1-activating receptor efficiently kill T-cell blasts and dendritic cells: implications in haploidentical HSCT.

    PubMed

    Sivori, Simona; Carlomagno, Simona; Falco, Michela; Romeo, Elisa; Moretta, Lorenzo; Moretta, Alessandro

    2011-04-21

    In allogeneic HSCT, NK-cell alloreactivity is determined by the presence in the donor of NK cells expressing inhibitory killer cell Ig-like receptors (KIRs) that recognize HLA class I allotypes present in the donor but lacking in the recipient. Dominant KIR ligands are the C1 and C2 epitopes of HLA-C. All HLA-C allotypes have either the C1 epitope, the ligand for KIR2DL2/L3, or the C2 epitope, the ligand for KIR2DL1/S1. Here, we show that, in alloreactive NK-cell responses, KIR2DS1 expression represents a remarkable advantage as it allows efficient killing of C2/C2 or C1/C2 myelomonocitic dendritic cells (DCs) and T-cell blasts. When DCs or T-cell blasts were derived from C2/C2, Bw4/Bw4 donors, the activating signals delivered by KIR2DS1 could override the inhibition generated by NKG2A or KIR2DL2/L3 expressed on the same NK-cell clone. Furthermore, substantial lysis of C2/C2, Bw4/Bw6 targets was mediated by KIR2DS1(+) NK cells coexpressing KIR3DL1. Importantly, in the case of C1/C2 targets, KIR2DS1(+) NK cells were inhibited by the coexpression of KIR2DL2/L3 but not of NKG2A. Thus, KIR2DS1 expression in HSC donors may substantially increase the size of the alloreactive NK-cell subset leading to an enhanced ability to limit GVHD and improve engrafment.

  3. [Dendritic cells and gliomas: a hope in immunotherapy?].

    PubMed

    Jouanneau, E; Poujol, D; Caux, C; Belin, M-F; Blay, J-Y; Puisieux, I

    2006-12-01

    Immunotherapy has been explored for several decades to try to improve the prognosis of gliomas, but until recently no therapeutic benefit has been achieved. The discovery of dendritic cells, the most potent professional antigen presenting cells to initiate specific immune response, and the possibility of producing them ex vivo gave rise to new protocols of active immunotherapy. In oncology, promising experimental and clinical therapeutic results were obtained using these dendritic cells loaded with tumor antigen. Patients bearing gliomas have deficit antigen presentation making this approach rational. In several experimental glioma models, independent research teams have showed specific antitumor responses using these dendritic cells. Phase I/II clinical trials have demonstrated the feasibility and the tolerance of this immunotherapeutic approach. In neuro-oncology, the efficiency of such an approach remains to be established, similarly in oncology where positive phase III studies are missing. Nevertheless, dendritic cells comprise a complex network which is only partially understood and capable of generating either immunotolerance or immune response. Numerous parameters remain to be explored before any definitive conclusion about their utility as an anticancer weapon can be drawn. It seems however logical that immunotherapy with dendritic cells could prevent or delay tumor recurrence in patients with minor active disease. A review on glioma and dendritic cells is presented.

  4. Activation of the inflammasome by amorphous silica and TiO2 nanoparticles in murine dendritic cells.

    PubMed

    Winter, Meike; Beer, Hans-Dietmar; Hornung, Veit; Krämer, Ursula; Schins, Roel P F; Förster, Irmgard

    2011-09-01

    Nanomaterials are increasingly used in various food applications. In particular, nanoparticulate amorphous SiO2 is already contained, e.g., in spices. Since intestinal dendritic cells (DC) could be critical targets for ingested particles, we compared the in vitro effects of amorphous silica nanoparticles with fine crystalline silica, and micron-sized with nano-sized TiO2 particles on DC. TiO2- and SiO2-nanoparticles, as well as crystalline silica led to an upregulation of MHC-II, CD80, and CD86 on DC. Furthermore, these particles activated the inflammasome, leading to significant IL-1β-secretion in wild-type (WT) but not Caspase-1- or NLRP3-deficient mice. Silica nanoparticles and crystalline silica induced apoptosis, while TiO2 nanoparticles led to enhanced production of reactive oxygen species (ROS). Since amorphous silica and TiO2 nanoparticles had strong effects on the activation-status of DC, we suggest that nanoparticles, used as food additives, should be intensively studied in vitro and in vivo, to ensure their safety for the consumer.

  5. Characterization of murine lung dendritic cells: similarities to Langerhans cells and thymic dendritic cells

    PubMed Central

    1990-01-01

    Dendritic cells (DC) are potent accessory cells (AC) for the initiation of primary immune responses. Although murine lymphoid DC and Langerhans cells have been extensively characterized, DC from murine lung have been incompletely described. We isolated cells from enzyme-digested murine lungs and bronchoalveolar lavages that were potent stimulators of a primary mixed lymphocyte response (MLR). The AC had a low buoyant density, were loosely adherent and nonphagocytic. AC function was unaffected by depletion of cells expressing the splenic DC marker, 33D1. In addition, antibody and complement depletion of cells bearing the macrophage marker F4/80, or removal of phagocytic cells with silica also failed to decrease AC activity. In contrast, AC function was decreased by depletion of cells expressing the markers J11d and the low affinity interleukin 2 receptor (IL-2R), both present on thymic and skin DC. AC function was approximately equal in FcR+ and FcR- subpopulations, indicating there was heterogeneity within the AC population. Consistent with the functional data, a combined two-color immunofluorescence and latex bead uptake technique revealed that lung cells high in AC activity were enriched in brightly Ia+ dendritic- shaped cells that (a) were nonphagocytic, (b) lacked specific T and B lymphocyte markers and the macrophage marker F4/80, but (c) frequently expressed C3biR, low affinity IL-2R, FcRII, and the markers NLDC-145 and J11d. Taken together, the functional and phenotypic data suggest the lung cells that stimulate resting T cells in an MLR and that might be important in local pulmonary immune responses are DC that bear functional and phenotypic similarity to other tissues DC, such as Langerhans cells and thymic DC. PMID:2162904

  6. Targeting dendritic cells--why bother?

    PubMed

    Kreutz, Martin; Tacken, Paul J; Figdor, Carl G

    2013-04-11

    Vaccination is among the most efficient forms of immunotherapy. Although sometimes inducing lifelong protective B-cell responses, T-cell-mediated immunity remains challenging. Targeting antigen to dendritic cells (DCs) is an extensively explored concept aimed at improving cellular immunity. The identification of various DC subsets with distinct functional characteristics now allows for the fine-tuning of targeting strategies. Although some of these DC subsets are regarded as superior for (cross-) priming of naive T cells, controversies still remain about which subset represents the best target for immunotherapy. Because targeting the antigen alone may not be sufficient to obtain effective T-cell responses, delivery systems have been developed to target multiple vaccine components to DCs. In this Perspective, we discuss the pros and cons of targeting DCs: if targeting is beneficial at all and which vaccine vehicles and immunization routes represent promising strategies to reach and activate DCs.

  7. Probiotics, dendritic cells and bladder cancer.

    PubMed

    Feyisetan, Oladapo; Tracey, Christopher; Hellawell, Giles O

    2012-06-01

    What's known on the subject? and What does the study add? The suppressor effect of probiotics on superficial bladder cancer is an observed phenomenon but the specific mechanism is poorly understood. The evidence strongly suggests natural killer (NK) cells are the anti-tumour effector cells involved and NK cell activity correlates with the observed anti-tumour effect in mice. It is also known that dendritic cells (DC) cells are responsible for the recruitment and mobilization of NK cells so therefore it may be inferred that DC cells are most likely to be the interphase point at which probiotics act. In support of this, purification of NK cells was associated with a decrease in NK cells activity. The current use of intravesical bacille Calmette-Guérin in the management of superficial bladder cancer is based on the effect of a localised immune response. In the same way, understanding the mechanism of action of probiotics and the role of DC may potentially offer another avenue via which the immune system may be manipulated to resist bladder cancer. Probiotic foods have been available in the UK since 1996 with the arrival of the fermented milk drink (Yakult) from Japan. The presence of live bacterial ingredients (usually lactobacilli species) may confer health benefits when present in sufficient numbers. The role of probiotics in colo-rectal cancer may be related in part to the suppression of harmful colonic bacteria but other immune mechanisms are involved. Anti-cancer effects outside the colon were suggested by a Japanese report of altered rates of bladder tumour recurrence after ingestion of a particular probiotic. Dendritic cells play a central role to the general regulation of the immune response that may be modified by probiotics. The addition of probiotics to the diet may confer benefit by altering rates of bladder tumour recurrence and also alter the response to immune mechanisms involved with the application of intravesical treatments (bacille Calmette-Guérin).

  8. Active dendrites, potassium channels and synaptic plasticity.

    PubMed Central

    Johnston, Daniel; Christie, Brian R; Frick, Andreas; Gray, Richard; Hoffman, Dax A; Schexnayder, Lalania K; Watanabe, Shigeo; Yuan, Li-Lian

    2003-01-01

    The dendrites of CA1 pyramidal neurons in the hippocampus express numerous types of voltage-gated ion channel, but the distributions or densities of many of these channels are very non-uniform. Sodium channels in the dendrites are responsible for action potential (AP) propagation from the axon into the dendrites (back-propagation); calcium channels are responsible for local changes in dendritic calcium concentrations following back-propagating APs and synaptic potentials; and potassium channels help regulate overall dendritic excitability. Several lines of evidence are presented here to suggest that back-propagating APs, when coincident with excitatory synaptic input, can lead to the induction of either long-term depression (LTD) or long-term potentiation (LTP). The induction of LTD or LTP is correlated with the magnitude of the rise in intracellular calcium. When brief bursts of synaptic potentials are paired with postsynaptic APs in a theta-burst pairing paradigm, the induction of LTP is dependent on the invasion of the AP into the dendritic tree. The amplitude of the AP in the dendrites is dependent, in part, on the activity of a transient, A-type potassium channel that is expressed at high density in the dendrites and correlates with the induction of the LTP. Furthermore, during the expression phase of the LTP, there are local changes in dendritic excitability that may result from modulation of the functioning of this transient potassium channel. The results support the view that the active properties of dendrites play important roles in synaptic integration and synaptic plasticity of these neurons. PMID:12740112

  9. Dendritic Kv3.3 potassium channels in cerebellar purkinje cells regulate generation and spatial dynamics of dendritic Ca2+ spikes.

    PubMed

    Zagha, Edward; Manita, Satoshi; Ross, William N; Rudy, Bernardo

    2010-06-01

    Purkinje cell dendrites are excitable structures with intrinsic and synaptic conductances contributing to the generation and propagation of electrical activity. Voltage-gated potassium channel subunit Kv3.3 is expressed in the distal dendrites of Purkinje cells. However, the functional relevance of this dendritic distribution is not understood. Moreover, mutations in Kv3.3 cause movement disorders in mice and cerebellar atrophy and ataxia in humans, emphasizing the importance of understanding the role of these channels. In this study, we explore functional implications of this dendritic channel expression and compare Purkinje cell dendritic excitability in wild-type and Kv3.3 knockout mice. We demonstrate enhanced excitability of Purkinje cell dendrites in Kv3.3 knockout mice, despite normal resting membrane properties. Combined data from local application pharmacology, voltage clamp analysis of ionic currents, and assessment of dendritic Ca(2+) spike threshold in Purkinje cells suggest a role for Kv3.3 channels in opposing Ca(2+) spike initiation. To study the physiological relevance of altered dendritic excitability, we measured [Ca(2+)](i) changes throughout the dendritic tree in response to climbing fiber activation. Ca(2+) signals were specifically enhanced in distal dendrites of Kv3.3 knockout Purkinje cells, suggesting a role for dendritic Kv3.3 channels in regulating propagation of electrical activity and Ca(2+) influx in distal dendrites. These findings characterize unique roles of Kv3.3 channels in dendrites, with implications for synaptic integration, plasticity, and human disease.

  10. Triggering of dendritic cell apoptosis by xanthohumol.

    PubMed

    Xuan, Nguyen Thi; Shumilina, Ekaterina; Gulbins, Erich; Gu, Shuchen; Götz, Friedrich; Lang, Florian

    2010-07-01

    Xanthohumol, a flavonoid from beer with anticancer activity is known to trigger apoptosis in a variety of tumor cells. Xanthohumol further has anti-inflammatory activity. However, little is known about the effect of xanthohumol on survival and function of immune cells. The present study thus addressed the effect of xanthohumol on dendritic cells (DCs), key players in the regulation of innate and adaptive immunity. To this end, mouse bone marrow-derived DCs were treated with xanthohumol with subsequent assessment of enzymatic activity of acid sphingomyelinase (Asm), ceramide formation determined with anti-ceramide antibodies in FACS and immunohistochemical analysis, caspase activity utilizing FITC conjugated anti-active caspase 8 or caspase 3 antibodies in FACS and by Western blotting, DNA fragmentation by determining the percentage of cells in the sub-G1 phase and cell membrane scrambling by annexin V binding in FACS analysis. As a result, xanthohumol stimulated Asm, enhanced ceramide formation, activated caspases 8 and 3, triggered DNA fragmentation and led to cell membrane scrambling, all effects virtually absent in DCs from gene targeted mice lacking functional Asm or in wild-type cells treated with sphingomyelinase inhibitor amitriptyline. In conclusion, xanthohumol stimulated Asm leading to caspase activation and apoptosis of bone marrow-derived DCs.

  11. Fasciola hepatica Kunitz type molecule decreases dendritic cell activation and their ability to induce inflammatory responses.

    PubMed

    Falcón, Cristian R; Masih, Diana; Gatti, Gerardo; Sanchez, María Cecilia; Motrán, Claudia C; Cervi, Laura

    2014-01-01

    The complete repertoire of proteins with immunomodulatory activity in Fasciola hepatica (Fh) has not yet been fully described. Here, we demonstrated that Fh total extract (TE) reduced LPS-induced DC maturation, and the DC ability to induce allogeneic responses. After TE fractionating, a fraction lower than 10 kDa (F<10 kDa) was able to maintain the TE properties to modulate the DC pro- and anti-inflammatory cytokine production induced by LPS. In addition, TE or F<10 kDa treatment decreased the ability of immature DC to stimulate the allogeneic responses and induced a novo allogeneic CD4+CD25+Foxp3+ T cells. In contrast, treatment of DC with T/L or F<10 kDa plus LPS (F<10/L) induced a regulatory IL-27 dependent mechanism that diminished the proliferative and Th1 and Th17 allogeneic responses. Finally, we showed that a Kunitz type molecule (Fh-KTM), present in F<10 kDa, was responsible for suppressing pro-inflammatory cytokine production in LPS-activated DC, by printing tolerogenic features on DC that impaired their ability to induce inflammatory responses. These results suggest a modulatory role for this protein, which may be involved in the immune evasion mechanisms of the parasite.

  12. Fasciola hepatica Kunitz Type Molecule Decreases Dendritic Cell Activation and Their Ability to Induce Inflammatory Responses

    PubMed Central

    Falcón, Cristian R.; Masih, Diana; Gatti, Gerardo; Sanchez, María Cecilia; Motrán, Claudia C.; Cervi, Laura

    2014-01-01

    The complete repertoire of proteins with immunomodulatory activity in Fasciola hepatica (Fh) has not yet been fully described. Here, we demonstrated that Fh total extract (TE) reduced LPS-induced DC maturation, and the DC ability to induce allogeneic responses. After TE fractionating, a fraction lower than 10 kDa (F<10 kDa) was able to maintain the TE properties to modulate the DC pro- and anti-inflammatory cytokine production induced by LPS. In addition, TE or F<10 kDa treatment decreased the ability of immature DC to stimulate the allogeneic responses and induced a novo allogeneic CD4+CD25+Foxp3+ T cells. In contrast, treatment of DC with T/L or F<10 kDa plus LPS (F<10/L) induced a regulatory IL-27 dependent mechanism that diminished the proliferative and Th1 and Th17 allogeneic responses. Finally, we showed that a Kunitz type molecule (Fh-KTM), present in F<10 kDa, was responsible for suppressing pro-inflammatory cytokine production in LPS-activated DC, by printing tolerogenic features on DC that impaired their ability to induce inflammatory responses. These results suggest a modulatory role for this protein, which may be involved in the immune evasion mechanisms of the parasite. PMID:25486609

  13. Distal gap junctions and active dendrites can tune network dynamics.

    PubMed

    Saraga, Fernanda; Ng, Leo; Skinner, Frances K

    2006-03-01

    Gap junctions allow direct electrical communication between CNS neurons. From theoretical and modeling studies, it is well known that although gap junctions can act to synchronize network output, they can also give rise to many other dynamic patterns including antiphase and other phase-locked states. The particular network pattern that arises depends on cellular, intrinsic properties that affect firing frequencies as well as the strength and location of the gap junctions. Interneurons or GABAergic neurons in hippocampus are diverse in their cellular characteristics and have been shown to have active dendrites. Furthermore, parvalbumin-positive GABAergic neurons, also known as basket cells, can contact one another via gap junctions on their distal dendrites. Using two-cell network models, we explore how distal electrical connections affect network output. We build multi-compartment models of hippocampal basket cells using NEURON and endow them with varying amounts of active dendrites. Two-cell networks of these model cells as well as reduced versions are explored. The relationship between intrinsic frequency and the level of active dendrites allows us to define three regions based on what sort of network dynamics occur with distal gap junction coupling. Weak coupling theory is used to predict the delineation of these regions as well as examination of phase response curves and distal dendritic polarization levels. We find that a nonmonotonic dependence of network dynamic characteristics (phase lags) on gap junction conductance occurs. This suggests that distal electrical coupling and active dendrite levels can control how sensitive network dynamics are to gap junction modulation. With the extended geometry, gap junctions located at more distal locations must have larger conductances for pure synchrony to occur. Furthermore, based on simulations with heterogeneous networks, it may be that one requires active dendrites if phase-locking is to occur in networks formed

  14. Nanoparticle-mediated combinatorial targeting of multiple human dendritic cell (DC) subsets leads to enhanced T cell activation via IL-15-dependent DC crosstalk.

    PubMed

    Sehgal, Kartik; Ragheb, Ragy; Fahmy, Tarek M; Dhodapkar, Madhav V; Dhodapkar, Kavita M

    2014-09-01

    Most vaccines depend on coadministration of Ags and adjuvants that activate APCs. Nanoparticles (NPs) have emerged as an attractive vehicle for synchronized delivery of Ags and adjuvants to APCs and can be targeted to specific cell types, such as dendritic cells (DCs), which are potent APCs. Which subset of human DCs should be targeted for optimal activation of T cell immunity, however, remains unknown. In this article, we describe a poly-lactic-coglycolic acid-based NP platform, wherein avidin-decorated NPs can be targeted to multiple human DC subsets via biotinylated Abs. Both BDCA3(+) and monocyte-derived DC-SIGN(+) NP-loaded DCs were equally effective at generating Ag-specific human T cells in culture, including against complex peptide mixtures from viral and tumor Ags across multiple MHC molecules. Ab-mediated targeting of NPs to distinct DC subsets led to enhanced T cell immunity. However, combination targeting to both DC-SIGN and BDCA3(+) DCs led to significantly greater activation of T cells compared with targeting either DC subset alone. Enhanced T cell activation following combination targeting depended on DC-mediated cytokine release and was IL-15 dependent. These data demonstrate that simultaneous targeting of multiple DC subsets may improve NP vaccines by engaging DC crosstalk and provides a novel approach to improving vaccines against pathogens and tumors.

  15. Cell-surface marker analysis of rat thymic dendritic cells.

    PubMed Central

    Bañuls, M P; Alvarez, A; Ferrero, I; Zapata, A; Ardavin, C

    1993-01-01

    Rat thymic dendritic cells have been isolated by collagenase digestion, separation of the low-density cell fraction by centrifugation on metrizamide, and differential adherence. The resulting dendritic cell preparation had a purity of > 90%, and has been analysed by flow cytometry (FCM) using a large panel of monoclonal antibodies (mAb). Dendritic cells expressed major histocompatibility (MHC) class I and class II molecules, the leucocyte common antigen CD45, the rat leucocyte antigen OX44, the rat macrophage marker ED1, and the adhesion molecules Mac-1, LFA-1 and ICAM-1. They were negative for the T- and B-cell-specific forms of CD45, CD45R and B220, and the B-cell marker OX12. Concerning T-cell marker expression, they were negative for T-cell receptor (TcR) and OX40, but they expressed CD2, CD4 and CD8, and interestingly, 50% of DC were CD5+, 50% expressed the alpha-chain of interleukin-2 receptor (IL-2R), and 80% were positive for the T-cell activation antigen recognized by the mAb OX48. Moreover, 60% of DC expressed high levels of Thy-1, whereas 40% displayed intermediate levels of this T-cell marker. PMID:8102122

  16. Dendritic Cells and Macrophages: Sentinels in the Kidney

    PubMed Central

    Weisheit, Christina K.; Engel, Daniel R.

    2015-01-01

    The mononuclear phagocytes (dendritic cells and macrophages) are closely related immune cells with central roles in anti-infectious defense and maintenance of organ integrity. The canonical function of dendritic cells is the activation of T cells, whereas macrophages remove apoptotic cells and microbes by phagocytosis. In the kidney, these cell types form an intricate system of mononuclear phagocytes that surveys against injury and infection and contributes to organ homeostasis and tissue repair but may also promote progression of CKD. This review summarizes the general functions and classification of dendritic cells and macrophages in the immune system and recapitulates why overlapping definitions and historically separate research have created controversy about their tasks. Their roles in acute kidney disease, CKD, and renal transplantation are described, and therapeutic strategy to modify these cells for therapeutic purposes is discussed. PMID:25568218

  17. Cupressaceae pollen grains modulate dendritic cell response and exhibit IgE-inducing adjuvant activity in vivo.

    PubMed

    Kamijo, Seiji; Takai, Toshiro; Kuhara, Takatoshi; Tokura, Tomoko; Ushio, Hiroko; Ota, Mikiko; Harada, Norihiro; Ogawa, Hideoki; Okumura, Ko

    2009-11-15

    Pollen is considered a source of not only allergens but also immunomodulatory substances, which could play crucial roles in sensitization and/or the exacerbation of allergies. We investigated how allergenic pollens from different plant species (Japanese cedar and Japanese cypress, which belong to the Cupressaceae family, and birch, ragweed, and grass) modulate murine bone marrow-derived dendritic cell (DC) responses and examined the effect of Cupressaceae pollen in vivo using mice. DCs were stimulated with pollen extracts or grains in the presence or absence of LPS. Cell maturation and cytokine production in DCs were analyzed by flow cytometry, ELISA, and/or quantitative PCR. Pollen extracts suppressed LPS-induced IL-12 production and the effect was greatest for birch and grass. Without LPS, pollen grains induced DC maturation and cytokine production without IL-12 secretion and the response, for which TLR 4 was dispensable, was greatest for the Cupressaceae family. Intranasal administration of Cupressaceae pollen in mice induced an elevation of serum IgE levels and airway eosinophil infiltration. Coadministration of ovalbumin with Cupressaceae pollen grains induced ovalbumin-specific IgE responses associated with eosinophil infiltration. The results suggest that modulation of DC responses by pollen differs among the plant families via (1) the promotion of DC maturation and cytokine production by direct contact and/or (2) the inhibition of IL-12 production by soluble factors. The strong DC stimulatory activity in vitro and IgE-inducing activity in mice support the clinical relevance of Cupressaceae pollen to allergies in humans.

  18. Linking Transcriptional Changes over Time in Stimulated Dendritic Cells to Identify Gene Networks Activated during the Innate Immune Response

    PubMed Central

    Patil, Ashwini; Kumagai, Yutaro; Liang, Kuo-ching; Suzuki, Yutaka; Nakai, Kenta

    2013-01-01

    The innate immune response is primarily mediated by the Toll-like receptors functioning through the MyD88-dependent and TRIF-dependent pathways. Despite being widely studied, it is not yet completely understood and systems-level analyses have been lacking. In this study, we identified a high-probability network of genes activated during the innate immune response using a novel approach to analyze time-course gene expression profiles of activated immune cells in combination with a large gene regulatory and protein-protein interaction network. We classified the immune response into three consecutive time-dependent stages and identified the most probable paths between genes showing a significant change in expression at each stage. The resultant network contained several novel and known regulators of the innate immune response, many of which did not show any observable change in expression at the sampled time points. The response network shows the dominance of genes from specific functional classes during different stages of the immune response. It also suggests a role for the protein phosphatase 2a catalytic subunit α in the regulation of the immunoproteasome during the late phase of the response. In order to clarify the differences between the MyD88-dependent and TRIF-dependent pathways in the innate immune response, time-course gene expression profiles from MyD88-knockout and TRIF-knockout dendritic cells were analyzed. Their response networks suggest the dominance of the MyD88-dependent pathway in the innate immune response, and an association of the circadian regulators and immunoproteasomal degradation with the TRIF-dependent pathway. The response network presented here provides the most probable associations between genes expressed in the early and the late phases of the innate immune response, while taking into account the intermediate regulators. We propose that the method described here can also be used in the identification of time-dependent gene sub

  19. Linking transcriptional changes over time in stimulated dendritic cells to identify gene networks activated during the innate immune response.

    PubMed

    Patil, Ashwini; Kumagai, Yutaro; Liang, Kuo-Ching; Suzuki, Yutaka; Nakai, Kenta

    2013-01-01

    The innate immune response is primarily mediated by the Toll-like receptors functioning through the MyD88-dependent and TRIF-dependent pathways. Despite being widely studied, it is not yet completely understood and systems-level analyses have been lacking. In this study, we identified a high-probability network of genes activated during the innate immune response using a novel approach to analyze time-course gene expression profiles of activated immune cells in combination with a large gene regulatory and protein-protein interaction network. We classified the immune response into three consecutive time-dependent stages and identified the most probable paths between genes showing a significant change in expression at each stage. The resultant network contained several novel and known regulators of the innate immune response, many of which did not show any observable change in expression at the sampled time points. The response network shows the dominance of genes from specific functional classes during different stages of the immune response. It also suggests a role for the protein phosphatase 2a catalytic subunit α in the regulation of the immunoproteasome during the late phase of the response. In order to clarify the differences between the MyD88-dependent and TRIF-dependent pathways in the innate immune response, time-course gene expression profiles from MyD88-knockout and TRIF-knockout dendritic cells were analyzed. Their response networks suggest the dominance of the MyD88-dependent pathway in the innate immune response, and an association of the circadian regulators and immunoproteasomal degradation with the TRIF-dependent pathway. The response network presented here provides the most probable associations between genes expressed in the early and the late phases of the innate immune response, while taking into account the intermediate regulators. We propose that the method described here can also be used in the identification of time-dependent gene sub

  20. The inclusion into PLGA nanoparticles enables α-bisabolol to efficiently inhibit the human dendritic cell pro-inflammatory activity

    NASA Astrophysics Data System (ADS)

    Marongiu, Laura; Donini, Marta; Bovi, Michele; Perduca, Massimiliano; Vivian, Federico; Romeo, Alessandro; Mariotto, Sofia; Monaco, Hugo L.; Dusi, Stefano

    2014-08-01

    α-bisabolol, a natural sesquiterpene alcohol, has generated considerable interest for its anti-inflammatory activity. Since the mechanisms of this anti-inflammatory action remain poorly understood, we investigated whether α-bisabolol affects the release of pro-inflammatory cytokines IL-12, IL-23, IL-6, and TNFα by human dendritic cells (DCs). We found that α-bisabolol did not induce the secretion of these cytokines and did not affect their release induced upon DC challenge with lipopolysaccharide (LPS), a well-known immune cell stimulator. As α-bisabolol is scarcely ingested by the cells, we wondered whether the inclusion of α-bisabolol into nanoparticles could favor its internalization by DCs and consequently its effects on cytokine secretion. We then prepared and characterized poly(lactic-co-glycolic acid) (PLGA) nanoparticles, with a dynamic light scattering peak centered at 154 nm and a half width at half maximum of about 48 nm. These particles were unable to affect per se cytokine secretion by both resting and LPS-stimulated DCs and were internalized by human DCs as demonstrated by confocal microscopy analysis. We then loaded PLGA nanoparticles with α-bisabolol and we observed that PLGA-associated α-bisabolol did not stimulate the cytokine release by resting DCs, but decreased IL-12, IL-23, IL-6, and TNFα secretion by LPS-stimulated DCs. Our results indicate that α-bisabolol inclusion into PLGA nanoparticles represents a very promising tool for designing new anti-inflammatory, anti-pyretic and, possibly, immunosuppressive therapeutic strategies.

  1. Sirtuin 1 promotes Th2 responses and airway allergy by repressing peroxisome proliferator-activated receptor-γ activity in dendritic cells.

    PubMed

    Legutko, Agnieszka; Marichal, Thomas; Fiévez, Laurence; Bedoret, Denis; Mayer, Alice; de Vries, Hilda; Klotz, Luisa; Drion, Pierre-Vincent; Heirman, Carlo; Cataldo, Didier; Louis, Renaud; Thielemans, Kris; Andris, Fabienne; Leo, Oberdan; Lekeux, Pierre; Desmet, Christophe J; Bureau, Fabrice

    2011-11-01

    Sirtuins are a unique class of NAD(+)-dependent deacetylases that regulate diverse biological functions such as aging, metabolism, and stress resistance. Recently, it has been shown that sirtuins may have anti-inflammatory activities by inhibiting proinflammatory transcription factors such as NF-κB. In contrast, we report in this study that pharmacological inhibition of sirtuins dampens adaptive Th2 responses and subsequent allergic inflammation by interfering with lung dendritic cell (DC) function in a mouse model of airway allergy. Using genetic engineering, we demonstrate that sirtuin 1 represses the activity of the nuclear receptor peroxisome proliferator-activated receptor-γ in DCs, thereby favoring their maturation toward a pro-Th2 phenotype. This study reveals a previously unappreciated function of sirtuin 1 in the regulation of DC function and Th2 responses, thus shedding new light on our current knowledge on the regulation of inflammatory processes by sirtuins.

  2. Characterization of chicken epidermal dendritic cells

    PubMed Central

    Igyártó, Botond-Zoltán; Lackó, Erzsébet; Oláh, Imre; Magyar, Attila

    2006-01-01

    It has been known for 15 years that the chicken epidermis contains ATPase+ and major histocompatibility complex class II-positive (MHCII+) dendritic cells. These cells were designated as Langerhans cells but neither their detailed phenotype nor their function was further investigated. In the present paper we demonstrate a complete overlapping of ATPase, CD45 and vimentin staining in all dendritic cells of the chicken epidermis. The CD45+ ATPase+ vimentin+ dendritic cells could be divided into three subpopulations: an MHCII+ CD3– KUL01+ and 68.1+ (monocyte-macrophage subpopulation markers) subpopulation, an MHCII– CD3– KUL01– and 68.1– subpopulation and an MHCII– CD3+ KUL01– and 68.1– subpopulation. The first population could be designated as chicken Langerhans cells. The last population represents CD4– CD8– T-cell receptor-αβ– and -γδ– natural killer cells with cytoplasmic CD3 positivity. The epidermal dendritic cells have a low proliferation rate as assessed by bromodeoxyuridine incorporation. Both in vivo and in vitro experiments showed that dendritic cells could be mobilized from the epidermis. Hapten treatment of epidermis resulted in the decrease of the frequency of epidermal dendritic cells and hapten-loaded dendritic cells appeared in the dermis or in in vitro culture of isolated epidermis. Hapten-positive cells were also found in the so-called dermal lymphoid nodules. We suggest that these dermal nodules are responsible for some regional immunological functions similar to the mammalian lymph nodes. PMID:16889640

  3. IL-25 promotes Th2 immunity responses in airway inflammation of asthmatic mice via activation of dendritic cells.

    PubMed

    Hongjia, Li; Caiqing, Zhang; Degan, Lu; Fen, Liu; Chao, Wang; Jinxiang, Wu; Liang, Dong

    2014-08-01

    Allergic asthma occurs as a consequence of inappropriate immunologic inflammation to allergens and characterized by Th2 adaptive immune response. Recent studies indicated that interleukin (IL)-25, a member of the IL-17 cytokine family, had been implicated in inducing Th2 cell-dependent inflammation in airway epithelium and IL-25-deficient mice exhibit impaired Th2 immunity responses; however, how these cytokines influence innate immune responses remains poorly understood. In this study, we used ovalbumin (OVA) sensitization and challenge to induce the murine asthmatic model and confirmed by histological analysis of lung tissues and serum levels of total and OVA-specific immunoglobulin (Ig)-E. The expression of IL-25 was detected by quantitative real-time PCR and immunohistochemistry, respectively, and the dendritic cells (DCs) activation was detected by levels of CD80 and CD86 in bronchoalveolar lavage fluid (BALF) by flow cytometry. The mice sensitized and challenged with OVA showed high expression of IL-25 in both mRNA and protein levels in lungs. We detected the expression of CD80 and CD86 in BALF was also increased. A tight correlation between IL-25 mRNA and other Th2 cells producing cytokines such as IL-4, IL-5, and IL-13 in BALF was identified. Furthermore, when the asthmatic mice were treated with inhaled corticosteroids, the inflammatory cells infiltration and the inflammatory cytokines secretion were significantly decreased. In this study, we show that IL-25 promoted the accumulation of co-stimulatory molecules of CD80 and CD86 on DCs and then induced the differentiation of prime naive CD4(+) T cells to become proinflammatory Th2 cells and promoted Th2 cytokine responses in OVA-induced airway inflammation. The ability of IL-25 to promote the activation and differentiation of DCs population was identified as a link between the IL-17 cytokine family and the innate immune response and suggested a previously unrecognized innate immune pathway that promotes Th2

  4. Differential Activation of Human Monocyte-Derived and Plasmacytoid Dendritic Cells by West Nile Virus Generated in Different Host Cells▿

    PubMed Central

    Silva, Maria Carlan; Guerrero-Plata, Antonieta; Gilfoy, Felicia D.; Garofalo, Roberto P.; Mason, Peter W.

    2007-01-01

    Dendritic cells (DCs) play a central role in innate immunity and antiviral responses. In this study, we investigated the production of alpha interferon (IFN-α) and inducible chemokines by human monocyte-derived dendritic cells (mDCs) and plasmacytoid dendritic cells (pDCs) infected with West Nile virus (WNV), an emergent pathogen whose infection can lead to severe cases of encephalitis in the elderly, children, and immunocompromised individuals. Our experiments demonstrated that WNV grown in mammalian cells (WNVVero) was a potent inducer of IFN-α secretion in pDCs and, to a lesser degree, in mDCs. The ability of WNVVero to induce IFN-α in pDCs did not require viral replication and was prevented by the treatment of cells with bafilomycin A1 and chloroquine, suggesting that it was dependent on endosomal Toll-like receptor recognition. On the other hand, IFN-α production in mDCs required viral replication and was associated with the nuclear translocation of IRF3 and viral antigen expression. Strikingly, pDCs failed to produce IFN-α when stimulated with WNV grown in mosquito cells (WNVC7/10), while mDCs responded similarly to WNVVero or WNVC7/10. Moreover, the IFN-dependent chemokine IP-10 was produced in substantial amounts by pDCs in response to WNVVero but not WNVC7/10, while interleukin-8 was produced in greater amounts by mDCs infected with WNVC7/10 than in those infected with WNVVero. These findings suggest that cell-specific mechanisms of WNV recognition leading to the production of type I IFN and inflammatory chemokines by DCs may contribute to both the innate immune response and disease pathogenesis in human infections. PMID:17913823

  5. Optimization of Assays to Assess Dendritic Cell Activation and/or Energy in Ebola Infection

    DTIC Science & Technology

    2011-10-01

    entry and infection, we hope to gain insight into the connection between host cell tropism and virulence and to identify cells targeted by EVLPs to...types, but did not exhibit the strict tropism for mouse cells as did the F88A mutant.  The mutant F225A displayed entry similar to wild-type

  6. Kv1 channels selectively prevent dendritic hyperexcitability in rat Purkinje cells

    PubMed Central

    Khavandgar, Simin; Walter, Joy T; Sageser, Kristin; Khodakhah, Kamran

    2005-01-01

    Purkinje cells, the sole output of the cerebellar cortex, encode the timing signals required for motor coordination in their firing rate and activity pattern. Dendrites of Purkinje cells express a high density of P/Q-type voltage-gated calcium channels and fire dendritic calcium spikes. Here we show that dendritic subthreshold Kv1.2 subunit-containing Kv1 potassium channels prevent generation of random spontaneous calcium spikes. With Kv1 channels blocked, dendritic calcium spikes drive bursts of somatic sodium spikes and prevent the cell from faithfully encoding motor timing signals. The selective dendritic function of Kv1 channels in Purkinje cells allows them to effectively suppress dendritic hyperexcitability without hindering the generation of somatic action potentials. Further, we show that Kv1 channels also contribute to dendritic integration of parallel fibre synaptic input. Kv1 channels are often targeted to soma and axon and the data presented support a major dendritic function for these channels. PMID:16210348

  7. Alarmins Link Neutrophils and Dendritic Cells

    PubMed Central

    Yang, De; de la Rosa, Gonzalo; Tewary, Poonam; Oppenheim, Joost J.

    2009-01-01

    Neutrophils are the first major population of leukocyte to infiltrate infected or injured tissues and are crucial for initiating host innate defense and adaptive immunity. Although the contribution of neutrophils to innate immune defense is mediated predominantly by phagocytosis and killing of microorganisms, neutrophils also participate in the induction of adaptive immune responses. At sites of infection and/or injury, neutrophils release numerous mediators upon degranulation or death, among these are alarmins which have a characteristic dual capacity to mobilize and activate antigen-presenting cells. We describe here how alarmins released by neutrophil degranulation and/or death can link neutrophils to dendritic cells by promoting their recruitment and activation, resulting in the augmentation of innate and adaptive immune responses. PMID:19699678

  8. Activation and Protection of Dendritic Cells in the Prostate Cancer Environment

    DTIC Science & Technology

    2010-10-01

    Cancer statistics, 2010. CA Cancer J Clin. 2010;60:277-300. 7. Kantoff PW, Higano CS, Shore ND, et al. Sipuleucel - T immunotherapy for castration...capability to express costimulatory molecules and promote T cell proliferation. Based on these data, in vivo experiments were carried out, in which mice with...with the mixed leukocyte reaction (MLR). Briefly, allogeneic T cells were generated from balb/c mice spleens using murine T cell enrichment columns (R

  9. Sodium action potentials in the dendrites of cerebellar Purkinje cells.

    PubMed

    Regehr, W G; Konnerth, A; Armstrong, C M

    1992-06-15

    We report here that in cerebellar Purkinje cells from which the axon has been removed, positive voltage steps applied to the voltage-clamped soma produce spikes of active current. The spikes are inward, are all-or-none, have a duration of approximately 1 ms, and are reversibly eliminated by tetrodotoxin, a Na channel poison. From cell to cell, the amplitude of the spikes ranges from 4 to 20 nA. Spike latency decreases as the depolarizing step is made larger. These spikes clearly arise at a site where the voltage is not controlled, remote from the soma. From these facts we conclude that Purkinje cell dendrites contain a sufficient density of Na channels to generate action potentials. Activation by either parallel fiber or climbing fiber synapses produces similar spikes, suggesting that normal input elicits Na action potentials in the dendrites. These findings greatly alter current views of how dendrites in these cells respond to synaptic input.

  10. Curcumin Suppressed Activation of Dendritic Cells via JAK/STAT/SOCS Signal in Mice with Experimental Colitis

    PubMed Central

    Zhao, Hai-Mei; Xu, Rong; Huang, Xiao-Ying; Cheng, Shao-Min; Huang, Min-Fang; Yue, Hai-Yang; Wang, Xin; Zou, Yong; Lu, Ai-Ping; Liu, Duan-Yong

    2016-01-01

    Dendritic cells (DCs) play a pivotal role as initiators in the pathogenesis of inflammatory bowel disease and are regulated by the JAK/STAT/SOCS signaling pathway. As a potent anti-inflammatory compound, curcumin represents a viable treatment alternative or adjunctive therapy in the management of chronic inflammatory bowel disease (IBD). The mechanism of curcumin treated IBD on DCs is not completely understood. In the present study, we explored the mechanism of curcumin treated experimental colitis by observing activation of DCs via JAK/STAT/SOCS signaling pathway in colitis mice. Experimental colitis was induced by 2, 4, 6-trinitrobenzene sulfonic acid. After 7 days treatment with curcumin, its therapeutic effect was verified by decreased colonic weight, histological scores, and remitting pathological injury. Meanwhile, the levels of major histocompatibility complex class II and DC costimulatory molecules (CD83, CD28, B7-DC, CD40, CD40 L, and TLR2) were inhibited and followed the up-regulated levels of IL-4, IL-10, and IFN-γ, and down-regulated GM-CSF, IL-12p70, IL-15, IL-23, and TGF-β1. A key finding was that the phosphorylation of the three members (JAK2, STAT3, and STAT6) of the JAK/STAT/SOCS signaling pathway was inhibited, and the three downstream proteins (SOCS1, SOCS3, and PIAS3) from this pathway were highly expressed. In conclusion, curcumin suppressed the activation of DCs by modulating the JAK/STAT/SOCS signaling pathway to restore immunologic balance to effectively treat experimental colitis. PMID:27932984

  11. Immunomodulatory activity of the water extract of Thymus vulgaris, Thymus daenensis, and Zataria multiflora on dendritic cells and T cells responses.

    PubMed

    Amirghofran, Zahra; Ahmadi, Hossein; Karimi, Mohammad Hossein

    2012-01-01

    Thymus vulgaris (thyme), Thymus daenensis, and Zataria multiflora are medicinal plants being used widely for infections and inflammatory diseases in folk medicine. In this study, the effects of the water extract of these plants on the activation of dendritic cells (DCs) and T cells was investigated. Both T. vulgaris and Z. multiflora decreased the proliferation of mitogen-stimulated lymphocytes, whereas T. daenensis induced cell proliferation in a dose-dependent manner (p < 0.001). All the three plants increased the CD40 expression on DCs (p < 0.04). The extent of allogenic T cell proliferation in the presence of T. vulgaris and Z. multiflora extracts was significantly decreased (p < 0.02). The effect of the extracts on secretion of IFN-γ and IL-4 cytokines showed that none of the extracts influenced the pattern of cytokine production by T helper (Th) cells toward a Thl or Th2 profile. In conclusion, all the extracts had the ability to activate DCs. Whereas Z. multiflora and T. vulgaris extracts showed immunoihibitory effects on allogenic T cell proliferation, the main effect of T. daenensis was on mitogenic T cell response. These data may partly explain the mechanisms underlying the beneficial immunomodulatory effects of these extracts in infections and immune-related diseases.

  12. Optimization of Assays to Assess Dendritic Cell Activation and/or Anergy in Ebola Infection.

    DTIC Science & Technology

    2012-09-01

    infection and the correlates of protective immunity in vaccinated macaques are not well understood. This study sought to develop assays that can predict...responses during lethal filovirus infection and the correlates of protective immunity in vaccinated macaques are not well understood. This study aims to...Points indicate values for individual macaques; cells were stained with antibodies to T-cell markers CD3, CD8, and CD4 and analyzed by flow

  13. Combined cytotoxic activity of an infectious, but non-replicative herpes simplex virus type 1 and plasmacytoid dendritic cells against tumour cells

    PubMed Central

    Thomann, Sabrina; Boscheinen, Jan B; Vogel, Karin; Knipe, David M; DeLuca, Neal; Gross, Stefanie; Schuler-Thurner, Beatrice; Schuster, Philipp; Schmidt, Barbara

    2015-01-01

    Malignant melanoma is an aggressive tumour of the skin with increasing incidence, frequent metastasis and poor prognosis. At the same time, it is an immunogenic type of cancer with spontaneous regressions. Most recently, the tumoricidal effect of plasmacytoid dendritic cells (pDC) and their capacity to overcome the immunosuppressive tumour microenvironment are being investigated. In this respect, we studied the effect of the infectious, but replication-deficient, herpes simplex virus 1 (HSV-1) d106S vaccine strain, which lacks essential immediate early genes, in pDC co-cultures with 11 melanoma cell lines. We observed a strong cytotoxic activity, inducing apoptotic and necrotic cell death in most melanoma cell lines. The cytotoxic activity of HSV-1 d106S plus pDC was comparable to the levels of cytotoxicity induced by natural killer cells, but required only a fraction of cells with effector : target ratios of 1 : 20 (P < 0·05). The suppressive activity of cell-free supernatants derived from virus-stimulated pDC was significantly neutralized using antibodies against the interferon-α receptor (P < 0·05). In addition to type I interferons, TRAIL and granzyme B contributed to the inhibitory effect of HSV-1 d106S plus pDC to a minor extent. UV-irradiated viral stocks were significantly less active than infectious particles, both in the absence and presence of pDC (P < 0·05), indicating that residual activity of HSV-1 d106S is a major component and sensitizes the tumour cells to interferon-producing pDC. Three leukaemic cell lines were also susceptible to this treatment, suggesting a general anti-tumour effect. In conclusion, the potential of HSV-1 d106S for therapeutic vaccination should be further evaluated in patients suffering from different malignancies. PMID:26194553

  14. A general principle governs vision-dependent dendritic patterning of retinal ganglion cells.

    PubMed

    Xu, Hong-Ping; Sun, Jin Hao; Tian, Ning

    2014-10-15

    Dendritic arbors of retinal ganglion cells (RGCs) collect information over a certain area of the visual scene. The coverage territory and the arbor density of dendrites determine what fraction of the visual field is sampled by a single cell and at what resolution. However, it is not clear whether visual stimulation is required for the establishment of branching patterns of RGCs, and whether a general principle directs the dendritic patterning of diverse RGCs. By analyzing the geometric structures of RGC dendrites, we found that dendritic arbors of RGCs underwent a substantial spatial rearrangement after eye-opening. Light deprivation blocked both the dendritic growth and the branch patterning, suggesting that visual stimulation is required for the acquisition of specific branching patterns of RGCs. We further showed that vision-dependent dendritic growth and arbor refinement occurred mainly in the middle portion of the dendritic tree. This nonproportional growth and selective refinement suggest that the late-stage dendritic development of RGCs is not a passive stretching with the growth of eyes, but rather an active process of selective growth/elimination of dendritic arbors of RGCs driven by visual activity. Finally, our data showed that there was a power law relationship between the coverage territory and dendritic arbor density of RGCs on a cell-by-cell basis. RGCs were systematically less dense when they cover larger territories regardless of their cell type, retinal location, or developmental stage. These results suggest that a general structural design principle directs the vision-dependent patterning of RGC dendrites.

  15. ESAT-6 and HspX Improve the Effectiveness of BCG to Induce Human Dendritic Cells-Dependent Th1 and NK Cells Activation

    PubMed Central

    Marongiu, Laura; Donini, Marta; Toffali, Lara; Zenaro, Elena; Dusi, Stefano

    2013-01-01

    The limited efficacy of the BCG vaccine against tuberculosis is partly due to the missing expression of immunogenic proteins. We analyzed whether the addition to BCG of ESAT-6 and HspX, two Mycobacterium tuberculosis (Mtb) antigens, could enhance its capacity to activate human dendritic cells (DCs). BCG showed a weak ability to induce DC maturation, cytokine release, and CD4+ lymphocytes and NK cells activation. The addition of ESAT-6 or HspX alone to BCG-stimulated DC did not improve these processes, whereas their simultaneous addition enhanced BCG-dependent DC maturation and cytokine release, as well as the ability of BCG-treated DCs to stimulate IFN-γ release and CD69 expression by CD4+ lymphocytes and NK cells. Addition of TLR2-blocking antibody decreased IL-12 release by BCG-stimulated DCs incubated with ESAT-6 and HspX, as well as IFN-γ secretion by CD4+ lymphocytes co-cultured with these cells. Moreover, HspX and ESAT-6 improved the capacity of BCG-treated DCs to induce the expression of memory phenotype marker CD45RO in naïve CD4+ T cells. Our results indicate that ESAT-6 and HspX cooperation enables BCG-treated human DCs to induce T lymphocyte and NK cell-mediated immune responses through TLR2-dependent IL-12 secretion. Therefore ESAT-6 and HspX represent good candidates for improving the effectiveness of BCG vaccination. PMID:24130733

  16. Monocytes immunoselected via the novel monocyte specific molecule, CD300e, differentiate into active migratory dendritic cells.

    PubMed

    Clark, Georgina J; Jamriska, Lubomira; Rao, Min; Hart, Derek N J

    2007-04-01

    Monocytes, immunoselected using MMRI-1, a monoclonal antibody specific for CD300e, were used to generate dendritic cells (DC). These CD300e immunoselected monocyte-derived DC (MoDC) were compared phenotypically and functionally to CD14 immunoselected MoDC. CD300e and CD14 immunoselected mature MoDC expressed similar levels of the DC marker, CD83 and costimulatory molecules, CD80, CD86, and CD40. Both preparations took up soluble antigen with similar efficiency by pinocytosis and receptor mediated uptake. The CD300e and CD14 immunoselected MoDC also induced comparable CD4+ T lymphocyte allogeneic responses and recall responses to tetanus toxoid. Similar magnitude CD8 T lymphocyte responses to the naive antigen, MART-1 and the recall antigen, FMP, were induced by both MoDC preparations. Cytokine secretion by each type of MoDC preparation was similar; each secreted interleukin-12, tumor necrosis factor-alpha, and low levels of interferon-gamma but in most cases no interleukin-10. Migration studies confirmed that both types of MoDC migrated towards the chemokine, CCL21 although CD300e immunoselected showed greater migration. Overall, the CD14 immunoselected MoDC had higher spontaneous background migration, compared with the CD300e immunoselected MoDC. Differential signaling from the antibodies used to immunoselect the monocytes may account for the slight differences in migratory capacity. These data identify the CD300e antigen as another monocyte-specific marker that can be used to purify monocytes for differentiation into functionally active MoDC.

  17. Transcriptional Control of Dendritic Cell Development

    PubMed Central

    Murphy, Theresa L.; Grajales-Reyes, Gary E.; Wu, Xiaodi; Tussiwand, Roxane; Briseño, Carlos G.; Iwata, Arifumi; Kretzer, Nicole M.; Durai, Vivek; Murphy, Kenneth M.

    2016-01-01

    The dendritic cells (DCs) of the immune system function in innate and adaptive responses by directing activity of various effector cells rather than serving as effectors themselves. DCs and closely related myeloid lineages share expression of many surface receptors, presenting a challenge in distinguishing their unique in vivo functions. Recent work has taken advantage of unique transcriptional programs to identify and manipulate murine DCs in vivo. This work has assigned several nonredundant in vivo functions to distinct DC lineages, consisting of plasmacytoid DCs and several subsets of classical DCs that promote different immune effector modules in response to pathogens. In parallel, a correspondence between human and murine DC subsets has emerged, underlying structural similarities for the DC lineages between these species. Recent work has begun to unravel the transcriptional circuitry that controls the development and diversification of DCs from common progenitors in the bone marrow. PMID:26735697

  18. Cell-free culture supernatant of Bifidobacterium breve CNCM I-4035 decreases pro-inflammatory cytokines in human dendritic cells challenged with Salmonella typhi through TLR activation.

    PubMed

    Bermudez-Brito, Miriam; Muñoz-Quezada, Sergio; Gomez-Llorente, Carolina; Matencio, Esther; Bernal, Maria J; Romero, Fernando; Gil, Angel

    2013-01-01

    Dendritic cells (DCs) constitute the first point of contact between gut commensals and our immune system. Despite growing evidence of the immunomodulatory effects of probiotics, the interactions between the cells of the intestinal immune system and bacteria remain largely unknown. Indeed,, the aim of this work was to determine whether the probiotic Bifidobacterium breve CNCM I-4035 and its cell-free culture supernatant (CFS) have immunomodulatory effects in human intestinal-like dendritic cells (DCs) and how they respond to the pathogenic bacterium Salmonella enterica serovar Typhi, and also to elucidate the molecular mechanisms involved in these interactions. Human DCs were directly challenged with B. breve/CFS, S. typhi or a combination of these stimuli for 4 h. The expression pattern of genes involved in Toll-like receptor (TLR) signaling pathway and cytokine secretion was analyzed. CFS decreased pro-inflammatory cytokines and chemokines in human intestinal DCs challenged with S. typhi. In contrast, the B. breve CNCM I-4035 probiotic strain was a potent inducer of the pro-inflammatory cytokines and chemokines tested, i.e., TNF-α, IL-8 and RANTES, as well as anti-inflammatory cytokines including IL-10. CFS restored TGF-β levels in the presence of Salmonella. Live B.breve and its supernatant enhanced innate immune responses by the activation of TLR signaling pathway. These treatments upregulated TLR9 gene transcription. In addition, CFS was a more potent inducer of TLR9 expression than the probiotic bacteria in the presence of S. typhi. Expression levels of CASP8 and IRAK4 were also increased by CFS, and both treatments induced TOLLIP gene expression. Our results indicate that the probiotic strain B. breve CNCM I-4035 affects the intestinal immune response, whereas its supernatant exerts anti-inflammatory effects mediated by DCs. This supernatant may protect immune system from highly infectious agents such as Salmonella typhi and can down-regulate pro

  19. Intralesional rose bengal in melanoma elicits tumor immunity via activation of dendritic cells by the release of high mobility group box 1

    PubMed Central

    Liu, Hao; Innamarato, Pasquale Patrick; Kodumudi, Krithika; Weber, Amy; Nemoto, Satoshi; Robinson, John L.; Crago, Georgina; McCardle, Timothy; Royster, Erica; Sarnaik, Amod A.; Pilon-Thomas, Shari

    2016-01-01

    Intralesional (IL) therapy is under investigation to treat dermal and subcutaneous metastatic cancer. Rose bengal (RB) is a staining agent that was originally used by ophthalmologists and in liver function studies. IL injection of RB has been shown to induce regression of injected and uninjected tumors in murine models and clinical trials. In this study, we have shown a mechanism of tumor-specific immune response induced by IL RB. In melanoma-bearing mice, IL RB induced regression of injected tumor and inhibited the growth of bystander lesions mediated by CD8+ T cells. IL RB resulted in necrosis of tumor cells and the release of High Mobility Group Box 1 (HMGB1), with increased dendritic cell (DC) infiltration into draining lymph nodes and the activation of tumor-specific T cells. Treatment of DC with tumor supernatants increased the ability of DCs to stimulate T cell proliferation, and blockade of HMGB1 in the supernatants suppressed DC activity. Additionally, increased HMGB1 levels were measured in the sera of melanoma patients treated with IL RB. These results support the role of IL RB to activate dendritic cells at the site of tumor necrosis for the induction of a systemic anti-tumor immune response. PMID:27177220

  20. β8 integrin expression and activation of TGF-β by intestinal dendritic cells is determined by both tissue microenvironment and cell lineage

    PubMed Central

    Boucard-Jourdin, Mathilde; Kugler, David; Endale Ahanda, Marie-Laure; This, Sébastien; De Calisto, Jaime; Zhang, Ailiang; Mora, J. Rodrigo; Stuart, Lynda M.; Savill, John; Lacy-Hulbert, Adam; Paidassi, Helena

    2016-01-01

    Activation of TGF-β by dendritic cells (DCs) expressing αvβ8 integrin is essential for the generation of intestinal regulatory T cells (Tregs) that in turn promote tolerance to intestinal antigens. We have recently shown that αvβ8 integrin is preferentially expressed by CD103+ DCs, and confers their ability to activate TGF-β and generate Tregs. However, how these DCs become specialized for this vital function is unknown. Here we show that β8 expression is controlled by a combination of factors that include DC lineage, and signals derived from the tissue microenvironment and microbiota. Specifically, our data demonstrate that TGF-β itself, along with retinoic acid (RA) and Toll-like receptor (TLR) signaling, drive expression of αvβ8 in DCs. However, these signals only result in high levels of β8 expression in cells of the cDC1 lineage, CD8α+ or CD103+CD11b- DCs, and this is associated with epigenetic changes in the Itgb8 locus. Together, these data provide a key illustrative example of how microenvironmental factors and cell lineage drive the generation of regulatory αvβ8-expressing DCs specialized for activation of TGF-β to facilitate Treg generation. PMID:27481847

  1. Dendritic cells and immunity against cancer

    PubMed Central

    Palucka, Karolina; Ueno, Hideki; Fay, Joseph; Banchereau, Jacques

    2010-01-01

    SUMMARY T cells can reject established tumors when adoptively transferred into patients, thereby demonstrating the power of the immune system for cancer therapy. However, it has proven difficult to maintain adoptively transferred T cells in the long term. Vaccines have the potential to induce tumor-specific effector and memory T cells. However, clinical efficacy of current vaccines is limited, possibly because tumors skew the immune system by means of myeloid-derived suppressor cells, inflammatory type 2 T cells and regulatory T cells (Tregs), all of which prevent the generation of effector cells. To improve the clinical efficacy of cancer vaccines in patients with metastatic disease, we need to design novel and improved strategies that can boost adaptive immunity to cancer, help overcome Tregs and allow the breakdown of the immunosuppressive tumor microenvironment. This can be achieved by exploiting the fast increasing knowledge about the dendritic cell (DC) system, including the existence of distinct DC subsets which respond differentially to distinct activation signals, (functional plasticity), both contributing to the generation of unique adaptive immune responses. We foresee that these novel cancer vaccines will be used as monotherapy in patients with resected disease, and in combination with drugs targeting regulatory/suppressor pathways in patients with metastatic disease. PMID:21158979

  2. Dendritic cells: sentinels of immunity and tolerance.

    PubMed

    Kubach, Jan; Becker, Christian; Schmitt, Edgar; Steinbrink, Kerstin; Huter, Eva; Tuettenberg, Andrea; Jonuleit, Helmut

    2005-04-01

    The induction of effective antigen-specific T-cell immunity to pathogens without the initiation of autoimmunity has evolved as a sophisticated and highly balanced immunoregulatory mechanism. This mechanism assures the generation of antigen-specific effector cells as well as the induction and maintenance of antigen-specific tolerance to self-structures of the body. As professional antigen-presenting cells of the immune system, dendritic cells (DC) are ideally positioned throughout the entire body and equipped with a unique capability to transport antigens from the periphery to lymphoid tissues. There is growing evidence that DC, besides their well-known immunostimulatory properties, also induce and regulate T-cell tolerance in the periphery. This regulatory function of DC is strictly dependent on their different stages of maturation and activation. Additionally, immunosuppressive agents and cytokines further influence the functions of maturing DC. The regulatory properties of DC include induction of T-cell anergy, apoptosis, and the generation of T-cells with regulatory capacities. This brief review summarizes the current knowledge about the immunoregulatory role of DC as guardians for the induction of T-cell immunity and tolerance.

  3. Microparticle Surface Modifications Targeting Dendritic Cells for Non-Activating Applications

    PubMed Central

    Lewis, Jamal S.; Zaveri, Toral D.; Crooks, Charles P.; Keselowsky, Benjamin G.

    2012-01-01

    Microparticulate systems for delivery of therapeutics to DCs for immunotherapy have gained attention recently. However, reports addressing the optimization of DC-targeting microparticle delivery systems are limited, particularly for cases where the goal is to deliver payload to DCs in a non-activating fashion. Here, we investigate targeting DCs using poly (d lactide-co-glycolide) microparticles (MPs) in a non-stimulatory manner and assess efficacy in vitro and in vivo. We modified MPs by surface immobilizing DC receptor targeting molecules – antibodies (anti-CD11c, anti-DEC-205) or peptides (P-D2, RGD), where anti-CD11c antibody, P-D2 and RGD peptides target integrins and anti-DEC-205 antibody targets the c-type lectin receptor DEC-205. Our results demonstrate the modified MPs are neither toxic nor activating, and DC uptake of MPs in vitro is improved by the anti-DEC-205 antibody, the anti-CD11c antibody and the P-D2 peptide modifications. The P-D2 peptide MP modification significantly improved DC antigen presentation in vitro both at immediate and delayed time points. Notably, MP functionalization with P-D2 peptide and anti-CD11c antibody increased the rate and extent of MP translocation in vivo by DCs and MΦs, with the P-D2 peptide modified MPs demonstrating the highest translocation. This work informs the design of non-activating polymeric microparticulate applications such as vaccines for autoimmune diseases. PMID:22796161

  4. Cutting Edge: Immature human dendritic cells express latency-associated peptide and inhibit T cell activation in a TGF-beta-dependent manner.

    PubMed

    Gandhi, Roopali; Anderson, David E; Weiner, Howard L

    2007-04-01

    Dendritic cells (DCs) play a critical role in both initiating immune responses and in maintaining peripheral tolerance. However, the exact mechanism by which DCs instruct/influence the generation of effector vs regulatory T cells is not clear. In this study, we present evidence that TGF-beta, an important immunoregulatory molecule, is present on the surface of ex vivo immature human DCs bound by latency-associated peptide (LAP). Maturation of DCs upon stimulation with LPS results in loss of membrane-bound LAP and up-regulation of HLA class II and costimulatory molecules. The presence of LAP on immature DCs selectively inhibits Th1 cell but not Th17 cell differentiation and is required for differentiation and/or survival of Foxp3-positive regulatory T cells. Taken together, our results indicate that surface expression of TGF-beta on DCs in association with LAP is one of the mechanisms by which immature DCs limit T cell activation and thus prevent autoimmune responses.

  5. The loss of renal dendritic cells and activation of host adaptive immunity are long-term effects of ischemia/reperfusion injury following syngeneic kidney transplantation.

    PubMed

    Ozaki, Kikumi S; Kimura, Shoko; Nalesnik, Michael A; Sico, Rita M; Zhang, Matthew; Ueki, Shinya; Ross, Mark A; Stolz, Donna B; Murase, Noriko

    2012-05-01

    Ischemia/reperfusion injury associated with kidney transplantation induces profound acute injury, influences early graft function, and affects long-term graft outcomes. To determine whether renal dendritic cells play any role during initial innate ischemia/reperfusion injury and the subsequent development of adaptive immune responses, we studied the behavior and function of renal graft and host infiltrating dendritic cells during early and late phases of renal ischemia/reperfusion injury. Wild type to green fluorescent protein (GFP) transgenic rat kidney transplantation was performed with and without 24-h cold storage. Ischemia/reperfusion injury in cold-stored grafts resulted in histopathological changes of interstitial fibrosis and tubular atrophy by 10 weeks, accompanied by upregulation of mRNAs of mediators of interstitial fibrosis and inflammation. In normal rat kidneys, we identified two populations of renal dendritic cells, predominant CD103(-)CD11b/c(+) and minor CD103(+)CD11b/c(+) cells. After transplantation without cold storage, grafts maintained CD103(-) but not CD103(+) GFP-negative renal dendritic cells for 10 weeks. In contrast, both cell subsets disappeared from cold-stored grafts, which associated with a significant GFP-expressing host CD11b/c(+) cell infiltration that included CD103(+) dendritic cells with a TNF-α-producing phenotype. These changes in graft/host dendritic cell populations were associated with progressive infiltration of host CD4(+) T cells with effector/effector-memory phenotypes and IFN-γ secretion. Thus, renal graft ischemia/reperfusion injury caused graft dendritic cell loss and was associated with progressive host dendritic cell and T-cell recruitment. Renal-resident dendritic cells might function as a protective regulatory network.

  6. GATA2 regulates dendritic cell differentiation

    PubMed Central

    Onodera, Koichi; Fujiwara, Tohru; Onishi, Yasushi; Itoh-Nakadai, Ari; Okitsu, Yoko; Fukuhara, Noriko; Ishizawa, Kenichi; Shimizu, Ritsuko; Yamamoto, Masayuki

    2016-01-01

    Dendritic cells (DCs) are critical immune response regulators; however, the mechanism of DC differentiation is not fully understood. Heterozygous germ line GATA2 mutations induce GATA2-deficiency syndrome, characterized by monocytopenia, a predisposition to myelodysplasia/acute myeloid leukemia, and a profoundly reduced DC population, which is associated with increased susceptibility to viral infections, impaired phagocytosis, and decreased cytokine production. To define the role of GATA2 in DC differentiation and function, we studied Gata2 conditional knockout and haploinsufficient mice. Gata2 conditional deficiency significantly reduced the DC count, whereas Gata2 haploinsufficiency did not affect this population. GATA2 was required for the in vitro generation of DCs from Lin−Sca-1+Kit+ cells, common myeloid-restricted progenitors, and common dendritic cell precursors, but not common lymphoid-restricted progenitors or granulocyte-macrophage progenitors, suggesting that GATA2 functions in the myeloid pathway of DC differentiation. Moreover, expression profiling demonstrated reduced expression of myeloid-related genes, including mafb, and increased expression of T-lymphocyte–related genes, including Gata3 and Tcf7, in Gata2-deficient DC progenitors. In addition, GATA2 was found to bind an enhancer element 190-kb downstream region of Gata3, and a reporter assay exhibited significantly reduced luciferase activity after adding this enhancer region to the Gata3 promoter, which was recovered by GATA sequence deletion within Gata3 +190. These results suggest that GATA2 plays an important role in cell-fate specification toward the myeloid vs T-lymphocyte lineage by regulating lineage-specific transcription factors in DC progenitors, thereby contributing to DC differentiation. PMID:27259979

  7. GATA2 regulates dendritic cell differentiation.

    PubMed

    Onodera, Koichi; Fujiwara, Tohru; Onishi, Yasushi; Itoh-Nakadai, Ari; Okitsu, Yoko; Fukuhara, Noriko; Ishizawa, Kenichi; Shimizu, Ritsuko; Yamamoto, Masayuki; Harigae, Hideo

    2016-07-28

    Dendritic cells (DCs) are critical immune response regulators; however, the mechanism of DC differentiation is not fully understood. Heterozygous germ line GATA2 mutations induce GATA2-deficiency syndrome, characterized by monocytopenia, a predisposition to myelodysplasia/acute myeloid leukemia, and a profoundly reduced DC population, which is associated with increased susceptibility to viral infections, impaired phagocytosis, and decreased cytokine production. To define the role of GATA2 in DC differentiation and function, we studied Gata2 conditional knockout and haploinsufficient mice. Gata2 conditional deficiency significantly reduced the DC count, whereas Gata2 haploinsufficiency did not affect this population. GATA2 was required for the in vitro generation of DCs from Lin(-)Sca-1(+)Kit(+) cells, common myeloid-restricted progenitors, and common dendritic cell precursors, but not common lymphoid-restricted progenitors or granulocyte-macrophage progenitors, suggesting that GATA2 functions in the myeloid pathway of DC differentiation. Moreover, expression profiling demonstrated reduced expression of myeloid-related genes, including mafb, and increased expression of T-lymphocyte-related genes, including Gata3 and Tcf7, in Gata2-deficient DC progenitors. In addition, GATA2 was found to bind an enhancer element 190-kb downstream region of Gata3, and a reporter assay exhibited significantly reduced luciferase activity after adding this enhancer region to the Gata3 promoter, which was recovered by GATA sequence deletion within Gata3 +190. These results suggest that GATA2 plays an important role in cell-fate specification toward the myeloid vs T-lymphocyte lineage by regulating lineage-specific transcription factors in DC progenitors, thereby contributing to DC differentiation.

  8. Suppression of Canine Dendritic Cell Activation/Maturation and Inflammatory Cytokine Release by Mesenchymal Stem Cells Occurs Through Multiple Distinct Biochemical Pathways.

    PubMed

    Wheat, William H; Chow, Lyndah; Kurihara, Jade N; Regan, Daniel P; Coy, Jonathan W; Webb, Tracy L; Dow, Steven W

    2017-02-15

    Mesenchymal stem cells (MSC) represent a readily accessible source of cells with potent immune modulatory activity. MSC can suppress ongoing inflammatory responses by suppressing T cell function, while fewer studies have examined the impact of MSC on dendritic cell (DC) function. The dog spontaneous disease model represents an important animal model with which to evaluate the safety and effectiveness of cellular therapy with MSC. This study evaluated the effects of canine MSC on the activation and maturation of canine monocyte-derived DC, as well as mechanisms underlying these effects. Adipose-derived canine MSC were cocultured with canine DC, and the MSC effects on DC maturation and activation were assessed by flow cytometry, cytokine ELISA, and confocal microscopy. We found that canine MSC significantly suppressed lipopolysaccharide (LPS)-stimulated upregulation of DC activation markers such as major histocompatibility class II (MHCII), CD86, and CD40. Furthermore, pretreatment of MSC with interferon gamma (IFNγ) augmented this suppressive activity. IFNγ-activated MSC also significantly reduced LPS-elicited DC secretion of tumor necrosis factor alpha without reducing secretion of interleukin-10. The suppressive effect of IFNγ-treated MSC on LPS-induced DC activation was mediated by soluble factors secreted by both MSC and DC. Pathways of DC functional suppression included programmed death ligand-1 expression and secretion of nitrous oxide, prostaglandin E2, and adenosine by activated MSC. Coculture of DC with IFNγ-treated MSC maintained DC in an immature state and prolonged DC antigen uptake during LPS maturation stimulus. Taken together, canine MSC are capable of potently suppressing DC function in a potentially inflammatory microenvironment through several separate immunological pathways and confirm the potential for immune therapy with MSC in canine immune-mediated disease models.

  9. Targeting a mimotope vaccine to activating Fcgamma receptors empowers dendritic cells to prime specific CD8+ T cell responses in tumor-bearing mice.

    PubMed

    Gil, Margaret; Bieniasz, Magdalena; Wierzbicki, Andrzej; Bambach, Barbara J; Rokita, Hanna; Kozbor, Danuta

    2009-11-15

    A major challenge for inducing antitumor immune responses with native or modified tumor/self-Ags in tumor-bearing hosts relates to achieving efficient uptake and processing by dendritic cells (DCs) to activate immune effector cells and limit the generation of regulatory T cell activity. We analyzed the ability of therapeutic DC vaccines expressing a CD166 cross-reactive mimotope of the GD2 ganglioside, 47-LDA, to selectively expand adoptively transferred, tumor-specific T cells in NXS2 neuroblastoma tumor-bearing syngeneic mice. Before the adoptive cell transfer and DC vaccination, the tumor-bearing mice were lymphodepleted by nonmyeloablative total body irradiation or a myeloablative regimen that required bone marrow transplantation. The 47-LDA mimotope was presented to DCs either as a linear polypeptide in conjunction with universal Th epitopes or as a fusion protein with the murine IgG2a Fc fragment (47-LDA-Fcgamma2a) to deliver the antigenic cassette to the activating Fcgamma receptors. We demonstrate that immunization of adoptively transferred T cells in tumor-bearing mice with the 47-LDA mimotope expressed in the context of the activating Fc fusion protein induced higher levels of antitumor immune responses and protection than the 47-LDA polypeptide-DC vaccine. The antitumor efficacy of the therapeutic 47-LDA-Fcgamma2a-DC vaccine was comparable to that achieved by a virotherapy-associated cancer vaccine using a recombinant oncolytic vaccinia virus expressing the 47-LDA-Fcgamma2a fusion protein. The latter treatment, however, did not require total body irradiation or adoptive cell transfer and resulted in induction of antitumor immune responses in the setting of established tolerance, paving the way for testing novel anticancer treatment strategies.

  10. Harnessing Dendritic Cells to Generate Cancer Vaccines

    PubMed Central

    Palucka, Karolina; Ueno, Hideki; Fay, Joseph; Banchereau, Jacques

    2009-01-01

    Passive immunotherapy of cancer, i.e., transfer of T cells or antibodies, can lead to some objective clinical responses, thus demonstrating that the immune system can reject tumors. However, passive immunotherapy is not expected to yield memory T cells that might control tumor outgrowth. Active immunotherapy with dendritic cell (DCs) vaccines has the potential to induce tumor-specific effector and memory T cells. Clinical trials testing first generation DC vaccines pulsed with tumor antigens provided a proof-of-principle that therapeutic immunity can be elicited. Newer generation DC vaccines are build on the increased knowledge of the DC system including the existence of distinct DC subsets and their plasticity all leading to generation of distinct types of immunity. Rather than the quantity of IFN-γ secreting CD8+ T cells, we should aim at generating high quality high avidity poly-functional effector CD8+ T cells able to reject tumors and long-lived memory CD8+ T cells able to prevent relapse. PMID:19769741

  11. Lack of galectin-3 increases Jagged1/Notch activation in bone marrow-derived dendritic cells and promotes dysregulation of T helper cell polarization.

    PubMed

    Fermino, Marise L; Dylon, L Sebastian D; Cecílio, Nerry T; Santos, Sofia N; Toscano, Marta A; Dias-Baruffi, Marcelo; Roque-Barreira, Maria C; Rabinovich, Gabriel A; Bernardes, Emerson S

    2016-08-01

    Galectin-3, an endogenous glycan-binding protein, is abundantly expressed at sites of inflammation and immune cell activation. Although this lectin has been implicated in the control of T helper (Th) polarization, the mechanisms underlying this effect are not well understood. Here, we investigated the role of endogenous galectin-3 during the course of experimental Leishmania major infection using galectin-3-deficient (Lgals3(-/-)) mice in a BALB/c background and the involvement of Notch signaling pathway in this process. Lgals3(-/-) mice displayed an augmented, although mixed Th1/Th2 responses compared with wild-type (WT) mice. Concomitantly, lymph node and footpad lesion cells from infected Lgals3(-/-) mice showed enhanced levels of Notch signaling components (Notch-1, Jagged1, Jagged2 and Notch target gene Hes-1). Bone marrow-derived dendritic cells (BMDCs) from uninfected Lgals3(-/-) mice also displayed increased expression of the Notch ligands Delta-like-4 and Jagged1 and pro-inflammatory cytokines. In addition, activation of Notch signaling in BMDCs upon stimulation with Jagged1 was more pronounced in Lgals3(-/-) BMDCs compared to WT BMDCs; this condition resulted in increased production of IL-6 by Lgals3(-/-) BMDCs. Finally, addition of exogenous galectin-3 to Lgals3(-/-) BMDCs partially reverted the increased sensitivity to Jagged1 stimulation. Our results suggest that endogenous galectin-3 regulates Notch signaling activation in BMDCs and influences polarization of T helper responses, thus increasing susceptibility to L. major infection.

  12. Silymarin inhibits ultraviolet radiation-induced immune suppression through DNA repair-dependent activation of dendritic cells and stimulation of effector T cells

    PubMed Central

    Vaid, Mudit; Prasad, Ram; Singh, Tripti; Elmets, Craig A.; Xu, Hui; Katiyar, Santosh K.

    2013-01-01

    Silymarin inhibits UVB-induced immunosuppression in mouse skin. To identify the molecular mechanisms underlying this effect, we used an adoptive transfer approach in which dendritic cells (DCs) from the draining lymph nodes of donor mice that had been UVB-exposed and sensitized to 2,4,-dinitrofluorobenzene (DNFB) were transferred into naïve recipient mice. The contact hypersensitivity (CHS) response of the recipient mice to DNFB was then measured. When DCs were obtained from UVB-exposed donor mice that were not treated with silymarin, the CHS response was suppressed confirming the role of DCs in the UVB-induced immunosuppression. Silymarin treatment of UVB-exposed donor mice relieved this suppression of the CHS response in the recipients. Silymarin treatment was associated with rapid repair of UVB-induced cyclobutane pyrimidine dimers (CPDs) in DCs and silymarin treatment did not prevent UV-induced immunosuppression in XPA-deficient mice which are unable to repair UV-induced DNA damage. The CHS response in mice receiving DCs from silymarin-treated UV-exposed donor mice also was associated with enhanced secretion of Th1-type cytokines and stimulation of T cells. Adoptive transfer of T cells revealed that transfer of either CD8+ or CD4+ cells from silymarin-treated, UVB-exposed donors resulted in enhancement of the CHS response. Cell culture study showed enhanced secretion of IL-2 and IFNγ by CD8+ T cells, and reduced secretion of Th2 cytokines by CD4+ cells, obtained from silymarin-treated UVB-exposed mice. These data suggest that DNA repair-dependent functional activation of DCs, a reduction in CD4+ regulatory T-cell activity, and stimulation of CD8+ effector T cells contribute to silymarin-mediated inhibition of UVB-induced immunosuppression. PMID:23395695

  13. IL-6 down-regulates HLA class II expression and IL-12 production of human dendritic cells to impair activation of antigen-specific CD4(+) T cells.

    PubMed

    Ohno, Yosuke; Kitamura, Hidemitsu; Takahashi, Norihiko; Ohtake, Junya; Kaneumi, Shun; Sumida, Kentaro; Homma, Shigenori; Kawamura, Hideki; Minagawa, Nozomi; Shibasaki, Susumu; Taketomi, Akinobu

    2016-02-01

    Immunosuppression in tumor microenvironments critically affects the success of cancer immunotherapy. Here, we focused on the role of interleukin (IL)-6/signal transducer and activator of transcription (STAT3) signaling cascade in immune regulation by human dendritic cells (DCs). IL-6-conditioned monocyte-derived DCs (MoDCs) impaired the presenting ability of cancer-related antigens. Interferon (IFN)-γ production attenuated by CD4(+) T cells co-cultured with IL-6-conditioned MoDCs corresponded with decreased DC IL-12p70 production. Human leukocyte antigen (HLA)-DR and CD86 expression was significantly reduced in CD11b(+)CD11c(+) cells obtained from peripheral blood mononuclear cells (PBMCs) of healthy donors by IL-6 treatment and was STAT3 dependent. Arginase-1 (ARG1), lysosomal protease, cathepsin L (CTSL), and cyclooxygenase-2 (COX2) were involved in the reduction of surface HLA-DR expression. Gene expressions of ARG1, CTSL, COX2, and IL6 were higher in tumor-infiltrating CD11b(+)CD11c(+) cells compared with PBMCs isolated from colorectal cancer patients. Expression of surface HLA-DR and CD86 on CD11b(+)CD11c(+) cells was down-regulated, and T cell-stimulating ability was attenuated compared with PBMCs, suggesting that an immunosuppressive phenotype might be induced by IL-6, ARG1, CTSL, and COX2 in tumor sites of colorectal cancer patients. There was a relationship between HLA-DR expression levels in tumor tissues and the size of CD4(+) T and CD8(+) T cell compartments. Our findings indicate that IL-6 causes a dysfunction in human DCs that activates cancer antigen-specific Th cells, suggesting that blocking the IL-6/STAT3 signaling pathway might be a promising strategy to improve cancer immunotherapy.

  14. ISOLATION OF CHICKEN FOLLICULAR DENDRITIC CELLS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aim of the present study was to isolate chicken follicular dendritic cells (FDC). A combination of methods involving panning, iodixanol density gradient centrifugation, and magnetic cell separation technology made it possible to obtain functional FDC from the cecal tonsils from chickens, which h...

  15. Cells with dendritic cell morphology and immunophenotype, binuclear morphology, and immunosuppressive function in dendritic cell cultures.

    PubMed

    Dong, Rong; Moulding, Dale; Himoudi, Nourredine; Adams, Stuart; Bouma, Gerben; Eddaoudi, Ayad; Basu, B Piku; Derniame, Sophie; Chana, Prabhjoat; Duncan, Andrew; Anderson, John

    2011-01-01

    Culturing of human peripheral blood CD14 positive monocytes is a method for generation of dendritic cells (DCs) for experimental purposes or for use in clinical grade vaccines. When culturing human DCs in this manner for clinical vaccine production, we noticed that 5-10% of cells within the bulk culture were binuclear or multiple nuclear, but had typical dendritic cell morphology and immunophenotype. We refer to the cells as binuclear cells in dendritic cell cultures (BNiDCs). By using single cell PCR analysis of mitochondrial DNA polymorphisms we demonstrated that approximately 20-25% of cells in DC culture undergo a fusion event. Flow sorted BNiDC express low HLA-DR and IL-12p70, but high levels of IL-10. In mixed lymphocyte reactions, purified BNiDC suppressed lymphocyte proliferation. Blockade of dendritic cell-specific transmembrane protein (DC-STAMP) decreased the number of binuclear cells in DC cultures. BNiDC represent a potentially tolerogenic population within DC preparations for clinical use.

  16. A phased strategy to differentiate human CD14+monocytes into classically and alternatively activated macrophages and dendritic cells.

    PubMed

    Zarif, Jelani C; Hernandez, James R; Verdone, James E; Campbell, Scott P; Drake, Charles G; Pienta, Kenneth J

    2016-01-01

    There are currently several in vitro strategies to differentiate human CD14(+) monocytes isolated from peripheral blood mononuclear cells (PBMCs) into the M1 or M2 macrophage cell types. Each cell type is then verified using flow cytometric analysis of cell-surface markers. Human CD14(+) monocytes have the potential to differentiate into M1 and M2 macrophages, both of which demonstrate varying degrees of cell-surface antigen overlap. Using multiple surface markers with current macrophage polarization protocols, our data reveal several limitations of currently used methods, such as highly ambiguous cell types that possess cell-surface marker overlap and functional similarities. Utilizing interleukin-6 (IL-6) and two phases of cytokine exposure, we have developed a protocol to differentiate human monocytes into M1, M2, or dendritic cells (DCs) with greater efficiency and fidelity relative to macrophages and DCs that are produced by commonly used methods. This is achieved via alterations in cytokine composition, dosing, and incubation times, as well as improvements in verification methodology. Our method reliably reproduces human in vitro monocyte-derived DCs and macrophage models that will aid in better defining and understanding innate and adaptive immunity, as well as pathologic states.

  17. The multifaceted biology of plasmacytoid dendritic cells

    PubMed Central

    Swiecki, Melissa; Colonna, Marco

    2015-01-01

    Plasmacytoid dendritic cells (pDCs) are a unique dendritic cell subset that specializes in the production of type I interferons (IFNs). pDCs promote antiviral immune responses and have been implicated in the pathogenesis of autoimmune diseases characterized by a type I IFN signature. However, pDCs can also induce tolerogenic immune responses. Here, we review recent progress from the field of pDC biology, focusing on: the molecular mechanisms that regulate pDC development and functions; the pathways involved in their sensing of pathogens and endogenous nucleic acids; the function of pDCs at mucosal sites; and their roles in infections, autoimmunity and cancer. PMID:26160613

  18. Synaptically activated Ca2+ waves and NMDA spikes locally suppress voltage-dependent Ca2+ signalling in rat pyramidal cell dendrites

    PubMed Central

    Manita, Satoshi; Miyazaki, Kenichi; Ross, William N

    2011-01-01

    Abstract Postsynaptic [Ca2+]i changes contribute to several kinds of plasticity in pyramidal neurons. We examined the effects of synaptically activated Ca2+ waves and NMDA spikes on subsequent Ca2+ signalling in CA1 pyramidal cell dendrites in hippocampal slices. Tetanic synaptic stimulation evoked a localized Ca2+ wave in the primary apical dendrites. The [Ca2+]i increase from a backpropagating action potential (bAP) or subthreshold depolarization was reduced if it was generated immediately after the wave. The suppression had a recovery time of 30–60 s. The suppression only occurred where the wave was generated and was not due to a change in bAP amplitude or shape. The suppression also could be generated by Ca2+ waves evoked by uncaging IP3, showing that other signalling pathways activated by the synaptic tetanus were not required. The suppression was proportional to the amplitude of the [Ca2+]i change of the Ca2+ wave and was not blocked by a spectrum of kinase or phosphatase inhibitors, consistent with suppression due to Ca2+-dependent inactivation of Ca2+ channels. The waves also reduced the frequency and amplitude of spontaneous, localized Ca2+ release events in the dendrites by a different mechanism, probably by depleting the stores at the site of wave generation. The same synaptic tetanus often evoked NMDA spike-mediated [Ca2+]i increases in the oblique dendrites where Ca2+ waves do not propagate. These NMDA spikes suppressed the [Ca2+]i increase caused by bAPs in those regions. [Ca2+]i increases by Ca2+ entry through voltage-gated Ca2+ channels also suppressed the [Ca2+]i increases from subsequent bAPs in regions where the voltage-gated [Ca2+]i increases were largest, showing that all ways of raising [Ca2+]i could cause suppression. PMID:21844002

  19. Activated myeloid dendritic cells accumulate and co-localize with CD3+ T cells in coronary artery lesions in patients with Kawasaki disease.

    PubMed

    Yilmaz, Atilla; Rowley, Anne; Schulte, Danica J; Doherty, Terence M; Schröder, Nicolas W J; Fishbein, Michael C; Kalelkar, Mitra; Cicha, Iwona; Schubert, Katja; Daniel, Werner G; Garlichs, Christoph D; Arditi, Moshe

    2007-08-01

    Emerging evidence implicating the participation of dendritic cells (DCs) and T cells in various vascular inflammatory diseases such as giant cell arteritis, Takayasu's arteritis, and atherosclerosis led us to hypothesize that they might also participate in the pathogenesis of coronary arteritis in Kawasaki disease (KD). Coronary artery specimens from 4 patients with KD and 6 control patients were obtained. Immunohistochemical and computer-assisted histomorphometric analyses were performed to detect all myeloid DCs (S-100(+), fascin(+)), all plasmacytoid DCs (CD123(+)) as well as specific DC subsets (mature myeloid DCs [CD83(+)], myeloid [BDCA-1(+)] and plasmacytoid DC precursors [BDCA-2(+)]), T cells (CD3(+)), and all antigen-presenting cells (HLA-DR(+)). Co-localization of DCs with T cells was assessed using double immunostaining. Significantly more myeloid DCs at a precursor, immature or mature stage were found in coronary lesions of KD patients than in controls. Myeloid DC precursors were distributed equally in the intima and adventitia. Mature myeloid DCs were particularly abundant in the adventitia. There was a significant correlation between mature DCs and HLA-DR expression. Double immunostaining demonstrated frequent contacts between myeloid DCs and T cells in the outer media and adventitia. Plasmacytoid DC precursors were rarely found in the adventitia. In conclusion, coronary artery lesions of KD patients contain increased numbers of mature myeloid DCs with high HLA-DR expression and frequent T cell contacts detected immunohistochemically. This suggests that mature arterial myeloid DCs might be activating T cells in situ and may be a significant factor in the pathogenesis of coronary arteritis in KD.

  20. Differentiation of apical and basal dendrites in pyramidal cells and granule cells in dissociated hippocampal cultures.

    PubMed

    Wu, You Kure; Fujishima, Kazuto; Kengaku, Mineko

    2015-01-01

    Hippocampal pyramidal cells and dentate granule cells develop morphologically distinct dendritic arbors, yet also share some common features. Both cell types form a long apical dendrite which extends from the apex of the cell soma, while short basal dendrites are developed only in pyramidal cells. Using quantitative morphometric analyses of mouse hippocampal cultures, we evaluated the differences in dendritic arborization patterns between pyramidal and granule cells. Furthermore, we observed and described the final apical dendrite determination during dendritic polarization by time-lapse imaging. Pyramidal and granule cells in culture exhibited similar dendritic patterns with a single principal dendrite and several minor dendrites so that the cell types were not readily distinguished by appearance. While basal dendrites in granule cells are normally degraded by adulthood in vivo, cultured granule cells retained their minor dendrites. Asymmetric growth of a single principal dendrite harboring the Golgi was observed in both cell types soon after the onset of dendritic growth. Time-lapse imaging revealed that up until the second week in culture, final principal dendrite designation was not stabilized, but was frequently replaced by other minor dendrites. Before dendritic polarity was stabilized, the Golgi moved dynamically within the soma and was repeatedly repositioned at newly emerging principal dendrites. Our results suggest that polarized growth of the apical dendrite is regulated by cell intrinsic programs, while regression of basal dendrites requires cue(s) from the extracellular environment in the dentate gyrus. The apical dendrite designation is determined from among multiple growing dendrites of young developing neurons.

  1. DENDRITIC CELLS: ARE THEY CLINICALLY RELEVANT?

    PubMed Central

    Palucka, Karolina; Ueno, Hideki; Roberts, Lee; Fay, Joseph; Banchereau, Jacques

    2010-01-01

    Cancer vaccines have undergone a renaissance due to recent clinical trials showing promising immunological data and some clinical benefit to patients. Current trials exploiting dendritic cells (DCs) as vaccines have shown durable tumor regressions in a fraction of patients. Clinical efficacy of current vaccines is hampered by myeloid-derived suppressor cells, inflammatory type 2 T cells and regulatory T cells (Tregs), all of which prevent the generation of effector cells. To improve the clinical efficacy of DC vaccines, we need to design novel and improved strategies that can boost adaptive immunity to cancer, help overcome Tregs and allow the breakdown of the immunosuppressive tumor microenvironment. This can be achieved by exploiting the fast increasing knowledge about the DC system, including the existence of distinct DC subsets. Critical to the design of better vaccines is the concept of distinct DC subsets and distinct DC activation pathways, all contributing to the generation of unique adaptive immune responses. Such novel DC vaccines will be used as monotherapy in patients with resected disease and in combination with antibodies and/or drugs targeting suppressor pathways and modulation of the tumor environment in patients with metastatic disease. PMID:20693842

  2. Visualization of RelB expression and activation at the single-cell level during dendritic cell maturation in Relb-Venus knock-in mice.

    PubMed

    Seki, Takao; Yamamoto, Mami; Taguchi, Yuu; Miyauchi, Maki; Akiyama, Nobuko; Yamaguchi, Noritaka; Gohda, Jin; Akiyama, Taishin; Inoue, Jun-ichiro

    2015-12-01

    RelB is activated by the non-canonical NF-κB pathway, which is crucial for immunity by establishing lymphoid organogenesis and B-cell and dendritic cell (DC) maturation. To elucidate the mechanism of the RelB-mediated immune cell maturation, a precise understanding of the relationship between cell maturation and RelB expression and activation at the single-cell level is required. Therefore, we generated knock-in mice expressing a fusion protein between RelB and fluorescent protein (RelB-Venus) from the Relb locus. The Relb(Venus/Venus) mice developed without any abnormalities observed in the Relb(-/-) mice, allowing us to monitor RelB-Venus expression and nuclear localization as RelB expression and activation. Relb(Venus/Venus) DC analyses revealed that DCs consist of RelB(-), RelB(low) and RelB(high) populations. The RelB(high) population, which included mature DCs with projections, displayed RelB nuclear localization, whereas RelB in the RelB(low) population was in the cytoplasm. Although both the RelB(low) and RelB(-) populations barely showed projections, MHC II and co-stimulatory molecule expression were higher in the RelB(low) than in the RelB(-) splenic conventional DCs. Taken together, our results identify the RelB(low) population as a possible novel intermediate maturation stage of cDCs and the Relb(Venus/Venus) mice as a useful tool to analyse the dynamic regulation of the non-canonical NF-κB pathway.

  3. PSM Peptides of Staphylococcus aureus Activate the p38-CREB Pathway in Dendritic Cells, Thereby Modulating Cytokine Production and T Cell Priming.

    PubMed

    Armbruster, Nicole S; Richardson, Jennifer R; Schreiner, Jens; Klenk, Juliane; Günter, Manina; Kretschmer, Dorothee; Pöschel, Simone; Schenke-Layland, Katja; Kalbacher, Hubert; Clark, Kristopher; Autenrieth, Stella E

    2016-02-01

    The challenging human pathogen Staphylococcus aureus has highly efficient immune evasion strategies for causing a wide range of diseases, from skin and soft tissue to life-threatening infections. Phenol-soluble modulin (PSM) peptides are major pathogenicity factors of community-associated methicillin-resistant S. aureus strains. In previous work, we demonstrated that PSMs in combination with TLR2 ligand from S. aureus induce tolerogenic dendritic cells (DCs) characterized by the production of high amounts of IL-10, but no proinflammatory cytokines. This in turn promotes the activation of regulatory T cells while impairing Th1 response; however, the signaling pathways modulated by PSMs remain elusive. In this study, we analyzed the effects of PSMs on signaling pathway modulation downstream of TLR2. TLR2 stimulation in combination with PSMα3 led to increased and prolonged phosphorylation of NF-κB, ERK, p38, and CREB in mouse bone marrow-derived DCs compared with single TLR2 activation. Furthermore, inhibition of p38 and downstream MSK1 prevented IL-10 production, which in turn reduced the capacity of DCs to activate regulatory T cells. Interestingly, the modulation of the signaling pathways by PSMs was independent of the known receptor for PSMs, as shown by experiments with DCs lacking the formyl peptide receptor 2. Instead, PSMs penetrate the cell membrane most likely by transient pore formation. Moreover, colocalization of PSMs and p38 was observed near the plasma membrane in the cytosol, indicating a direct interaction. Thus, PSMs from S. aureus directly modulate the signaling pathway p38-CREB in DCs, thereby impairing cytokine production and in consequence T cell priming to increase the tolerance toward the pathogen.

  4. Intermediate-conductance Calcium-activated Potassium Channel KCa3.1 and Chloride Channel Modulate Chemokine Ligand (CCL19/CCL21)-induced Migration of Dendritic Cells

    PubMed Central

    Shao, Zhifei; Gaurav, Rohit; Agrawal, Devendra K

    2014-01-01

    The role of ion channels is largely unknown in chemokine-induced migration in non-excitable cells such as dendritic cells. Here, we examined the role of KCa3.1 and chloride channels in lymphatic chemokines-induced migration of dendritic cells. The amplitude and kinetics of CCL19/21-induced Ca2+ influx were associated with CCR7 expression levels, extracellular free Ca2+ and Cl−, and independent of extracellular K+. Chemokines, CCL19 and CCL21, and KCa3.1 activator, 1-EBIO, induced plasma membrane hyperpolarization and K+ efflux, which was blocked by TRAM-34, suggesting that KCa3.1 carried larger conductance than the inward CRAC. Blockade of KCa3.1, low Cl− in the medium, and low dose of DIDS impaired CCL19/CCL21-induced Ca2+ influx, cell volume change, and DC migration. High doses of DIDS completely blocked DC migration possibly by significantly disrupting mitochondrial membrane potential. In conclusion, KCa3.1 and chloride channel are critical in human DC migration by synergistically regulating membrane potential, chemokine-induced Ca2+ influx, and cell volume. PMID:25583444

  5. A mucin-like peptide from Fasciola hepatica instructs dendritic cells with parasite specific Th1-polarizing activity

    PubMed Central

    Noya, Verónica; Brossard, Natalie; Rodríguez, Ernesto; Dergan-Dylon, L. Sebastián; Carmona, Carlos; Rabinovich, Gabriel A.; Freire, Teresa

    2017-01-01

    Fasciolosis is a trematode zoonosis of interest in public health and cattle production. We report here the immunostimulatory effect of a 66 mer mucin-like peptide from Fasciola hepatica (Fhmuc), which synergizes with lipopolysaccharide (LPS) to promote dendritic cell (DC) maturation, endowing these cells with Th1-polarizing capacity. Exposure of DCs to Fhmuc in presence of LPS induced enhanced secretion of pro-inflammatory cytokines and expression of co-stimulatory molecules by DCs, promoting their T cell stimulatory capacity and selectively augmenting IFN-γ secretion by allogeneic T cells. Furthermore, exposure of DCs to Fhmuc augmented LPS-induced Toll-like receptor (TLR) 4 expression on the cell surface. Finally, Fhmuc-conditioned DCs induced parasite specific-adaptive immunity with increased levels of IFN-γ secreted by splenocytes from vaccinated animals, and higher parasite-specific IgG antibodies. However, Fhmuc-treated DC conferred modest protection against F. hepatica infection highlighting the potent immuno-regulatory capacity of the parasite. In summary, this work highlights the capacity of a mucin-derived peptide from F. hepatica to enhance LPS-maturation of DCs and induce parasite-specific immune responses with potential implications in vaccination and therapeutic strategies. PMID:28079156

  6. A mucin-like peptide from Fasciola hepatica instructs dendritic cells with parasite specific Th1-polarizing activity.

    PubMed

    Noya, Verónica; Brossard, Natalie; Rodríguez, Ernesto; Dergan-Dylon, L Sebastián; Carmona, Carlos; Rabinovich, Gabriel A; Freire, Teresa

    2017-01-12

    Fasciolosis is a trematode zoonosis of interest in public health and cattle production. We report here the immunostimulatory effect of a 66 mer mucin-like peptide from Fasciola hepatica (Fhmuc), which synergizes with lipopolysaccharide (LPS) to promote dendritic cell (DC) maturation, endowing these cells with Th1-polarizing capacity. Exposure of DCs to Fhmuc in presence of LPS induced enhanced secretion of pro-inflammatory cytokines and expression of co-stimulatory molecules by DCs, promoting their T cell stimulatory capacity and selectively augmenting IFN-γ secretion by allogeneic T cells. Furthermore, exposure of DCs to Fhmuc augmented LPS-induced Toll-like receptor (TLR) 4 expression on the cell surface. Finally, Fhmuc-conditioned DCs induced parasite specific-adaptive immunity with increased levels of IFN-γ secreted by splenocytes from vaccinated animals, and higher parasite-specific IgG antibodies. However, Fhmuc-treated DC conferred modest protection against F. hepatica infection highlighting the potent immuno-regulatory capacity of the parasite. In summary, this work highlights the capacity of a mucin-derived peptide from F. hepatica to enhance LPS-maturation of DCs and induce parasite-specific immune responses with potential implications in vaccination and therapeutic strategies.

  7. The serotonin receptor 5-HT₇R regulates the morphology and migratory properties of dendritic cells.

    PubMed

    Holst, Katrin; Guseva, Daria; Schindler, Susann; Sixt, Michael; Braun, Armin; Chopra, Himpriya; Pabst, Oliver; Ponimaskin, Evgeni

    2015-08-01

    Dendritic cells are potent antigen-presenting cells endowed with the unique ability to initiate adaptive immune responses upon inflammation. Inflammatory processes are often associated with an increased production of serotonin, which operates by activating specific receptors. However, the functional role of serotonin receptors in regulation of dendritic cell functions is poorly understood. Here, we demonstrate that expression of serotonin receptor 5-HT7 (5-HT7R) as well as its downstream effector Cdc42 is upregulated in dendritic cells upon maturation. Although dendritic cell maturation was independent of 5-HT7R, receptor stimulation affected dendritic cell morphology through Cdc42-mediated signaling. In addition, basal activity of 5-HT7R was required for the proper expression of the chemokine receptor CCR7, which is a key factor that controls dendritic cell migration. Consistent with this, we observed that 5-HT7R enhances chemotactic motility of dendritic cells in vitro by modulating their directionality and migration velocity. Accordingly, migration of dendritic cells in murine colon explants was abolished after pharmacological receptor inhibition. Our results indicate that there is a crucial role for 5-HT7R-Cdc42-mediated signaling in the regulation of dendritic cell morphology and motility, suggesting that 5-HT7R could be a new target for treatment of a variety of inflammatory and immune disorders.

  8. Glycogen synthase kinase 3 activation is important for anthrax edema toxin-induced dendritic cell maturation and anthrax toxin receptor 2 expression in macrophages.

    PubMed

    Larabee, Jason L; Maldonado-Arocho, Francisco J; Pacheco, Sergio; France, Bryan; DeGiusti, Kevin; Shakir, Salika M; Bradley, Kenneth A; Ballard, Jimmy D

    2011-08-01

    Anthrax edema toxin (ET) is one of two binary toxins produced by Bacillus anthracis that contributes to the virulence of this pathogen. ET is an adenylate cyclase that generates high levels of cyclic AMP (cAMP), causing alterations in multiple host cell signaling pathways. We previously demonstrated that ET increases cell surface expression of the anthrax toxin receptors (ANTXR) in monocyte-derived cells and promotes dendritic cell (DC) migration toward the lymph node-homing chemokine MIP-3β. In this work, we sought to determine if glycogen synthase kinase 3 (GSK-3) is important for ET-induced modulation of macrophage and DC function. We demonstrate that inhibition of GSK-3 dampens ET-induced maturation and migration processes of monocyte-derived dendritic cells (MDDCs). Additional studies reveal that the ET-induced expression of ANTXR in macrophages was decreased when GSK-3 activity was disrupted with chemical inhibitors or with small interfering RNA (siRNA) targeting GSK-3. Further examination of the ET induction of ANTXR revealed that a dominant negative form of CREB could block the ET induction of ANTXR, suggesting that CREB or a related family member was involved in the upregulation of ANTXR. Because CREB and GSK-3 activity appeared to be important for ET-induced ANTXR expression, the impact of GSK-3 on ET-induced CREB activity was examined in RAW 264.7 cells possessing a CRE-luciferase reporter. As with ANTXR expression, the ET induction of the CRE reporter was decreased by reducing GSK-3 activity. These studies not only provide insight into host pathways targeted by ET but also shed light on interactions between GSK-3 and CREB pathways in host immune cells.

  9. Role of dendritic cells in cardiovascular diseases

    PubMed Central

    Zhang, Yi; Zhang, Cuihua

    2010-01-01

    Dendritic cells (DCs) are potent antigen-presenting cells that bridge innate and adaptive immune responses. Recent work has elucidated the DC life cycle, including several important stages such as maturation, migration and homeostasis, as well as DC classification and subsets/locations, which provided etiological insights on the role of DCs in disease processes. DCs have a close relationship to endothelial cells and they interact with each other to maintain immunity. DCs are deposited in the atherosclerotic plaque and contribute to the pathogenesis of atherosclerosis. In addition, the necrotic cardiac cells induced by ischemia activate DCs by Toll-like receptors, which initiate innate and adaptive immune responses to renal, hepatic and cardiac ischemia reperfusion injury (IRI). Furthermore, DCs are involved in the acute/chronic rejection of solid organ transplantation and mediate transplant tolerance as well. Advancing our knowledge of the biology of DCs will aid development of new approaches to treat many cardiovascular diseases, including atherosclerosis, cardiac IRI and transplantation. PMID:21179302

  10. [Dendritic cell-based therapeutic cancer vaccines].

    PubMed

    Rizzo, Manglio; Alaniz, Laura; Mazzolini, Guillermo D

    2016-01-01

    In recent years immunotherapy has revolutionized the treatment of patients with advanced cancer. The increased knowledge in the tumor immune-biology has allowed developing rational treatments by manipulation of the immune system with significant clinical impact. This rapid development has significantly changed the prognosis of many tumors without treatment options up to date. Other strategies have explored the use of therapeutic vaccines based on dendritic cells (DC) by inducing antitumor immunity. DC are cells of hematopoietic origin, constitutively expressing molecules capable to present antigens, that are functionally the most potent inducers of the activation and proliferation of antigen specific T lymphocytes. The CD8+ T cells proliferate and acquire cytotoxic capacity after recognizing their specific antigen presented on the surface of DC, although only some types of DC can present antigens internalized from outside the cell to precursors of cytotoxic T lymphocytes (this function is called cross-presentation) requiring translocation mechanisms of complex antigens. The induction of an effective adaptive immune response is considered a good option given its specificity, and prolonged duration of response. The DC, thanks to its particular ability of antigen presentation and lymphocyte stimulation, are able to reverse the poor antitumor immune response experienced by patients with cancer. The DC can be obtained from various sources, using different protocols to generate differentiation and maturation, and are administered by various routes such as subcutaneous, intravenous or intranodal. The wide variety of protocols resulted in heterogeneous clinical responses.

  11. How Follicular Dendritic Cells Shape the B-Cell Antigenome

    PubMed Central

    Kranich, Jan; Krautler, Nike Julia

    2016-01-01

    Follicular dendritic cells (FDCs) are stromal cells residing in primary follicles and in germinal centers of secondary and tertiary lymphoid organs (SLOs and TLOs). There, they play a crucial role in B-cell activation and affinity maturation of antibodies. FDCs have the unique capacity to bind and retain native antigen in B-cell follicles for long periods of time. Therefore, FDCs shape the B-cell antigenome (the sum of all B-cell antigens) in SLOs and TLOs. In this review, we discuss recent findings that explain how this stromal cell type can arise in almost any tissue during TLO formation and, furthermore, focus on the mechanisms of antigen capture and retention involved in the generation of long-lasting antigen depots displayed on FDCs. PMID:27446069

  12. Dendritic Cells, New Tools for Vaccination

    DTIC Science & Technology

    2003-01-01

    19], Borrelia burgdorferi [20] Chlamydia trachomatis [21] and Candida albicans [22]. C. albicans provides a paradigmatic example of how this ap... Borrelia burgdorferi -pulsed dendritic cells induce a protective immune response against tick-transmitted spirochetes, Infect. Immun. 65 (1997) 3386–3390

  13. Characterization of chicken dendritic cell markers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Animal and Natural Resources Institute, ARS-USDA, Beltsville, MD, USA. New mouse monoclonal antibodies which detect CD80 and CD83 were developed to characterize chicken dendritic cells (DCs). The characteristics of these molecules have been studied in human, swine, ovine, feline, and canine but not ...

  14. Differential activation of dendritic cells by toll-like receptors causes diverse differentiation of naïve CD4+ T cells from allergic patients

    PubMed Central

    Deifl, S.; Kitzmüller, C.; Steinberger, P.; Himly, M.; Jahn-Schmid, B.; Fischer, G. F.; Zlabinger, G. J.; Bohle, B.

    2014-01-01

    Background To avert the differentiation of allergen-specific Th2 cells in atopic individuals is a major goal in the prevention and therapy of IgE-mediated allergy. We aimed to compare different toll-like receptor (TLR) agonists regarding their effects on antigen-presenting cells and the differentiation of naïve T cells from allergic patients. Methods Monocytes and monocyte-derived dendritic cells (mdDC) from allergic patients were stimulated with Pam3CSK4 (TLR1/2 ligand), FSL-1 (TLR2/6 ligand), monophosphoryl lipid (MPL)-A, lipopolysaccharide (LPS, both TLR4 ligands), and flagellin (TLR5 ligand). Allergen uptake and upregulation of CD40, CD80, CD83, CD86, CD58, CCR7 and PD-L1 were analyzed by flow cytometry. Functional maturation of mdDC was tested in mixed leukocyte reactions, and the synthesis of proinflammatory cytokines, IL-10 and members of the IL-12 family was assessed. TLR-ligand-activated mdDC were used to stimulate naïve CD4+ T cells, and cytokine responses were assessed in supernatants and intracellularly. Results All TLR ligands except flagellin enhanced allergen uptake. All TLR ligands induced functional maturation of mdDC with differential expression of surface molecules and cytokines and promoted the differentiation of IFN-γ-producing T cells. LPS-matured mdDC exclusively induced Th1-like responses, whereas mdDC stimulated with the other TLR ligands induced both Th1- and Th0-like cells. Pam3CSK4 and flagellin additionally induced Th2-like cells. Th1-like responses were associated with higher expression levels of co-stimulatory molecules, PD-L1, IL-6, TNF-α, and IL-12p70. None of the TLR-ligand-stimulated mdDC induced IL-10- or IL-17-producing T cells. Conclusion Different TLR ligands differently influence T-cell responses due to varying activation of the three signals relevant for T-cell activation, that is, antigen presentation, co-stimulation and cytokine milieu. PMID:25093709

  15. Antifungal Activity of Plasmacytoid Dendritic Cells against Cryptococcus neoformans In Vitro Requires Expression of Dectin-3 (CLEC4D) and Reactive Oxygen Species

    PubMed Central

    Hole, Camaron R.; Leopold Wager, Chrissy M.; Mendiola, Andrew S.; Wozniak, Karen L.; Campuzano, Althea; Lin, Xin

    2016-01-01

    Conventional dendritic cells (cDCs) are critical for protection against pulmonary infection with the opportunistic fungal pathogen Cryptococcus neoformans; however, the role of plasmacytoid dendritic cells (pDCs) is unknown. We show for the first time that murine pDCs have direct activity against C. neoformans via reactive oxygen species (ROS), a mechanism different from that employed to control Aspergillus fumigatus infections. The anticryptococcal activity of murine pDCs is independent of opsonization but appears to require the C-type lectin receptor Dectin-3, a receptor not previously evaluated during cryptococcal infections. Human pDCs can also inhibit cryptococcal growth by a mechanism similar to that of murine pDCs. Experimental pulmonary infection of mice with a C. neoformans strain that induces protective immunity demonstrated that recruitment of pDCs to the lungs is CXCR3 dependent. Taken together, our results show that pDCs inhibit C. neoformans growth in vitro via the production of ROS and that Dectin-3 is required for optimal growth-inhibitory activity. PMID:27324480

  16. [Dendritic cells in cancer immunotherapy].

    PubMed

    Gato, M; Liechtenstein, T; Blanco-Luquín, I; Zudaire, M I; Kochan, G; Escors, D

    2015-01-01

    Since the beginning of the 20th century, biomedical scientists have tried to take advantage of the natural anti-cancer activities of the immune system. However, all the scientific and medical efforts dedicated to this have not resulted in the expected success. In fact, classical antineoplastic treatments such as surgery, radio and chemotherapy are still first line treatments. Even so, there is a quantity of experimental evidence demonstrating that cancer cells are immunogenic. However, the effective activation of anti-cancer T cell responses closely depends on an efficient antigen presentation carried out by professional antigen presenting cells such as DC. Although there are a number of strategies to strengthen antigen presentation by DC, anti-cancer immunotherapy is not as effective as we would expect according to preclinical data accumulated in recent decades. We do not aim to make an exhaustive review of DC immunotherapy here, which is an extensive research subject already dealt with in many specialised reviews. Instead, we present the experimental approaches undertaken by our group over the last decade, by modifying DC to improve their anti-tumour capacities.

  17. Ceramide Inhibits Antigen Uptake and Presentation by Dendritic Cells

    PubMed Central

    Sallusto, Federica; Nicolò, Chiara; De Maria, Ruggero; Corinti, Silvia; Testi, Roberto

    1996-01-01

    Ceramides are intramembrane diffusible mediators involved in transducing signals originated from a variety of cell surface receptors. Different adaptive and differentiative cellular responses, including apoptotic cell death, use ceramide-mediated pathways as an essential part of the program. Here, we show that human dendritic cells respond to CD40 ligand, as well as to tumor necrosis factor-α and IL-1β, with intracellular ceramide accumulation, as they are induced to differentiate. Dendritic cells down-modulate their capacity to take up soluble antigens in response to exogenously added or endogenously produced ceramides. This is followed by an impairment in presenting soluble antigens to specific T cell clones, while cell viability and the capacity to stimulate allogeneic responses or to present immunogenic peptides is fully preserved. Thus, ceramide-mediated pathways initiated by different cytokines can actively modulate professional antigen-presenting cell function and antigen-specific immune responses. PMID:8976196

  18. Dendritic cell-activated cytokine-induced killer cell-mediated immunotherapy is safe and effective for cancer patients >65 years old

    PubMed Central

    Liu, Yanfeng; Liu, Haibo; Liu, Hausheng; He, Pengcheng; Li, Jing; Liu, Xin; Chen, Limei; Wang, Mengchang; Xi, Jiejing; Wang, Huaiyu; Zhang, Haitao; Zhu, Ying; Zhu, Wei; Ning, Jing; Guo, Caili; Sun, Chunhong; Zhang, Mei

    2016-01-01

    Individuals >65 years old account for a large proportion of cancer patients, and usually have poor prognoses due to relative weaker physiological function and lower drug tolerance. To characterize the efficacy and safety of dendritic cell (DC)-activated cytokine-induced killer cell (CIK)-mediated treatment, and develop an adoptive immunotherapy for cancer patients >65 years old, a retrospective study was performed in 58 cancer sufferers who received 1–4 cycles of DC-activated CIK (DC-CIK) treatment and evaluated the response (tumor remission rate) and toxicity (side effects to the treatment). The present results showed that DCs and CIKs could be expanded rapidly in vitro, and following co-culture with DCs, the population of cluster of differentiation (CD) 3+, CD3+CD4+, CD3+CD8+ and CD3+CD56+ CIKs was significantly increased compared to CIKs without DC activation (P=0.044). In addition, DC-CIK infusion produced marked clinical outcomes, resulting in an objective remission rate, overall clinical benefit rate and Karnofsky performance status of 44.83, 75.86 and 87.28±5.46%, respectively, which was significantly improved compared with prior to treatment (P<0.05). Additionally, subsequent to two cycles of this immunotherapy, several tumor marker expression levels declined, returning to the normal range. The proportion of CD3+CD4+ (P=0.017) and CD3+CD8+ (P=0.023) lymphocytes, and the population of CD4/CD8 cells (P=0.024) were also increased. In conclusion, the present study suggests that the immunotherapy mediated by DC-CIK is safe and effective for cancer patients aged >65 years. PMID:28105230

  19. Active dendrites support efficient initiation of dendritic spikes in hippocampal CA3 pyramidal neurons

    PubMed Central

    Kim, Sooyun; Guzman, Segundo J; Hu, Hua; Jonas, Peter

    2013-01-01

    CA3 pyramidal neurons are important for memory formation and pattern completion in the hippocampal network. It is generally thought that proximal synapses from the mossy fibers activate these neurons most efficiently, whereas distal inputs from the perforant path have a weaker modulatory influence. We used confocally targeted patch-clamp recording from dendrites and axons to map the activation of rat CA3 pyramidal neurons at the subcellular level. Our results reveal two distinct dendritic domains. In the proximal domain, action potentials initiated in the axon backpropagate actively with large amplitude and fast time course. In the distal domain, Na+ channel–mediated dendritic spikes are efficiently initiated by waveforms mimicking synaptic events. CA3 pyramidal neuron dendrites showed a high Na+-to-K+ conductance density ratio, providing ideal conditions for active backpropagation and dendritic spike initiation. Dendritic spikes may enhance the computational power of CA3 pyramidal neurons in the hippocampal network. PMID:22388958

  20. Tumor-derived alpha-fetoprotein impairs the differentiation and T cell stimulatory activity of human dendritic cells

    PubMed Central

    Pardee, Angela D.; Shi, Jian; Butterfield, Lisa H.

    2014-01-01

    Several tumor-derived factors have been implicated in DC dysfunction in cancer patients. Alpha-fetoprotein (AFP) is an oncofetal antigen that is highly expressed in abnormalities of prenatal development and several epithelial cancers, including hepatocellular carcinoma (HCC). In HCC patients exhibiting high levels of serum AFP, we have observed a lower ratio of myeloid-to-plasmacytoid circulating DC compared to patients with low serum AFP levels and healthy donors. To test the effect of AFP on DC differentiation in vitro, peripheral blood monocytes from healthy donors were cultured in the presence of cord blood-derived normal AFP (nAFP) or HCC tumor-derived AFP (tAFP), and DC phenotype and function was assessed. Although the nAFP and tAFP isoforms only differ at one carbohydrate group, low (physiological) levels of tAFP, but not nAFP, significantly inhibited DC differentiation. tAFP-conditioned DC expressed diminished levels of DC maturation markers, retained a monocyte-like morphology, exhibited limited production of inflammatory mediators, and failed to induce robust T cell proliferative responses. Mechanistic studies revealed that the suppressive activity of tAFP is dependent on the presence of low molecular weight (LMW) species that i) co-purify with tAFP, and ii) function equivalently to the LMW fractions of both tumor and non-tumor cell lysates. These data reveal the unique ability of tAFP to serve as a chaperone protein for LMW molecules, both endogenous and ubiquitous in nature, which function cooperatively to impair DC differentiation and function. Therefore, novel therapeutic approaches that antagonize the regulatory properties of tAFP will be critical to enhance immunity and improve clinical outcomes. PMID:25355916

  1. Comparative activity of biodegradable nanoparticles with aluminum adjuvants: antigen uptake by dendritic cells and induction of immune response in mice.

    PubMed

    Uto, Tomofumi; Akagi, Takami; Toyama, Masaaki; Nishi, Yosuke; Shima, Fumiaki; Akashi, Mitsuru; Baba, Masanori

    2011-10-30

    Biodegradable poly(γ-glutamic acid) (γ-PGA) nanoparticles (NPs) are considered to be an excellent antigen carrier. Antigen-carrying γ-PGA NPs were examined for their uptake by murine dendritic cells (DCs) and subsequent induction of antigen-specific immune responses in mice and compared with aluminum (AL) adjuvants. Ovalbumin (OVA)-carrying NPs (FITC-OVA-NPs) were taken up much more efficiently by DCs than OVA alone or its AL-associated form. Both OVA-NPs and OVA+AL were detected in an intracellular lysosome compartment of DCs. Furthermore, the uptake of γ-PGA NPs was inhibited in the presence of pinocytosis and phagocytosis inhibitors. Significantly higher induction of antigen-specific CD8(+) T cells was observed in mice immunized with OVA-carrying γ-PGA NPs than in those immunized with OVA alone, OVA+AL, OVA+3-O-desacyl-4'-monophosphoryl lipid A (MPL), and OVA+AL+MPL. Thus, γ-PGA NPs may have great potential as an effective vaccine carrier and adjuvant for clinical use.

  2. Rapid reconstitution of functionally active 6-sulfoLacNAc+ dendritic cells (slanDCs) of donor origin following allogeneic haematopoietic stem cell transplant

    PubMed Central

    Mimiola, E; Marini, O; Perbellini, O; Micheletti, A; Vermi, W; Lonardi, S; Costantini, C; Meneghelli, E; Andreini, A; Bonetto, C; Vassanelli, A; Cantini, M; Zoratti, E; Massi, D; Zamo', A; Leso, A; Quaresmini, G; Benedetti, F; Pizzolo, G; Cassatella, M A; Tecchio, C

    2014-01-01

    The role of dendritic cells (DCs) and macrophages in allogeneic haematopoietic stem cell transplant (HSCT) is critical in determining the extent of graft-versus-host response. The goal of this study was to analyse slanDCs, a subset of human proinflammatory DCs, in haematopoietic stem cell (HSC) sources, as well as to evaluate their 1-year kinetics of reconstitution, origin and functional capacities in peripheral blood (PB) and bone marrow (BM) of patients who have undergone HSCT, and their presence in graft-versus-host disease (GVHD) tissue specimens. slanDCs were also compared to myeloid (m)DCs, plasmacytoid (p)DCs and monocytes in HSC sources and in patients' PB and BM throughout reconstitution. slanDCs accounted for all HSC sources. In patients' PB and BM, slanDCs were identified from day +21, showing median frequencies comparable to healthy donors, donor origin and kinetics of recovery similar to mDCs, pDCs, and monocytes. Under cyclosporin treatment, slanDCs displayed a normal pattern of maturation, and maintained an efficient chemotactic activity and capacity of releasing tumour necrosis factor (TNF)-α upon lipopolysaccharide (LPS) stimulation. None the less, they were almost undetectable in GVHD tissue specimens, being present only in intestinal acute GVHD samples. slanDCs reconstitute early, being donor-derived and functionally competent. The absence of slanDCs from most of the GVHD-targeted tissue specimens seems to rule out the direct participation of these cells in the majority of the local reactions characterizing GVHD. PMID:24853271

  3. Effects of dendritic cell-activated and cytokine-induced killer cell therapy on 22 children with acute myeloid leukemia after chemotherapy.

    PubMed

    Bai, Yan; Zheng, Jin-e; Wang, Nan; Cai, He-hua; Zhai, Li-na; Wu, Yao-hui; Wang, Fang; Jin, Run-ming; Zhou, Dong-feng

    2015-10-01

    The efficiency of dendritic cell-activated and cytokine-induced killer cell (DC-CIK) therapy on children with acute myeloid leukemia (AML) after chemotherapy was investigated. Mononuclear cells were collected from children achieving complete remission after chemotherapy, cultured in vitro and transfused back into the same patient. Interleukin-2 (IL-2) was injected subcutaneously every other day 10 times at the dose of 1 × 10(6) units. Peripheral blood lymphocyte subsets and minimal residual disease (MRD) were detected by flow cytometry. Function of bone marrow was monitored by methods of morphology, immunology, cytogenetics and molecular biology. The side effects were also observed during the treatment. The average follow-up period for all the 22 patients was 71 months and relapse occurred in two AML patients (9.1%). The percentage of CD3(+)/CD8(+) cells in peripheral blood of 15 patients at the 3rd month after DC-CIK treatment (36.73% ± 12.51%) was dramatically higher than that before treatment (29.20% ± 8.34%, P < 0.05). The MRD rate was >0.1% in 5 patients before the treatment, and became lower than 0.1% 3 months after the treatment. During the transfusion of DC-CIK, side effects including fever, chills and hives appeared in 7 out of 22 (31.82%) cases but disappeared quickly after symptomatic treatments. There were no changes in electrocardiography and liver-renal functions after the treatment. MRD in children with AML can be eliminated by DC-CIK therapy which is safe and has fewer side effects.

  4. Differential distribution of NCX1 contributes to spine–dendrite compartmentalization in CA1 pyramidal cells

    PubMed Central

    Lőrincz, Andrea; Rózsa, Balázs; Katona, Gergely; Vizi, E. Sylvester; Tamás, Gábor

    2007-01-01

    Compartmentalization of Ca2+ between dendritic spines and shafts is governed by diffusion barriers and a range of Ca2+ extrusion mechanisms. The distinct contribution of different Ca2+ clearance systems to Ca2+ compartmentalization in dendritic spines versus shafts remains elusive. We applied a combination of ultrastructural and functional imaging methods to assess the subcellular distribution and role of NCX1 in rat CA1 pyramidal cells. Quantitative electron microscopic analysis of preembedding immunogold reactions revealed uniform densities of NCX1 along the shafts of apical and basal dendrites, but densities in dendritic shafts were approximately seven times higher than in dendritic spines. In line with these results, two-photon imaging of synaptically activated Ca2+ transients during NCX blockade showed preferential action localized to the dendritic shafts for NCXs in regulating spine–dendrite coupling. PMID:17215351

  5. Dendritic Cells and HIV-1 Trans-Infection

    PubMed Central

    McDonald, David

    2010-01-01

    Dendritic cells initiate and sustain immune responses by migrating to sites of pathogenic insult, transporting antigens to lymphoid tissues and signaling immune specific activation of T cells through the formation of the immunological synapse. Dendritic cells can also transfer intact, infectious HIV-1 to CD4 T cells through an analogous structure, the infectious synapse. This replication independent mode of HIV-1 transmission, known as trans-infection, greatly increases T cell infection in vitro and is thought to contribute to viral dissemination in vivo. This review outlines the recent data defining the mechanisms of trans-infection and provides a context for the potential contribution of trans-infection in HIV-1 disease. PMID:21994702

  6. Replication of human immunodeficiency virus type 1 in primary dendritic cell cultures.

    PubMed Central

    Langhoff, E; Terwilliger, E F; Bos, H J; Kalland, K H; Poznansky, M C; Bacon, O M; Haseltine, W A

    1991-01-01

    The ability of the human immunodeficiency virus type 1 (HIV-1) to replicate in primary blood dendritic cells was investigated. Dendritic cells compose less than 1% of the circulating leukocytes and are nondividing cells. Highly purified preparations of dendritic cells were obtained using recent advances in cell fractionation. The results of these experiments show that dendritic cells, in contrast to monocytes and T cells, support the active replication of all strains of HIV-1 tested, including T-cell tropic and monocyte/macrophage tropic isolates. The dendritic cell cultures supported much more virus production than did cultures of primary unseparated T cells, CD4+ T cells, and adherent as well as nonadherent monocytes. Replication of HIV-1 in dendritic cells produces no noticeable cytopathic effect nor does it decrease total cell number. The ability of the nonreplicating dendritic cells to support high levels of replication of HIV-1 suggests that this antigen-presenting cell population, which is also capable of supporting clonal T-cell growth, may play a central role in HIV pathogenesis, serving as a source of continued infection of CD4+ T cells and as a reservoir of virus infection. Images PMID:1910172

  7. Direct Type I IFN but Not MDA5/TLR3 Activation of Dendritic Cells Is Required for Maturation and Metabolic Shift to Glycolysis after Poly IC Stimulation

    PubMed Central

    Haddad, Elias; Wood, Elizabeth G.; Longhi, M. Paula

    2014-01-01

    Type I interferons (IFNs) play an important role in direct antiviral defense as well as linking the innate and adaptive immune responses. On dendritic cells (DCs), IFNs facilitate their activation and contribute to CD8+ and CD4+ T cell priming. However, the precise molecular mechanism by which IFNs regulate maturation and immunogenicity of DCs in vivo has not been studied in depth. Here we show that, after in vivo stimulation with the TLR ligand poly IC, IFNs dominate transcriptional changes in DCs. In contrast to direct TLR3/mda5 signaling, IFNs are required for upregulation of all pathways associated with DC immunogenicity. In addition, metabolic pathways, particularly the switch from oxidative phosphorylation to glycolysis, are also regulated by IFNs and required for DC maturation. These data provide evidence for a metabolic reprogramming concomitant with DC maturation and offer a novel mechanism by which IFNs modulate DC maturation. PMID:24409099

  8. Transforming growth factor beta-activated kinase 1 (TAK1)-dependent checkpoint in the survival of dendritic cells promotes immune homeostasis and function.

    PubMed

    Wang, Yanyan; Huang, Gonghua; Vogel, Peter; Neale, Geoffrey; Reizis, Boris; Chi, Hongbo

    2012-02-07

    Homeostatic control of dendritic cell (DC) survival is crucial for adaptive immunity, but the molecular mechanism is not well defined. Moreover, how DCs influence immune homeostasis under steady state remains unclear. Combining DC-specific and -inducible deletion systems, we report that transforming growth factor beta-activated kinase 1 (TAK1) is an essential regulator of DC survival and immune system homeostasis and function. Deficiency of TAK1 in CD11c(+) cells induced markedly elevated apoptosis, leading to the depletion of DC populations, especially the CD8(+) and CD103(+) DC subsets in lymphoid and nonlymphoid tissues, respectively. TAK1 also contributed to DC development by promoting the generation of DC precursors. Prosurvival signals from Toll-like receptors, CD40 and receptor activator of nuclear factor-κB (RANK) are integrated by TAK1 in DCs, which in turn mediated activation of downstream NF-κB and AKT-Foxo pathways and established a gene-expression program. TAK1 deficiency in DCs caused a myeloid proliferative disorder characterized by expansion of neutrophils and inflammatory monocytes, disrupted T-cell homeostasis, and prevented effective T-cell priming and generation of regulatory T cells. Moreover, TAK1 signaling in DCs was required to prevent myeloid proliferation even in the absence of lymphocytes, indicating a previously unappreciated regulatory mechanism of DC-mediated control of myeloid cell-dependent inflammation. Therefore, TAK1 orchestrates a prosurvival checkpoint in DCs that affects the homeostasis and function of the immune system.

  9. Role of Dendritic Cells in Immune Dysfunction

    NASA Technical Reports Server (NTRS)

    Savary, Cherylyn A.

    1997-01-01

    Specific aims include: (1) Application of the bioreactor to enhance cytokine-regulated proliferation and maturation of dendritic cells (DC); (2) Based on clues from spaceflight: compare the frequency and function of DC in normal donors and immunocompromised cancer patients; and (3) Initiate studies on the efficiency of cytokine therapy and DC-assisted immunotherapy (using bioreactor-expanded DC) in animal models of experimental fungal infections.

  10. Adherent cells in granulocyte-macrophage colony-stimulating factor-induced bone marrow-derived dendritic cell culture system are qualified dendritic cells.

    PubMed

    Li, Gong-Bo; Lu, Guang-Xiu

    2010-01-01

    A widely-used method for generating dendritic cell (DC) is to culture bone marrow cells in granulocyte-macrophage colony-stimulating factor (GM-CSF)-containing medium for 6-10 days. Usually, non-adherent cells are used as qualified dendritic cells while the adherent ones are discarded as "non-dendritic cells" or macrophages. In this study, we show that the adherent cells are nearly identical to the non-adherent cells in both dendritic cell surface markers expression and main dendritic cell-related functions, hence to prove that these "junk cells" are actually qualified dendritic cells.

  11. [Ag85B and BCG enhance immune activity of dendritic cells in patients with initially treated tuberculosis].

    PubMed

    Guo, Yun; Su, Yuanyuan; Sun, Yang; Guan, Weiwei; Yang, Li; Zhang, Zhi; Wang, Yuling; Dai, Erhei

    2016-06-01

    Objective To investigate the regulatory effects of Mycobacterium tuberculosis major secreted protein Ag85B and Bacillus Calmette-Guerin (BCG) on the immune function of dendritic cells (DCs) in the patients with tuberculosis who have received an initial treatment. Methods The peripheral blood mononuclear cells were collected and separated in 26 healthy subjects and 31 patients with tuberculosis who had been treated initially. Every specimen was divided into 4 groups and DCs were induced and cultured. On the 6th day, the DCs in the three experimental groups were treated by lipopolysaccharide (LPS), BCG, Ag85B, respectively and no-treated DCs served as a control group. After 24-hour treatment, DCs were collected and examined for the levels of CD83, CD86, HLA-DR and CD11c using flow cytometry. Moreover, the levels of interleukin 12 (IL-12), IL-10 and interferon γ (IFN-γ) in the supernatants were measured by ELISA. Results The expression levels of CD83 and IL-10 in the patient control group were significantly lower than those in healthy subject control group. The levels of CD83, CD86 and IFN-γ in the Ag85B treated group were obviously high than those in the control group. The level of IFN-γ in the BCG treated group was significantly high than that in the control group. The levels of CD83, CD86, HLA-DR and IL-10 in the LPS treated group were remarkably higher than those in the control group. The levels of CD83, CD86 and IL-10 in the healthy subject LPS treated group were significantly higher than those in the healthy subject control group. Conclusion The immune-enhancing effect of Ag85B on DCs is superior to that of BCG in the patients with initially treated tuberculosis.

  12. Dendritic cell therapy for oncology roundtable conference

    PubMed Central

    2011-01-01

    2-3 September 2010, Brussels, Belgium The Dendritic Cell Therapy for Oncology Roundtable Conference was organized by Reliable Cancer Therapies and moderated by Prof. Dr. Steven De Vleeschouwer. The organizer, Reliable Cancer Therapies, is a Swiss non-profit organization that provides information on evidence-based cancer treatments and funding for the development of a selection of promising cancer therapies. In order to be able to give valuable information about dendritic cell (DC) therapy to patients and physicians, the organizing committee felt it necessary to organize this conference to get an up-to-date status of the academic DC therapy field, collect ideas to guide patients towards clinical trials and to induce cross-fertilization for protocol optimization. In total, 31 experts participated to an in-depth discussion about the status and the future development path for dendritic cell vaccines. The conference started with general presentations about cancer immunotherapy, followed by comprehensive overview presentations about the progress in DC vaccine development achieved by each speaker. At the end of the meeting, a thorough general discussion focused on key questions about what is needed to improve DC vaccines. This report does not cover all presentations, but aims to highlight selected points of interest, particularly relating to possible limitations and potential approaches to improvement of DC therapies specifically, and also immunotherapeutic interventions in general terms. PMID:21226916

  13. Generation of Th17 cells in response to intranasal infection requires TGF-β1 from dendritic cells and IL-6 from CD301b+ dendritic cells.

    PubMed

    Linehan, Jonathan L; Dileepan, Thamotharampillai; Kashem, Sakeen W; Kaplan, Daniel H; Cleary, Patrick; Jenkins, Marc K

    2015-10-13

    Intranasal (i.n.) infections preferentially generate Th17 cells. We explored the basis for this anatomic preference by tracking polyclonal CD4(+) T cells specific for an MHC class II-bound peptide from the mucosal pathogen Streptococcus pyogenes. S. pyogenes MHC class II-bound peptide-specific CD4(+) T cells were first activated in the cervical lymph nodes following i.n. inoculation and then differentiated into Th17 cells. S. pyogenes-induced Th17 formation depended on TGF-β1 from dendritic cells and IL-6 from a CD301b(+) dendritic cell subset located in the cervical lymph nodes but not the spleen. Thus, the tendency of i.n. infection to induce Th17 cells is related to cytokine production by specialized dendritic cells that drain this site.

  14. Distinct mechanisms of neonatal tolerance induced by dendritic cells and thymic B cells

    PubMed Central

    1991-01-01

    To assess the role of different types of antigen-presenting cells (APC) in the induction of tolerance, we isolated B cells, macrophages, and dendritic cells from thymus and spleen, and injected these into neonatal BALB/c mice across an Mls-1 antigenic barrier. One week after injection of APC from Mls-1-incompatible mice or from control syngeneic mice, we measured the number of thymic, Mls-1a-reactive, V beta 6+ T cells and the capacity of thymocytes to induce a graft-vs.-host (GVH) reaction in popliteal lymph nodes of Mls-1a mice. Injection of thymic but not spleen B cells deleted thymic, Mls-1a-reactive V beta 6+ T cells and induced tolerance in the GVH assay. The thymic B cells were primarily of the CD5+ type, and fluorescence-activated cell sorter- purified CD5+ thymic B cells were active. Injection of dendritic cells from spleen or thymus also induced tolerance, but the V beta 6 cells were anergized rather than deleted. Macrophages from thymus did not induce tolerance. Dendritic cells and thymic B cells were also effective in inducing tolerance even when injected into Mls-, major histocompatibility complex-incompatible, I-E- mice, but only thymic B cells depleted V beta 6-expressing T cells. Therefore, different types of bone marrow-derived APC have different capacities for inducing tolerance, and the active cell types (dendritic cells and CD5+ thymic B cells) can act by distinct mechanisms. PMID:1900075

  15. Immunological Characterization of Whole Tumour Lysate-Loaded Dendritic Cells for Cancer Immunotherapy

    PubMed Central

    Ottobrini, Luisa; Biasin, Mara; Borelli, Manuela; Lucignani, Giovanni; Trabattoni, Daria; Clerici, Mario

    2016-01-01

    Introduction Dendritic cells play a key role as initiators of T-cell responses, and even if tumour antigen-loaded dendritic cells can induce anti-tumour responses, their efficacy has been questioned, suggesting a need to enhance immunization strategies. Matherials & Methods We focused on the characterization of bone marrow-derived dendritic cells pulsed with whole tumour lysate (TAA-DC), as a source of known and unknown antigens, in a mouse model of breast cancer (MMTV-Ras). Dendritic cells were evaluated for antigen uptake and for the expression of MHC class I/II and costimulatory molecules and markers associated with maturation. Results Results showed that antigen-loaded dendritic cells are characterized by a phenotypically semi-mature/mature profile and by the upregulation of genes involved in antigen presentation and T-cell priming. Activated dendritic cells stimulated T-cell proliferation and induced the production of high concentrations of IL-12p70 and IFN-γ but only low levels of IL-10, indicating their ability to elicit a TH1-immune response. Furthermore, administration of Antigen loaded-Dendritic Cells in MMTV-Ras mice evoked a strong anti-tumour response in vivo as demonstrated by a general activation of immunocompetent cells and the release of TH1 cytokines. Conclusion Data herein could be useful in the design of antitumoral DC-based therapies, showing a specific activation of immune system against breast cancer. PMID:26795765

  16. Generation of regulatory dendritic cells after treatment with paeoniflorin.

    PubMed

    Chen, Dan; Li, Yingxi; Wang, Xiaodong; Li, Keqiu; Jing, Yaqing; He, Jinghua; Qiang, Zhaoyan; Tong, Jingzhi; Sun, Ke; Ding, Wen; Kang, Yi; Li, Guang

    2016-08-01

    Regulatory dendritic cells are a potential therapeutic tool for assessing a variety of immune overreaction diseases. Paeoniflorin, a bioactive glucoside extracted from the Chinese herb white paeony root, has been shown to be effective at inhibiting the maturation and immunostimulatory function of murine bone marrow-derived dendritic cells. However, whether paeoniflorin can program conventional dendritic cells toward regulatory dendritic cells and the underlying mechanism remain unknown. Here, our study demonstrates that paeoniflorin can induce the production of regulatory dendritic cells from human peripheral blood monocyte-derived immature dendritic cells in the absence or presence of lipopolysaccharide (LPS) but not from mature dendritic cells, thereby demonstrating the potential of paeoniflorin as a specific immunosuppressive drug with fewer complications and side effects. These regulatory dendritic cells treated with paeoniflorin exhibited high CD11b/c and low CD80, CD86 and CD40 expression levels as well as enhanced abilities to capture antigen and promote the proliferation of CD4(+)CD25(+) T cells and reduced abilities to migrate and promote the proliferation of CD4(+) T cells, which is associated with the upregulation of endogenous transforming growth factor (TGF)-β-mediated indoleamine 2,3-dioxygenase (IDO) expression. Collectively, paeoniflorin could program immature dendritic cells (imDCs) and imDCs stimulated with LPS toward a regulatory DC fate by upregulating the endogenous TGF-β-mediated IDO expression level, thereby demonstrating its potential as a specific immunosuppressive drug.

  17. Intermediate-conductance calcium-activated potassium channel KCa3.1 and chloride channel modulate chemokine ligand (CCL19/CCL21)-induced migration of dendritic cells.

    PubMed

    Shao, Zhifei; Gaurav, Rohit; Agrawal, Devendra K

    2015-07-01

    The role of ion channels is largely unknown in chemokine-induced migration in nonexcitable cells such as dendritic cells (DCs). Here, we examined the role of intermediate-conductance calcium-activated potassium channel (KCa3.1) and chloride channel (CLC3) in lymphatic chemokine-induced migration of DCs. The amplitude and kinetics of chemokine ligand (CCL19/CCL21)-induced Ca(2+) influx were associated with chemokine receptor 7 expression levels, extracellular-free Ca(2+) and Cl(-), and independent of extracellular K(+). Chemokines (CCL19 and CCL21) and KCa3.1 activator (1-ethyl-1,3-dihydro-2H-benzimidazol-2-one) induced plasma membrane hyperpolarization and K(+) efflux, which was blocked by 1-[(2-chlorophenyl)diphenylmethyl]-1H-pyrazole, suggesting that KCa3.1 carried larger conductance than the inward calcium release-activated calcium channel. Blockade of KCa3.1, low Cl(-) in the medium, and low dose of 4,4'-diisothiocyano-2,2'-stilbenedisulfonic acid (DIDS) impaired CCL19/CCL21-induced Ca(2+) influx, cell volume change, and DC migration. High doses of DIDS completely blocked DC migration possibly by significantly disrupting mitochondrial membrane potential. In conclusion, KCa3.1 and CLC3 are critical in human DC migration by synergistically regulating membrane potential, chemokine-induced Ca(2+) influx, and cell volume.

  18. Minor genomic differences between related B6 and B10 mice affect severity of schistosome infection by governing the mode of dendritic cell activation.

    PubMed

    Smith, Patrick M; Sproule, Thomas J; Philip, Vivek M; Roopenian, Derry C; Stadecker, Miguel J

    2015-08-01

    Infection with the helminth Schistosoma mansoni results in hepatointestinal granulomatous inflammation mediated by CD4 T cells directed against parasite eggs. The severity of disease varies greatly in humans and mice; however, the genetic basis of such a heterogenous immune response remains poorly understood. Here we show that, despite their close genetic relationship, C57BL/10SnJ (B10) mice developed significantly more pronounced immunopathology and higher T helper 17 cell responses than C57BL/6J (B6) mice. Similarly, live egg-stimulated B10-derived dendritic cells (DCs) produced significantly more IL-1β and IL-23, resulting in higher IL-17 production by CD4 T cells. Gene expression analysis disclosed a heightened proinflammatory cytokine profile together with a strikingly lower expression of Ym1 in B10 versus B6 mice, consistent with failure of B10 DCs to attain alternative activation. To genetically dissect the differential response, we developed and analyzed congenic mouse strains that capture major regions of allelic variation, and found that the level of inflammation was controlled by a relatively small number of genes in a locus mapping to chromosome 4 117-143 MB. Our study has thus identified novel genomic regions that regulate the severity of the schistosome infection by way of controlling the mode of DC activation and consequent CD4 T-cell subset development.

  19. T Cell Cancer Therapy Requires CD40-CD40L Activation of Tumor Necrosis Factor and Inducible Nitric-Oxide-Synthase-Producing Dendritic Cells.

    PubMed

    Marigo, Ilaria; Zilio, Serena; Desantis, Giacomo; Mlecnik, Bernhard; Agnellini, Andrielly H R; Ugel, Stefano; Sasso, Maria Stella; Qualls, Joseph E; Kratochvill, Franz; Zanovello, Paola; Molon, Barbara; Ries, Carola H; Runza, Valeria; Hoves, Sabine; Bilocq, Amélie M; Bindea, Gabriela; Mazza, Emilia M C; Bicciato, Silvio; Galon, Jérôme; Murray, Peter J; Bronte, Vincenzo

    2016-09-12

    Effective cancer immunotherapy requires overcoming immunosuppressive tumor microenvironments. We found that local nitric oxide (NO) production by tumor-infiltrating myeloid cells is important for adoptively transferred CD8(+) cytotoxic T cells to destroy tumors. These myeloid cells are phenotypically similar to inducible nitric oxide synthase (NOS2)- and tumor necrosis factor (TNF)-producing dendritic cells (DC), or Tip-DCs. Depletion of immunosuppressive, colony stimulating factor 1 receptor (CSF-1R)-dependent arginase 1(+) myeloid cells enhanced NO-dependent tumor killing. Tumor elimination via NOS2 required the CD40-CD40L pathway. We also uncovered a strong correlation between survival of colorectal cancer patients and NOS2, CD40, and TNF expression in their tumors. Our results identify a network of pro-tumor factors that can be targeted to boost cancer immunotherapies.

  20. Immunometabolism governs dendritic cell and macrophage function

    PubMed Central

    2016-01-01

    Recent studies on intracellular metabolism in dendritic cells (DCs) and macrophages provide new insights on the functioning of these critical controllers of innate and adaptive immunity. Both cell types undergo profound metabolic reprogramming in response to environmental cues, such as hypoxia or nutrient alterations, but importantly also in response to danger signals and cytokines. Metabolites such as succinate and citrate have a direct impact on the functioning of macrophages. Immunogenicity and tolerogenicity of DCs is also determined by anabolic and catabolic processes, respectively. These findings provide new prospects for therapeutic manipulation in inflammatory diseases and cancer. PMID:26694970

  1. Reduced Purkinje cell dendritic arborization and loss of dendritic spines in essential tremor.

    PubMed

    Louis, Elan D; Lee, Michelle; Babij, Rachel; Ma, Karen; Cortés, Etty; Vonsattel, Jean-Paul G; Faust, Phyllis L

    2014-12-01

    Based on accumulating post-mortem evidence of abnormalities in Purkinje cell biology in essential tremor, we hypothesized that regressive changes in dendritic morphology would be apparent in the Purkinje cell population in essential tremor cases versus age-matched controls. Cerebellar cortical tissue from 27 cases with essential tremor and 27 age-matched control subjects was processed by the Golgi-Kopsch method. Purkinje cell dendritic anatomy was quantified using a Neurolucida microscopic system interfaced with a motorized stage. In all measures, essential tremor cases demonstrated significant reductions in dendritic complexity compared with controls. Median values in essential tremor cases versus controls were: 5712.1 versus 10 403.2 µm (total dendrite length, P=0.01), 465.9 versus 592.5 µm (branch length, P=0.01), 22.5 versus 29.0 (maximum branch order, P=0.001), and 165.3 versus 311.7 (number of terminations, P=0.008). Furthermore, the dendritic spine density was reduced in essential tremor cases (medians=0.82 versus 1.02 µm(-1), P=0.03). Our demonstration of regressive changes in Purkinje cell dendritic architecture and spines in essential tremor relative to control brains provides additional evidence of a pervasive abnormality of Purkinje cell biology in this disease, which affects multiple neuronal cellular compartments including their axon, cell body, dendrites and spines.

  2. Deletion of the Mucin-Like Molecule Muc1 Enhances Dendritic Cell Activation in Response to Toll-Like Receptor Ligands

    PubMed Central

    Williams, Marc A.; Bauer, Stephen; Lu, Wenju; Guo, Jia; Walter, Scott; Bushnell, Timothy P.; Lillehoj, Erik P.; Georas, Steve N.

    2010-01-01

    Dendritic cells (DC) are potent professional antigen-presenting cells that drive primary immune responses to infections or other agonists perceived as ‘dangerous’. Muc1 is the only cell surface mucin or MUC gene product that is expressed in DC. Unlike other members of this glycoprotein family, Muc1 possesses a unique cytosolic region capable of signal transduction and attenuating toll-like receptor (TLR) activation. The expression and function of Muc1 has been intensively investigated on epithelial and tumor cells, but relatively little is known about its function on DC. We hypothesized that Muc1 would influence in vitro generation and primary DC activation in response to the TLR4 and TLR5 ligands lipopolysaccharide and flagellin. Compared with Muc1+/+ DC, we found that Muc1−/− DC were constitutively activated, as determined by higher expression of co-stimulatory molecules (CD40, CD80 and CD86), greater secretion of immunoregulatory cytokines (TNF-α and VEGF), and better stimulation of allogeneic naïve CD4+ T cell proliferation. After activation by either LPS or flagellin and co-culture with allogeneic CD4+ T cells, Muc1−/− DC also induced greater secretion of TNF-α and IFN-γ compared to similarly activated Muc1+/+ DC. Taken together, our results indicate that deletion of Muc1 promotes a heightened functional response of DC in response to TLR4 and TLR5 signaling pathways, and suggests a previously under-appreciated role for Muc1 in regulating innate immune responses of DC. PMID:20375631

  3. Dendritic planarity of Purkinje cells is independent of Reelin signaling.

    PubMed

    Kim, Jinkyung; Park, Tae-Ju; Kwon, Namseop; Lee, Dongmyeong; Kim, Seunghwan; Kohmura, Yoshiki; Ishikawa, Tetsuya; Kim, Kyong-Tai; Curran, Tom; Je, Jung Ho

    2015-07-01

    The dendritic planarity of Purkinje cells is critical for cerebellar circuit formation. In the absence of Crk and CrkL, the Reelin pathway does not function resulting in partial Purkinje cell migration and defective dendritogenesis. However, the relationships among Purkinje cell migration, dendritic development and Reelin signaling have not been clearly delineated. Here, we use synchrotron X-ray microscopy to obtain 3-D images of Golgi-stained Purkinje cell dendrites. Purkinje cells that failed to migrate completely exhibited conical dendrites with abnormal 3-D arborization and reduced dendritic complexity. Furthermore, their spines were fewer in number with a distorted morphology. In contrast, Purkinje cells that migrated successfully displayed planar dendritic and spine morphologies similar to normal cells, despite reduced dendritic complexity. These results indicate that, during cerebellar formation, Purkinje cells migrate into an environment that supports development of dendritic planarity and spine formation. While Reelin signaling is important for the migration process, it does not make a direct major contribution to dendrite formation.

  4. Homophilic Protocadherin Cell-Cell Interactions Promote Dendrite Complexity.

    PubMed

    Molumby, Michael J; Keeler, Austin B; Weiner, Joshua A

    2016-05-03

    Growth of a properly complex dendrite arbor is a key step in neuronal differentiation and a prerequisite for neural circuit formation. Diverse cell surface molecules, such as the clustered protocadherins (Pcdhs), have long been proposed to regulate circuit formation through specific cell-cell interactions. Here, using transgenic and conditional knockout mice to manipulate γ-Pcdh repertoire in the cerebral cortex, we show that the complexity of a neuron's dendritic arbor is determined by homophilic interactions with other cells. Neurons expressing only one of the 22 γ-Pcdhs can exhibit either exuberant or minimal dendrite complexity, depending only on whether surrounding cells express the same isoform. Furthermore, loss of astrocytic γ-Pcdhs, or disruption of astrocyte-neuron homophilic matching, reduces dendrite complexity cell non-autonomously. Our data indicate that γ-Pcdhs act locally to promote dendrite arborization via homophilic matching, and they confirm that connectivity in vivo depends on molecular interactions between neurons and between neurons and astrocytes.

  5. Macrophages, dendritic cells, and regression of atherosclerosis

    PubMed Central

    Feig, Jonathan E.; Feig, Jessica L.

    2012-01-01

    Atherosclerosis is the number one cause of death in the Western world. It results from the interaction between modified lipoproteins and cells such as macrophages, dendritic cells (DCs), T cells, and other cellular elements present in the arterial wall. This inflammatory process can ultimately lead to the development of complex lesions, or plaques, that protrude into the arterial lumen. Ultimately, plaque rupture and thrombosis can occur leading to the clinical complications of myocardial infarction or stroke. Although each of the cell types plays roles in the pathogenesis of atherosclerosis, the focus of this review will be primarily on the macrophages and DCs. The role of these two cell types in atherosclerosis is discussed, with a particular emphasis on their involvement in atherosclerosis regression. PMID:22934038

  6. Differential regulation by leukotrienes and calcium of Fc gamma receptor-induced phagocytosis and Syk activation in dendritic cells versus macrophages.

    PubMed

    Canetti, Claudio; Aronoff, David M; Choe, Mun; Flamand, Nicolas; Wettlaufer, Scott; Toews, Galen B; Chen, Gwo-Hsiao; Peters-Golden, Marc

    2006-06-01

    Macrophage (MØ) phagocytosis via the Fc receptor for immunoglobulin G (Fc gammaR) requires the spleen tyrosine kinase (Syk) and serves an important antimicrobial function. We have reported previously that Fc gammaR-mediated ingestion and Syk activation in MØ are amplified by and depend on the proinflammatory lipid mediator leukotriene B4 (LTB4). Although Fc gammaR-mediated ingestion is also important for antigen uptake, there is no information about LTB4 regulation of these processes in dendritic cells (DCs). In this study, we compared murine bone marrow (BM)-derived DCs to MØ from BM, peritoneum, and the pulmonary alveolar space. Neither phagocytosis nor Syk activation in DCs was influenced by exogenous LTB4. Unlike the various MØ populations, Syk activation in DCs was likewise unaffected by pharmacologic or genetic strategies to inhibit endogenous LTB4 synthesis or to block the high-affinity LTB4 receptor BLT1. DCs were refractory to regulation by LTB4 despite the fact that they expressed BLT1 and mobilized intracellular calcium in response to its ligation. This resistance to LTB4 in DCs instead reflected the fact that in contrast to MØ, Syk activation in DCs was itself entirely independent of calcium. These results identify a fundamental difference in Fc gammaR signaling between DCs and MØ, which may relate to the divergent, functional consequences of target ingestion in the two cell types.

  7. Giardia lamblia binding immunoglobulin protein triggers maturation of dendritic cells via activation of TLR4-MyD88-p38 and ERK1/2 MAPKs.

    PubMed

    Lee, H-Y; Kim, J; Noh, H J; Kim, H-P; Park, S-J

    2014-12-01

    Much remains unknown about the mammalian immune response to Giardia lamblia, a protozoan pathogen that causes diarrhoeal outbreaks. We fractionated protein extracts of G. lamblia trophozoites by Viva-spin centrifugation, DEAE ion exchange and gel filtration chromatography. Resultant fractions were screened for antigenic molecules by western blots analysis using anti-G. lamblia antibodies (Abs), resulting in identification of G. lamblia binding immunoglobulin protein (GlBiP). Maturation of mouse dendritic cells (DCs) in response to recombinant GlBiP (rGlBiP) was detected by increased expression of surface molecules such as CD80, CD86 and MHC class II; these mature DCs, produced pro-inflammatory cytokines (TNF-α, IL-12 and IL-6). Especially, the truncated rGlBiP containing the heat-shock protein 70 domain-induced cytokine production from mouse DCs. rGlBiP-induced DC activation was initiated by TLR4 in a MyD88-dependent way and occurred through activation of p38 and ERK1/2 MAPKs as well as increased activity of NF-κB and AP-1. Moreover, CD4(+) T cells stimulated with rGlBiP-treated DCs produced high levels of IL-2 and IFN-γ. Together, our results suggest that GlBiP contributes to maturation of DCs via activation of TLR4-MyD88-p38, ERK1/2 MAPK, NF-κB and AP-1.

  8. Collagen I-induced dendritic cells activation is regulated by TNF-alpha production through down-regulation of IRF4.

    PubMed

    Poudel, Barun; Ki, Hyeon-Hui; Lee, Young-Mi; Kim, Dae-Ki

    2015-03-01

    Previously we have shown that collagen I enhances the maturation and function of dendritic cells (DCs). Inflammatory mediators such as tumour necrosis factor (TNF)- alpha, interleukin (IL)-1 beta and lipopolysaccharide (LPS) are also known to activate DCs. Here we investigated the involvement of TNF-alpha on the collagen I-induced DCs activation. TNF-a neutralization inhibited collagen I-induced IL-12 secretions by DCs. Additionally, we observed suppression of collagen I-induced costimulatory molecules expression along with down-regulation of genes involved in DCs activation pathway. Furthermore, TNF- alpha inhibition upon collagen Istimulation up-regulated the expression of interferon regulatory transcription factor IRF4, when compared to collagen I only treated cells. Collectively, our data demonstrate that collagen I induce TNF- alpha production, which is crucial for the activation and function of DCs, through down-regulation of IRF4, and implicates the importance in development of anti- TNF-alpha therapeutics for several inflammatory diseases.

  9. Olfactory Sensory Neurons Control Dendritic Complexity of Mitral Cells via Notch Signaling

    PubMed Central

    Saito, Tetsuichiro

    2016-01-01

    Mitral cells (MCs) of the mammalian olfactory bulb have a single primary dendrite extending into a single glomerulus, where they receive odor information from olfactory sensory neurons (OSNs). Molecular mechanisms for controlling dendritic arbors of MCs, which dynamically change during development, are largely unknown. Here we found that MCs displayed more complex dendritic morphologies in mouse mutants of Maml1, a crucial gene in Notch signaling. Similar phenotypes were observed by conditionally misexpressing a dominant negative form of MAML1 (dnMAML1) in MCs after their migration. Conversely, conditional misexpression of a constitutively active form of Notch reduced their dendritic complexity. Furthermore, the intracellular domain of Notch1 (NICD1) was localized to nuclei of MCs. These findings suggest that Notch signaling at embryonic stages is involved in the dendritic complexity of MCs. After the embryonic misexpression of dnMAML1, many MCs aberrantly extended dendrites to more than one glomerulus at postnatal stages, suggesting that Notch signaling is essential for proper formation of olfactory circuits. Moreover, dendrites in cultured MCs were shortened by Jag1-expressing cells. Finally, blocking the activity of Notch ligands in OSNs led to an increase in dendritic complexity as well as a decrease in NICD1 signals in MCs. These results demonstrate that the dendritic complexity of MCs is controlled by their presynaptic partners, OSNs. PMID:28027303

  10. Active action potential propagation but not initiation in thalamic interneuron dendrites

    PubMed Central

    Casale, Amanda E.; McCormick, David A.

    2012-01-01

    Inhibitory interneurons of the dorsal lateral geniculate nucleus of the thalamus modulate the activity of thalamocortical cells in response to excitatory input through the release of inhibitory neurotransmitter from both axons and dendrites. The exact mechanisms by which release can occur from dendrites are, however, not well understood. Recent experiments using calcium imaging have suggested that Na/K based action potentials can evoke calcium transients in dendrites via local active conductances, making the back-propagating action potential a candidate for dendritic neurotransmitter release. In this study, we employed high temporal and spatial resolution voltage-sensitive dye imaging to assess the characteristics of dendritic voltage deflections in response to Na/K action potentials in interneurons of the mouse dorsal lateral geniculate nucleus. We found that trains or single action potentials elicited by somatic current injection or local synaptic stimulation led to action potentials that rapidly and actively back-propagated throughout the entire dendritic arbor and into the fine filiform dendritic appendages known to release GABAergic vesicles. Action potentials always appeared first in the soma or proximal dendrite in response to somatic current injection or local synaptic stimulation, and the rapid back-propagation into the dendritic arbor depended upon voltage-gated sodium and TEA-sensitive potassium channels. Our results indicate that thalamic interneuron dendrites integrate synaptic inputs that initiate action potentials, most likely in the axon initial segment, that then back-propagate with high-fidelity into the dendrites, resulting in a nearly synchronous release of GABA from both axonal and dendritic compartments. PMID:22171033

  11. Uncoupling Dendrite Growth and Patterning: Single Cell Knockout Analysis of NMDA Receptor 2B

    PubMed Central

    Espinosa, J. Sebastian; Wheeler, Damian G.; Tsien, Richard W.; Luo, Liqun

    2009-01-01

    SUMMARY N-Methyl-D-aspartate receptors (NMDARs) play important functions in neural development. NR2B is the predominant NR2 subunit of NMDAR in the developing brain. Here we use MADM (Mosaic Analysis with Double Markers) to knock out NR2B in isolated single cells and analyze its cell-autonomous function in dendrite development. NR2B mutant dentate gyrus granule cells (dGCs) and barrel cortex layer 4 spiny stellate cells (bSCs) have similar dendritic growth rates, total length and branch number as control cells. However, mutant dGCs maintain supernumerary primary dendrites resulting from a pruning defect. Furthermore, while control bSCs restrict dendritic growth to a single barrel, mutant bSCs maintain dendritic growth in multiple barrels. Thus, NR2B functions cell-autonomously to regulate dendrite patterning to ensure that sensory information is properly represented in the cortex. Our study also indicates that molecular mechanisms that regulate activity-dependent dendrite patterning can be separated from those that control general dendrite growth and branching. PMID:19409266

  12. Uncoupling dendrite growth and patterning: single-cell knockout analysis of NMDA receptor 2B.

    PubMed

    Espinosa, J Sebastian; Wheeler, Damian G; Tsien, Richard W; Luo, Liqun

    2009-04-30

    N-methyl-D-aspartate receptors (NMDARs) play important functions in neural development. NR2B is the predominant NR2 subunit of NMDAR in the developing brain. Here we use mosaic analysis with double markers (MADM) to knock out NR2B in isolated single cells and analyze its cell-autonomous function in dendrite development. NR2B mutant dentate gyrus granule cells (dGCs) and barrel cortex layer 4 spiny stellate cells (bSCs) have similar dendritic growth rates, total length, and branch number as control cells. However, mutant dGCs maintain supernumerary primary dendrites resulting from a pruning defect. Furthermore, while control bSCs restrict dendritic growth to a single barrel, mutant bSCs maintain dendritic growth in multiple barrels. Thus, NR2B functions cell autonomously to regulate dendrite patterning to ensure that sensory information is properly represented in the cortex. Our study also indicates that molecular mechanisms that regulate activity-dependent dendrite patterning can be separated from those that control general dendrite growth and branching.

  13. A new benzenediamine derivative modulates Toll-like receptors-induced myeloid dendritic cells activation and ameliorates lupus-like syndrome in MRLlpr/lpr mice.

    PubMed

    Gao, Sheng; Gong, Yongsheng; Ji, Jianjian; Yuan, Linbo; Han, Liping; Guo, Yimin; Fan, Xiaofang; Hou, Yayi; Hua, Chunyan

    2017-03-23

    Modulators of the over-activation of myeloid dendritic cells (mDCs) by Toll-like receptors (TLRs) have an advantage in the treatment of systemic lupus erythematosus (SLE). This study was designed to evaluate the effects of FC-99, a novel benzenediamine derivative, on TLR-induced activation of mDCs, and to assess the efficacy of FC-99 in a murine model of SLE. In vitro, FC-99 inhibited the phenotypic (CD40 and MHC-II) and functional activation (IL-12 and CXCL10) of mDCs induced by TLR ligands. In vivo, MRLlpr/lpr mice displayed renal diseases associated with increased levels of proteinuria and immunoglobulin, which were ameliorated by FC-99. Enhanced accumulation and activation of mDCs in lymphoid organs was also impaired by FC-99. Additionally, FC-99 inhibited the activation of IκB-α and upregulated the expression of TNFα-induced protein 3 (TNFAIP3) in vitro and in vivo. These results indicate that FC-99 modulates TLR-induced activation of mDCs and ameliorates lupus-like syndrome in MRLlpr/lpr mice. This effect is closely associated with the inhibition of IκB-α and upregulation of TNFAIP3.

  14. Lignin-rich Enzyme Lignin (LREL), a Cellulase-treated Lignin-Carbohydrate Derived from Plants, Activates Myeloid Dendritic Cells via Toll-like Receptor 4 (TLR4)

    PubMed Central

    Tsuji, Ryohei; Koizumi, Hideki; Aoki, Dan; Watanabe, Yuta; Sugihara, Yoshihiko; Matsushita, Yasuyuki; Fukushima, Kazuhiko; Fujiwara, Daisuke

    2015-01-01

    Lignin-carbohydrates, one of the major cell wall components, are believed to be the structures that form chemical linkage between lignin and cell wall polysaccharides. Due to the molecular complexity of lignin-containing substances, their isolation and the assignment of their biological activities have so far remained a difficult task. Here, we extracted two lignin-containing carbohydrates, lignin-rich enzyme lignin (LREL) and pure enzyme lignin (PEL), from barley husk and demonstrated that they act as immune stimulators of dendritic cells (DCs), which are particularly important in linking innate and adaptive immunity. Thioacidolysis, acid hydrolysis, and mild alkali hydrolysis of both LREL and PEL revealed that their immunostimulatory activities depended on the lignin structure and/or content, neutral sugar content (especially the characteristic distribution of galactose and mannose), and presence of an ester bond. Furthermore, we showed that the immunostimulatory potency of the lignin-carbohydrate depended on its molecular weight and degree of polymerization. We also demonstrated that the LREL-induced activation of DCs was mediated via TLR4. Thus, LREL-induced increases in the expression levels of several cell surface marker proteins, production of inflammatory cytokines IL-12p40 and TNF-α, and activation and nuclear translocation of transcription factors, as was observed in the WT DCs, were completely abrogated in DCs derived from the TLR4−/− mice but not in DCs derived from the TLR2−/−, TLR7−/−, and TLR9−/− mice. We further demonstrated that LRELs isolated from other plant tissues also activated DCs. These immunostimulatory activities of lignin-carbohydrates, extracted from edible plant tissues, could have potential relevance in anti-infectious immunity and vaccine adjuvants. PMID:25548274

  15. Divergent Effects of Dendritic Cells on Pancreatitis

    DTIC Science & Technology

    2015-09-01

    responses. Our work utilizes murine models and human tissues. Dendritic cells in mice express MHC II and the integrin CD11c. They are proficient in...CD54), and co-stimulatory molecules (CD80, CD86) in the pancreas and spleen in control mice and in models of pancreatitis. We showed that DC... generated BMDC in vitro from BM progenitors using GMCSF (20 ng/ml) in 8 day cultures. Mice were adoptively transferred with 1x106 BMDC after daily caerulein

  16. Metamaterial absorber with random dendritic cells

    NASA Astrophysics Data System (ADS)

    Zhu, Weiren; Zhao, Xiaopeng

    2010-05-01

    The metamaterial absorber composed of random dendritic cells has been investigated at microwave frequencies. It is found that the absorptivities come to be weaker and the resonant frequency get red shift as the disordered states increasing, however, the random metamaterial absorber still presents high absorptivity more than 95%. The disordered structures can help understanding of the metamaterial absorber and may be employed for practical design of infrared metamaterial absorber, which may play important roles in collection of radiative heat energy and directional transfer enhancement.

  17. Lactobacillus rhamnosus GG Activation of Dendritic Cells and Neutrophils Depends on the Dose and Time of Exposure

    PubMed Central

    Bay, Boon Huat

    2016-01-01

    This study evaluates the ability of Lactobacillus rhamnosus GG (LGG) to activate DC and neutrophils and modulate T cell activation and the impact of bacterial dose on these responses. Murine bone marrow derived DC or neutrophils were stimulated with LGG at ratios of 5 : 1, 10 : 1, and 100 : 1 (LGG : cells) and DC maturation (CD40, CD80, CD86, CD83, and MHC class II) and cytokine production (IL-10, TNF-α, and IL-12p70) were examined after 2 h and 18 h coculture and compared to the ability of BCG (the present immunotherapeutic agent for bladder cancer) to stimulate these cells. A 2 h exposure to 100 : 1 (high dose) or an 18 h exposure to 5 : 1 or 10 : 1 (low dose), LGG : cells, induced the highest production of IL-12 and upregulation of CD40, CD80, CD86, and MHC II on DC. In DCs stimulated with LGG activated neutrophils IL-12 production decreased with increasing dose. LGG induced 10-fold greater IL-12 production than BCG. T cell IFNγ and IL-2 production was significantly greater when stimulated with DC activated with low dose LGG. In conclusion, DC or DC activated with neutrophils exposed to low dose LGG induced greater Th1 polarization in T cells and this could potentially exert stronger antitumor effects. Thus the dose of LGG used for immunotherapy could determine treatment efficacy. PMID:27525288

  18. Mycobacterium tuberculosis PE25/PPE41 protein complex induces activation and maturation of dendritic cells and drives Th2-biased immune responses.

    PubMed

    Chen, Wei; Bao, Yige; Chen, Xuerong; Burton, Jeremy; Gong, Xueli; Gu, Dongqing; Mi, Youjun; Bao, Lang

    2016-04-01

    Mycobacterium tuberculosis evades innate host immune responses by parasitizing macrophages and causes significant morbidity and mortality around the world. A mycobacterial antigen that can activate dendritic cells (DCs) and elicit effective host innate immune responses will be vital to the development of an effective TB vaccine. The M. tuberculosis genes PE25/PPE41 encode proteins which have been associated with evasion of the host immune response. We constructed a PE25/PPE41 complex gene via splicing by overlapping extension and expressed it successfully in E. coli. We investigated whether this protein complex could interact with DCs to induce effective host immune responses. The PE25/PPE41 protein complex induced maturation of isolated mouse DCs in vitro, increasing expression of cell surface markers (CD80, CD86 and MHC-II), thereby promoting Th2 polarization via secretion of pro-inflammatory cytokines IL-4 and IL-10. In addition, PE25/PPE41 protein complex-activated DCs induced proliferation of mouse CD4(+) and CD8(+) T cells, and a strong humoral response in immunized mice. The sera of five TB patients were also highly reactive to this antigen. These findings suggest that interaction of the PE25/PPE41 protein complex with DCs may be of great immunological significance.

  19. Rapid dendritic cell activation and resistance to allotolerance induction in anti-CD154-treated mice receiving CD47-deficient donor-specific transfusion.

    PubMed

    Wang, Yuantao; Wang, Hui; Bronson, Roderick; Fu, Yaowen; Yang, Yong-Guang

    2014-03-01

    CD47-SIRPα signaling plays an important role in regulating macrophage and dendritic cell (DC) activation. Here we investigated the role of CD47 expression on donor cells in tolerance induction by combined treatment with donor-specific transfusion (DST) plus anti-CD154 mAb in a mouse model of fully MHC-mismatched heart allotransplantation. The majority of BALB/c recipient mice that received anti-CD154 and CD47(+/+) B6 splenocytes (DST) showed indefinite donor heart survival (median survival time, MST > 150 days). Donor heart survival was improved in anti-CD154-treated BALB/c mice that received CD47(+/-) (MST = 90 days) or CD47(-/-) B6 DST (MST = 42 days) when compared to the nontreated (MST = 7 days) and anti-CD154 alone-treated (MST = 15 days) controls, but significantly reduced when compared to mice receiving anti-CD154 plus CD47(+/+) B6 DST. Recipient mice treated with anti-CD154 plus CD47(-/-) or CD47(+/-) DST also showed significantly increased antidonor, but not anti-third-party, MLR responses compared to those receiving anti-CD154 and CD47(+/+) DST. Furthermore, CD47(-/-) DST induced rapid activation of CD11c(hi)SIRPα(hi)CD8α(-) DCs via a mechanism independent of donor alloantigens. These results demonstrated that CD47 expression on donor cells is essential to the success of tolerance induction by combined therapy with DST and CD40/CD154 blockade.

  20. Heat-killed and γ-irradiated Brucella strain RB51 stimulates enhanced dendritic cell activation, but not function compared with the virulent smooth strain 2308.

    PubMed

    Surendran, Naveen; Hiltbold, Elizabeth M; Heid, Bettina; Sriranganathan, Nammalwar; Boyle, Stephen M; Zimmerman, Kurt L; Witonsky, Sharon G

    2010-11-01

    Brucella spp. are Gram-negative, facultative intracellular bacterial pathogens that cause abortion in livestock and undulant fever in humans worldwide. Brucella abortus strain 2308 is a pathogenic strain that affects cattle and humans. Currently, there are no efficacious human vaccines available. However, B. abortus strain RB51, which is approved by the USDA, is a live-attenuated rough vaccine against bovine brucellosis. Live strain RB51 induces protection via CD4(+) and CD8(+) T-cell-mediated immunity. To generate an optimal T-cell response, strong innate immune responses by dendritic cells (DCs) are crucial. Because of safety concerns, the use of live vaccine strain RB51 in humans is limited. Therefore, in this study, we analyzed the differential ability of the same doses of live, heat-killed (HK) and γ-irradiated (IR) strain RB51 in inducing DC activation and function. Smooth strain 2308, live strain RB51 and lipopolysaccharide were used as controls. Studies using mouse bone marrow-derived DCs revealed that, irrespective of viability, strain RB51 induced greater DC activation than smooth strain 2308. Live strain RB51 induced significantly (P≤0.05) higher DC maturation than HK and IR strains, and only live strain RB51-infected DCs (at multiplicity of infection 1:100) induced significant (P≤0.05) tumor necrosis factor-α and interleukin-12 secretion.

  1. Expansion and Activation of CD103(+) Dendritic Cell Progenitors at the Tumor Site Enhances Tumor Responses to Therapeutic PD-L1 and BRAF Inhibition.

    PubMed

    Salmon, Hélène; Idoyaga, Juliana; Rahman, Adeeb; Leboeuf, Marylène; Remark, Romain; Jordan, Stefan; Casanova-Acebes, Maria; Khudoynazarova, Makhzuna; Agudo, Judith; Tung, Navpreet; Chakarov, Svetoslav; Rivera, Christina; Hogstad, Brandon; Bosenberg, Marcus; Hashimoto, Daigo; Gnjatic, Sacha; Bhardwaj, Nina; Palucka, Anna Karolina; Brown, Brian D; Brody, Joshua; Ginhoux, Florent; Merad, Miriam

    2016-04-19

    Large numbers of melanoma lesions develop resistance to targeted inhibition of mutant BRAF or fail to respond to checkpoint blockade. We explored whether modulation of intratumoral antigen-presenting cells (APCs) could increase responses to these therapies. Using mouse melanoma models, we found that CD103(+) dendritic cells (DCs) were the only APCs transporting intact antigens to the lymph nodes and priming tumor-specific CD8(+) T cells. CD103(+) DCs were required to promote anti-tumoral effects upon blockade of the checkpoint ligand PD-L1; however, PD-L1 inhibition only led to partial responses. Systemic administration of the growth factor FLT3L followed by intratumoral poly I:C injections expanded and activated CD103(+) DC progenitors in the tumor, enhancing responses to BRAF and PD-L1 blockade and protecting mice from tumor rechallenge. Thus, the paucity of activated CD103(+) DCs in tumors limits checkpoint-blockade efficacy and combined FLT3L and poly I:C therapy can enhance tumor responses to checkpoint and BRAF blockade.

  2. Calcium Signaling in Mitral Cell Dendrites of Olfactory Bulbs of Neonatal Rats and Mice during Olfactory Nerve Stimulation and Beta-Adrenoceptor Activation

    ERIC Educational Resources Information Center

    Yuan, Qi; Mutoh, Hiroki; Debarbieux, Franck; Knopfel, Thomas

    2004-01-01

    Synapses formed by the olfactory nerve (ON) provide the source of excitatory synaptic input onto mitral cells (MC) in the olfactory bulb. These synapses, which relay odor-specific inputs, are confined to the distally tufted single primary dendrites of MCs, the first stage of central olfactory processing. Beta-adrenergic modulation of electrical…

  3. Full restoration of Brucella-infected dendritic cell functionality through Vγ9Vδ2 T helper type 1 crosstalk.

    PubMed

    Ni, Ming; Martire, Delphine; Scotet, Emmanuel; Bonneville, Marc; Sanchez, Francoise; Lafont, Virginie

    2012-01-01

    Vγ9Vδ2 T cells play an important role in the immune response to infectious agents but the mechanisms contributing to this immune process remain to be better characterized. Following their activation, Vγ9Vδ2 T cells develop cytotoxic activity against infected cells, secrete large amounts of cytokines and influence the function of other effectors of immunity, notably cells playing a key role in the initiation of the adaptive immune response such as dendritic cells. Brucella infection dramatically impairs dendritic cell maturation and their capacity to present antigens to T cells. Herein, we investigated whether V T cells have the ability to restore the full functional capacities of Brucella-infected dendritic cells. Using an in vitro multicellular infection model, we showed that: 1/Brucella-infected dendritic cells activate Vγ9Vδ2 T cells through contact-dependent mechanisms, 2/activated Vγ9Vδ2 T cells induce full differentiation into IL-12 producing cells of Brucella-infected dendritic cells with functional antigen presentation activity. Furthermore, phosphoantigen-activated Vγ9Vδ2 T cells also play a role in triggering the maturation process of dendritic cells already infected for 24 h. This suggests that activated Vγ9Vδ2 T cells could be used to modulate the outcome of infectious diseases by promoting an adjuvant effect in dendritic cell-based cellular therapies.

  4. Dendritic cell-derived nitric oxide inhibits the differentiation of effector dendritic cells

    PubMed Central

    Wu, Tianshu; Lu, Geming; Hu, Yuan; Zhang, Hui; Xu, Feihong; Wei, Peter; Chen, Kang; Tang, Hua; Yeretssian, Garabet; Xiong, Huabao

    2016-01-01

    Dendritic cells (DCs) play a pivotal role in the development of effective immune defense while avoiding detrimental inflammation and autoimmunity by regulating the balance of adaptive immunity and immune tolerance. However, the mechanisms that govern the effector and regulatory functions of DCs are incompletely understood. Here, we show that DC-derived nitric oxide (NO) controls the balance of effector and regulatory DC differentiation. Mice deficient in the NO-producing enzyme inducible nitric oxide synthase (iNOS) harbored increased effector DCs that produced interleukin-12, tumor necrosis factor (TNF) and IL-6 but normal numbers of regulatory DCs that expressed IL-10 and programmed cell death-1 (PD-1). Furthermore, an iNOS-specific inhibitor selectively enhanced effector DC differentiation, mimicking the effect of iNOS deficiency in mice. Conversely, an NO donor significantly suppressed effector DC development. Furthermore, iNOS−/− DCs supported enhanced T cell activation and proliferation. Finally iNOS−/− mice infected with the enteric pathogen Citrobacter rodentium suffered more severe intestinal inflammation with concomitant expansion of effector DCs in colon and spleen. Collectively, our results demonstrate that DC-derived iNOS restrains effector DC development, and offer the basis of therapeutic targeting of iNOS in DCs to treat autoimmune and inflammatory diseases. PMID:27556858

  5. Dendrite

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Researchers have found that as melted metals and alloys (combinations of metals) solidify, they can form with different arrangements of atoms, called microstructures. These microstructures depend on the shape of the interface (boundary) between the melted metal and the solid crystal it is forming. There are generally three shapes that the interface can take: planar, or flat; cellular, which looks like the cells of a beehive; and dendritic, which resembles tiny fir trees. Convection at this interface can affect the interface shape and hide the other phenomena (physical events). To reduce the effects of convection, researchers conduct experiments that examine and control conditions at the interface in microgravity. Microgravity also helps in the study of alloys composed of two metals that do not mix. On Earth, the liquid mixtures of these alloys settle into different layers due to gravity. In microgravity, the liquid metals do not settle, and a solid more uniform mixture of both metals can be formed.

  6. Harnessing Human Dendritic Cell Subsets for Medicine

    PubMed Central

    Ueno, Hideki; Schmitt, Nathalie; Klechevsky, Eynav; Pedroza-Gonzales, Alexander; Matsui, Toshimichi; Zurawski, Gerard; Oh, SangKon; Fay, Joseph; Pascual, Virginia; Banchereau, Jacques; Palucka, Karolina

    2010-01-01

    Summary Immunity results from a complex interplay between the antigen-nonspecific innate immune system and the antigen-specific adaptive immune system. The cells and molecules of the innate system employ non-clonal recognition receptors including lectins, Toll-like receptors, NOD-like receptors and helicases. B and T lymphocytes of the adaptive immune system employ clonal receptors recognizing antigens or their derived peptides in a highly specific manner. An essential link between innate and adaptive immunity is provided by dendritic cells (DCs). DCs can induce such contrasting states as immunity and tolerance. The recent years have brought a wealth of information on the biology of DCs revealing the complexity of this cell system. Indeed, DC plasticity and subsets are prominent determinants of the type and quality of elicited immune responses. Here we summarize our recent studies aimed at a better understanding of the DC system to unravel the pathophysiology of human diseases and design novel human vaccines. PMID:20193020

  7. Pasteurella multocida toxin (PMT) activates RhoGTPases, induces actin polymerization and inhibits migration of human dendritic cells, but does not influence macropinocytosis.

    PubMed

    Blöcker, Dagmar; Berod, Luciana; Fluhr, Joachim W; Orth, Joachim; Idzko, Marco; Aktories, Klaus; Norgauer, Johannes

    2006-03-01

    Dendritic cells (DCs) are considered as one of the principal initiators of immune responses. In their immature state, they migrate into peripheral tissue in order to uptake antigen and to patrol for danger signals. Upon maturation, they acquire the ability to migrate to the lymph nodes and present the captured antigens to T cells in order to direct the development of specific immune responses. There is evidence that microbial compounds interfere with proper functions of DCs in order to block innate and specific immunity. Here we characterized the influence of Pasteurella multocida toxin (PMT) on monocyte-derived DCs. Using pull-down assays with recombinant rhotekin or p21-activated kinase, we demonstrated the activation of RhoGTPases by PMT in DCs. Moreover, PMT induced changes in DC morphology and actin polymerization, impaired chemotaxin-induced actin re-organization and inhibited their migration response. However, macropinocytosis was not influenced by PMT. In summary, these data indicate that PMT inhibits proper function of the motility machinery in DCs, which might limit the development of adaptive immune surveillance during infection with Pasteurella multocida.

  8. Disease activity in systemic lupus erythematosus is associated with an altered expression of low-affinity Fcγ receptors and costimulatory molecules on dendritic cells

    PubMed Central

    Carreño, Leandro J; Pacheco, Rodrigo; Gutierrez, Miguel A; Jacobelli, Sergio; Kalergis, Alexis M

    2009-01-01

    Dendritic cells (DCs) play a pivotal role in the interface between immunity and maintenance of peripheral tolerance. The capture of immunoglobulin G (IgG)-containing immune complexes (ICs) by low-affinity Fcγ receptors (FcγRs) expressed on DCs may influence the immunogenicity/tolerogenicity of these cells, depending on the activating/inhibitory potential of FcγRs. Because of the key role that low-affinity FcγRs play in determining the magnitude of the response in IC-driven inflammation, these receptors are likely to play a role in autoimmune diseases, such as systemic lupus erythematosus (SLE). To evaluate if an altered expression of costimulatory molecules and/or FcγRs could account for disease severity, we evaluated the expression of these molecules on immature and mature DCs derived from peripheral blood monocytes of SLE patients and healthy donors. Our results show an increased expression of the costimulatory molecules CD40 and CD86. Furthermore, the ratio of CD86/CD80 is higher in SLE patients compared with healthy donors. Conversely, while the expression of activating FcγRs was higher on DCs from SLE patients, expression of inhibitory FcγRs was lower, compared with DCs obtained from healthy donors. As a result, the activating to inhibitory FcγR ratio was significantly higher in DCs from SLE patients. The altered ratio of activating/inhibitory FcγRs on mature DCs showed a significant correlation with the activity of SLE, as determined by the SLE Disease Activity Index (SLEDAI) score. We postulate that the increased ratio of activating/inhibitory FcγRs expressed on DCs from SLE patients can contribute to the failure of peripheral tolerance in the IC-mediated phase of autoimmune pathogenesis. PMID:20067533

  9. High molecular weight components containing N-linked oligosaccharides of Ascaris suum extract inhibit the dendritic cells activation through DC-SIGN and MR.

    PubMed

    Favoretto, Bruna C; Casabuono, Adriana A C; Portes-Junior, José A; Jacysyn, Jacqueline F; Couto, Alicia S; Faquim-Mauro, Eliana L

    2017-04-09

    Helminths, as well as their secretory/excretory products, induce a tolerogenic immune microenvironment. High molecular weight components (PI) from Ascaris suum extract down-modulate the immune response against ovalbumin (OVA). The PI exerts direct effect on dendritic cells (DCs) independent of TLR 2, 4 and MyD88 molecule and, thus, decreases the T lymphocytes response. Here, we studied the glycoconjugates in PI and the role of C-type lectin receptors (CLRs), DC-SIGN and MR, in the modulation of DCs activity. Our data showed the presence of glycoconjugates with high mannose- and complex-type N-linked oligosaccharide chains and phosphorylcholine residues on PI. In addition, these N-linked glycoconjugates inhibited the DCs maturation induced by LPS. The binding and internalization of PI-Alexa were decreased on DCs previously incubated with mannan, anti-DC-SIGN and/or anti-MR antibodies. In agreement with this, the incubation of DCs with mannan, anti-DC-SIGN and/or anti-MR antibodies abolished the down-modulatory effect of PI on these cells. It was also observed that the blockage of CLRs, DC-SIGN and MR on DCs reverted the inhibitory effect of PI in in vitro T cells proliferation. Therefore, our data show the involvement of DC-SIGN and MR in the recognition and consequent modulatory effect of N-glycosylated components of PI on DCs.

  10. Kaposi's-sarcoma-associated-herpesvirus-activated dendritic cells promote HIV-1 trans-infection and suppress CD4{sup +} T cell proliferation

    SciTech Connect

    Liu, Wan; Qin, Yan; Bai, Lei; Lan, Ke; Wang, Jian-Hua

    2013-06-05

    Infection of Kaposi's sarcoma-associated herpesvirus (KSHV) is commonly occurred in AIDS patients. KSHV and HIV-1 act cooperatively in regulating infection with each other and in human carcinogenesis. Dendritic cells (DCs), as the pivotal cells in host immunity, may be modulated by both viruses, for immunoevasion and dissemination, therefore, the interaction between DCs and each virus has been a prior focus for pathogenesis elucidation. Here, we assessed the potential effect of KSHV on DC–HIV-1 interaction. We found that KSHV stimulation could promote maturation of monocyte-derived DCs (MDDCs) and impaired the ability of MDDCs to drive proliferation of resting CD4{sup +} T cells, demonstrating the immunosuppression induced by KSHV. More importantly, KSHV-stimulated MDDCs could capture more HIV-1 and efficiently transferred these infectious viruses to Hut/CCR5 T cell line. Our results reveal the novel modulation of DC-mediated HIV-1 dissemination by KSHV, and highlight the importance of studying DC–HIV-1 interaction to elucidate HIV/AIDS pathogenesis. - Highlights: ► KSHV impaired the ability of MDDCs to drive proliferation of resting CD4{sup +} T cells. ► KSHV stimulation matured MDDCs and enhanced HIV-1 endocytosis. ► KSHV stimulated MDDCs increased ICAM-1 expression and tighten contact with T cells. ► KSHV-stimulated MDDCs promoted HIV-1 trans-infection of CD4{sup +} T cells.

  11. Enterovirus-71 Virus-Like Particles Induce the Activation and Maturation of Human Monocyte-Derived Dendritic Cells through TLR4 Signaling

    PubMed Central

    Lin, Yu-Li; Hu, Yu-Chen; Liang, Cheng-Chao; Lin, Shih-Yeh; Liang, Yu-Chih; Yuan, Hui-Ping; Chiang, Bor-Luen

    2014-01-01

    Enterovirus 71 (EV71) causes seasonal epidemics of hand-foot-and-mouth disease and has a high mortality rate among young children. We recently demonstrated potent induction of the humoral and cell-mediated immune response in monkeys immunized with EV71 virus-like particles (VLPs), with a morphology resembling that of infectious EV71 virions but not containing a viral genome, which could potentially be safe as a vaccine for EV71. To elucidate the mechanisms through which EV71 VLPs induce cell-mediated immunity, we studied the immunomodulatory effects of EV71 VLPs on human monocyte-derived dendritic cells (DCs), which bind to and incorporate EV71 VLPs. DC treatment with EV71 VLPs enhanced the expression of CD80, CD86, CD83, CD40, CD54, and HLA-DR on the cell surface; increased the production of interleukin (IL)-12 p40, IL-12 p70, and IL-10 by DCs; and suppressed the capacity of DCs for endocytosis. Treatment with EV71 VLPs also enhanced the ability of DCs to stimulate naïve T cells and induced secretion of interferon (IFN)-γ by T cells and Th1 cell responses. Neutralization with antibodies against Toll-like receptor (TLR) 4 suppressed the capacity of EV71 VLPs to induce the production of IL-12 p40, IL-12 p70, and IL-10 by DCs and inhibited EV71 VLPs binding to DCs. Our study findings clarified the important role for TLR4 signaling in DCs in response to EV71 VLPs and showed that EV71 VLPs induced inhibitor of kappaB alpha (IκBα) degradation and nuclear factor of kappaB (NF-κB) activation. PMID:25360749

  12. Enterovirus-71 virus-like particles induce the activation and maturation of human monocyte-derived dendritic cells through TLR4 signaling.

    PubMed

    Lin, Yu-Li; Hu, Yu-Chen; Liang, Cheng-Chao; Lin, Shih-Yeh; Liang, Yu-Chih; Yuan, Hui-Ping; Chiang, Bor-Luen

    2014-01-01

    Enterovirus 71 (EV71) causes seasonal epidemics of hand-foot-and-mouth disease and has a high mortality rate among young children. We recently demonstrated potent induction of the humoral and cell-mediated immune response in monkeys immunized with EV71 virus-like particles (VLPs), with a morphology resembling that of infectious EV71 virions but not containing a viral genome, which could potentially be safe as a vaccine for EV71. To elucidate the mechanisms through which EV71 VLPs induce cell-mediated immunity, we studied the immunomodulatory effects of EV71 VLPs on human monocyte-derived dendritic cells (DCs), which bind to and incorporate EV71 VLPs. DC treatment with EV71 VLPs enhanced the expression of CD80, CD86, CD83, CD40, CD54, and HLA-DR on the cell surface; increased the production of interleukin (IL)-12 p40, IL-12 p70, and IL-10 by DCs; and suppressed the capacity of DCs for endocytosis. Treatment with EV71 VLPs also enhanced the ability of DCs to stimulate naïve T cells and induced secretion of interferon (IFN)-γ by T cells and Th1 cell responses. Neutralization with antibodies against Toll-like receptor (TLR) 4 suppressed the capacity of EV71 VLPs to induce the production of IL-12 p40, IL-12 p70, and IL-10 by DCs and inhibited EV71 VLPs binding to DCs. Our study findings clarified the important role for TLR4 signaling in DCs in response to EV71 VLPs and showed that EV71 VLPs induced inhibitor of kappaB alpha (IκBα) degradation and nuclear factor of kappaB (NF-κB) activation.

  13. Active subthreshold dendritic conductances shape the local field potential

    PubMed Central

    Ness, Torbjørn V.; Remme, Michiel W. H.

    2016-01-01

    Key points The local field potential (LFP), the low‐frequency part of extracellular potentials recorded in neural tissue, is often used for probing neural circuit activity. Interpreting the LFP signal is difficult, however.While the cortical LFP is thought mainly to reflect synaptic inputs onto pyramidal neurons, little is known about the role of the various subthreshold active conductances in shaping the LFP.By means of biophysical modelling we obtain a comprehensive qualitative understanding of how the LFP generated by a single pyramidal neuron depends on the type and spatial distribution of active subthreshold currents.For pyramidal neurons, the h‐type channels probably play a key role and can cause a distinct resonance in the LFP power spectrum.Our results show that the LFP signal can give information about the active properties of neurons and imply that preferred frequencies in the LFP can result from those cellular properties instead of, for example, network dynamics. Abstract The main contribution to the local field potential (LFP) is thought to stem from synaptic input to neurons and the ensuing subthreshold dendritic processing. The role of active dendritic conductances in shaping the LFP has received little attention, even though such ion channels are known to affect the subthreshold neuron dynamics. Here we used a modelling approach to investigate the effects of subthreshold dendritic conductances on the LFP. Using a biophysically detailed, experimentally constrained model of a cortical pyramidal neuron, we identified conditions under which subthreshold active conductances are a major factor in shaping the LFP. We found that, in particular, the hyperpolarization‐activated inward current, I h, can have a sizable effect and cause a resonance in the LFP power spectral density. To get a general, qualitative understanding of how any subthreshold active dendritic conductance and its cellular distribution can affect the LFP, we next performed a systematic

  14. The microRNA bantam functions in epithelial cells to regulate scaling growth of dendrite arbors in drosophila sensory neurons.

    PubMed

    Parrish, Jay Z; Xu, Peizhang; Kim, Charles C; Jan, Lily Yeh; Jan, Yuh Nung

    2009-09-24

    In addition to establishing dendritic coverage of the receptive field, neurons need to adjust their dendritic arbors to match changes of the receptive field. Here, we show that dendrite arborization (da) sensory neurons establish dendritic coverage of the body wall early in Drosophila larval development and then grow in precise proportion to their substrate, the underlying body wall epithelium, as the larva more than triples in length. This phenomenon, referred to as scaling growth of dendrites, requires the function of the microRNA (miRNA) bantam (ban) in the epithelial cells rather than the da neurons themselves. We further show that ban in epithelial cells dampens Akt kinase activity in adjacent neurons to influence dendrite growth. This signaling between epithelial cells and neurons receiving sensory input from the body wall synchronizes their growth to ensure proper dendritic coverage of the receptive field.

  15. Expression of the Receptor Tyrosine Kinase EphB2 on Dendritic Cells Is Modulated by Toll-Like Receptor Ligation but Is Not Required for T Cell Activation.

    PubMed

    Mimche, Patrice N; Brady, Lauren M; Keeton, Shirley; Fenne, David S J; King, Thayer P; Quicke, Kendra M; Hudson, Lauren E; Lamb, Tracey J

    2015-01-01

    The Eph receptor tyrosine kinases interact with their ephrin ligands on adjacent cells to facilitate contact-dependent cell communication. Ephrin B ligands are expressed on T cells and have been suggested to act as co-stimulatory molecules during T cell activation. There are no detailed reports of the expression and modulation of EphB receptors on dendritic cells, the main antigen presenting cells that interact with T cells. Here we show that mouse splenic dendritic cells (DC) and bone-marrow derived DCs (BMDC) express EphB2, a member of the EphB family. EphB2 expression is modulated by ligation of TLR4 and TLR9 and also by interaction with ephrin B ligands. Co-localization of EphB2 with MHC-II is also consistent with a potential role in T cell activation. However, BMDCs derived from EphB2 deficient mice were able to present antigen in the context of MHC-II and produce T cell activating cytokines to the same extent as intact DCs. Collectively our data suggest that EphB2 may contribute to DC responses, but that EphB2 is not required for T cell activation. This result may have arisen because DCs express other members of the EphB receptor family, EphB3, EphB4 and EphB6, all of which can interact with ephrin B ligands, or because EphB2 may be playing a role in another aspect of DC biology such as migration.

  16. Expression of the Receptor Tyrosine Kinase EphB2 on Dendritic Cells Is Modulated by Toll-Like Receptor Ligation but Is Not Required for T Cell Activation

    PubMed Central

    Mimche, Patrice N.; Brady, Lauren M.; Keeton, Shirley; Fenne, David S. J.; King, Thayer P.; Quicke, Kendra M.; Hudson, Lauren E.; Lamb, Tracey J.

    2015-01-01

    The Eph receptor tyrosine kinases interact with their ephrin ligands on adjacent cells to facilitate contact-dependent cell communication. Ephrin B ligands are expressed on T cells and have been suggested to act as co-stimulatory molecules during T cell activation. There are no detailed reports of the expression and modulation of EphB receptors on dendritic cells, the main antigen presenting cells that interact with T cells. Here we show that mouse splenic dendritic cells (DC) and bone-marrow derived DCs (BMDC) express EphB2, a member of the EphB family. EphB2 expression is modulated by ligation of TLR4 and TLR9 and also by interaction with ephrin B ligands. Co-localization of EphB2 with MHC-II is also consistent with a potential role in T cell activation. However, BMDCs derived from EphB2 deficient mice were able to present antigen in the context of MHC-II and produce T cell activating cytokines to the same extent as intact DCs. Collectively our data suggest that EphB2 may contribute to DC responses, but that EphB2 is not required for T cell activation. This result may have arisen because DCs express other members of the EphB receptor family, EphB3, EphB4 and EphB6, all of which can interact with ephrin B ligands, or because EphB2 may be playing a role in another aspect of DC biology such as migration. PMID:26407069

  17. LAB/NTAL facilitates fungal/PAMP-induced IL-12 and IFN-γ production by repressing β-catenin activation in dendritic cells.

    PubMed

    Orr, Selinda J; Burg, Ashley R; Chan, Tim; Quigley, Laura; Jones, Gareth W; Ford, Jill W; Hodge, Deborah; Razzook, Catherine; Sarhan, Joseph; Jones, Yava L; Whittaker, Gillian C; Boelte, Kimberly C; Lyakh, Lyudmila; Cardone, Marco; O'Connor, Geraldine M; Tan, Cuiyan; Li, Hongchuan; Anderson, Stephen K; Jones, Simon A; Zhang, Weiguo; Taylor, Philip R; Trinchieri, Giorgio; McVicar, Daniel W

    2013-05-01

    Fungal pathogens elicit cytokine responses downstream of immunoreceptor tyrosine-based activation motif (ITAM)-coupled or hemiITAM-containing receptors and TLRs. The Linker for Activation of B cells/Non-T cell Activating Linker (LAB/NTAL) encoded by Lat2, is a known regulator of ITAM-coupled receptors and TLR-associated cytokine responses. Here we demonstrate that LAB is involved in anti-fungal immunity. We show that Lat2-/- mice are more susceptible to C. albicans infection than wild type (WT) mice. Dendritic cells (DCs) express LAB and we show that it is basally phosphorylated by the growth factor M-CSF or following engagement of Dectin-2, but not Dectin-1. Our data revealed a unique mechanism whereby LAB controls basal and fungal/pathogen-associated molecular patterns (PAMP)-induced nuclear β-catenin levels. This in turn is important for controlling fungal/PAMP-induced cytokine production in DCs. C. albicans- and LPS-induced IL-12 and IL-23 production was blunted in Lat2-/- DCs. Accordingly, Lat2-/- DCs directed reduced Th1 polarization in vitro and Lat2-/- mice displayed reduced Natural Killer (NK) and T cell-mediated IFN-γ production in vivo/ex vivo. Thus our data define a novel link between LAB and β-catenin nuclear accumulation in DCs that facilitates IFN-γ responses during anti-fungal immunity. In addition, these findings are likely to be relevant to other infectious diseases that require IL-12 family cytokines and an IFN-γ response for pathogen clearance.

  18. Differential partial activation phenotype and production of tumour necrosis factor-α by conventional dendritic cells in response to lipopolysaccharide in HIV+ viraemic subjects and HIV+ controllers.

    PubMed

    Camacho-Sandoval, R; Del Río Estrada, P M; Rivero-Arrieta, A; Reyes-Terán, G; Bonifaz, L C

    2014-12-01

    HIV(+) subjects are reported to have increased soluble CD14 (sCD14) in plasma, an indicator of microbial translocation. We evaluated if microbial translocation has a differential impact on the activation and function of conventional dendritic cells (cDC) from viraemic HIV(+) subjects and HIV(+) controllers (CTs). The HIV(+) subjects were classified into two groups according to their plasma viral load (pVL): CT and viraemic. Subjects without HIV were included as controls (HIV(-) ). The frequencies and phenotypes of cDC from these subjects were evaluated by multi-parameter flow cytometry. In addition, peripheral blood mononuclear cells (PBMCs) were stimulated with lipopolysaccharide (LPS) or single-stranded RNA40 (ssRNA40), the phenotype of the cDC and the intracellular production of tumour necrosis factor (TNF)-α by the cDC were evaluated by flow cytometry. We observed a partial activation phenotype for the cDC in the viraemic subjects and CTs ex vivo and after LPS activation, which showed differences in the expression of CD40 and CD86. Furthermore, in response to LPS the cDC from the viraemic subjects produced more TNF-α compared to the cDC from CTs. Interestingly, the percentage of TNF-α(+) cDC was found to be correlated positively with the pVL. The partial activation of cDC and the over-production of TNF-α in response to LPS in viraemic HIV(+) subjects might be related to the increased chronic activation observed in these subjects. In contrast, cDC from CTs seem to have a regulated response to LPS, indicating that they respond differently to chronic immune activation. These results may have implications in the development of HIV therapies and vaccines using DC.

  19. Differential partial activation phenotype and production of tumour necrosis factor-α by conventional dendritic cells in response to lipopolysaccharide in HIV+ viraemic subjects and HIV+ controllers

    PubMed Central

    Camacho-Sandoval, R; Del Río Estrada, P M; Rivero-Arrieta, A; Reyes-Terán, G; Bonifaz, L C

    2014-01-01

    HIV+ subjects are reported to have increased soluble CD14 (sCD14) in plasma, an indicator of microbial translocation. We evaluated if microbial translocation has a differential impact on the activation and function of conventional dendritic cells (cDC) from viraemic HIV+ subjects and HIV+ controllers (CTs). The HIV+ subjects were classified into two groups according to their plasma viral load (pVL): CT and viraemic. Subjects without HIV were included as controls (HIV–). The frequencies and phenotypes of cDC from these subjects were evaluated by multi-parameter flow cytometry. In addition, peripheral blood mononuclear cells (PBMCs) were stimulated with lipopolysaccharide (LPS) or single-stranded RNA40 (ssRNA40), the phenotype of the cDC and the intracellular production of tumour necrosis factor (TNF)-α by the cDC were evaluated by flow cytometry. We observed a partial activation phenotype for the cDC in the viraemic subjects and CTs ex vivo and after LPS activation, which showed differences in the expression of CD40 and CD86. Furthermore, in response to LPS the cDC from the viraemic subjects produced more TNF-α compared to the cDC from CTs. Interestingly, the percentage of TNF-α+ cDC was found to be correlated positively with the pVL. The partial activation of cDC and the over-production of TNF-α in response to LPS in viraemic HIV+ subjects might be related to the increased chronic activation observed in these subjects. In contrast, cDC from CTs seem to have a regulated response to LPS, indicating that they respond differently to chronic immune activation. These results may have implications in the development of HIV therapies and vaccines using DC. PMID:25130456

  20. Carthamus tinctorius Enhances the Antitumor Activity of Dendritic Cell Vaccines via Polarization toward Th1 Cytokines and Increase of Cytotoxic T Lymphocytes

    PubMed Central

    Chang, Jia-Ming; Hung, Le-Mei; Chyan, Yau-Jan; Cheng, Chun-Ming; Wu, Rey-Yuh

    2011-01-01

    Carthamus tinctorius (CT), also named safflower, is a traditional Chinese medicine widely used to improve blood circulation. CT also has been studied for its antitumor activity in certain cancers. To investigate the effects of CT on the dendritic cell (DC)-based vaccine in cancer treatment, cytokine secretion of mouse splenic T lymphocytes and the maturation of DCs in response to CT were analyzed. To assess the antitumor activity of CT extract on mouse CD117+ (c-kit)-derived DCs pulsed with JC mammal tumor antigens, the JC tumor was challenged by the CT-treated DC vaccine in vivo. CT stimulated IFN-γ and IL-10 secretion of splenic T lymphocytes and enhanced the maturation of DCs by enhancing immunological molecule expression. When DC vaccine was pulsed with tumor antigens along with CT extract, the levels of TNF-α and IL-1β were dramatically increased with a dose-dependent response and more immunologic and co-stimulatory molecules were expressed on the DC surface. In addition, CT-treated tumor lysate-pulsed DC vaccine reduced the tumor weight in tumor-bearing mice by 15.3% more than tumor lysate-pulsed DC vaccine without CT treatment. CT polarized cytokine secretion toward the Th1 pathway and also increased the population of cytotoxic T lymphocytes ex vivo. In conclusion, CT activates DCs might promote the recognition of antigens and facilitate antigen presentation to Th1 immune responses. PMID:19001481

  1. Dendritic cell control of tolerogenic responses

    PubMed Central

    Manicassamy, Santhakumar; Pulendran, Bali

    2011-01-01

    Summary One of the most fundamental problems in immunology is the seemingly schizophrenic ability of the immune system to launch robust immunity against pathogens, while acquiring and maintaining a state of tolerance to the body’s own tissues and the trillions of commensal microorganisms and food antigens that confront it every day. A fundamental role for the innate immune system, particularly dendritic cells (DCs), in orchestrating immunological tolerance has been appreciated, but emerging studies have highlighted the nature of the innate receptors and the signaling pathways that program DCs to a tolerogenic state. Furthermore, several studies have emphasized the major role played by cellular interactions, and the microenvironment in programming tolerogenic DCs. Here we review these studies and suggest that the innate control of tolerogenic responses can be viewed as different hierarchies of organization, in which DCs, their innate receptors and signaling networks, and their interactions with other cells and local microenvironments represent different levels of the hierarchy. PMID:21488899

  2. A life stage of particle-laden rat dendritic cells in vivo: their terminal division, active phagocytosis, and translocation from the liver to the draining lymph.

    PubMed

    Matsuno, K; Ezaki, T; Kudo, S; Uehara, Y

    1996-04-01

    Initiation of an adoptive immune response against pathogenic organisms, such as bacteria and fungi, may involve phagocytic activity of dendritic cells (DC) or their immature precursors as a prelude to antigen processing and presentation. After intravenous injection of rats with particulate matter, particle-laden cells were detected in the peripheral hepatic lymph. Since it has been known there is a constant efflux of DC from nonlymphoid organs into the draining peripheral lymph, we examined whether these particle-laden cells belonged to the DC or macrophage lineage. The majority of particle-laden cells in lymph showed immature monocyte-like cytology, and the amount of ingested particles was small relative to typical macrophages. We identified these particle-laden cells as DC based on a number of established criteria: (a) they had a phenotype characteristic of rat DC, that is, major histocompatibility complex class Ihigh+ and IIhigh+, intercellular adhesion molecule 1+ and 80% positive with the rat DC-specific mAb OX62; (b) they showed strong stimulating capacity in primary allogeneic mixed leukocyte reaction; (c) in vitro, they had little phagocytic activity; and (d) the kinetics of translocation was similar to that of lymph DC in that they migrated to the thymus-dependent area of the regional nodes. Furthermore, bromodeoxyuridine feeding studies revealed that most of the particle-laden DC were recently produced by the terminal division of precursor cells, at least 45% of them being <5.5 d old. The particle-laden DC, defined as OX62+ latex-laden cells, were first found in the sinusoidal area of the liver, in the liver perfusate, and in spleen cell suspensions, suggesting that the site of particle capture was mainly in the blood marginating pool. It is concluded that the particle-laden cells in the hepatic lymph are recently produced immature DC that manifest a temporary phagocytic activity for intravascular particles during or after the terminal division and that

  3. Follicular dendritic cells in health and disease

    PubMed Central

    El Shikh, Mohey Eldin M.; Pitzalis, Costantino

    2012-01-01

    Follicular dendritic cells (FDCs) are unique immune cells that contribute to the regulation of humoral immune responses. These cells are located in the B-cell follicles of secondary lymphoid tissues where they trap and retain antigens (Ags) in the form of highly immunogenic immune complexes (ICs) consisting of Ag plus specific antibody (Ab) and/or complement proteins. FDCs multimerize Ags and present them polyvalently to B-cells in periodically arranged arrays that extensively crosslink the B-cell receptors for Ag (BCRs). FDC-FcγRIIB mediates IC periodicity, and FDC-Ag presentation combined with other soluble and membrane bound signals contributed by FDCs, like FDC-BAFF, -IL-6, and -C4bBP, are essential for the induction of the germinal center (GC) reaction, the maintenance of serological memory, and the remarkable ability of FDC-Ags to induce specific Ab responses in the absence of cognate T-cell help. On the other hand, FDCs play a negative role in several disease conditions including chronic inflammatory diseases, autoimmune diseases, HIV/AIDS, prion diseases, and follicular lymphomas. Compared to other accessory immune cells, FDCs have received little attention, and their functions have not been fully elucidated. This review gives an overview of FDC structure, and recapitulates our current knowledge on the immunoregulatory functions of FDCs in health and disease. A better understanding of FDCs should permit better regulation of Ab responses to suit the therapeutic manipulation of regulated and dysregulated immune responses. PMID:23049531

  4. CD8+ immunoregulatory cells in the graft-versus-host reaction: CD8 T cells activate dendritic cells to secrete interleukin-12/interleukin-18 and induce T helper 1 autoantibody

    PubMed Central

    Noble, Alistair; Leggat, Jamie A; Inderberg, Else M

    2003-01-01

    Initiation of cell-mediated immunity or autoimmunity requires secretion of interleukin (IL)-12 from dendritic cells (DC), which drives the generation of T helper 1 (Th1) effector cells in synergy with IL-18. Induction of IL-12 can be triggered by microbial stimuli but also requires signals from activated T cells. We investigated interactions between alloreactive CD4 and CD8 T cells in mixed lymphocyte reactions (MLR) in vitro and in the graft-versus-host reaction (GVHR) in vivo. In a parent-into-F1 model of GVHR, donor CD8 cells were found to suppress the hyper-immunoglobulin E (IgE) syndrome, anti-DNA immunoglobulin G1 (IgG1) autoantibodies and donor CD4-cell expansion, but were essential for Th1-dependent immunoglobulin G2a (IgG2a) autoantibody production and release of serum IL-12 p40. In vitro, addition of alloreactive CD8 cells to CD4 cells and mature DC enhanced Th1 development. CD4 and CD8 T cells induced IL-18 from DC and primed for IL-12 p70 secretion via interferon-γ (IFN-γ) or tumour necrosis factor-α (TNF-α). However CD8 T cells, but not CD4 cells, released IFN-γ/TNF-α after primary stimulation. The data suggest that rapid release of inflammatory cytokines from central memory-type CD8 cells early in immunity is critical for induction of Th1 cells via DC activation and IL-12 production. This pathway could provide a means for amplification of cell-mediated autoimmunity in the absence of microbial stimuli. PMID:12871213

  5. Clusters of synaptic inputs on dendrites of layer 5 pyramidal cells in mouse visual cortex

    PubMed Central

    Gökçe, Onur; Bonhoeffer, Tobias; Scheuss, Volker

    2016-01-01

    The spatial organization of synaptic inputs on the dendritic tree of cortical neurons plays a major role for dendritic integration and neural computations, yet, remarkably little is known about it. We mapped the spatial organization of glutamatergic synapses between layer 5 pyramidal cells by combining optogenetics and 2-photon calcium imaging in mouse neocortical slices. To mathematically characterize the organization of inputs we developed an approach based on combinatorial analysis of the likelihoods of specific synapse arrangements. We found that the synapses of intralaminar inputs form clusters on the basal dendrites of layer 5 pyramidal cells. These clusters contain 4 to 14 synapses within ≤30 µm of dendrite. According to the spatiotemporal characteristics of synaptic summation, these numbers suggest that there will be non-linear dendritic integration of synaptic inputs during synchronous activation. DOI: http://dx.doi.org/10.7554/eLife.09222.001 PMID:27431612

  6. Antigen-Pulsed CpG-ODN-Activated Dendritic Cells Induce Host-Protective Immune Response by Regulating the T Regulatory Cell Functioning in Leishmania donovani-Infected Mice: Critical Role of CXCL10

    PubMed Central

    Majumder, Saikat; Bhattacharjee, Amrita; Paul Chowdhury, Bidisha; Bhattacharyya Majumdar, Suchandra; Majumdar, Subrata

    2014-01-01

    Visceral leishmaniasis (VL), caused by Leishmania donovani, is a systemic infection of reticulo-endothelial system. There is currently no protective vaccine against VL and chemotherapy is increasingly limited due to appearance of drug resistance to first line drugs such as antimonials and amphotericin B. In the present study, by using a murine model of leishmaniasis we evaluated the function played by soluble leishmanial antigen (SLA)-pulsed CpG-ODN-stimulated dendritic cells (SLA–CpG–DCs) in restricting the intracellular parasitic growth. We establish that a single dose of SLA–CpG–DC vaccination is sufficient in rendering complete protection against L. donovani infection. In probing the possible mechanism, we observe that SLA–CpG–DCs vaccination results in the significant decrease in Foxp3+GITR+CTLA4+CD4+CD25+ regulatory T cells (Treg) cell population in Leishmania-infected mice. Vaccination with these antigen-stimulated dendritic cells results in the decrease in the secretion of TGF-β by these Treg cells by possible regulation of the SMAD signaling. Moreover, we demonstrate that a CXC chemokine, IFN-γ-inducible protein 10 (IP-10; CXCL10), has a direct role in the regulation of CD4+CD25+ Treg cells in SLA–CpG–DC-vaccinated parasitized mice as Treg cells isolated from IP-10-depleted vaccinated mice showed significantly increased TGF-β production and suppressive activity. PMID:24926293

  7. Mycobacterium-Infected Dendritic Cells Disseminate Granulomatous Inflammation

    PubMed Central

    Harding, Jeffrey S.; Rayasam, Aditya; Schreiber, Heidi A.; Fabry, Zsuzsanna; Sandor, Matyas

    2015-01-01

    The disappearance and reformation of granulomas during tuberculosis has been described using PET/CT/X-ray in both human clinical settings and animal models, but the mechanisms of granuloma reformation during active disease remains unclear. Granulomas can recruit inflammatory dendritic cells (iDCs) that can regulate local T-cell responses and can carry bacteria into the lymph nodes, which is crucial for generating systemic T-cell responses against mycobacteria. Here, we report that a subset of mycobacterium-infected iDCs are associated with bacteria-specific T-cells in infected tissue, outside the granuloma, and that this results in the formation of new and/or larger multi-focal lesions. Mycobacterium-infected iDCs express less CCR7 and migrate less efficiently compared to the non-infected iDCs, which may support T-cell capture in granulomatous tissue. Capture may reduce antigen availability in the lymph node, thereby decreasing systemic priming, resulting in a possible regulatory loop between systemic T-cell responses and granuloma reformation. T-cell/infected iDCs clusters outside the granuloma can be detected during the acute and chronic phase of BCG and Mtb infection. Our studies suggest a direct role for inflammatory dendritic cells in the dissemination of granulomatous inflammation. PMID:26515292

  8. Mycobacterium-Infected Dendritic Cells Disseminate Granulomatous Inflammation.

    PubMed

    Harding, Jeffrey S; Rayasam, Aditya; Schreiber, Heidi A; Fabry, Zsuzsanna; Sandor, Matyas

    2015-10-30

    The disappearance and reformation of granulomas during tuberculosis has been described using PET/CT/X-ray in both human clinical settings and animal models, but the mechanisms of granuloma reformation during active disease remains unclear. Granulomas can recruit inflammatory dendritic cells (iDCs) that can regulate local T-cell responses and can carry bacteria into the lymph nodes, which is crucial for generating systemic T-cell responses against mycobacteria. Here, we report that a subset of mycobacterium-infected iDCs are associated with bacteria-specific T-cells in infected tissue, outside the granuloma, and that this results in the formation of new and/or larger multi-focal lesions. Mycobacterium-infected iDCs express less CCR7 and migrate less efficiently compared to the non-infected iDCs, which may support T-cell capture in granulomatous tissue. Capture may reduce antigen availability in the lymph node, thereby decreasing systemic priming, resulting in a possible regulatory loop between systemic T-cell responses and granuloma reformation. T-cell/infected iDCs clusters outside the granuloma can be detected during the acute and chronic phase of BCG and Mtb infection. Our studies suggest a direct role for inflammatory dendritic cells in the dissemination of granulomatous inflammation.

  9. Maturation-Resistant Dendritic Cells Ameliorate Experimental Autoimmune Uveoretinitis

    PubMed Central

    Oh, Keunhee; Kim, Yon Su

    2011-01-01

    Background Endogenous uveitis is a chronic inflammatory eye disease of human, which frequently leads to blindness. Experimental autoimmune uveoretinitis (EAU) is an animal disease model of human endogenous uveitis and can be induced in susceptible animals by immunization with retinal antigens. EAU resembles the key immunological characteristics of human disease in that both are CD4+ T-cell mediated diseases. Dendritic cells (DCs) are specialized antigen-presenting cells that are uniquely capable of activating naïve T cells. Regulation of immune responses through modulation of DCs has thus been tried extensively. Recently our group reported that donor strain-derived immature DC pretreatment successfully controlled the adverse immune response during allogeneic transplantation. Methods EAU was induced by immunization with human interphotoreceptor retinoid-binding protein (IRBP) peptide1-20. Dendritic cells were differentiated from bone marrow in the presence of recombinant GM-CSF. Results In this study, we used paraformaldehyde-fixed bone marrow-derived DCs to maintain them in an immature state. Pretreatment with fixed immature DCs, but not fixed mature DCs, ameliorated the disease progression of EAU by inhibiting uveitogenic CD4+ T cell activation and differentiation. Conclusion Application of iBMDC prepared according to the protocol of this study would provide an important treatment modality for the autoimmune diseases and transplantation rejection. PMID:22346781

  10. Altered heme-mediated modulation of dendritic cell function in sickle cell alloimmunization

    PubMed Central

    Godefroy, Emmanuelle; Liu, Yunfeng; Shi, Patricia; Mitchell, W. Beau; Cohen, Devin; Chou, Stella T.; Manwani, Deepa; Yazdanbakhsh, Karina

    2016-01-01

    Transfusions are the main treatment for patients with sickle cell disease. However, alloimmunization remains a major life-threatening complication for these patients, but the mechanism underlying pathogenesis of alloimmunization is not known. Given the chronic hemolytic state characteristic of sickle cell disease, resulting in release of free heme and activation of inflammatory cascades, we tested the hypothesis that anti-inflammatory response to heme is compromised in alloimmunized sickle patients, increasing their risk of alloimmunization. Heme-exposed monocyte-derived dendritic cells from both non-alloimmunized sickle patients and healthy donors inhibited priming of pro-inflammatory CD4+ type 1 T cells, and exhibited significantly reduced levels of the maturation marker CD83. In contrast, in alloimmunized patients, heme did not reverse priming of pro-inflammatory CD4+ cells by monocyte-derived dendritic cells or their maturation. Furthermore, heme dampened NF-κB activation in non-alloimmunized, but not in alloimmunized monocyte-derived dendritic cells. Heme-mediated CD83 inhibition depended on Toll-like receptor 4 but not heme oxygenase 1. These data suggest that extracellular heme limits CD83 expression on dendritic cells in non-alloimmunized sickle patients through a Toll-like receptor 4-mediated pathway, involving NF-κB, resulting in dampening of pro-inflammatory responses, but that in alloimmunized patients this pathway is defective. This opens up the possibility of developing new therapeutic strategies to prevent sickle cell alloimmunization. PMID:27229712

  11. 4,4′-diaponeurosporene, a C30 carotenoid, effectively activates dendritic cells via CD36 and NF-κB signaling in a ROS independent manner

    PubMed Central

    Liu, Haofei; Xu, Wenwen; Chang, Xiaojing; Qin, Tao; Yin, Yinyan; Yang, Qian

    2016-01-01

    Carotenoids could be divided into C30 carotenoids and C40 carotenoids. The immune functions of C40 carotenoids had been extensively researched, while those of C30 carotenoids still remain unclear. In this study, the immune functions of a biosynthetic C30 carotenoid, 4,4′-diaponeurosporene (Dia), were identified on dendritic cells (DCs). DCs treated with 1 μM Dia for 24 h showed morphologic and phenotypic characteristics of mature state and had an increased production of IL-6, IL-10, IL-12p70 and TNFα, while β-carotene had a suppressive effect on DCs maturation. Moreover, Dia promoted antigen uptake of DCs in vitro and increased the quantity of antigen loaded DCs in mesenteric lymph nodes (MLN). Dia-treated DCs also had an enhanced ability to stimulate T cell proliferation and Th1 polarization. Further researches showed that Dia activated DCs via CD36 as well as ERK, JNK, and NF-κB signals in a reactive oxygen species (ROS) independent manner. PMID:27276712

  12. Disruption of Early Tumor Necrosis Factor Alpha Signaling Prevents Classical Activation of Dendritic Cells in Lung-Associated Lymph Nodes and Development of Protective Immunity against Cryptococcal Infection

    PubMed Central

    Xu, Jintao; Eastman, Alison J.; Flaczyk, Adam; Neal, Lori M.; Zhao, Guolei; Carolan, Jacob; Malachowski, Antoni N.; Stolberg, Valerie R.; Yosri, Mohammed; Chensue, Stephen W.; Curtis, Jeffrey L.; Osterholzer, John J.

    2016-01-01

    ABSTRACT Anti-tumor necrosis factor alpha (anti-TNF-α) therapies have been increasingly used to treat inflammatory diseases and are associated with increased risk of invasive fungal infections, including Cryptococcus neoformans infection. Using a mouse model of cryptococcal infection, we investigated the mechanism by which disruption of early TNF-α signaling results in the development of nonprotective immunity against C. neoformans. We found that transient depletion of TNF-α inhibited pulmonary fungal clearance and enhanced extrapulmonary dissemination of C. neoformans during the adaptive phase of the immune response. Higher fungal burdens in TNF-α-depleted mice were accompanied by markedly impaired Th1 and Th17 responses in the infected lungs. Furthermore, early TNF-α depletion also resulted in disrupted transcriptional initiation of the Th17 polarization program and subsequent upregulation of Th1 genes in CD4+ T cells in the lung-associated lymph nodes (LALN) of C. neoformans-infected mice. These defects in LALN T cell responses were preceded by a dramatic shift from a classical toward an alternative activation of dendritic cells (DC) in the LALN of TNF-α-depleted mice. Taken together, our results indicate that early TNF-α signaling is required for optimal DC activation, and the initial Th17 response followed by Th1 transcriptional prepolarization of T cells in the LALN, which further drives the development of protective immunity against cryptococcal infection in the lungs. Thus, administration of anti-TNF-α may introduce a particularly greater risk for newly acquired fungal infections that require generation of protective Th1/Th17 responses for their containment and clearance. PMID:27406560

  13. Dendritic integration in pyramidal neurons during network activity and disease.

    PubMed

    Palmer, Lucy M

    2014-04-01

    Neurons have intricate dendritic morphologies which come in an array of shapes and sizes. Not only do they give neurons their unique appearance, but dendrites also endow neurons with the ability to receive and transform synaptic inputs. We now have a wealth of information about the functioning of dendrites which suggests that the integration of synaptic inputs is highly dependent on both dendritic properties and neuronal input patterns. It has been shown that dendrites can perform non-linear processing, actively transforming synaptic input into Na(+) spikes, Ca(2+) plateau spikes and NMDA spikes. These membrane non-linearities can have a large impact on the neuronal output and have been shown to be regulated by numerous factors including synaptic inhibition. Many neuropathological diseases involve changes in how dendrites receive and package synaptic input by altering dendritic spine characteristics, ion channel expression and the inhibitory control of dendrites. This review focuses on the role of dendrites in integrating and transforming input and what goes wrong in the case of neuropathological diseases.

  14. A novel cancer therapeutic using thrombospondin 1 in dendritic cells.

    PubMed

    Weng, Tzu-Yang; Huang, Shih-Shien; Yen, Meng-Chi; Lin, Chi-Chen; Chen, Yi-Ling; Lin, Chiu-Mei; Chen, Wei-Ching; Wang, Chih-Yang; Chang, Jang-Yang; Lai, Ming-Derg

    2014-02-01

    Induction of thrombospondin 1 (TSP-1) is generally assumed to suppress tumor growth through inhibiting angiogenesis; however, it is less clear how TSP-1 in dendritic cells (DCs) influences tumor progression. We investigated tumor growth and immune mechanism by downregulation of TSP-1 in dendritic cells. Administration of TSP-1 small hairpin RNA (shRNA) through the skin produced anticancer therapeutic effects. Tumor-infiltrating CD4(+) and CD8(+) T cells were increased after the administration of TSP-1 shRNA. The expression of interleukin-12 and interferon-γ in the lymph nodes was enhanced by injection of TSP-1 shRNA. Lymphocytes from the mice injected with TSP-1 shRNA selectively killed the tumor cells, and the cytotoxicity of lymphocytes was abolished by depletion of CD8(+) T cells. Injection of CD11c(+) TSP-1-knockout (TSP-1-KO) bone marrow-derived DCs (BMDCs) delayed tumor growth in tumor-bearing mice. Similarly, antitumor activity induced by TSP-1-KO BMDCs was abrogated by depletion of CD8(+) T cells. In contrast, the administration of shRNAs targeting TSP-2, another TSP family member, did not extend the survival of tumor-bearing mice. Finally, TSP-1 shRNA functioned as an immunotherapeutic adjuvant to augment the therapeutic efficacy of Neu DNA vaccination. Collectively, the downregulation of TSP-1 in DCs produces an effective antitumor response that is opposite to the protumor effects by silencing of TSP-1 within tumor cells.

  15. Exosome from chaperone-rich cell lysates-loaded dendritic cells produced by CELLine 1000 culture system exhibits potent immune activity.

    PubMed

    Bu, Ning; Wu, Haiqin; Zhang, Guilian; Ma, Xiaoling; Zhao, Ping; Zhai, Nina; Xiang, Li; Cao, Huifang; Yang, Xinli; Liu, Jingjie

    2015-01-02

    Dendritic cells (DCs) pulsed with exosomes can stimulate efficient cytotoxic T-lymphocyte responses and anti-tumor immunity. However, the quantity of DC-derived exosomes (DCex) obtained from various culture systems is very low, which is a significant practical issue hampering progress in this research area and needs to be addressed. Gliomas were particularly aggressive, with high morbidity and mortality, indicating that this is a form of incurable highly malignant tumor of the brain with poor prognosis. In the present study, we demonstrate that the CELLine 1000 culture system can dramatically increase the production of DCex. The morphology, phenotype and immune molecules of these DCex were found to be identical to those using traditional methods. Our researches supply a cost-effective, useful method for significantly increasing the quantity of exosomes. In addition, GL261 glioma cells were chosen to separate chaperone-rich cell lysates (CRCL). The results indicate that CRCL-GL261 cell lysates can trigger the most intense expression of immune molecules on DCex or DCs, which has important implications for the research into tumor treatment and diagnosis.

  16. Modulation of pro-inflammatory activation of monocytes and dendritic cells by aza-bis-phosphonate dendrimer as an experimental therapeutic agent

    PubMed Central

    2014-01-01

    Introduction Our objective was to assess the capacity of dendrimer aza-bis-phosphonate (ABP) to modulate phenotype of monocytes (Mo) and monocytes derived dendritic cells (MoDC) activated in response to toll-like receptor 4 (TLR4) and interferon γ (IFN- γ) stimulation. Methods Mo (n = 12) and MoDC (n = 11) from peripheral blood of healthy donors were prepared. Cells were preincubated or not for 1 hour with dendrimer ABP, then incubated with lipopolysaccharide (LPS; as a TLR4 ligand) and (IFN-γ) for 38 hours. Secretion of tumor necrosis factor α (TNFα), interleukin (IL) -1, IL-6, IL-12, IL-10 and IL-23 in the culture medium was measured by enzyme-linked immunosorbent assay (ELISA) and Cytokine Bead Array. Differentiation and subsequent maturation of MoDC from nine donors in the presence of LPS were analyzed by flow cytometry using CD80, CD86, CD83 and CD1a surface expression as markers. Results Mo and MoDC were orientated to a pro-inflammatory state. In activated Mo, TNFα, IL-1β and IL-23 levels were significantly lower after prior incubation with dendrimer ABP. In activated MoDC, dendrimer ABP promoted IL-10 secretion while decreasing dramatically the level of IL-12. TNFα and IL-6 secretion were significantly lower in the presence of dendrimer ABP. LPS driven maturation of MoDC was impaired by dendrimer ABP treatment, as attested by the significantly lower expression of CD80 and CD86. Conclusion Our data indicate that dendrimer ABP possesses immunomodulatory properties on human Mo and MoDC, in TLR4 + IFN-γ stimulation model, by inducing M2 alternative activation of Mo and promoting tolerogenic MoDC. PMID:24745366

  17. Retrograde plasticity and differential competition of bipolar cell dendrites and axons in the developing retina.

    PubMed

    Johnson, Robert E; Kerschensteiner, Daniel

    2014-10-06

    Most neurons function in the context of pathways that process and propagate information through a series of stages, e.g., from the sensory periphery to cerebral cortex. Because activity at each stage of a neural pathway depends on connectivity at the preceding one, we hypothesized that during development, axonal output of a neuron may regulate synaptic development of its dendrites (i.e., retrograde plasticity). Within pathways, neurons often receive input from multiple partners and provide output to targets shared with other neurons (i.e., convergence). Converging axons can intermingle or occupy separate territories on target dendrites. Activity-dependent competition has been shown to bias target innervation by overlapping axons in several systems. By contrast, whether territorial axons or dendrites compete for targets and inputs, respectively, has not been tested. Here, we generate transgenic mice in which glutamate release from specific sets of retinal bipolar cells (BCs) is suppressed. We find that dendrites of silenced BCs recruit fewer inputs when their neighbors are active and that dendrites of active BCs recruit more inputs when their neighbors are silenced than either active or silenced BCs with equal neighbors. By contrast, axons of silenced BCs form fewer synapses with their targets, irrespective of the activity of their neighbors. These findings reveal that retrograde plasticity guides BC dendritic development in vivo and demonstrate that dendrites, but not territorial axons, in a convergent neural pathway engage in activity-dependent competition. We propose that at a population level, retrograde plasticity serves to maximize functional representation of inputs.

  18. Role of Dendritic Cells in Immune Dysfunction

    NASA Technical Reports Server (NTRS)

    Savary, Cherylyn A.

    1998-01-01

    The specific aims of the project were: (1) Application of the NASA bioreactor to enhance cytokine-regulated proliferation and maturation of dendritic cells (DC). (2) Compare the frequency and function of DC in normal donors and immunocompromised cancer patients. (3) Analyze the effectiveness of cytokine therapy and DC-assisted immunotherapy (using bioreactor-expanded DC) in a murine model of experimental fungal disease. Our investigations have provided new insight into DC immunobiology and have led to the development of methodology to evaluate DC in blood of normal donors and patients. Information gained from these studies has broadened our understanding of possible mechanisms involved in the immune dysfunction of space travelers and earth-bound cancer patients, and could contribute to the design of novel therapies to restore/preserve immunity in these individuals. Several new avenues of investigation were also revealed. The results of studies completed during Round 2 are summarized.

  19. Dendritic cell-based immunotherapy in mesothelioma.

    PubMed

    Cornelissen, Robin; Lievense, Lysanne A; Heuvers, Marlies E; Maat, Alexander P; Hendriks, Rudi W; Hoogsteden, Henk C; Hegmans, Joost P; Aerts, Joachim G

    2012-10-01

    Mesothelioma is a rare thoracic malignancy with a dismal prognosis. Current treatment options are scarce and clinical outcomes are rather disappointing. Due to the immunogenic nature of mesothelioma, several studies have investigated immunotherapeutic strategies to improve the prognosis of patients with mesothelioma. In the last decade, progress in knowledge of the modulation of the immune system to attack the tumor has been remarkable, but the optimal strategy for immunotherapy has yet to be unraveled. Because of their potent antigen-presenting capacity, dendritic cells are acknowledged as a promising agent in immunotherapeutic approaches in a number of malignancies. This review gives an update and provides a future perspective in which immunotherapy may improve the outcome of mesothelioma therapy.

  20. DNA-like class R inhibitory oligonucleotides (INH-ODNs) preferentially block autoantigen-induced B-cell and dendritic cell activation in vitro and autoantibody production in lupus-prone MRL-Faslpr/lpr mice in vivo

    PubMed Central

    Lenert, Petar; Yasuda, Kei; Busconi, Liliana; Nelson, Patrice; Fleenor, Courtney; Ratnabalasuriar, Radhika S; Nagy, Peter L; Ashman, Robert F; Rifkin, Ian R; Marshak-Rothstein, Ann

    2009-01-01

    Introduction B cells have many different roles in systemic lupus erythematosus (SLE), ranging from autoantigen recognition and processing to effector functions (for example, autoantibody and cytokine secretion). Recent studies have shown that intracellular nucleic acid-sensing receptors, Toll-like receptor (TLR) 7 and TLR9, play an important role in the pathogenesis of SLE. Dual engagement of rheumatoid factor-specific AM14 B cells through the B-cell receptor (BCR) and TLR7/9 results in marked proliferation of autoimmune B cells. Thus, strategies to preferentially block innate activation through TLRs in autoimmune B cells may be preferred over non-selective B-cell depletion. Methods We have developed a new generation of DNA-like compounds named class R inhibitory oligonucleotides (INH-ODNs). We tested their effectiveness in autoimmune B cells and interferon-alpha-producing dendritic cells in vitro and in lupus-prone MRL-Faslpr/lpr mice in vivo. Results Class R INH-ODNs have 10- to 30-fold higher inhibitory potency when autoreactive B cells are synergistically activated through the BCR and associated TLR7 or 9 than when stimulation occurs via non-BCR-engaged TLR7/9. Inhibition of TLR9 requires the presence of both CCT and GGG triplets in an INH-ODN, whereas the inhibition of the TLR7 pathway appears to be sequence-independent but dependent on the phosphorothioate backbone. This difference was also observed in the MRL-Faslpr/lpr mice in vivo, where the prototypic class R INH-ODN was more effective in curtailing abnormal autoantibody secretion and prolonging survival. Conclusions The increased potency of class R INH-ODNs for autoreactive B cells and dendritic cells may be beneficial for lupus patients by providing pathway-specific inhibition yet allowing them to generate protective immune response when needed. PMID:19476613

  1. Somatic versus Dendritic Resonance: Differential Filtering of Inputs through Non-Uniform Distributions of Active Conductances

    PubMed Central

    Zhuchkova, Ekaterina; Remme, Michiel W. H.; Schreiber, Susanne

    2013-01-01

    Synaptic inputs to neurons are processed in a frequency-dependent manner, with either low-pass or resonant response characteristics. These types of filtering play a key role in the frequency-specific information flow in neuronal networks. While the generation of resonance by specific ionic conductances is well investigated, less attention has been paid to the spatial distribution of the resonance-generating conductances across a neuron. In pyramidal neurons – one of the major excitatory cell-types in the mammalian brain – a steep gradient of resonance-generating h-conductances with a 60-fold increase towards distal dendrites has been demonstrated experimentally. Because the dendritic trees of these cells are large, spatial compartmentalization of resonant properties can be expected. Here, we use mathematical descriptions of spatially extended neurons to investigate the consequences of such a distal, dendritic localization of h-conductances for signal processing. While neurons with short dendrites do not exhibit a pronounced compartmentalization of resonance, i.e. the filter properties of dendrites and soma are similar, we find that neurons with longer dendrites ( space constant) can show distinct filtering of dendritic and somatic inputs due to electrotonic segregation. Moreover, we show that for such neurons, experimental classification as resonant versus nonresonant can be misleading when based on somatic recordings, because for these morphologies a dendritic resonance could easily be undetectable when using somatic input. Nevertheless, noise-driven membrane-potential oscillations caused by dendritic resonance can propagate to the soma where they can be recorded, hence contrasting with the low-pass filtering at the soma. We conclude that non-uniform distributions of active conductances can underlie differential filtering of synaptic input in neurons with spatially extended dendrites, like pyramidal neurons, bearing relevance for the localization

  2. Macrophages and Dendritic Cells: Partners in Atherogenesis.

    PubMed

    Cybulsky, Myron I; Cheong, Cheolho; Robbins, Clinton S

    2016-02-19

    Atherosclerosis is a complex chronic disease. The accumulation of myeloid cells in the arterial intima, including macrophages and dendritic cells (DCs), is a feature of early stages of disease. For decades, it has been known that monocyte recruitment to the intima contributes to the burden of lesion macrophages. Yet, this paradigm may require reevaluation in light of recent advances in understanding of tissue macrophage ontogeny, their capacity for self-renewal, as well as observations that macrophages proliferate throughout atherogenesis and that self-renewal is critical for maintenance of macrophages in advanced lesions. The rate of atherosclerotic lesion formation is profoundly influenced by innate and adaptive immunity, which can be regulated locally within atherosclerotic lesions, as well as in secondary lymphoid organs, the bone marrow and the blood. DCs are important modulators of immunity. Advances in the past decade have cemented our understanding of DC subsets, functions, hematopoietic origin, gene expression patterns, transcription factors critical for differentiation, and provided new tools for study of DC biology. The functions of macrophages and DCs overlap to some extent, thus it is important to reassess the contributions of each of these myeloid cells taking into account strict criteria of cell identification, ontogeny, and determine whether their key roles are within atherosclerotic lesions or secondary lymphoid organs. This review will highlight key aspect of macrophage and DC biology, summarize how these cells participate in different stages of atherogenesis and comment on complexities, controversies, and gaps in knowledge in the field.

  3. Despite Increased Type 1 IFN, Autoimmune Nonobese Diabetic Mice Display Impaired Dendritic Cell Response to CpG and Decreased Nuclear Localization of IFN-Activated STAT1

    PubMed Central

    Rahman, M. Jubayer; Rahir, Gwendoline; Dong, Matthew B.; Zhao, Yongge; Rodrigues, Kameron B.; Hotta-Iwamura, Chie; Chen, Ye; Guerrero, Alan; Tarbell, Kristin V.

    2016-01-01

    Innate immune signals help break self-tolerance to initiate autoimmune diseases such as type 1 diabetes, but innate contributions to subsequent regulation of disease progression are less clear. Most studies have measured in vitro innate responses of GM-CSF dendritic cells (DCs) that are functionally distinct from conventional DCs (cDCs) and do not reflect in vivo DC subsets. To determine whether autoimmune NOD mice have alterations in type 1 IFN innate responsiveness, we compared cDCs from prediabetic NOD and control C57BL/6 (B6) mice stimulated in vivo with the TLR9 ligand CpG, a strong type 1 IFN inducer. In response to CpG, NOD mice produce more type 1 IFN and express higher levels of CD40, and NOD monocyte DCs make more TNF. However, the overall CpG-induced transcriptional response is muted in NOD cDCs. Of relevance the costimulatory proteins CD80/CD86, signals needed for regulatory T cell homeostasis, are upregulated less on NOD cDCs. Interestingly, NOD Rag1−/− mice also display a defect in CpG-induced CD86 upregulation compared with B6 Rag1−/−, indicating this particular innate alteration precedes adaptive autoimmunity. The impaired response in NOD DCs is likely downstream of the IFN-α/β receptor because DCs from NOD and B6 mice show similar CpG-induced CD86 levels when anti–IFN-α/β receptor Ab is added. IFN-α–induced nuclear localization of activated STAT1 is markedly reduced in NOD CD11c+ cells, consistent with lower type 1 IFN responsiveness. In conclusion, NOD DCs display altered innate responses characterized by enhanced type 1 IFN and activation of monocyte-derived DCs but diminished cDC type 1 IFN response. PMID:26826238

  4. Infection of human monocyte-derived dendritic cells by ANDES Hantavirus enhances pro-inflammatory state, the secretion of active MMP-9 and indirectly enhances endothelial permeability

    PubMed Central

    2011-01-01

    Background Andes virus (ANDV), a rodent-borne Hantavirus, is the major etiological agent of Hantavirus cardiopulmonary syndrome (HCPS) in South America, which is mainly characterized by a vascular leakage with high rate of fatal outcomes for infected patients. Currently, neither specific therapy nor vaccines are available against this pathogen. ANDV infects both dendritic and epithelial cells, but in despite that the severity of the disease directly correlates with the viral RNA load, considerable evidence suggests that immune mechanisms rather than direct viral cytopathology are responsible for plasma leakage in HCPS. Here, we assessed the possible effect of soluble factors, induced in viral-activated DCs, on endothelial permeability. Activated immune cells, including DC, secrete gelatinolytic matrix metalloproteases (gMMP-2 and -9) that modulate the vascular permeability for their trafficking. Methods A clinical ANDES isolate was used to infect DC derived from primary PBMC. Maturation and pro-inflammatory phenotypes of ANDES-infected DC were assessed by studying the expression of receptors, cytokines and active gMMP-9, as well as some of their functional status. The ANDES-infected DC supernatants were assessed for their capacity to enhance a monolayer endothelial permeability using primary human vascular endothelial cells (HUVEC). Results Here, we show that in vitro primary DCs infected by a clinical isolate of ANDV shed virus RNA and proteins, suggesting a competent viral replication in these cells. Moreover, this infection induces an enhanced expression of soluble pro-inflammatory factors, including TNF-α and the active gMMP-9, as well as a decreased expression of anti-inflammatory cytokines, such as IL-10 and TGF-β. These viral activated cells are less sensitive to apoptosis. Moreover, supernatants from ANDV-infected DCs were able to indirectly enhance the permeability of a monolayer of primary HUVEC. Conclusions Primary human DCs, that are primarily

  5. Simulated Responses of Cerebellar Purkinje Cells are Independent of the Dendritic Location of Granule Cell Synaptic Inputs

    NASA Astrophysics Data System (ADS)

    de Schutter, Erik; Bower, James M.

    1994-05-01

    Cerebellar Purkinje cell responses to granule cell synaptic inputs were examined with a computer model including active dendritic conductances. Dendritic P-type Ca2+ channels amplified postsynaptic responses when the model was firing at a physiological rate. Small synchronous excitatory inputs applied distally on the large dendritic tree resulted in somatic responses of similar size to those generated by more proximal inputs. In contrast, in a passive model the somatic postsynaptic potentials to distal inputs were 76% smaller. The model predicts that the somatic firing response of Purkinje cells is relatively insensitive to the exact dendritic location of synaptic inputs. We describe a mechanism of Ca2+-mediated synaptic amplification, based on the subspiking threshold recruitment of P-type Ca2+ channels in the dendritic branches surrounding the input site.

  6. Genetic targeting of the active transcription factor XBP1s to dendritic cells potentiates vaccine-induced prophylactic and therapeutic antitumor immunity.

    PubMed

    Tian, Shenghe; Liu, Zuqiang; Donahue, Cara; Falo, Louis D; You, Zhaoyang

    2012-02-01

    In vivo dendritic cells (DC) targeting is an attractive approach with potential advantages in vaccine efficacy, cost, and availability. Identification of molecular adjuvants to in vivo "modulate " DC to coordinately render improved Th1 and CD8 T cell immunity, and attenuated deleterious Treg effects, is a critical challenge. Here, we report that in vivo genetic targeting of the active transcription factor XBP1s to DC (XBP1s/DC) potentiated vaccine-induced prophylactic and therapeutic antitumor immunity in multiple tumor models. This immunization strategy is based on a genetic vaccine encoding both cytomegalovirus (CMV)-driven vaccine Aghsp70 and DC-specific CD11c-driven XBP1s. The novel targeted vaccine induced durable Th1 and CD8 T cell responses to poorly immunogenic self/tumor antigen (Ag) and attenuated tumor-associated Treg suppressive function. Bone marrow (BM)-derived DC genetically modified to simultaneously overexpress XBP1s and express Aghsp70 upregulated CD40, CD70, CD86, interleukin (IL)-15, IL-15Rα, and CCR7 expression, and increased IL-6, IL-12, and tumor necrosis factor (TNF)-α production in vitro. XBP1s/DC elevated functional DEC205(+)CD8α(+)DC in the draining lymph nodes (DLN). The data suggest a novel role for XBP1s in modulating DC to potentiate tumor vaccine efficacy via overcoming two major obstacles to tumor vaccines (i.e., T cell hyporesponsiveness against poorly immunologic self/tumor Ag and tumor-associated Treg-mediated suppression) and improving DEC205(+)CD8α(+)DC.

  7. RORα Regulates Multiple Aspects of Dendrite Development in Cerebellar Purkinje Cells In Vivo.

    PubMed

    Takeo, Yukari H; Kakegawa, Wataru; Miura, Eriko; Yuzaki, Michisuke

    2015-09-09

    The establishment of cell-type-specific dendritic arbors is fundamental for proper neural circuit formation. Here, using temporal- and cell-specific knock-down, knock-out, and overexpression approaches, we show that multiple aspects of the dendritic organization of cerebellar Purkinje cells (PCs) are controlled by a single transcriptional factor, retinoic acid-related orphan receptor-alpha (RORα), a gene defective in staggerer mutant mice. As reported earlier, RORα was required for regression of primitive dendrites before postnatal day 4 (P4). RORα was also necessary for PCs to form a single Purkinje layer from P0 to P4. The knock-down of RORα from P4 impaired the elimination of perisomatic dendrites and maturation of single stem dendrites in PCs at P8. Filopodia and spines were also absent in these PCs. The knock-down of RORα from P8 impaired the formation and maintenance of terminal dendritic branches of PCs at P14. Finally, even after dendrite formation was completed at P21, RORα was required for PCs to maintain dendritic complexity and functional synapses, but their mature innervation pattern by single climbing fibers was unaffected. Interestingly, overexpression of RORα in PCs at various developmental stages did not facilitate dendrite development, but had specific detrimental effects on PCs. Because RORα deficiency during development is closely related to the severity of spinocerebellar ataxia type 1, delineating the specific roles of RORα in PCs in vivo at different time windows during development and throughout adulthood would facilitate our understanding of the pathogenesis of cerebellar disorders. Significance statement: The genetic programs by which each neuron subtype develops and maintains dendritic arbors have remained largely unclear. This is partly because dendrite development is modulated dynamically by neuronal activities and interactions with local environmental cues in vivo. In addition, dendrites are formed and maintained by the

  8. Primary peripheral T cells become susceptible to 2,3,7,8-tetrachlorodibenzo-p-dioxin-mediated apoptosis in vitro upon activation and in the presence of dendritic cells.

    PubMed

    Singh, Narendra P; Nagarkatti, Mitzi; Nagarkatti, Prakash

    2008-06-01

    Although the toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on T cells in vivo have been well characterized, attempts to reproduce these findings in vitro have not been successful. In the current study, we examined whether activation or the presence of dendritic cells (DCs) would make primary naive T cells from C57BL/6 mice susceptible to TCDD-induced apoptosis in vitro. Although nonactivated primary T cells cultured with 10 to 1000 nM TCDD were relatively resistant to apoptosis, they became sensitive to apoptosis upon activation with concanavalin A (ConA). Moreover, ConA-activated T cells cultured in the presence of DCs showed highest levels of TCDD-induced apoptosis. Likewise, primary T cells from OT.II.2a mice cultured with specific ovalbumin peptide and syngeneic DCs showed higher levels of apoptosis compared with similar nonactivated T cells. T-cell activation led to up-regulation of aryl hydrocarbon receptor (AhR), Fas, and Fas-ligand (FasL) expression. In addition, DC maturation and culture with TCDD caused significant induction of FasL. TCDD-mediated apoptosis in activated peripheral T cells was AhR-dependent. Analysis of why nonactivated T cells are more resistant, whereas activated T cells are sensitive to TCDD-induced apoptosis revealed that TCDD treatment of activated but not nonactivated T cells led to down-regulation of cellular FLICE inhibitory protein (c-FLIP), an inhibitor of apoptosis. Moreover, down-regulation of c-FLIP using small interfering RNA in nonactivated T cells made them sensitive to TCDD-induced apoptosis. The current study demonstrates for the first time that TCDD can induce apoptosis in vitro in peripheral T cells upon activation and in the presence of DCs and that this may be mediated by down-regulation of c-FLIP.

  9. Primary Peripheral T Cells Become Susceptible to 2,3,7,8-Tetrachlorodibenzo-p-Dioxin-Mediated Apoptosis in Vitro upon Activation and in the Presence of Dendritic Cells

    PubMed Central

    Singh, Narendra P.; Nagarkatti, Mitzi; Nagarkatti, Prakash

    2009-01-01

    Although the toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on T cells in vivo have been well characterized, attempts to reproduce these findings in vitro have not been successful. In the current study, we examined whether activation or the presence of dendritic cells (DCs) would make primary naive T cells from C57BL/6 mice susceptible to TCDD-induced apoptosis in vitro. Although nonactivated primary T cells cultured with 10 to 1000 nM TCDD were relatively resistant to apoptosis, they became sensitive to apoptosis upon activation with concanavalin A (ConA). Moreover, ConA-activated T cells cultured in the presence of DCs showed highest levels of TCDD-induced apoptosis. Likewise, primary T cells from OT.II.2a mice cultured with specific ovalbumin peptide and syngeneic DCs showed higher levels of apoptosis compared with similar nonactivated T cells. T-cell activation led to up-regulation of aryl hydrocarbon receptor (AhR), Fas, and Fas-ligand (FasL) expression. In addition, DC maturation and culture with TCDD caused significant induction of FasL. TCDD-mediated apoptosis in activated peripheral T cells was AhR-dependent. Analysis of why nonactivated T cells are more resistant, whereas activated T cells are sensitive to TCDD-induced apoptosis revealed that TCDD treatment of activated but not nonactivated T cells led to down-regulation of cellular FLICE inhibitory protein (c-FLIP), an inhibitor of apoptosis. Moreover, down-regulation of c-FLIP using small interfering RNA in nonactivated T cells made them sensitive to TCDD-induced apoptosis. The current study demonstrates for the first time that TCDD can induce apoptosis in vitro in peripheral T cells upon activation and in the presence of DCs and that this may be mediated by down-regulation of c-FLIP. PMID:18334599

  10. Metabolism Is Central to Tolerogenic Dendritic Cell Function

    PubMed Central

    Sim, Wen Jing; Ahl, Patricia Jennifer; Connolly, John Edward

    2016-01-01

    Immunological tolerance is a fundamental tenant of immune homeostasis and overall health. Self-tolerance is a critical component of the immune system that allows for the recognition of self, resulting in hyporeactivity instead of immunogenicity. Dendritic cells are central to the establishment of dominant immune tolerance through the secretion of immunosuppressive cytokines and regulatory polarization of T cells. Cellular metabolism holds the key to determining DC immunogenic or tolerogenic cell fate. Recent studies have demonstrated that dendritic cell maturation leads to a shift toward a glycolytic metabolic state and preferred use of glucose as a carbon source. In contrast, tolerogenic dendritic cells favor oxidative phosphorylation and fatty acid oxidation. This dichotomous metabolic reprogramming of dendritic cells drives differential cellular function and plays a role in pathologies, such as autoimmune disease. Pharmacological alterations in metabolism have promising therapeutic potential. PMID:26980944

  11. Transcriptional profiling of dendritic cells matured in different osmolarities.

    PubMed

    Chessa, Federica; Hielscher, Thomas; Mathow, Daniel; Gröne, Hermann-Josef; Popovic, Zoran V

    2016-03-01

    Tissue-specific microenvironments shape the fate of mononuclear phagocytes [1-3]. Interstitial osmolarity is a tissue biophysical parameter which considerably modulates the phenotype and function of dendritic cells [4]. In the present report we provide a detailed description of our experimental workflow and bioinformatic analysis applied to our gene expression dataset (GSE72174), aiming to investigate the influence of different osmolarity conditions on the gene expression signature of bone marrow-derived dendritic cells. We established a cell culture system involving murine bone marrow cells, cultured under different NaCl-induced osmolarity conditions in the presence of the dendritic cell growth factor GM-CSF. Gene expression analysis was applied to mature dendritic cells (day 7) developed in different osmolarities, with and without prior stimulation with the TLR2/4 ligand LPS.

  12. Follicular dendritic cell sarcoma of the abdomen: the imaging findings.

    PubMed

    Kang, Tae Wook; Lee, Soon Jin; Song, Hye Jong

    2010-01-01

    Follicular dendritic cell sarcoma is a rare neoplasm that originates from follicular dendritic cells in lymphoid follicles. This disease usually involves the lymph nodes, and especially the head and neck area. Rarely, extranodal sites may be affected, including tonsil, the oral cavity, liver, spleen and the gastrointestinal tract. We report here on the imaging findings of follicular dendritic cell sarcoma of the abdomen that involved the retroperitoneal lymph nodes and colon. It shows as a well-defined, enhancing homogenous mass with internal necrosis and regional lymphadenopathy.

  13. Stimulation of dendritic cells enhances immune response after photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Mroz, Pawel; Castano, Ana P.; Hamblin, Michael R.

    2009-02-01

    Photodynamic therapy (PDT) involves the administration of photosensitizers followed by illumination of the primary tumor with red light producing reactive oxygen species that cause vascular shutdown and tumor cell necrosis and apoptosis. Anti-tumor immunity is stimulated after PDT due to the acute inflammatory response, priming of the immune system to recognize tumor-associated antigens (TAA). The induction of specific CD8+ Tlymphocyte cells that recognize major histocompatibility complex class I (MHC-I) restricted epitopes of TAAs is a highly desirable goal in cancer therapy. The PDT killed tumor cells may be phagocytosed by dendritic cells (DC) that then migrate to draining lymph nodes and prime naÃve T-cells that recognize TAA epitopes. This process is however, often sub-optimal, in part due to tumor-induced DC dysfunction. Instead of DC that can become mature and activated and have a potent antigen-presenting and immune stimulating phenotype, immature dendritic cells (iDC) are often found in tumors and are part of an immunosuppressive milieu including regulatory T-cells and immunosuppressive cytokines such as TGF-beta and IL10. We here report on the use of a potent DC activating agent, an oligonucleotide (ODN) that contains a non-methylated CpG motif and acts as an agonist of toll like receptor (TLR) 9. TLR activation is a danger signal to notify the immune system of the presence of invading pathogens. CpG-ODN (but not scrambled non-CpG ODN) increased bone-marrow DC activation after exposure to PDT-killed tumor cells, and significantly increased tumor response to PDT and mouse survival after peri-tumoral administration. CpG may be a valuable immunoadjuvant to PDT especially for tumors that produce DC dysfunction.

  14. Dendritic morphogenesis of cerebellar Purkinje cells through extension and retraction revealed by long-term tracking of living cells in vitro.

    PubMed

    Tanaka, M; Yanagawa, Y; Obata, K; Marunouchi, T

    2006-08-25

    Cerebellar Purkinje cells have the most elaborate dendritic trees among the neurons in the CNS. To investigate the dynamic aspects of dendritic morphogenesis of Purkinje cells, we performed a long-term analysis of living cells in cerebellar cell cultures derived from glutamate decarboxylase 67-green fluorescent protein mice. Most Purkinje cells had several primary dendrites during the 25-day culture period. Repeated observation of green fluorescent protein-expressing Purkinje cells over a period of 10-25 days in vitro demonstrated that not only extension, but also retraction of primary dendrites occurred during this culture period. Interestingly, both extension and retraction of primary dendrites were active between 10 and 15 days in vitro, and retraction of a primary dendrite occurred concomitantly with elongation of other primary dendrites in the same cell. Analysis of the morphological characteristics of the retracted primary dendrites demonstrated that shorter and less branched primary dendrites tended to retract. Furthermore, treatment with an inhibitor of calcium/calmodulin-dependent protein kinase II reduced the number of primary dendrites specifically during 5-15 days in vitro, the culture period when the extension and retraction of primary dendrites occurred actively. Blockade of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/kainate-type glutamate receptors also reduced the number of primary dendrites during the same culture period, while inhibition of glutamate transporters increased the number. These findings suggest that the final morphology of Purkinje cells is achieved not only through extension, but also through retraction of their dendrites, and that calcium/calmodulin-dependent protein kinase II and neuronal activity are involved in this dendritic morphogenesis.

  15. Classification of dendritic cell phenotypes from gene expression data

    PubMed Central

    2011-01-01

    protocol was confirmed by the accuracy for a human data set, when using only the following three genes: Il12b, Cd40 and Socs3. In summary, we analysed the longitudinal pattern of expression in dendritic cells stimulated with activating agents with the aim of identifying signatures that would predict or explain the dentritic cell response to an inflammatory agent. PMID:21875438

  16. Building on Dendritic Cell Subsets to Improve Cancer Vaccines

    PubMed Central

    Palucka, Karolina; Ueno, Hideki; Zurawski, Gerard; Fay, Joseph; Banchereau, Jacques

    2010-01-01

    SUMMARY T cells can reject established tumors when adoptively transferred into patients, thereby demonstrating that the immune system can be harnessed for cancer therapy. However, such passive immunotherapy is unlikely to maintain memory T cells that might control tumor outgrowth on the long term. Active immunotherapy with vaccines has the potential to induce tumor-specific effector and memory T cells. Vaccines act through dendritic cells (DCs) which induce, regulate and maintain T cell immunity. Clinical trials testing first generation DC vaccines pulsed with tumor antigens provided a proof-of-principle that therapeutic immunity can be elicited. The increased knowledge of the DC system, including the existence of distinct DC subsets is leading to new trials which aim at improved immune and clinical outcomes. PMID:20226644

  17. A novel dendritic-cell-targeting DNA vaccine for hepatitis B induces T cell and humoral immune responses and potentiates the antivirus activity in HBV transgenic mice.

    PubMed

    Yu, Debin; Liu, Hong; Shi, Shuai; Dong, Liwei; Wang, Hongge; Wu, Nuoting; Gao, Hui; Cheng, Zhaojun; Zheng, Qun; Cai, Jiaojiao; Zou, Libo; Zou, Zhihua

    2015-12-01

    Strategies for inducing an effective immune response following vaccination have focused on targeting antigens to dendritic cells (DCs) through the DC-specific surface molecule DEC-205. The immunogenicity and efficacy of DNA vaccination can also be enhanced by fusing the encoded antigen to single-chain antibodies directed against DEC-205. Here, we investigated this promising approach for its enhancement of hepatitis B virus (HBV)-specific cellular and humoral immune responses and its antiviral effects in HBV transgenic mice. A plasmid DNA vaccine encoding mouse DEC-205 single-chain fragment variable (mDEC-205-scFv) linked with the hepatitis B surface antigen (HBsAg) was constructed. Vaccination with this fusion DNA vaccine in HBV transgenic mice induced robust antiviral T cell and antibody immunity against HBsAg. The levels of serum-circulating HBsAg and the HBV DNA copy number were downregulated by the induction of a higher HBsAg-specific response. Thus, in this study, we demonstrated the therapeutic efficacy of the novel mDEC-205-scFv-fused DNA vaccine in a mouse model of immune-tolerant, chronic HBV infection.

  18. Mechanisms of Dendritic Cell Lysosomal Killing of Cryptococcus

    NASA Astrophysics Data System (ADS)

    Hole, Camaron R.; Bui, Hoang; Wormley, Floyd L.; Wozniak, Karen L.

    2012-10-01

    Cryptococcus neoformans is an opportunistic pulmonary fungal pathogen that disseminates to the CNS causing fatal meningitis in immunocompromised patients. Dendritic cells (DCs) phagocytose C. neoformans following inhalation. Following uptake, cryptococci translocate to the DC lysosomal compartment and are killed by oxidative and non-oxidative mechanisms. DC lysosomal extracts kill cryptococci in vitro; however, the means of antifungal activity remain unknown. Our studies determined non-oxidative antifungal activity by DC lysosomal extract. We examined DC lysosomal killing of cryptococcal strains, anti-fungal activity of purified lysosomal enzymes, and mechanisms of killing against C. neoformans. Results confirmed DC lysosome fungicidal activity against all cryptococcal serotypes. Purified lysosomal enzymes, specifically cathepsin B, inhibited cryptococcal growth. Interestingly, cathepsin B combined with its enzymatic inhibitors led to enhanced cryptococcal killing. Electron microscopy revealed structural changes and ruptured cryptococcal cell walls following treatment. Finally, additional studies demonstrated that osmotic lysis was responsible for cryptococcal death.

  19. Leukemia-derived immature dendritic cells differentiate into functionally competent mature dendritic cells that efficiently stimulate T cell responses.

    PubMed

    Cignetti, Alessandro; Vallario, Antonella; Roato, Ilaria; Circosta, Paola; Allione, Bernardino; Casorzo, Laura; Ghia, Paolo; Caligaris-Cappio, Federico

    2004-08-15

    Primary acute myeloid leukemia cells can be induced to differentiate into dendritic cells (DC). In the presence of GM-CSF, TNF-alpha, and/or IL-4, leukemia-derived DC are obtained that display features of immature DC (i-DC). The aim of this study was to determine whether i-DC of leukemic origin could be further differentiated into mature DC (m-DC) and to evaluate the possibility that leukemic m-DC could be effective in vivo as a tumor vaccine. Using CD40L as maturating agent, we show that leukemic i-DC can differentiate into cells that fulfill the phenotypic criteria of m-DC and, compared with normal counterparts, are functionally competent in vitro in terms of: 1) production of cytokines that support T cell activation and proliferation and drive Th1 polarization; 2) generation of autologous CD8(+) CTLs and CD4(+) T cells that are MHC-restricted and leukemia-specific; 3) migration from tissues to lymph nodes; 4) amplification of Ag presentation by monocyte attraction; 5) attraction of naive/resting and activated T cells. Irradiation of leukemic i-DC after CD40L stimulation did not affect their differentiating and functional capacity. Our data indicate that acute myeloid leukemia cells can fully differentiate into functionally competent m-DC and lay the ground for testing their efficacy as a tumor vaccine.

  20. Inorganic arsenic impairs differentiation and functions of human dendritic cells

    SciTech Connect

    Macoch, Mélinda; Morzadec, Claudie; Fardel, Olivier; Vernhet, Laurent

    2013-01-15

    Experimental studies have demonstrated that the antileukemic trivalent inorganic arsenic prevents the development of severe pro-inflammatory diseases mediated by excessive Th1 and Th17 cell responses. Differentiation of Th1 and Th17 subsets is mainly regulated by interleukins (ILs) secreted from dendritic cells (DCs) and the ability of inorganic arsenic to impair interferon-γ and IL-17 secretion by interfering with the physiology of DCs is unknown. In the present study, we demonstrate that high concentrations of sodium arsenite (As(III), 1–2 μM) clinically achievable in plasma of arsenic-treated patients, block differentiation of human peripheral blood monocytes into immature DCs (iDCs) by inducing their necrosis. Differentiation of monocytes in the presence of non-cytotoxic concentrations of As(III) (0.1 to 0.5 μM) only slightly impacts endocytotic activity of iDCs or expression of co-stimulatory molecules in cells activated with lipopolysaccharide. However, this differentiation in the presence of As(III) strongly represses secretion of IL-12p70 and IL-23, two major regulators of Th1 and Th17 activities, from iDCs stimulated with different toll-like receptor (TLR) agonists in metalloid-free medium. Such As(III)-exposed DCs also exhibit reduced mRNA levels of IL12A and/or IL12B genes when activated with TLR agonists. Finally, differentiation of monocytes with non-cytotoxic concentrations of As(III) subsequently reduces the ability of activated DCs to stimulate the release of interferon-γ and IL-17 from Th cells. In conclusion, our results demonstrate that clinically relevant concentrations of inorganic arsenic markedly impair in vitro differentiation and functions of DCs, which may contribute to the putative beneficial effects of the metalloid towards inflammatory autoimmune diseases. Highlights: ► Inorganic arsenic impairs differentiation and functions of human dendritic cells (DCs) ► Arsenite (> 1 μM) blocks differentiation of dendritic cells by

  1. Type I TARPs promote dendritic growth of early postnatal neocortical pyramidal cells in organotypic cultures.

    PubMed

    Hamad, Mohammad I K; Jack, Alexander; Klatt, Oliver; Lorkowski, Markus; Strasdeit, Tobias; Kott, Sabine; Sager, Charlotte; Hollmann, Michael; Wahle, Petra

    2014-04-01

    The ionotropic α-amino-3-hydroxy-5-methyl-4-isoxazole propionate glutamate receptors (AMPARs) have been implicated in the establishment of dendritic architecture. The transmembrane AMPA receptor regulatory proteins (TARPs) regulate AMPAR function and trafficking into synaptic membranes. In the current study, we employ type I and type II TARPs to modulate expression levels and function of endogenous AMPARs and investigate in organotypic cultures (OTCs) of rat occipital cortex whether this influences neuronal differentiation. Our results show that in early development [5-10 days in vitro (DIV)] only the type I TARP γ-8 promotes pyramidal cell dendritic growth by increasing spontaneous calcium amplitude and GluA2/3 expression in soma and dendrites. Later in development (10-15 DIV), the type I TARPs γ-2, γ-3 and γ-8 promote dendritic growth, whereas γ-4 reduced dendritic growth. The type II TARPs failed to alter dendritic morphology. The TARP-induced dendritic growth was restricted to the apical dendrites of pyramidal cells and it did not affect interneurons. Moreover, we studied the effects of short hairpin RNA-induced knockdown of endogenous γ-8 and showed a reduction of dendritic complexity and amplitudes of spontaneous calcium transients. In addition, the cytoplasmic tail (CT) of γ-8 was required for dendritic growth. Single-cell calcium imaging showed that the γ-8 CT domain increases amplitude but not frequency of calcium transients, suggesting a regulatory mechanism involving the γ-8 CT domain in the postsynaptic compartment. Indeed, the effect of γ-8 overexpression was reversed by APV, indicating a contribution of NMDA receptors. Our results suggest that selected type I TARPs influence activity-dependent dendritogenesis of immature pyramidal neurons.

  2. Stromal fibroblasts support dendritic cells to maintain IL-23/Th17 responses after exposure to ionizing radiation

    PubMed Central

    Malecka, Anna; Wang, Qunwei; Shah, Sabaria; Sutavani, Ruhcha V.; Spendlove, Ian; Ramage, Judith M.; Greensmith, Julie; Franks, Hester A.; Gough, Michael J.; Saalbach, Anja; Patel, Poulam M.; Jackson, Andrew M.

    2016-01-01

    Dendritic cell function is modulated by stromal cells, including fibroblasts. Although poorly understood, the signals delivered through this crosstalk substantially alter dendritic cell biology. This is well illustrated with release of TNF-α/IL-1β from activated dendritic cells, promoting PGE2 secretion from stromal fibroblasts. This instructs dendritic cells to up-regulate IL-23, a key Th17-polarizing cytokine. We previously showed that ionizing radiation inhibited IL-23 production by human dendritic cells in vitro. In the present study, we investigated the hypothesis that dendritic cell-fibroblast crosstalk overcomes the suppressive effect of ionizing radiation to support appropriately polarized Th17 responses. Radiation (1–6 Gy) markedly suppressed IL-23 secretion by activated dendritic cells (P < 0.0001) without adversely impacting their viability and consequently, inhibited the generation of Th17 responses. Cytokine suppression by ionizing radiation was selective, as there was no effect on IL-1β, -6, -10, and -27 or TNF-α and only a modest (11%) decrease in IL-12p70 secretion. Coculture with fibroblasts augmented IL-23 secretion by irradiated dendritic cells and increased Th17 responses. Importantly, in contrast to dendritic cells, irradiated fibroblasts maintained their capacity to respond to TNF-α/IL-1β and produce PGE2, thus providing the key intermediary signals for successful dendritic cell-fibroblasts crosstalk. In summary, stromal fibroblasts support Th17-polarizing cytokine production by dendritic cells that would otherwise be suppressed in an irradiated microenvironment. This has potential ramifications for understanding the immune response to local radiotherapy. These findings underscore the need to account for the impact of microenvironmental factors, including stromal cells, in understanding the control of immunity. PMID:27049023

  3. Neuroimmune interactions: dendritic cell modulation by the sympathetic nervous system.

    PubMed

    Takenaka, Maisa C; Guereschi, Marcia G; Basso, Alexandre S

    2017-02-01

    Dendritic cells are of paramount importance bridging innate and adaptive immune responses. Depending on the context, after sensing environmental antigens, commensal microorganisms, pathogenic agents, or antigens from the diet, dendritic cells may drive either different effector adaptive immune responses or tolerance, avoiding tissue damage. Although the plasticity of the immune response and the capacity to regulate itself are considered essential to orchestrate appropriate physiological responses, it is known that the nervous system plays a relevant role controlling immune cell function. Dendritic cells present in the skin, the intestine, and lymphoid organs, besides expressing adrenergic receptors, can be reached by neurotransmitters released by sympathetic fibers innervating these tissues. These review focus on how neurotransmitters from the sympathetic nervous system can modulate dendritic cell function and how this may impact the immune response and immune-mediated disorders.

  4. Increased FcγRII expression and aberrant tumour necrosis factor α production by mature dendritic cells from patients with active rheumatoid arthritis

    PubMed Central

    Radstake, T; Blom, A; Sloetjes, A; van Gorselen, E O F; Pesman, G; Engelen, L; Torensma, R; van den Berg, W B; Figdor, C; van Lent, P L E M; Adema, G; Barrera, P

    2004-01-01

    Objectives: To investigate potential differences in phenotype and behaviour of immature (iDC) and mature dendritic cells (mDC) from patients with RA and healthy subjects. Methods: iDC and mDC were derived from blood monocytes of patients with RA and healthy controls following standardised protocols. FACS was used to analyse expression of FcγRI, II, and III and molecules to characterise DC. Discrimination between FcγRIIa and FcγRIIb was achieved by RT-PCR. Immunohistochemistry was performed on synovial biopsy specimens of three patients with RA and three healthy controls. TNFα production by iDC and mDC upon FcγR dependent stimulation was compared between patients with RA and controls by ELISA. Results: iDC from patients with active RA but not from patients with inactive RA or healthy controls markedly up regulated FcγRII. mDC from patients with active RA also lacked the physiological down regulation of FcγRII that occurs upon maturation in both control groups. RT-PCR analysis confirmed the increased expression of FcγRII in RA—especially marked for FcγRIIb. FcγR dependent stimulation of DC using antigen-IgG immune complexes (IC) significantly increased TNFα production by DC from healthy subjects, but significantly decreased TNFα by DC from patients with RA. Overlapping expression patterns between FcγRII and DC-LAMP in the synovial tissue of patients with RA imply that in vivo, also, mature DC express increased levels of FcγRIIb. Conclusion: The presence and altered characteristics of DC during active RA suggest that DC help to modulate autoimmunity in RA. Further studies should elucidate the role of local factors in altering the function of DC in RA and in increasing expression of FcγRII. PMID:15547078

  5. BDNF over-expression increases olfactory bulb granule cell dendritic spine density in vivo

    PubMed Central

    McDole, Brittnee; Isgor, Ceylan; Pare, Christopher; Guthrie, Kathleen

    2015-01-01

    Olfactory bulb granule cells are axon-less, inhibitory interneurons that regulate the activity of the excitatory output neurons, the mitral and tufted cells, through reciprocal dendrodendritic synapses located on granule cell spines. These contacts are established in the distal apical dendritic compartment, while granule cell basal dendrites and more proximal apical segments bear spines that receive glutamatergic inputs from the olfactory cortices. This synaptic connectivity is vital to olfactory circuit function and is remodeled during development, and in response to changes in sensory activity and lifelong granule cell neurogenesis. Manipulations that alter levels of the neurotrophin brain-derived neurotrophic factor (BDNF) in vivo have significant effects on dendritic spine morphology, maintenance and activity-dependent plasticity for a variety of CNS neurons, yet little is known regarding BDNF effects on bulb granule cell spine maturation or maintenance. Here we show that, in vivo, sustained bulbar over-expression of BDNF produces a marked increase in granule cell spine density that includes an increase in mature spines on their apical dendrites. Morphometric analysis demonstrated that changes in spine density were most notable in the distal and proximal apical domains, indicating that multiple excitatory inputs are potentially modified by BDNF. Our results indicate that increased levels of endogenous BDNF can promote the maturation and/or maintenance of dendritic spines on granule cells, suggesting a role for this factor in modulating granule cell functional connectivity within adult olfactory circuitry. PMID:26211445

  6. Investigating Evolutionary Conservation of Dendritic Cell Subset Identity and Functions

    PubMed Central

    Vu Manh, Thien-Phong; Bertho, Nicolas; Hosmalin, Anne; Schwartz-Cornil, Isabelle; Dalod, Marc

    2015-01-01

    Dendritic cells (DCs) were initially defined as mononuclear phagocytes with a dendritic morphology and an exquisite efficiency for naïve T-cell activation. DC encompass several subsets initially identified by their expression of specific cell surface molecules and later shown to excel in distinct functions and to develop under the instruction of different transcription factors or cytokines. Very few cell surface molecules are expressed in a specific manner on any immune cell type. Hence, to identify cell types, the sole use of a small number of cell surface markers in classical flow cytometry can be deceiving. Moreover, the markers currently used to define mononuclear phagocyte subsets vary depending on the tissue and animal species studied and even between laboratories. This has led to confusion in the definition of DC subset identity and in their attribution of specific functions. There is a strong need to identify a rigorous and consensus way to define mononuclear phagocyte subsets, with precise guidelines potentially applicable throughout tissues and species. We will discuss the advantages, drawbacks, and complementarities of different methodologies: cell surface phenotyping, ontogeny, functional characterization, and molecular profiling. We will advocate that gene expression profiling is a very rigorous, largely unbiased and accessible method to define the identity of mononuclear phagocyte subsets, which strengthens and refines surface phenotyping. It is uniquely powerful to yield new, experimentally testable, hypotheses on the ontogeny or functions of mononuclear phagocyte subsets, their molecular regulation, and their evolutionary conservation. We propose defining cell populations based on a combination of cell surface phenotyping, expression analysis of hallmark genes, and robust functional assays, in order to reach a consensus and integrate faster the huge but scattered knowledge accumulated by different laboratories on different cell types, organs, and

  7. Tolerogenic and Activatory Plasmacytoid Dendritic Cells in Autoimmunity

    PubMed Central

    Guéry, Leslie; Hugues, Stéphanie

    2013-01-01

    Plasmacytoid dendritic cells (pDCs) are a particular subset of DCs that link innate and adaptive immunity. They are responsible for the substantial production of type 1 interferon (IFN-I) in response to viral RNA or DNA through activation of TLR7 and 9. Furthermore, pDCs present antigens (Ag) and induce naïve T cell differentiation. It has been demonstrated that pDCs can induce immunogenic T cell responses through differentiation of cytotoxic CD8+ T cells and effector CD4+ T cells. Conversely, pDCs exhibit strong tolerogenic functions by inducing CD8+ T cell deletion, CD4+ T cell anergy, and Treg differentiation. However, since IFN-I produced by pDCs efficiently activates and recruits conventional DCs, B cells, T cells, and NK cells, pDCs also indirectly affect the nature and the amplitude of adaptive immune responses. As a consequence, the precise role of Ag-presenting functions of pDCs in adaptive immunity has been difficult to dissect in vivo. Additionally, different experimental procedures led to conflicting results regarding the outcome of T cell responses induced by pDCs. During the development of autoimmunity, pDCs have been shown to play both immunogenic and tolerogenic functions depending on disease, disease progression, and the experimental conditions. In this review, we will discuss the relative contribution of innate and adaptive pDC functions in modulating T cell responses, particularly during the development of autoimmunity. PMID:23508732

  8. Metabolic reprogramming in macrophages and dendritic cells in innate immunity

    PubMed Central

    Kelly, Beth; O'Neill, Luke AJ

    2015-01-01

    Activation of macrophages and dendritic cells (DCs) by pro-inflammatory stimuli causes them to undergo a metabolic switch towards glycolysis and away from oxidative phosphorylation (OXPHOS), similar to the Warburg effect in tumors. However, it is only recently that the mechanisms responsible for this metabolic reprogramming have been elucidated in more detail. The transcription factor hypoxia-inducible factor-1α (HIF-1α) plays an important role under conditions of both hypoxia and normoxia. The withdrawal of citrate from the tricarboxylic acid (TCA) cycle has been shown to be critical for lipid biosynthesis in both macrophages and DCs. Interference with this process actually abolishes the ability of DCs to activate T cells. Another TCA cycle intermediate, succinate, activates HIF-1α and promotes inflammatory gene expression. These new insights are providing us with a deeper understanding of the role of metabolic reprogramming in innate immunity. PMID:26045163

  9. Phenotype and function of nasal dendritic cells

    PubMed Central

    Lee, Haekyung; Ruane, Darren; Law, Kenneth; Ho, Yan; Garg, Aakash; Rahman, Adeeb; Esterházy, Daria; Cheong, Cheolho; Goljo, Erden; Sikora, Andrew G.; Mucida, Daniel; Chen, Benjamin; Govindraj, Satish; Breton, Gaëlle; Mehandru, Saurabh

    2015-01-01

    Intranasal vaccination generates immunity across local, regional and distant sites. However, nasal dendritic cells (DC), pivotal for the induction of intranasal vaccine- induced immune responses, have not been studied in detail. Here, using a variety of parameters, we define nasal DCs in mice and humans. Distinct subsets of “classical” DCs, dependent on the transcription factor zbtb46 were identified in the murine nose. The murine nasal DCs were FLT3 ligand-responsive and displayed unique phenotypic and functional characteristics including the ability to present antigen, induce an allogeneic T cell response and migrate in response to LPS or live bacterial pathogens. Importantly, in a cohort of human volunteers, BDCA-1+ DCs were observed to be the dominant nasal DC population at steady state. During chronic inflammation, the frequency of both BDCA-1+ and BDCA-3hi DCs was reduced in the nasal tissue, associating the loss of these immune sentinels with chronic nasal inflammation. The present study is the first detailed description of the phenotypic, ontogenetic and functional properties of nasal DCs and will inform the design of preventative immunization strategies as well as therapeutic modalities against chronic rhinosinusitis. PMID:25669151

  10. Contribution of Fcγ receptors to human respiratory syncytial virus pathogenesis and the impairment of T-cell activation by dendritic cells.

    PubMed

    Gómez, Roberto S; Ramirez, Bruno A; Céspedes, Pablo F; Cautivo, Kelly M; Riquelme, Sebastián A; Prado, Carolina E; González, Pablo A; Kalergis, Alexis M

    2016-01-01

    Human respiratory syncytial virus (hRSV) is the leading cause of infant hospitalization related to respiratory disease. Infection with hRSV produces abundant infiltration of immune cells into the airways, which combined with an exacerbated pro-inflammatory immune response can lead to significant damage to the lungs. Human RSV re-infection is extremely frequent, suggesting that this virus may have evolved molecular mechanisms that interfere with host adaptive immunity. Infection with hRSV can be reduced by administering a humanized neutralizing antibody against the virus fusion protein in high-risk infants. Although neutralizing antibodies against hRSV effectively block the infection of airway epithelial cells, here we show that both, bone marrow-derived dendritic cells (DCs) and lung DCs undergo infection with IgG-coated virus (hRSV-IC), albeit abortive. Yet, this is enough to negatively modulate DC function. We observed that such a process is mediated by Fcγ receptors (FcγRs) expressed on the surface of DCs. Remarkably, we also observed that in the absence of hRSV-specific antibodies FcγRIII knockout mice displayed significantly less cellular infiltration in the lungs after hRSV infection, compared with wild-type mice, suggesting a potentially harmful, IgG-independent role for this receptor in hRSV disease. Our findings support the notion that FcγRs can contribute significantly to the modulation of DC function by hRSV and hRSV-IC. Further, we provide evidence for an involvement of FcγRIII in the development of hRSV pathogenesis.

  11. Oral Wild-Type Salmonella Typhi Challenge Induces Activation of Circulating Monocytes and Dendritic Cells in Individuals Who Develop Typhoid Disease.

    PubMed

    Toapanta, Franklin R; Bernal, Paula J; Fresnay, Stephanie; Darton, Thomas C; Jones, Claire; Waddington, Claire S; Blohmke, Christoph J; Dougan, Gordon; Angus, Brian; Levine, Myron M; Pollard, Andrew J; Sztein, Marcelo B

    2015-06-01

    A new human oral challenge model with wild-type Salmonella Typhi (S. Typhi) was recently developed. In this model, ingestion of 104 CFU of Salmonella resulted in 65% of subjects developing typhoid fever (referred here as typhoid diagnosis -TD-) 5-10 days post-challenge. TD criteria included meeting clinical (oral temperature ≥38°C for ≥12 h) and/or microbiological (S. Typhi bacteremia) endpoints. One of the first lines of defense against pathogens are the cells of the innate immune system (e.g., monocytes, dendritic cells -DCs-). Various changes in circulating monocytes and DCs have been described in the murine S. Typhimurium model; however, whether similar changes are present in humans remains to be explored. To address these questions, a subset of volunteers (5 TD and 3 who did not develop typhoid despite oral challenge -NoTD-) were evaluated for changes in circulating monocytes and DCs. Expression of CD38 and CD40 were upregulated in monocytes and DCs in TD volunteers during the disease days (TD-0h to TD-96h). Moreover, integrin α4β7, a gut homing molecule, was upregulated on monocytes but not DCs. CD21 upregulation was only identified in DCs. These changes were not observed among NoTD volunteers despite the same oral challenge. Moreover, monocytes and DCs from NoTD volunteers showed increased binding to S. Typhi one day after challenge. These monocytes showed phosphorylation of p38MAPK, NFkB and Erk1/2 upon stimulation with S. Typhi-LPS-QDot micelles. In contrast, monocytes from TD volunteers showed only a moderate increase in S. Typhi binding 48 h and 96 h post-TD, and only Erk1/2 phosphorylation. This is the first study to describe different activation and migration profiles, as well as differential signaling patterns, in monocytes and DCs which relate directly to the clinical outcome following oral challenge with wild type S. Typhi.

  12. Spatial modelling of brief and long interactions between T cells and dendritic cells.

    PubMed

    Beltman, Joost B; Marée, Athanasius F M; de Boer, Rob J

    2007-06-01

    In the early phases of an immune response, T cells of appropriate antigen specificity become activated by antigen-presenting cells in secondary lymphoid organs. Two-photon microscopy imaging experiments have shown that this stimulation occurs in distinct stages during which T cells exhibit different motilities and interactions with dendritic cells (DCs). In this paper, we utilize the Cellular Potts Model, a model formalism that takes cell shapes and cellular interactions explicitly into account, to simulate the dynamics of, and interactions between, T cells and DCs in the lymph node paracortex. Our three-dimensional simulations suggest that the initial decrease in T-cell motility after antigen appearance is due to "stop signals" transmitted by activated DCs to T cells. The long-lived interactions that occur at a later stage can only be explained by the presence of both stop signals and a high adhesion between specific T cells and antigen-bearing DCs. Furthermore, our results indicate that long-lasting contacts with T cells are promoted when DCs retract dendrites that detect a specific contact at lower velocities than other dendrites. Finally, by performing long simulations (after prior fitting to short time scale data) we are able to provide an estimate of the average contact duration between T cells and DCs.

  13. Local GM-CSF-Dependent Differentiation and Activation of Pulmonary Dendritic Cells and Macrophages Protect against Progressive Cryptococcal Lung Infection in Mice.

    PubMed

    Chen, Gwo-Hsiao; Teitz-Tennenbaum, Seagal; Neal, Lori M; Murdock, Benjamin J; Malachowski, Antoni N; Dils, Anthony J; Olszewski, Michal A; Osterholzer, John J

    2016-02-15

    Patients with acquired deficiency in GM-CSF are susceptible to infections with Cryptococcus neoformans and other opportunistic fungi. We previously showed that GM-CSF protects against progressive fungal disease using a murine model of cryptococcal lung infection. To better understand the cellular and molecular mechanisms through which GM-CSF enhances antifungal host defenses, we investigated temporal and spatial relationships between myeloid and lymphoid immune responses in wild-type C57BL/6 mice capable of producing GM-CSF and GM-CSF-deficient mice infected with a moderately virulent encapsulated strain of C. neoformans (strain 52D). Our data demonstrate that GM-CSF deficiency led to a reduction in: 1) total lung leukocyte recruitment; 2) Th2 and Th17 responses; 3) total numbers of CD11b(+) dendritic cells (DC) and CD11b(-) and CD11b(+) macrophages (Mϕ); 4) DC and Mϕ activation; and 5) localization of DC and Mϕ to the microanatomic sites of alveolar infection. In contrast, GM-CSF deficiency resulted in increased accumulation of DC and Mϕ precursors, namely Ly-6C(high) monocytes, in the blood and lungs of infected mice. Collectively, these results show that GM-CSF promotes the local differentiation, accumulation, activation, and alveolar localization of lung DC and Mϕ in mice with cryptococcal lung infection. These findings identify GM-CSF as central to the protective immune response that prevents progressive fungal disease and thus shed new light on the increased susceptibility to these infections observed in patients with acquired GM-CSF deficiency.

  14. Integrin Activation Through the Hematopoietic Adapter Molecule ADAP Regulates Dendritic Development of Hippocampal Neurons.

    PubMed

    Thiere, Marlen; Kliche, Stefanie; Müller, Bettina; Teuber, Jan; Nold, Isabell; Stork, Oliver

    2016-01-01

    Integrin-mediated cell adhesion and signaling is of critical importance for neuronal differentiation. Recent evidence suggests that an "inside-out" activation of β1-integrin, similar to that observed in hematopoietic cells, contributes to the growth and branching of dendrites. In this study, we investigated the role of the hematopoietic adaptor protein adhesion and degranulation promoting adapter protein (ADAP) in these processes. We demonstrate the expression of ADAP in the developing and adult nervous hippocampus, and in outgrowing dendrites of primary hippocampal neurons. We further show that ADAP occurs in a complex with another adaptor protein signal-transducing kinase-associated phosphoprotein-homolog (SKAP-HOM), with the Rap1 effector protein RAPL and the Hippo kinase macrophage-stimulating 1 (MST1), resembling an ADAP/SKAP module that has been previously described in T-cells and is critically involved in "inside-out" activation of integrins. Knock down of ADAP resulted in reduced expression of activated β1-integrin on dendrites. It furthermore reduced the differentiation of developing neurons, as indicated by reduced dendrite growth and decreased expression of the dendritic marker microtubule-associated protein 2 (MAP2). Our data suggest that an ADAP-dependent integrin-activation similar to that described in hematopoietic cells contributes to the differentiation of neuronal cells.

  15. Integrin Activation Through the Hematopoietic Adapter Molecule ADAP Regulates Dendritic Development of Hippocampal Neurons

    PubMed Central

    Thiere, Marlen; Kliche, Stefanie; Müller, Bettina; Teuber, Jan; Nold, Isabell; Stork, Oliver

    2016-01-01

    Integrin-mediated cell adhesion and signaling is of critical importance for neuronal differentiation. Recent evidence suggests that an “inside-out” activation of β1-integrin, similar to that observed in hematopoietic cells, contributes to the growth and branching of dendrites. In this study, we investigated the role of the hematopoietic adaptor protein adhesion and degranulation promoting adapter protein (ADAP) in these processes. We demonstrate the expression of ADAP in the developing and adult nervous hippocampus, and in outgrowing dendrites of primary hippocampal neurons. We further show that ADAP occurs in a complex with another adaptor protein signal-transducing kinase-associated phosphoprotein-homolog (SKAP-HOM), with the Rap1 effector protein RAPL and the Hippo kinase macrophage-stimulating 1 (MST1), resembling an ADAP/SKAP module that has been previously described in T-cells and is critically involved in “inside-out” activation of integrins. Knock down of ADAP resulted in reduced expression of activated β1-integrin on dendrites. It furthermore reduced the differentiation of developing neurons, as indicated by reduced dendrite growth and decreased expression of the dendritic marker microtubule-associated protein 2 (MAP2). Our data suggest that an ADAP-dependent integrin-activation similar to that described in hematopoietic cells contributes to the differentiation of neuronal cells. PMID:27746719

  16. Endogenous Galectin-3 Is Localized in Membrane Lipid Rafts and Regulates Migration of Dendritic Cells

    PubMed Central

    Hsu, Daniel K.; Chernyavsky, Alexander I.; Chen, Huan-Yuan; Yu, Lan; Grando, Sergei A.; Liu, Fu-Tong

    2008-01-01

    This study reveals a function of endogenous galectin-3, an animal lectin recognizing β-galactosides, in regulating dendritic cell motility both in vitroand in vivo,which to our knowledge is unreported. First, galectin-3-deficient (gal3−/−) bone marrow-derived dendritic cells exhibited defective chemotaxis compared to gal3+/+ cells. Second, cutaneous dendritic cells in gal3−/− mice displayed reduced migration to draining lymph nodes upon hapten stimulation compared to gal3+/+ mice. Moreover, gal3−/− mice were impaired in the development of contact hypersensitivity relative to gal3+/+ mice in response to a hapten, a process in which dendritic cell trafficking to lymph nodes is critical. In addition, defective signaling was detected in gal3−/− cells upon chemokine receptor activation. By immunofluorescence microscopy, we observed that galectin-3 is localized in membrane ruffles and lamellipodia in stimulated dendritic cells and macrophages. Furthermore, galectin-3 was enriched in lipid raft domains under these conditions. Finally, we determined that ruffles on gal3−/− cells contained structures with lower complexity compared to gal3+/+ cells. In view of the participation of membrane ruffles in signal transduction and cell motility, we conclude that galectin-3 regulates cell migration by functioning at these structures. PMID:18843294

  17. Lipopolysaccharide-pretreated plasmacytoid dendritic cells ameliorate experimental chronic kidney disease.

    PubMed

    Zheng, Dong; Cao, Qi; Lee, Vincent W S; Wang, Ya; Zheng, Guoping; Wang, YuanMin; Tan, Thian Kui; Wang, Changqi; Alexander, Stephen I; Harris, David C H; Wang, Yiping

    2012-05-01

    Plasmacytoid dendritic cells play important roles in inducing immune tolerance, preventing allograft rejection, and regulating immune responses in both autoimmune disease and graft-versus-host disease. In order to evaluate a possible protective effect of plasmacytoid dendritic cells against renal inflammation and injury, we purified these cells from mouse spleens and adoptively transferred lipopolysaccharide (LPS)-treated cells, modified ex vivo, into mice with adriamycin nephropathy. These LPS-treated cells localized to the kidney cortex and the lymph nodes draining the kidney, and protected the kidney from injury during adriamycin nephropathy. Glomerulosclerosis, tubular atrophy, interstitial expansion, proteinuria, and creatinine clearance were significantly reduced in mice with adriamycin nephropathy subsequently treated with LPS-activated plasmacytoid dendritic cells as compared to the kidney injury in mice given naive plasmacytoid dendritic cells. In addition, LPS-pretreated cells, but not naive plasmacytoid dendritic cells, convert CD4+CD25- T cells into Foxp3+ regulatory T cells and suppress the proinflammatory cytokine production of endogenous renal macrophages. This may explain their ability to protect against renal injury in adriamycin nephropathy.

  18. Bovine NK cells acquire cytotoxic activity and produce IFN-gamma after stimulation by Mycobacterium bovis BCG- or Babesia bovis-exposed splenic dendritic cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early interactions of innate immune cell populations such as DC, monocytes/macrophages and NK cells, can affect the ability of the acquired immune response to control infection of intracellular microorganisms. In this study, we investigated the activation of bovine NK cells by CD13+ splenic DC or CD...

  19. Impaired dendritic inhibition leads to epileptic activity in a computer model of CA3.

    PubMed

    Sanjay, M; Neymotin, Samuel A; Krothapalli, Srinivasa B

    2015-11-01

    Temporal lobe epilepsy (TLE) is a common type of epilepsy with hippocampus as the usual site of origin. The CA3 subfield of hippocampus is reported to have a low epileptic threshold and hence initiates the disorder in patients with TLE. This study computationally investigates how impaired dendritic inhibition of pyramidal cells in the vulnerable CA3 subfield leads to generation of epileptic activity. A model of CA3 subfield consisting of 800 pyramidal cells, 200 basket cells (BC) and 200 Oriens-Lacunosum Moleculare (O-LM) interneurons was used. The dendritic inhibition provided by O-LM interneurons is reported to be selectively impaired in some TLEs. A step-wise approach is taken to investigate how alterations in network connectivity lead to generation of epileptic patterns. Initially, dendritic inhibition alone was reduced, followed by an increase in the external inputs received at the distal dendrites of pyramidal cells, and finally additional changes were made at the synapses between all neurons in the network. In the first case, when the dendritic inhibition of pyramidal cells alone was reduced, the local field potential activity changed from a theta-modulated gamma pattern to a prominently gamma frequency pattern. In the second case, in addition to this reduction of dendritic inhibition, with a simultaneous large increase in the external excitatory inputs received by pyramidal cells, the basket cells entered a state of depolarization block, causing the network to generate a typical ictal activity pattern. In the third case, when the dendritic inhibition onto the pyramidal cells was reduced and changes were simultaneously made in synaptic connectivity between all neurons in the network, the basket cells were again observed to enter depolarization block. In the third case, impairment of dendritic inhibition required to generate an ictal activity pattern was lesser than the two previous cases. Moreover, the ictal like activity began earlier in the third case

  20. Melanoma cell-derived exosomes alter macrophage and dendritic cell functions in vitro.

    PubMed

    Marton, Annamaria; Vizler, Csaba; Kusz, Erzsebet; Temesfoi, Viktoria; Szathmary, Zsuzsa; Nagy, Krisztina; Szegletes, Zsolt; Varo, Gyorgy; Siklos, Laszlo; Katona, Robert L; Tubak, Vilmos; Howard, O M Zack; Duda, Erno; Minarovits, Janos; Nagy, Katalin; Buzas, Krisztina

    2012-01-01

    To clarify controversies in the literature of the field, we have purified and characterized B16F1 melanoma cell derived exosomes (mcd-exosomes) then we attempted to dissect their immunological activities. We tested how mcd-exosomes influence CD4+ T cell proliferation induced by bone marrow derived dendritic cells; we quantified NF-κB activation in mature macrophages stimulated with mcd-exosomes, and we compared the cytokine profile of LPS-stimulated, IL-4 induced, and mcd-exosome treated macrophages. We observed that mcd-exosomes helped the maturation of dendritic cells, enhancing T cell proliferation induced by the treated dendritic cells. The exosomes also activated macrophages, as measured by NF-κB activation. The cytokine and chemokine profile of macrophages treated with tumor cell derived exosomes showed marked differences from those induced by either LPS or IL-4, and it suggested that exosomes may play a role in the tumor progression and metastasis formation through supporting tumor immune escape mechanisms.

  1. New generation of dendritic cell vaccines.

    PubMed

    Radford, Kristen J; Caminschi, Irina

    2013-02-01

    Dendritic cells (DC) play a pivotal role in the induction and regulation of immune responses, including the induction of cytotoxic T lymphocytes (CTL) responses. These are essential for the eradication of cancers and pathogens including HIV and malaria, for which there are currently no effective vaccines. New developments in our understanding of DC biology have identified the key DC subset responsible for CTL induction, which is now an attractive candidate to target for vaccination. These DC are characterized by expression of novel markers Clec9A and XCR1, and a specialized capacity to cross-present antigen (Ag) from tumors and pathogens that do not directly infect DC. New generation DC vaccines that specifically target the cross-presenting DC in vivo have already demonstrated potential in preclinical animal models but the challenge remains to translate these findings into clinically efficacous vaccines in man. This has been greatly facilitated by the recent identification of the equivalent Clec9A(+) XCR1(+) cross-presenting DC in human lymphoid tissues and peripheral tissues that are key sites for vaccination administration. These findings combined with further studies on DC subset biology have important implications for the design of new CTL-mediated vaccines.

  2. Role of plasmacytoid dendritic cells in lung-associated inflammation.

    PubMed

    Sorrentino, Rosalinda; Morello, Silvana; Pinto, Aldo

    2010-06-01

    Plasmacytoid Dendritic Cells (pDCs) are important immune orchestrators. One of the most important features of pDCs is the high production of IFN type I that can promote the polarization of T cells towards a Th1 phenotype. Recent evidence has highlighted the relevance of pDCs in therapy for asthma, lung infections and cancer. However, it is to note that pDCs can also participate in suppressive networks via the recruitment of T regulatory cells. Further studies are needed to understand pDCs activity in the lung, not only to elucidate pathological mechanisms, but also to lead towards new therapeutic approaches for lung inflammatory-based diseases. The article also outlines recent patents on plasmacytoid DCs.

  3. The effect of dendritic cells on the retinal cell transplantation

    SciTech Connect

    Oishi, Akio; Nagai, Takayuki; Mandai, Michiko Takahashi, Masayo; Yoshimura, Nagahisa

    2007-11-16

    The potential of bone marrow cell-derived immature dendritic cells (myeloid iDCs) in modulating the efficacy of retinal cell transplantation therapy was investigated. (1) In vitro, myeloid iDCs but not BMCs enhanced the survival and proliferation of embryonic retinal cells, and the expression of various neurotrophic factors by myeloid iDCs was confirmed with RT-PCR. (2) In subretinal transplantation, neonatal retinal cells co-transplanted with myeloid iDCs showed higher survival rate compared to those transplanted without myeloid iDCs. (3) CD8 T-cells reactive against donor retinal cells were significantly increased in the mice with transplantation of retinal cells alone. These results suggested the beneficial effects of the use of myeloid iDCs in retinal cell transplantation therapy.

  4. Activation of Langerhans-Type Dendritic Cells Alters Human Cytomegalovirus Infection and Reactivation in a Stimulus-Dependent Manner

    PubMed Central

    Coronel, Roxanne; Jesus, Desyree M.; Dalle Ore, Lucia; Mymryk, Joe S.; Hertel, Laura

    2016-01-01

    Oral mucosal Langerhans cells (LC) are likely to play important roles in host defense against infection by human cytomegalovirus (CMV). We previously showed that in vitro-differentiated immature LC (iLC) populations contain smaller amounts of infected cells but produce higher yields than mature LC (mLC) cultures, obtained by iLC stimulation with fetal bovine serum (FBS), CD40 ligand (CD40L) and lipopolysaccharide (LPS). Here, we sought to determine if exposure to select stimuli can improve LC permissiveness to infection, if specific components of the mLC cocktail are responsible for lowering viral yields, if this is due to defects in progeny production or release, and if these restrictions are also effective against reactivated virus. None of the stimuli tested extended the proportion of infected cells to 100%, suggesting that the block to infection onset cannot be fully removed. While CD40L and FBS exerted positive effects on viral progeny production per cell, stimulation with LPS alone or in combination with CD40L was detrimental. Reductions in viral titers were not due to defects in progeny release, and the permissive or restrictive intracellular environment established upon exposure to each stimulus appeared to act in a somewhat similar way toward lytic and latent infections. PMID:27683575

  5. Regulation of AMPA and NMDA receptor-mediated EPSPs in dendritic trees of thalamocortical cells

    PubMed Central

    Lajeunesse, Francis; Kröger, Helmut

    2013-01-01

    Two main excitatory synapses are formed at the dendritic arbor of first-order nuclei thalamocortical (TC) neurons. Ascending sensory axons primarily establish contacts at large proximal dendrites, whereas descending corticothalamic fibers form synapses on thin distal dendrites. With the use of a multicomparment computational model based on fully reconstructed TC neurons from the ventroposterolateral nucleus of the cat, we compared local responses at the site of stimulation as well as somatic responses induced by both α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)- and N-methyl-d-aspartate receptor (NMDAR)-mediated currents. We found that AMPAR-mediated responses, when synapses were located at proximal dendrites, induced a larger depolarization at the level of soma, whereas NMDAR-mediated responses were more efficient for synapses located at distal dendrites. The voltage transfer and transfer impedance were higher for NMDAR than for AMPAR activation at any location. For both types of synaptic current and for both input locations at the dendritic arbor, somatic responses were characterized by a low variability despite the large variability found in local responses in dendrites. The large neurons had overall smaller somatic responses than small neurons, but this relation was not found in local dendritic responses. We conclude that in TC cells, the dendritic location of small synaptic inputs does not play a major role in the amplitude of a somatic response, but the size of the neuron does. The variability of response amplitude between cells was much larger than the variability within cells. This suggests possible functional segregation of TC neurons of different size. PMID:23100131

  6. Dendrites of rod bipolar cells sprout in normal aging retina.

    PubMed

    Liets, Lauren C; Eliasieh, Kasra; van der List, Deborah A; Chalupa, Leo M

    2006-08-08

    The aging nervous system is known to manifest a variety of degenerative and regressive events. Here we report the unexpected growth of dendrites in the retinas of normal old mice. The dendrites of many rod bipolar cells in aging mice were observed to extend well beyond their normal strata within the outer plexiform layer to innervate the outer nuclear layer where they appeared to form contacts with the spherules of rod photoreceptors. Such dendritic sprouting increased with age and was evident at all retinal eccentricities. These results provide evidence of retinal plasticity associated with normal aging.

  7. Organization of pyramidal cell apical dendrites and composition of dendritic clusters in the mouse: emphasis on primary motor cortex.

    PubMed

    Lev, D L; White, E L

    1997-02-01

    It has been proposed that neurons in sensory cortices are organized into modules that centre on clusters of apical dendrites belonging to layer V pyramidal neurons. In the present study, sections reacted for microtubule-associated protein (MAP2) were examined in order to determine the three-dimensional inter-relationships of pyramidal cell dendrites in mouse primary motor cortex (MsI) cortex. Results indicate that pyramidal cell dendrites in MsI cortex can be interpreted to be arranged in a modular fashion, and that these modules are organized similarly to those in the sensory areas of the cortex. Also included in the present study are experiments designed to determine if the clusters of apical dendrites, around which the modules are centred, are composed of dendrites belonging to one or to more than one type of projection cell. Callosal neurons in MsI cortex were labelled by the retrograde transport of horseradish peroxidase deposited onto severed callosal fibres in the contralateral hemisphere. Examination of tangential thin sections through layer IV of MsI cortex shows clusters of apical dendrites in which every dendrite is labelled with horseradish peroxidase. Adjacent clusters are composed of unlabelled dendrites, suggesting that the apical dendrites of callosal neurons aggregate to form clusters that are composed exclusively of dendrites belonging to this type of projection cell. These findings suggest a hitherto unsuspected degree of specificity in the cellular composition of cortical modules.

  8. Supralinear dendritic Ca2+ signalling in young developing CA1 pyramidal cells

    PubMed Central

    Pohle, Jörg; Bischofberger, Josef

    2014-01-01

    Although Ca2+ is critically important in activity-dependent neuronal development, not much is known about the regulation of dendritic Ca2+ signals in developing neurons. Here, we used ratiometric Ca2+ imaging to investigate dendritic Ca2+ signalling in rat hippocampal pyramidal cells during the first 1–4 weeks of postnatal development. We show that active dendritic backpropagation of Nav channel-dependent action potentials (APs) evoked already large dendritic Ca2+ transients in animals aged 1 week with amplitudes of ∼150 nm, similar to the amplitudes of ∼160 nM seen in animals aged 4 weeks. Although the AP-evoked dendritic Ca2+ load increased about four times during the first 4 weeks, the peak amplitude of free Ca2+ concentration was balanced by a four-fold increase in Ca2+ buffer capacity κs (∼70 vs. ∼280). Furthermore, Ca2+ extrusion rates increased with postnatal development, leading to a slower decay time course (∼0.2 s vs. ∼0.1 s) and more effective temporal summation of Ca2+ signals in young cells. Most importantly, during prolonged theta-burst stimulation dendritic Ca2+ signals were up to three times larger in cells at 1 week than at 4 weeks of age and much larger than predicted by linear summation, which is attributable to an activity-dependent slow-down of Ca2+ extrusion. As Ca2+ influx is four-fold smaller in young cells, the larger Ca2+ signals are generated using four times less ATP consumption. Taken together, the data suggest that active backpropagations regulate dendritic Ca2+ signals during early postnatal development. Remarkably, during prolonged AP firing, Ca2+ signals are several times larger in young than in mature cells as a result of activity-dependent regulation of Ca2+ extrusion rates. PMID:25239458

  9. Dendritic-tumor fusion cells in cancer immunotherapy.

    PubMed

    Takakura, Kazuki; Kajihara, Mikio; Ito, Zensho; Ohkusa, Toshifumi; Gong, Jianlin; Koido, Shigeo

    2015-03-01

    A promising area of clinical investigation is the use of cancer immunotherapy to treat cancer patients. Dendritic cells (DCs) operate as professional antigen-presenting cells (APCs) and play a critical role in the induction of antitumor immune responses. Thus, DC-based cancer immunotherapy represents a powerful strategy. One DC-based cancer immunotherapy strategy that has been investigated is the administration of fusion cells generated with DCs and whole tumor cells (DC-tumor fusion cells). The DC-tumor fusion cells can process a broad array of tumor-associated antigens (TAAs), including unidentified molecules, and present them through major histocompatibility complex (MHC) class I and II pathways in the context of co-stimulatory signals. Improving the therapeutic efficacy of DC-tumor fusion cell-based cancer immunotherapy requires increased immunogenicity of DCs and whole tumor cells. We discuss the potential ability of DC-tumor fusion cells to activate antigen-specific T cells and strategies to improve the immunogenicity of DC-tumor fusion cells as anticancer vaccines.

  10. Modulation of Dendritic Cell Immunobiology via Inhibition of 3-Hydroxy-3-Methylglutaryl-CoA (HMG-CoA) Reductase

    PubMed Central

    Luessi, Felix; Bendix, Ivo; Paterka, Magdalena; Prozorovski, Timour; Treue, Denise; Luenstedt, Sarah; Herz, Josephine; Siffrin, Volker; Infante-Duarte, Carmen; Zipp, Frauke; Waiczies, Sonia

    2014-01-01

    The maturation status of dendritic cells determines whether interacting T cells are activated or if they become tolerant. Previously we could induce T cell tolerance by applying a 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase inhibitor (HMGCRI) atorvastatin, which also modulates MHC class II expression and has therapeutic potential in autoimmune disease. Here, we aimed at elucidating the impact of this therapeutic strategy on T cell differentiation as a consequence of alterations in dendritic cell function. We investigated the effect of HMGCRI during differentiation of peripheral human monocytes and murine bone marrow precursors to immature DC in vitro and assessed their phenotype. To examine the stimulatory and tolerogenic capacity of these modulated immature dendritic cells, we measured proliferation and suppressive function of CD4+ T cells after stimulation with the modulated immature dendritic cells. We found that an HMGCRI, atorvastatin, prevents dendrite formation during the generation of immature dendritic cells. The modulated immature dendritic cells had a diminished capacity to take up and present antigen as well as to induce an immune response. Of note, the consequence was an increased capacity to differentiate naïve T cells towards a suppressor phenotype that is less sensitive to proinflammatory stimuli and can effectively inhibit the proliferation of T effector cells in vitro. Thus, manipulation of antigen-presenting cells by HMGCRI contributes to an attenuated immune response as shown by promotion of T cells with suppressive capacities. PMID:25013913

  11. Differential dendritic Ca2+ signalling in young and mature hippocampal granule cells

    PubMed Central

    Stocca, Gabriella; Schmidt-Hieber, Christoph; Bischofberger, Josef

    2008-01-01

    Neuronal activity is critically important for development and plasticity of dendrites, axons and synaptic connections. Although Ca2+ is an important signal molecule for these processes, not much is known about the regulation of the dendritic Ca2+ concentration in developing neurons. Here we used confocal Ca2+ imaging to investigate dendritic Ca2+ signalling in young and mature hippocampal granule cells, identified by the expression of the immature neuronal marker polysialated neural cell adhesion molecule (PSA-NCAM). Using the Ca2+-sensitive fluorescent dye OGB-5N, we found that both young and mature granule cells showed large action-potential evoked dendritic Ca2+ transients with similar amplitude of ∼200 nm, indicating active backpropagation of action potentials. However, the decay of the dendritic Ca2+ concentration back to baseline values was substantially different with a decay time constant of 550 ms in young versus 130 ms in mature cells, leading to a more efficient temporal summation of Ca2+ signals during theta-frequency stimulation in the young neurons. Comparison of the peak Ca2+ concentration and the decay measured with different Ca2+ indicators (OGB-5N, OGB-1) in the two populations of neurons revealed that the young cells had an ∼3 times smaller endogenous Ca2+-binding ratio (∼75 versus∼220) and an ∼10 times slower Ca2+ extrusion rate (∼170 s−1versus∼1800 s−1). These data suggest that the large dendritic Ca2+ signals due to low buffer capacity and slow extrusion rates in young granule cells may contribute to the activity-dependent growth and plasticity of dendrites and new synaptic connections. This will finally support differentiation and integration of young neurons into the hippocampal network. PMID:18591186

  12. Phenotypic and functional activation of hyporesponsive KIRnegNKG2Aneg human NK-cell precursors requires IL12p70 provided by Poly(I:C)-matured monocyte-derived dendritic cells.

    PubMed

    Curran, Shane A; Romano, Emanuela; Kennedy, Michael G; Hsu, Katharine C; Young, James W

    2014-10-01

    A functionally responsive natural killer (NK)-cell repertoire requires the acquisition of inhibitory NKG2A and killer immunoglobulin-like receptors (KIR) through pathways that remain undefined. Functional donor NK cells expressing KIRs for non-self class I MHC ligands contribute to a positive outcome after allogeneic hematopoietic stem cell transplantation (alloHSCT) by targeting HLA-matched recipient leukemic cells. Insofar as circulating donor conventional dendritic cells (DC) reconstitute with comparable kinetics with donor NK cells after alloHSCT, we used hyporesponsive KIRnegNKG2Aneg precursor cells to evaluate how specific DC subtypes generate a functionally active NK-cell repertoire. Both monocyte-derived DCs (moDC) and Langerhans-type DCs (LC) induce KIRnegNKG2Aneg precursor cells to express the inhibitory receptors NKG2A and KIR, without requiring cell proliferation. Poly(I:C)-matured moDCs significantly augmented the expression of NKG2A, but not KIR, in an IL12p70-dependent manner. Although all DC-stimulated KIRnegNKG2Aneg cells were able to acquire cytolytic activity against class I MHC-negative targets, the ability to secrete IFNγ was restricted to cells that were stimulated by IL12p70-producing, poly(I:C)-matured moDCs. This critical ability of poly(I:C)-matured moDCs to provide IL12p70 to developing KIRnegNKG2Aneg precursors results in a dom4inant, multifunctional, NKG2Apos NK-cell population that is capable of both cytolysis and IFNγ production. Poly(I:C)-matured moDCs are, therefore, the most effective conventional DC subtype for generating a functionally competent NK-cell repertoire by an IL12p70-dependent mechanism.

  13. Insights into dendritic cell function using advanced imaging modalities.

    PubMed

    Vyas, Jatin M

    2012-11-15

    The application of advanced imaging techniques to fundamental questions in immunology has provided insight into dendritic cell function and has challenged dogma created using static imaging of lymphoid tissue. The history of dendritic cell biology has a storied past and is tightly linked to imaging. The development of imaging techniques that emphasize live cell imaging in situ has provided not only breath-taking movies, but also novel insights into the importance of spatiotemporal relationships between antigen presenting cells and T cells. This review serves to provide a primer on two-photon microscopy, TIRF microscopy, spinning disk confocal microscopy and optical trapping and provides selective examples of insights gained from these tools on dendritic cell biology.

  14. Dendritic cell MST1 inhibits Th17 differentiation

    PubMed Central

    Li, Chunxiao; Bi, Yujing; Li, Yan; Yang, Hui; Yu, Qing; Wang, Jian; Wang, Yu; Su, Huilin; Jia, Anna; Hu, Ying; Han, Linian; Zhang, Jiangyuan; Li, Simin; Tao, Wufan; Liu, Guangwei

    2017-01-01

    Although the differentiation of CD4+T cells is widely studied, the mechanisms of antigen-presenting cell-dependent T-cell modulation are unclear. Here, we investigate the role of dendritic cell (DC)-dependent T-cell differentiation in autoimmune and antifungal inflammation and find that mammalian sterile 20-like kinase 1 (MST1) signalling from DCs negatively regulates IL-17 producing-CD4+T helper cell (Th17) differentiation. MST1 deficiency in DCs increases IL-17 production by CD4+T cells, whereas ectopic MST1 expression in DCs inhibits it. Notably, MST1-mediated DC-dependent Th17 differentiation regulates experimental autoimmune encephalomyelitis and antifungal immunity. Mechanistically, MST1-deficient DCs promote IL-6 secretion and regulate the activation of IL-6 receptor α/β and STAT3 in CD4+T cells in the course of inducing Th17 differentiation. Activation of the p38 MAPK signal is responsible for IL-6 production in MST1-deficient DCs. Thus, our results define the DC MST1–p38MAPK signalling pathway in directing Th17 differentiation. PMID:28145433

  15. Hyperactivation of STAT3 is involved in abnormal differentiation of dendritic cells in cancer.

    PubMed

    Nefedova, Yulia; Huang, Mei; Kusmartsev, Sergei; Bhattacharya, Raka; Cheng, Pingyan; Salup, Raoul; Jove, Richard; Gabrilovich, Dmitry

    2004-01-01

    Abnormal differentiation of myeloid cells is one of the hallmarks of cancer. However, the molecular mechanisms of this process remain elusive. In this study, we investigated the effect of tumor-derived factors on Janus kinase (Jak)/STAT signaling in myeloid cells during their differentiation into dendritic cells. Tumor cell conditioned medium induced activation of Jak2 and STAT3, which was associated with an accumulation of immature myeloid cells. Jak2/STAT3 activity was localized primarily in these myeloid cells, which prevented the differentiation of immature myeloid cells into mature dendritic cells. This differentiation was restored after removal of tumor-derived factors. Inhibition of STAT3 abrogated the negative effects of these factors on myeloid cell differentiation, and overexpression of STAT3 reproduced the effects of tumor-derived factors. Thus, this is a first demonstration that tumor-derived factors may affect myeloid cell differentiation in cancer via constitutive activation of Jak2/STAT3.

  16. Vaccination with Dendritic Cell Myeloma Fusions in Conjuction with Stem Cell Transplantation and PD-1 Blockade

    DTIC Science & Technology

    2015-07-01

    Award Number: W81XWH-09-1-0296 TITLE: Vaccination with Dendritic Cell Myeloma Fusions in Conjuction with Stem Cell Transplantation and PD-1...Addendum 3. DATES COVERED (From - To) 1May2014 - 30Apr2015 4. TITLE AND SUBTITLE Vaccination with Dendritic Cell Myeloma Fusions in Conjuction with Stem...anti-PD1 antibody (CT-011) alone (Cohort 1) and in conjunction with a dendritic cell/myeloma fusion cell vaccine (Cohort 2) following autologous

  17. Optimizing dendritic cell-based immunotherapy for cancer.

    PubMed

    Zhong, Hua; Shurin, Michael R; Han, Baohui

    2007-06-01

    Dendritic cells (DCs) are the most powerful professional antigen-presenting cells and are unique in their capability to initiate, maintain and regulate the intensity of primary immune responses, including specific antitumor responses. Development of practical procedures to prepare sufficient numbers of functional human DCs in culture from the peripheral blood precursors, paved the way for clinical trials to evaluate various DC-based strategies in patients with malignant diseases. However, no definite conclusions regarding the clinical and even immunological efficacy of DC vaccination can be stated, despite the fact that 12 years have passed since the first clinical trial utilizing DCs in cancer patients. Many unanswered questions hamper the development of DC-based vaccines, including the source of DC preparation and protocols for DC generation, activation and loading with tumor antigens, source of tumor antigens, route of vaccine administration and methods of immunomonitoring. Fortunately, in spite of the many obstacles, DC vaccines continue to hold promise for cancer therapy.

  18. Optimizing Dendritic Cell-Based Approaches for Cancer Immunotherapy

    PubMed Central

    Datta, Jashodeep; Terhune, Julia H.; Lowenfeld, Lea; Cintolo, Jessica A.; Xu, Shuwen; Roses, Robert E.; Czerniecki, Brian J.

    2014-01-01

    Dendritic cells (DC) are professional antigen-presenting cells uniquely suited for cancer immunotherapy. They induce primary immune responses, potentiate the effector functions of previously primed T-lymphocytes, and orchestrate communication between innate and adaptive immunity. The remarkable diversity of cytokine activation regimens, DC maturation states, and antigen-loading strategies employed in current DC-based vaccine design reflect an evolving, but incomplete, understanding of optimal DC immunobiology. In the clinical realm, existing DC-based cancer immunotherapy efforts have yielded encouraging but inconsistent results. Despite recent U.S. Federal and Drug Administration (FDA) approval of DC-based sipuleucel-T for metastatic castration-resistant prostate cancer, clinically effective DC immunotherapy as monotherapy for a majority of tumors remains a distant goal. Recent work has identified strategies that may allow for more potent “next-generation” DC vaccines. Additionally, multimodality approaches incorporating DC-based immunotherapy may improve clinical outcomes. PMID:25506283

  19. Deciphering the transcriptional network of the dendritic cell lineage.

    PubMed

    Miller, Jennifer C; Brown, Brian D; Shay, Tal; Gautier, Emmanuel L; Jojic, Vladimir; Cohain, Ariella; Pandey, Gaurav; Leboeuf, Marylene; Elpek, Kutlu G; Helft, Julie; Hashimoto, Daigo; Chow, Andrew; Price, Jeremy; Greter, Melanie; Bogunovic, Milena; Bellemare-Pelletier, Angelique; Frenette, Paul S; Randolph, Gwendalyn J; Turley, Shannon J; Merad, Miriam

    2012-09-01

    Although much progress has been made in the understanding of the ontogeny and function of dendritic cells (DCs), the transcriptional regulation of the lineage commitment and functional specialization of DCs in vivo remains poorly understood. We made a comprehensive comparative analysis of CD8(+), CD103(+), CD11b(+) and plasmacytoid DC subsets, as well as macrophage DC precursors and common DC precursors, across the entire immune system. Here we characterized candidate transcriptional activators involved in the commitment of myeloid progenitor cells to the DC lineage and predicted regulators of DC functional diversity in tissues. We identified a molecular signature that distinguished tissue DCs from macrophages. We also identified a transcriptional program expressed specifically during the steady-state migration of tissue DCs to the draining lymph nodes that may control tolerance to self tissue antigens.

  20. The role of the vascular dendritic cell network in atherosclerosis

    PubMed Central

    Alberts-Grill, Noah; Denning, Timothy L.; Rezvan, Amir

    2013-01-01

    A complex role has been described for dendritic cells (DCs) in the potentiation and control of vascular inflammation and atherosclerosis. Resident vascular DCs are found in the intima of atherosclerosis-prone vascular regions exposed to disturbed blood flow patterns. Several phenotypically and functionally distinct vascular DC subsets have been described. The functional heterogeneity of these cells and their contributions to vascular homeostasis, inflammation, and atherosclerosis are only recently beginning to emerge. Here, we review the available literature, characterizing the origin and function of known vascular DC subsets and their important role contributing to the balance of immune activation and immune tolerance governing vascular homeostasis under healthy conditions. We then discuss how homeostatic DC functions are disrupted during atherogenesis, leading to atherosclerosis. The effectiveness of DC-based “atherosclerosis vaccine” therapies in the treatment of atherosclerosis is also reviewed. We further provide suggestions for distinguishing DCs from macrophages and discuss important future directions for the field. PMID:23552284

  1. The diverging roles of dendritic cells in kidney allotransplantation.

    PubMed

    Podestà, Manuel Alfredo; Cucchiari, David; Ponticelli, Claudio

    2015-07-01

    Dendritic cells (DCs) are a family of antigen presenting cells that play a paramount role in bridging innate and adaptive immunity. In murine models several subtypes of DCs have been identified, including classical DCs, monocyte-derived DCs, and plasmacytoid DCs. Quiescent, immature DCs and some subtypes of plasmacytoid cells favor the expression of regulatory T cells, but in an inflammatory milieu DCs become mature and after intercepting the antigen migrate to lymphatic system where they present the antigen to naïve T cells. Transplant rejection largely depends on the phenotype and maturation of DCs. The ischemia-reperfusion injury causes the release of endogenous molecules that are recognized as danger signals by the pattern recognition receptor of the innate immunity with subsequent activation of inflammatory cells and mediators. In this environment DCs become mature and migrate to lymphonodes where they present the alloantigen to T cells and direct their differentiation towards Th1 and Th17 effector cells. On the other hand, manipulation of DCs may favor T cell differentiation towards tolerant Th2 and T regulators (Treg). Experimental studies in murine models showed the possibility of inducing an operational tolerance by injecting immature tolerogenic DCs. Recently, such a possibility has been also confirmed in primates. Although manipulation of DCs may represent an important step ahead in kidney transplantation, a number of technical and ethical issues should be solved before its clinical application.

  2. Drinking a lot is good for dendritic cells

    PubMed Central

    Norbury, Christopher C

    2006-01-01

    Macropinocytosis is the actin-dependent formation of large vesicles, which allow the internalization of large quantities of fluid-phase solute. In the majority of cells examined, an exogenous stimulus is required to induce the initiation of this endocytic pathway. However, dendritic cells are thought to constitutively macropinocytose large quantities of exogenous solute as part of their sentinel function. In this review we discuss the evidence that dendritic cells macropinocytose exogenous solute and subsequently present antigenic peptides derived from internalized material to T cells. In addition, we put these data into the context of immune surveillance in vivo. PMID:16556257

  3. Macrophages as APC and the dendritic cell myth.

    PubMed

    Hume, David A

    2008-11-01

    Dendritic cells have been considered an immune cell type that is specialized for the presentation of Ag to naive T cells. Considerable effort has been applied to separate their lineage, pathways of differentiation, and effectiveness in Ag presentation from those of macrophages. This review summarizes evidence that dendritic cells are a part of the mononuclear phagocyte system and are derived from a common precursor, responsive to the same growth factors (including CSF-1), express the same surface markers (including CD11c), and have no unique adaptation for Ag presentation that is not shared by other macrophages.

  4. A multi-trimeric fusion of CD40L and gp100 tumor antigen activates dendritic cells and enhances survival in a B16-F10 melanoma DNA vaccine model.

    PubMed

    Gupta, Sachin; Termini, James M; Rivas, Yaelis; Otero, Miguel; Raffa, Francesca N; Bhat, Vikas; Farooq, Amjad; Stone, Geoffrey W

    2015-09-11

    Vaccination with tumor-associated antigens can induce cancer-specific CD8+ T cells. A recent improvement has been the targeting of antigen to dendritic cells (DC) using antibodies that bind DC surface molecules. This study explored the use of multi-trimers of CD40L to target the gp100 melanoma tumor antigen to DC. The spontaneously-multimerizing gene Surfactant Protein D (SPD) was used to fuse gp100 tumor antigen and CD40L, creating the recombinant protein SPD-gp100-CD40L. This "third generation" DC-targeting vaccine was designed to both target antigen to DC and optimally activate dendritic cells by aggregating CD40 trimers on the DC membrane surface. SPD-gp100-CD40L expressed as a 110kDa protein. Analytical light scattering analysis gave elution data corresponding to 4-trimer and multi-trimer SPD-gp100-CD40L oligomers. The protein was biologically active on dendritic cells and induced CD40-mediated NF-κB signaling. DNA vaccination with SPD-gp100-CD40L plasmid, together with plasmids encoding IL-12p70 and GM-CSF, significantly enhanced survival and inhibited tumor growth in a B16-F10 melanoma model. Expression of gp100 and SPD-CD40L as separate molecules did not enhance survival, highlighting the requirement to encode gp100 within SPD-CD40L for optimal vaccine activity. These data support a model where DNA vaccination with SPD-gp100-CD40L targets gp100 to DC in situ, induces activation of these DC, and generates a protective anti-tumor response when given in combination with IL-12p70 and GM-CSF plasmids.

  5. Development of cell-based tuberculosis vaccines: genetically modified dendritic cell vaccine is a much more potent activator of CD4 and CD8 T cells than peptide- or protein-loaded counterparts.

    PubMed

    Malowany, Janet I; McCormick, Sarah; Santosuosso, Michael; Zhang, Xizhong; Aoki, Naoko; Ngai, Patricia; Wang, Jun; Leitch, Jaina; Bramson, Jonathan; Wan, Yonghong; Xing, Zhou

    2006-04-01

    Genetically modified dendritic cell (DC)-based vaccines have not been explored for immunization against tuberculosis. A gene-modified DC vaccine expressing Mycobacterium tuberculosis (M.tb) antigen 85A (Ag85A) was developed by using a recombinant replication-deficient adenoviral gene transfer vector (AdAg85A). AdAg85A-transduced DC vaccine (AdAg85/DC) expressed higher levels of IL-12 and was much more immunogenic than Ag85 protein-loaded (pro/DC) or CD4/CD8 T cell peptide-loaded (pep/DC) DC vaccines. Compared to pro/DC or pep/DC, AdAg85/DC elicited a remarkably higher level of ex vivo IFN-gamma production by CD4 and CD8 T cells at weeks 2, 6, and 12 postimmunization, which was coupled with higher frequencies of antigen-specific T cells. By an in vivo CD8 or CD4 T cell cytotoxicity (CTL) assay, AdAg85/DC was shown to provoke much higher and more sustained levels of CD8 and CD4 CTL activity up to 12 weeks postimmunization. Intramuscular (im) AdAg85/DC immunization was more potent than the iv route of AdAg85/DC immunization. Such stronger immunogenicity of im AdAg85/DC vaccination was corroborated with better protection from M.tb challenge. Our results thus suggest that genetically modified DC-based TB vaccine is superior to subunit DC vaccines and has the potential for therapeutic applications.

  6. Viral infection triggers rapid differentiation of human blood monocytes into dendritic cells.

    PubMed

    Hou, Wanqiu; Gibbs, James S; Lu, Xiuju; Brooke, Christopher B; Roy, Devika; Modlin, Robert L; Bennink, Jack R; Yewdell, Jonathan W

    2012-03-29

    Surprisingly little is known about the interaction of human blood mononuclear cells with viruses. Here, we show that monocytes are the predominant cell type infected when peripheral blood mononuclear cells are exposed to viruses ex vivo. Remarkably, infection with vesicular stomatitis virus, vaccinia virus, and a variety of influenza A viruses (including circulating swine-origin virus) induces monocytes to differentiate within 18 hours into CD16(-)CD83(+) mature dendritic cells with enhanced capacity to activate T cells. Differentiation into dendritic cells does not require cell division and occurs despite the synthesis of viral proteins, which demonstrates that monocytes counteract the capacity of these highly lytic viruses to hijack host cell biosynthetic capacity. Indeed, differentiation requires infectious virus and viral protein synthesis. These findings demonstrate that monocytes are uniquely susceptible to viral infection among blood mononuclear cells, with the likely purpose of generating cells with enhanced capacity to activate innate and acquired antiviral immunity.

  7. Hypergravity Effects on Dendritic Cells and Vascular Wall Interactions

    NASA Astrophysics Data System (ADS)

    Bellik, L.; Parenti, A.; Ledda, F.; Basile, V.; Romano, G.; Fusi, F.; Monici, M.

    2009-01-01

    Dendritic cells (DCs), the most potent antigen-presenting cells inducing specific immune responses, are involved in the pathogenesis of atherosclerosis. In this inflammatory disease, DCs increase in number, being particularly abundant in the shoulder regions of plaques. Since the exposure to altered gravitational conditions results in a significant impairment of the immune function, the aim of this study was to investigate the effects of hypergravity on both the function of DCs and their interactions with the vascular wall cells. Monocytes from peripheral blood mononuclear cells of healthy volunteers were sorted by CD14+ magnetic beads selection, cultured for 6 days in medium supplemented with GM-CSF and IL-4, followed by a further maturation stimulus. DC phenotype, assessed by flow cytometry, showed a high expression of the specific DC markers CD80, CD86, HLA-DR and CD83. The DCs obtained were then exposed to hypergravitational stimuli and their phenotype, cytoskeleton, ability to activate lymphocytes and interaction with vascular wall cells were investigated. The findings showed that the exposure to hypergravity conditions resulted in a significant impairment of DC cytoskeletal organization, without affecting the expression of DC markers. Moreover, an increase in DC adhesion to human vascular smooth muscle cells and in their ability to activate lymphocytes was observed.

  8. PDIA3 gene induces visceral hypersensitivity in rats with irritable bowel syndrome through the dendritic cell-mediated activation of T cells

    PubMed Central

    Zhuang, Zhaomeng; Zhang, Lu; Wang, Xiaoteng; Tao, Liyuan

    2016-01-01

    This study investigated the mechanism of protein disulfide-isomerase A3 (PDIA3)-induced visceral hypersensitivity in irritable bowel syndrome (IBS). Rats were treated with saline (control), acetic acid and restraint stress (IBS model), empty vector (RNAi control) and PDIA3-RNAi vector (PDIA3-RNAi). Mesenteric lymph node DCs (MLNDCs) and splenic CD4+/CD8+ T cells were isolated for co-cultivation. Compared with control, MLNDCs co-cultured with CD4+ or CD8+ T cells showed an increased ability to promote T cell proliferation and produced more IL-4 or IL-9 secretion. Compared with the RNAi control, MLNDCs from the PDIA3 knockdown models were less effective in promoting the proliferation of CD4+/CD8+ T cells. It is concluded that PDIA3 plays an important role in the development of IBS through the DC-mediated activation of T cells, resulting in degranulation of MCs and visceral hypersensitivity. PMID:27896022

  9. Stress-activated Dendritic Cells (DC) Induce Dual Interleukin (IL)-15- and IL1β-mediated Pathways, Which May Elicit CD4+ Memory T Cells and Interferon (IFN)-stimulated Genes.

    PubMed

    Wang, Yufei; Lavender, Paul; Watson, Julie; Arno, Matthew; Lehner, Thomas

    2015-06-19

    The prevailing evidence suggests that immunological memory does not require antigenic re-stimulation but is maintained by low level tonic stimulation. We examined the hypothesis that stress agents contribute to tonic cellular activation and maintain immunological memory. Stimulation of monocyte-derived dendritic cells (DC) with stress agents elicits reactive oxygen species and HSP70. NFκB is activated, which up-regulates membrane-associated (ma) IL-15, caspase-1 and IL-1β. Co-culture of stress-treated DC with mononuclear cells activates IL-15 and IL-1β receptors on CD4(+) T cells, eliciting CD40L, proliferation, and up-regulation of CD45RO(+) memory T cells. The transcription factors Tbet(high) and RORγt are up-regulated, whereas FoxP3 is down-regulated, resulting in enhanced Th1 and Th17 expression and the corresponding cytokines. The interaction between maIL-15 expressed by DC and IL-15R on CD4(+) T cells results in one pathway and the corresponding cells expressing IL-1β and IL1βR as a second pathway. Importantly, inhibition studies with IL-15 antibodies and IL-1βR inhibitor suggest that both pathways may be required for optimum CD4(+) CD45RO(+) memory T cell expression. Type 1 IFN expression in splenic CD11c DC of stress-treated mice demonstrated a significant increase of IFN-α in CD11c CD317(+) and CD8α(+) DC. Analysis of RNA in human CD4(+) memory T cells showed up-regulation of type 1 IFN-stimulated genes and inhibition with histone methyltransferase inhibitor. We suggest the paradigm that stress-induced tonic stimulation might be responsible for the robust persistence of the immune response in vaccination and that epigenetic changes are involved in maintaining CD4(+) T cell memory.

  10. Downregulation of transient K+ channels in dendrites of hippocampal CA1 pyramidal neurons by activation of PKA and PKC.

    PubMed

    Hoffman, D A; Johnston, D

    1998-05-15

    We have reported recently a high density of transient A-type K+ channels located in the distal dendrites of CA1 hippocampal pyramidal neurons and shown that these channels shape EPSPs, limit the back-propagation of action potentials, and prevent dendritic action potential initiation (). Because of the importance of these channels in dendritic signal propagation, their modulation by protein kinases would be of significant interest. We investigated the effects of activators of cAMP-dependent protein kinase (PKA) and the Ca2+-dependent phospholipid-sensitive protein kinase (PKC) on K+ channels in cell-attached patches from the distal dendrites of hippocampal CA1 pyramidal neurons. Inclusion of the membrane-permeant PKA activators 8-bromo-cAMP (8-br-cAMP) or forskolin in the dendritic patch pipette resulted in a depolarizing shift in the activation curve for the transient channels of approximately 15 mV. Activation of PKC by either of two phorbol esters also resulted in a 15 mV depolarizing shift of the activation curve. Neither PKA nor PKC activation affected the sustained or slowly inactivating component of the total outward current. This downregulation of transient K+ channels in the distal dendrites may be responsible for some of the frequently reported increases in cell excitability found after PKA and PKC activation. In support of this hypothesis, we found that activation of either PKA or PKC significantly increased the amplitude of back-propagating action potentials in distal dendrites.

  11. Bone marrow plasmacytoid dendritic cells can differentiate into myeloid dendritic cells upon virus infection

    PubMed Central

    Zuniga, Elina I; McGavern, Dorian B; Pruneda-Paz, Jose L; Teng, Chao; Oldstone, Michael B A

    2017-01-01

    Two subsets of dendritic cell (DCs), plasmacytoid (p) and myeloid (m) DCs, have been described in humans and mice. These subsets are known to have divergent roles during an immune response, but their developmental course is unclear. Here we report that virus infection induces bone marrow pDCs to differentiate into mDCs, thereby undergoing profound phenotypic and functional changes including the acquisition of enhanced antigen-presenting capacity and the ability to recognize different microbial structures through Toll-like receptor 4. The conversion of pDCs into mDCs is also induced by the injection of double-stranded RNA and requires type I interferons. Our results establish a precursor-product developmental relationship between these two DC subsets and highlight unexpected plasticity of bone marrow pDCs. PMID:15531885

  12. Angioimmunoblastic T-Cell Lymphoma: A Questionable Association with Follicular Dendritic Cell Sarcoma

    PubMed Central

    Zekzer, Miriam; Nalbandyan, Karen

    2017-01-01

    An elderly woman presented with generalized lymphadenopathy, several systemic symptoms, and splenomegaly. An inguinal lymph node excision revealed a compound picture. One aspect of the lymph node morphology, including cells with follicular T-helper cell phenotype, was most consistent with angioimmunoblastic T-cell lymphoma. The other component, revealing spindle cells forming whorls with immunostaining for CD21, CD23, and fascin, might be an integral part of this T-cell lymphoma. However, due to the often massive involvement of the nodal tissue by these follicular dendritic cells, these areas were questionably suggestive of involvement by follicular dendritic cell sarcoma. We raise herein the issue of the borderline area between advanced follicular dendritic cell expansion in angioimmunoblastic T-cell lymphoma and a massive follicular dendritic cell proliferation consistent with follicular dendritic cells sarcoma, in the absence of a genomic analysis. PMID:28197348

  13. Candida albicans mannoprotein influences the biological function of dendritic cells.

    PubMed

    Pietrella, Donatella; Bistoni, Giovanni; Corbucci, Cristina; Perito, Stefano; Vecchiarelli, Anna

    2006-04-01

    Cell wall components of fungi involved in induction of host immune response are predominantly proteins and glycoproteins, the latter being mainly mannoproteins (MP). In this study we analyse the interaction of the MP from Candida albicans (MP65) with dendritic cells (DC) and demonstrate that MP65 stimulates DC and induces the release of TNF-alpha, IL-6 and the activation of IL-12 gene, with maximal value 6 h post treatment. MP65 induces DC maturation by increasing costimulatory molecules and decreasing CD14 and FcgammaR molecule expression. The latter effect is partly mediated by toll-like receptor 2 (TLR2) and TLR4, and the MyD88-dependent pathway is involved in the process. MP65 enables DC to activate T cell response, its protein core is essential for induction of T cell activation, while its glycosylated portion primarily promotes cytokine production. The mechanisms involved in induction of protective response against C. albicans could be mediated by the MP65 antigen, suggesting that MP65 may be a suitable candidate vaccine.

  14. Role of Dendritic Cells in the Pathogenesis of Whipple's Disease

    PubMed Central

    Schinnerling, Katina; Geelhaar-Karsch, Anika; Allers, Kristina; Friebel, Julian; Conrad, Kristina; Loddenkemper, Christoph; Kühl, Anja A.; Erben, Ulrike; Ignatius, Ralf; Schneider, Thomas

    2014-01-01

    Accumulation of Tropheryma whipplei-stuffed macrophages in the duodenum, impaired T. whipplei-specific Th1 responses, and weak secretion of interleukin-12 (IL-12) are hallmarks of classical Whipple's disease (CWD). This study addresses dendritic cell (DC) functionality during CWD. We documented composition, distribution, and functionality of DC ex vivo or after in vitro maturation by fluorescence-activated cell sorting (FACS) and by immunohistochemistry in situ. A decrease in peripheral DC of untreated CWD patients compared to healthy donors was due to reduced CD11chigh myeloid DC (M-DC). Decreased maturation markers CD83, CD86, and CCR7, as well as low IL-12 production in response to stimulation, disclosed an immature M-DC phenotype. In vitro-generated monocyte-derived DC from CWD patients showed normal maturation and T cell-stimulatory capacity under proinflammatory conditions but produced less IL-12 and failed to activate T. whipplei-specific Th1 cells. In duodenal and lymphoid tissues, T. whipplei was found within immature DC-SIGN+ DC. DC and proliferating lymphocytes were reduced in lymph nodes of CWD patients compared to levels in controls. Our results indicate that dysfunctional IL-12 production by DC provides suboptimal conditions for priming of T. whipplei-specific T cells during CWD and that immature DC carrying T. whipplei contribute to the dissemination of the bacterium. PMID:25385798

  15. Thrombin regulates the function of human blood dendritic cells

    SciTech Connect

    Yanagita, Manabu; Kobayashi, Ryohei; Kashiwagi, Yoichiro; Shimabukuro, Yoshio; Murakami, Shinya E-mail: ipshinya@dent.osaka-u.ac.jp

    2007-12-14

    Thrombin is the key enzyme in the coagulation cascade and activates endothelial cells, neutrophils and monocytes via protease-activated receptors (PARs). At the inflammatory site, immune cells have an opportunity to encounter thrombin. However little is known about the effect of thrombin for dendritic cells (DC), which are efficient antigen-presenting cells and play important roles in initiating and regulating immune responses. The present study revealed that thrombin has the ability to stimulate blood DC. Plasmacytoid DC (PDC) and myeloid DC (MDC) isolated from PBMC expressed PAR-1 and released MCP-1, IL-10, and IL-12 after thrombin stimulation. Unlike blood DC, monocyte-derived DC (MoDC), differentiated in vitro did not express PAR-1 and were unresponsive to thrombin. Effects of thrombin on blood DC were significantly diminished by the addition of anti-PAR-1 Ab or hirudin, serine protease inhibitor. Moreover, thrombin induced HLA-DR and CD86 expression on DC and the thrombin-treated DC induced allogenic T cell proliferation. These findings indicate that thrombin plays a role in the regulation of blood DC functions.

  16. The transcription factor Fli-1 regulates monocyte, macrophage and dendritic cell development in mice.

    PubMed

    Suzuki, Eiji; Williams, Sarah; Sato, Shuzo; Gilkeson, Gary; Watson, Dennis K; Zhang, Xian K

    2013-07-01

    Fli-1 belongs to the Ets transcription factor family and is expressed in haematopoietic cells, including most of the cells that are active in immunity. The mononuclear phagocytes, i.e. monocytes, macrophages and dendritic cells, originate in haematopoietic stem cells and play an important role in immunity. To assess the role of Fli-1 in mononuclear phagocyte development in vivo, we generated mice that express a truncated Fli-1 protein, lacking the C-terminal transcriptional activation domain (Fli-1(Δ) (CTA) ). Fli-1(Δ) (CTA) (/Δ) (CTA) mice had significantly increased populations of haematopoietic stem cells and common dendritic cell precursors in bone marrow compared with wild-type littermates. Significantly increased classical dendritic cells, plasmacytoid dendritic cells, and macrophage populations were found in spleens from Fli-1(∆) (CTA) (/∆) (CTA) mice compared with wild-type littermates. Fli-1(Δ) (CTA) (/Δ) (CTA) mice also had increased pre-classical dendritic cell and monocyte populations in peripheral blood mononuclear cells. Furthermore, bone marrow reconstitution studies demonstrated that expression of Fli-1 in both haematopoietic cells and stromal cells affected mononuclear phagocyte development in mice. Expression of Fms-like tyrosine kinase 3 ligand (Flt3L), a haematopoietic growth factor, in multipotent progenitors was statistically significantly increased from Fli-1(∆) (CTA) (/∆) (CTA) mice compared with wild-type littermates. Fli-1 protein binds directly to the promoter region of the Flt3L gene. Hence, Fli-1 plays an important role in the mononuclear phagocyte development, and the C-terminal transcriptional activation domain of Fli-1 negatively modulates mononuclear phagocyte development.

  17. Designing vaccines based on biology of human dendritic cell subsets

    PubMed Central

    Palucka, Karolina; Banchereau, Jacques; Mellman, Ira

    2010-01-01

    The effective vaccines developed against a variety of infectious agents, including polio, measles and Hepatitis B, represent major achievements in medicine. These vaccines, usually composed of microbial antigens, are often associated with an adjuvant that activates dendritic cells (DCs). Many infectious diseases are still in need of an effective vaccine including HIV, malaria, hepatitis C and tuberculosis. In some cases, the induction of cellular rather than humoral responses may be more important as the goal is to control and eliminate the existing infection rather than to prevent it. Our increased understanding of the mechanisms of antigen presentation, particularly with the description of DC subsets with distinct functions, as well as their plasticity in responding to extrinsic signals, represent opportunities to develop novel vaccines. In addition, we foresee that this increased knowledge will permit us to design vaccines that will reprogram the immune system to intervene therapeutically in cancer, allergy and autoimmunity. PMID:21029958

  18. Developmental expression of the SRF co-activator MAL in brain: role in regulating dendritic morphology.

    PubMed

    Shiota, Jun; Ishikawa, Mitsuru; Sakagami, Hiroyuki; Tsuda, Masaaki; Baraban, Jay M; Tabuchi, Akiko

    2006-09-01

    The dynamic changes in dendritic morphology displayed by developing and mature neurons have stimulated interest in deciphering the signaling pathways involved. Recent studies have identified megakaryocytic acute leukemia (MAL), a serum response factor (SRF) co-activator, as a key component of a signaling pathway linking changes in the actin cytoskeleton to SRF-mediated transcription. To help define the role of this pathway in regulating dendritic morphology, we have characterized the pattern of MAL expression in the developing and adult brain, and have examined its role in regulating dendritic morphology in cultured cortical neurons. In histological studies of mouse brain, we found prominent expression of MAL in neurons in adult hippocampus and cerebral cortex. MAL immunostaining revealed localization of this protein in neuronal cell bodies and apical dendrites. During development, an increase in MAL expression occurs during the second post-natal week. Expression of dominant negative MAL constructs or MAL siRNA in cortical neurons grown in primary culture reduces the number of dendritic processes and decreases the basal level of SRF-mediated transcription. Taken together, these findings indicate that the MAL-SRF signaling pathway plays a key role in regulating dendritic morphology.

  19. Timothy syndrome is associated with activity-dependent dendritic retraction in rodent and human neurons.

    PubMed

    Krey, Jocelyn F; Paşca, Sergiu P; Shcheglovitov, Aleksandr; Yazawa, Masayuki; Schwemberger, Rachel; Rasmusson, Randall; Dolmetsch, Ricardo E

    2013-02-01

    L-type voltage gated calcium channels have an important role in neuronal development by promoting dendritic growth and arborization. A point mutation in the gene encoding Ca(V)1.2 causes Timothy syndrome, a neurodevelopmental disorder associated with autism spectrum disorders (ASDs). We report that channels with the Timothy syndrome alteration cause activity-dependent dendrite retraction in rat and mouse neurons and in induced pluripotent stem cell (iPSC)-derived neurons from individuals with Timothy syndrome. Dendrite retraction was independent of calcium permeation through the mutant channel, was associated with ectopic activation of RhoA and was inhibited by overexpression of the channel-associated GTPase Gem. These results suggest that Ca(V)1.2 can activate RhoA signaling independently of Ca(2+) and provide insights into the cellular basis of Timothy syndrome and other ASDs.

  20. Mycobacterium tuberculosis PstS1 amplifies IFN-γ and induces IL-17/IL-22 responses by unrelated memory CD4+ T cells via dendritic cell activation.

    PubMed

    Palma, Carla; Schiavoni, Giovanna; Abalsamo, Laura; Mattei, Fabrizio; Piccaro, Giovanni; Sanchez, Massimo; Fernandez, Carmen; Singh, Mahavir; Gabriele, Lucia

    2013-09-01

    The immunological mechanisms that modulate protection during Mycobacterium tuberculosis (Mtb) infection or vaccination are not fully understood. Secretion of IFN-γ and, to a lesser extent, of IL-17 by CD4(+) T cells plays a major role both in protection and immunopathology. Few Mtb Ags interacting with DCs affect priming, activation, and regulation of Ag-unrelated CD4(+) T-cell responses. Here we demonstrate that PstS1, a 38 kDa-lipoprotein of Mtb, promotes Ag-independent activation of memory T lymphocytes specific for Ag85B or Ag85A, two immunodominant protective Ags of Mtb. PstS1 expands CD4(+) and CD8(+) memory T cells, amplifies secretion of IFN-γ and IL-22 and induces IL-17 production by effector memory cells in an Ag-unrelated manner in vitro and in vivo. These effects were mediated through the stimulation of DCs, particularly of the CD8α(-) subtype, which respond to PstS1 by undergoing phenotypic maturation and by secreting IL-6, IL-1β and, to a lower extent, IL-23. IL-6 secretion by PstS1-stimulated DCs was required for IFN-γ, and to a lesser extent for IL-22 responses by Ag85B-specific memory T cells. These results may open new perspectives for immunotherapeutic strategies to control Th1/Th17 immune responses in Mtb infections and in vaccinations against tuberculosis.

  1. Antithymocyte Globulin Induces a Tolerogenic Phenotype in Human Dendritic Cells

    PubMed Central

    Roider, Tobias; Katzfuß, Michael; Matos, Carina; Singer, Katrin; Renner, Kathrin; Oefner, Peter J.; Dettmer-Wilde, Katja; Herr, Wolfgang; Holler, Ernst; Kreutz, Marina; Peter, Katrin

    2016-01-01

    Antithymocyte globulin (ATG) is used in the prevention of graft-versus-host disease during allogeneic hematopoietic stem cell transplantation. It is generally accepted that ATG mediates its immunosuppressive effect primarily via depletion of T cells. Here, we analyzed the impact of ATG-Fresenius (now Grafalon®) on human monocyte-derived dendritic cells (DC). ATG induced a semi-mature phenotype in DC with significantly reduced expression of CD14, increased expression of HLA-DR, and intermediate expression of CD54, CD80, CD83, and CD86. ATG-DC showed an increase in IL-10 secretion but no IL-12 production. In line with this tolerogenic phenotype, ATG caused a significant induction of indoleamine 2,3-dioxygenase expression and a concomitant increase in levels of tryptophan metabolites in the supernatants of DC. Further, ATG-DC did not induce the proliferation of allogeneic T cells in a mixed lymphocyte reaction but actively suppressed the T cell proliferation induced by mature DC. These data suggest that besides its well-known effect on T cells, ATG modulates the phenotype of DC in a tolerogenic way, which might constitute an essential part of its immunosuppressive action in vivo. PMID:27973435

  2. Dendritic Cell-Mediated In Vivo Bone Resorption

    PubMed Central

    Maitra, Radhashree; Follenzi, Antonia; Yaghoobian, Arash; Montagna, Cristina; Merlin, Simone; Cannizzo, Elvira S.; Hardin, John A.; Cobelli, Neil; Stanley, E. Richard; Santambrogio, Laura

    2013-01-01

    Osteoclasts are resident cells of the bone that are primarily involved in the physiological and pathological remodeling of this tissue. Mature osteoclasts are multinucleated giant cells that are generated from the fusion of circulating precursors originating from the monocyte/macrophage lineage. During inflammatory bone conditions in vivo, de novo osteoclastogenesis is observed but it is currently unknown whether, besides increased osteoclast differentiation from undifferentiated precursors, other cell types can generate a multinucleated giant cell phenotype with bone resorbing activity. In this study, an animal model of calvaria-induced aseptic osteolysis was used to analyze possible bone resorption capabilities of dendritic cells (DCs). We determined by FACS analysis and confocal microscopy that injected GFP-labeled immature DCs were readily recruited to the site of osteolysis. Upon recruitment, the cathepsin K-positive DCs were observed in bone-resorbing pits. Additionally, chromosomal painting identified nuclei from female DCs, previously injected into a male recipient, among the nuclei of giant cells at sites of osteolysis. Finally, osteolysis was also observed upon recruitment of CD11c-GFP conventional DCs in Csf1r–/– mice, which exhibit a severe depletion of resident osteoclasts and tissue macrophages. Altogether, our analysis indicates that DCs may have an important role in bone resorption associated with various inflammatory diseases. PMID:20581147

  3. Dendritic cell targeted vaccines: Recent progresses and challenges

    PubMed Central

    Chen, Pengfei; Liu, Xinsheng; Sun, Yuefeng; Zhou, Peng; Wang, Yonglu; Zhang, Yongguang

    2016-01-01

    ABSTRACT Dendritic cells (DCs) are known to be a set of morphology, structure and function of heterogeneous professional antigen presenting cells (APCs), as well as the strongest functional antigen presenting cells, which can absorb, process and present antigens. As the key regulators of innate and adaptive immune responses, DCs are at the center of the immune system and capable of interacting with both B cells and T cells, thereby manipulating the humoral and cellular immune responses. DCs provide an essential link between the innate and adaptive immunity, and the strong immune activation function of DCs and their properties of natural adjuvants, make them a valuable target for antigen delivery. Targeting antigens to DC-specific endocytic receptors in combination with the relevant antibodies or ligands along with immunostimulatory adjuvants has been recently recognized as a promising strategy for designing an effective vaccine that elicits a strong and durable T cell response against intracellular pathogens and cancer. This opinion article provides a brief summary of the rationales, superiorities and challenges of existing DC-targeting approaches. PMID:26513200

  4. Active dendrites regulate the impact of gliotransmission on rat hippocampal pyramidal neurons

    PubMed Central

    Ashhad, Sufyan

    2016-01-01

    An important consequence of gliotransmission, a signaling mechanism that involves glial release of active transmitter molecules, is its manifestation as N-methyl-d-aspartate receptor (NMDAR)-dependent slow inward currents in neurons. However, the intraneuronal spatial dynamics of these events or the role of active dendrites in regulating their amplitude and spatial spread have remained unexplored. Here, we used somatic and/or dendritic recordings from rat hippocampal pyramidal neurons and demonstrate that a majority of NMDAR-dependent spontaneous slow excitatory potentials (SEP) originate at dendritic locations and are significantly attenuated through their propagation across the neuronal arbor. We substantiated the astrocytic origin of SEPs through paired neuron–astrocyte recordings, where we found that specific infusion of inositol trisphosphate (InsP3) into either distal or proximal astrocytes enhanced the amplitude and frequency of neuronal SEPs. Importantly, SEPs recorded after InsP3 infusion into distal astrocytes exhibited significantly slower kinetics compared with those recorded after proximal infusion. Furthermore, using neuron-specific infusion of pharmacological agents and morphologically realistic conductance-based computational models, we demonstrate that dendritically expressed hyperpolarization-activated cyclic-nucleotide–gated (HCN) and transient potassium channels play critical roles in regulating the strength, kinetics, and compartmentalization of neuronal SEPs. Finally, through the application of subtype-specific receptor blockers during paired neuron–astrocyte recordings, we provide evidence that GluN2B- and GluN2D-containing NMDARs predominantly mediate perisomatic and dendritic SEPs, respectively. Our results unveil an important role for active dendrites in regulating the impact of gliotransmission on neurons and suggest astrocytes as a source of dendritic plateau potentials that have been implicated in localized plasticity and place

  5. Human cytomegalovirus alters localization of MHC class II and dendrite morphology in mature Langerhans cells.

    PubMed

    Lee, Andrew W; Hertel, Laura; Louie, Ryan K; Burster, Timo; Lacaille, Vashti; Pashine, Achal; Abate, Davide A; Mocarski, Edward S; Mellins, Elizabeth D

    2006-09-15

    Hemopoietic stem cell-derived mature Langerhans-type dendritic cells (LC) are susceptible to productive infection by human CMV (HCMV). To investigate the impact of infection on this cell type, we examined HLA-DR biosynthesis and trafficking in mature LC cultures exposed to HCMV. We found decreased surface HLA-DR levels in viral Ag-positive as well as in Ag-negative mature LC. Inhibition of HLA-DR was independent of expression of unique short US2-US11 region gene products by HCMV. Indeed, exposure to UV-inactivated virus, but not to conditioned medium from infected cells, was sufficient to reduce HLA-DR on mature LC, implicating particle binding/penetration in this effect. Reduced surface levels reflected an altered distribution of HLA-DR because total cellular HLA-DR was not diminished. Accumulation of HLA-DR was not explained by altered cathepsin S activity. Mature, peptide-loaded HLA-DR molecules were retained within cells, as assessed by the proportion of SDS-stable HLA-DR dimers. A block in egress was implicated, as endocytosis of surface HLA-DR was not increased. Immunofluorescence microscopy corroborated the intracellular retention of HLA-DR and revealed markedly fewer HLA-DR-positive dendritic projections in infected mature LC. Unexpectedly, light microscopic analyses showed a dramatic loss of the dendrites themselves and immunofluorescence revealed that cytoskeletal elements crucial for the formation and maintenance of dendrites are disrupted in viral Ag-positive cells. Consistent with these dendrite effects, HCMV-infected mature LC exhibit markedly reduced chemotaxis in response to lymphoid chemokines. Thus, HCMV impedes MHC class II molecule trafficking, dendritic projections, and migration of mature LC. These changes likely contribute to the reduced activation of CD4+ T cells by HCMV-infected mature LC.

  6. Design of phosphorylated dendritic architectures to promote human monocyte activation.

    PubMed

    Poupot, Mary; Griffe, Laurent; Marchand, Patrice; Maraval, Alexandrine; Rolland, Olivier; Martinet, Ludovic; L'Faqihi-Olive, Fatima-Ezzahra; Turrin, Cédric-Olivier; Caminade, Anne-Marie; Fournié, Jean-Jacques; Majoral, Jean-Pierre; Poupot, Rémy

    2006-11-01

    As first defensive line, monocytes are a pivotal cell population of innate immunity. Monocyte activation can be relevant to a range of immune conditions and responses. Here we present new insights into the activation of monocytes by a series of phosphonic acid-terminated, phosphorus-containing dendrimers. Various dendritic or subdendritic structures were synthesized and tested, revealing the basic structural requirements for monocyte activation. We showed that multivalent character and phosphonic acid capping of dendrimers are crucial for monocyte targeting and activation. Confocal videomicroscopy showed that a fluorescein-tagged dendrimer binds to isolated monocytes and gets internalized within a few seconds. We also found that dendrimers follow the phagolysosomial route during internalization by monocytes. Finally, we performed fluorescence resonance energy transfer (FRET) experiments between a specifically designed fluorescent dendrimer and phycoerythrin-coupled antibodies. We showed that the typical innate Toll-like receptor (TLR)-2 is clearly involved, but not alone, in the sensing of dendrimers by monocytes. In conclusion, phosphorus-containing dendrimers appear as precisely tunable nanobiotools able to target and activate human innate immunity and thus prove to be good candidates to develop new drugs for immunotherapies.

  7. Development of Retinal Amacrine Cells and Their Dendritic Stratification

    PubMed Central

    Balasubramanian, Revathi

    2014-01-01

    Themammalian retina containsmultiple neurons, each of which contributes differentially to visual processing. Of these retinal neurons, amacrine cells have recently come to prime light since they facilitate majority of visual processing that takes place in the retina. Amacrine cells are also the most diverse group of neurons in the retina, classified majorly based on the neurotransmitter type they express and morphology of their dendritic arbors. Currently, little is known about the molecular basis contributing to this diversity during development. Amacrine cells also contribute to most of the synapses in the inner plexiform layer and mediate visual information input from bipolar cells onto retinal ganglion cells. In this review, we will describe the current understanding of amacrine cell and cell subtype development. Furthermore, we will address the molecular basis of retinal lamination at the inner plexiform layer. Overall, our review will provide a developmental perspective of amacrine cell subtype classification and their dendritic stratification. PMID:25170430

  8. Programmed Cell Death of Dendritic Cells in Immune Regulation

    PubMed Central

    Chen, Min; Wang, Jin

    2010-01-01

    Summary Programmed cell death is essential for the maintenance of lymphocyte homeostasis and immune tolerance. Dendritic cells (DCs), the most efficient antigen presenting cells, represent a small cell population in the immune system. However, DCs play major roles in the regulation of both innate and adaptive immune responses. Programmed cell death in DCs is essential for regulating DC homeostasis and consequently, the scope of immune responses. Interestingly, different DC subsets show varied turnover rates in vivo. The conventional DCs are relatively short-lived in most lymphoid organs, while plasmacytoid DCs are long-lived cells. Mitochondrion-dependent programmed cell death plays an important role in regulating spontaneous DC turnover. Antigen-specific T cells are also capable of killing DCs, thereby providing a mechanism for negative feedback regulation of immune responses. It has been shown that a surplus of DCs due to defects in programmed cell death leads to overactivation of lymphocytes and the onset of autoimmunity. Studying programmed cell death in DCs will shed light on the roles for DC turnover in the regulation of the duration and magnitude of immune responses in vivo, and in the maintenance of immune tolerance. PMID:20636805

  9. Adiponectin Receptor Signaling on Dendritic Cells Blunts Antitumor Immunity

    PubMed Central

    Tan, Peng H.; Tyrrell, Helen E.J.; Gao, Liquan; Xu, Danmei; Quan, Jianchao; Gill, Dipender; Rai, Lena; Ding, Yunchuan; Plant, Gareth; Chen, Yuan; Xue, John Z.; Handa, Ashok I.; Greenall, Michael J.; Walsh, Kenneth; Xue, Shao-An

    2015-01-01

    Immune escape is a fundamental trait of cancer. Dendritic cells (DC) that interact with T cells represent a crucial site for the development of tolerance to tumor antigens, but there remains incomplete knowledge about how DC-tolerizing signals evolve during tumorigenesis. In this study, we show that DCs isolated from patients with metastatic or locally advanced breast cancer express high levels of the adiponectin receptors AdipoR1 and AdipoR2, which are sufficient to blunt antitumor immunity. Mechanistic investigations of ligand–receptor interactions on DCs revealed novel signaling pathways for each receptor. AdipoR1 stimulated IL10 production by activating the AMPK and MAPKp38 pathways, whereas AdipoR2 modified inflammatory processes by activating the COX-2 and PPARγ pathways. Stimulation of these pathways was sufficient to block activation of NF-κB in DC, thereby attenuating their ability to stimulate antigen-specific T-cell responses. Together, our findings reveal novel insights into how DC-tolerizing signals evolve in cancer to promote immune escape. Furthermore, by defining a critical role for adiponectin signaling in this process, our work suggests new and broadly applicable strategies for immunometabolic therapy in patients with cancer. PMID:25261236

  10. BDNF over-expression increases olfactory bulb granule cell dendritic spine density in vivo.

    PubMed

    McDole, B; Isgor, C; Pare, C; Guthrie, K

    2015-09-24

    Olfactory bulb granule cells (GCs) are axon-less, inhibitory interneurons that regulate the activity of the excitatory output neurons, the mitral and tufted cells, through reciprocal dendrodendritic synapses located on GC spines. These contacts are established in the distal apical dendritic compartment, while GC basal dendrites and more proximal apical segments bear spines that receive glutamatergic inputs from the olfactory cortices. This synaptic connectivity is vital to olfactory circuit function and is remodeled during development, and in response to changes in sensory activity and lifelong GC neurogenesis. Manipulations that alter levels of the neurotrophin brain-derived neurotrophic factor (BDNF) in vivo have significant effects on dendritic spine morphology, maintenance and activity-dependent plasticity for a variety of CNS neurons, yet little is known regarding BDNF effects on bulb GC spine maturation or maintenance. Here we show that, in vivo, sustained bulbar over-expression of BDNF in transgenic mice produces a marked increase in GC spine density that includes an increase in mature spines on their apical dendrites. Morphometric analysis demonstrated that changes in spine density were most notable in the distal and proximal apical domains, indicating that multiple excitatory inputs are potentially modified by BDNF. Our results indicate that increased levels of endogenous BDNF can promote the maturation and/or maintenance of dendritic spines on GCs, suggesting a role for this factor in modulating GC functional connectivity within adult olfactory circuitry.

  11. [ILT3+/ILT4+ tolerogenic dendritic cells and their influence on allograft survival].

    PubMed

    Arboleda, John F; García, Luis F; Alvarez, Cristiam M

    2011-06-01

    Dendritic cells, the most powerful antigen-presenting cells, are important for triggering of the immune responses to allo-antigens. However, they also play a fundamental role in the peripheral tolerance maintenance. Tolerance is enhanced by the presence on the dendritic cell surface of the inhibitor receptors ILT3 and ILT4. They recruit protein tyrosine-phosphatases to their ITIM domains and inhibit antigen-presenting cell activation, leading T cell hypo-responsivensess. Moreover, these receptors favor a bidirectional interaction with T-suppressor and T-regulator cells, generating an antigen-specific immunoregulator cascade, in which the dendritic cell behaves as a tolerogenic cell. In the current review, analysis is centered on the biology and behavior of the tolerogenic dendritic cells that express high levels of ILT3 and ILT4. Some molecular and genetics aspects of these receptors are discussed as well as their importance in the modulation of the allo-specific antigen immune response to transplants.

  12. Reactivity of chemical sensitizers toward amino acids in cellulo plays a role in the activation of the Nrf2-ARE pathway in human monocyte dendritic cells and the THP-1 cell line.

    PubMed

    Migdal, Camille; Botton, Jérémie; El Ali, Zeina; Azoury, Marie-Eliane; Guldemann, Joan; Giménez-Arnau, Elena; Lepoittevin, Jean-Pierre; Kerdine-Römer, Saadia; Pallardy, Marc

    2013-06-01

    Allergic contact dermatitis resulting from skin sensitization is an inflammatory skin disease linked to the use of chemicals termed haptens. Chemical reactivity is necessary for a chemical to be a sensitizer, allowing both covalent binding to proteins and maturation of dendritic cells (DCs) by mimicking "danger signals." The aim of this study was to evaluate how the reactivity of chemical sensitizers toward amino acids translates into a biological response using the activation of the nuclear factor-erythroid 2-related factor 2 (Nrf2) pathway, which was assessed by the induction of three Nrf2 target genes (ho-1, nqo1, and il-8) and Nrf2 protein accumulation. Nrf2 activation is known to play a role in numerous detoxification mechanisms that could regulate danger signal outcomes in myeloid cells. Monocyte-derived DCs and THP-1 cells were exposed to (a) haptens with cysteine, lysine, or cysteine/lysine reactivity, (b) pro-/prehaptens, and (c) nonsensitizing molecules with reducing or oxidative properties (17 molecules in total). Chemicals were classified as "Nrf2 pathway activators" when at least two Nrf2 target genes associated with Nrf2 protein expression were induced. Results showed that most chemical sensitizers having cysteine and cysteine/lysine affinities were inducers of the Nrf2 pathway in both cell models, whereas lysine-reactive chemicals were less efficient. In THP-1 cells, the Nrf2 pathway was also activated by pro-/prehaptens. Regression analysis revealed that ho-1 and nqo1 expressions were found to be associated with chemical sensitizer reactivity to cysteine, providing evidence of the importance of chemical reactivity, as a part of danger signals, in DC biology.

  13. Hemopoietic cell kinase (Hck) and p21-activated kinase 2 (PAK2) are involved in the down-regulation of CD1a lipid antigen presentation by HIV-1 Nef in dendritic cells.

    PubMed

    Shinya, Eiji; Shimizu, Masumi; Owaki, Atsuko; Paoletti, Samantha; Mori, Lucia; De Libero, Gennaro; Takahashi, Hidemi

    2016-01-01

    Dendritic cells (DCs) play a major role in in vivo pathogenesis of HIV-1 infection. Therefore, DCs may provide a promising strategy to control and eventually overcome the fatal infection. Especially, immature DCs express all CD1s, the non-MHC lipid antigen -presenting molecules, and HIV-1 Nef down-regulates CD1 expression besides MHC. Moreover, CD1d-restricted CD4(+) NKT cells are infected by HIV-1, reducing the number of these cells in HIV-1-infected individuals. To understand the exact role of DCs and CD1-mediated immune response during HIV-1 infection, Nef down-regulation of CD1a-restricted lipid/glycolipid Ag presentation in iDCs was analyzed. We demonstrated the involvement of the association of Nef with hemopoietic cell kinase (Hck) and p21-activated kinase 2 (PAK2), and that Hck, which is expressed strongly in iDCs, augmented this mutual interaction. Hck might be another therapeutic target to preserve the function of HIV-1 infected DCs, which are potential reservoirs of HIV-1 even after antiretroviral therapy.

  14. Probiotic modulation of dendritic cell function is influenced by ageing.

    PubMed

    You, Jialu; Dong, Honglin; Mann, Elizabeth R; Knight, Stella C; Yaqoob, Parveen

    2014-02-01

    Dendritic cells (DCs) are critical for the generation of T-cell responses. DC function may be modulated by probiotics, which confer health benefits in immunocompromised individuals, such as the elderly. This study investigated the effects of four probiotics, Bifidobacterium longum bv. infantis CCUG 52486, B. longum SP 07/3, Lactobacillus rhamnosus GG (L.GG) and L. casei Shirota (LcS), on DC function in an allogeneic mixed leucocyte reaction (MLR) model, using DCs and T-cells from young and older donors in different combinations. All four probiotics enhanced expression of CD40, CD80 and CCR7 on both young and older DCs, but enhanced cytokine production (TGF-β, TNF-α) by old DCs only. LcS induced IL-12 and IFNγ production by DC to a greater degree than other strains, while B. longum bv. infantis CCUG 52486 favoured IL-10 production. Stimulation of young T cells in an allogeneic MLR with DC was enhanced by probiotic pretreatment of old DCs, which demonstrated greater activation (CD25) than untreated controls. However, pretreatment of young or old DCs with LPS or probiotics failed to enhance the proliferation of T-cells derived from older donors. In conclusion, this study demonstrates that ageing increases the responsiveness of DCs to probiotics, but this is not sufficient to overcome the impact of immunosenescence in the MLR.

  15. Paracoccidioides brasilinsis-Induced Migration of Dendritic Cells and Subsequent T-Cell Activation in the Lung-Draining Lymph Nodes

    PubMed Central

    Silvana dos Santos, Suelen; Ferreira, Karen Spadari; Almeida, Sandro Rogerio

    2011-01-01

    Paracoccidioidomycosis is a mycotic disease caused by a dimorphic fungus, Paracoccidioides brasiliensis (Pb), that starts with inhalation of the fungus; thus, lung cells such as DC are part of the first line of defense against this microorganism. Migration of DC to the lymph nodes is the first step in initiating T cell responses. The mechanisms involved in resistance to Pb infection are poorly understood, but it is likely that DC play a pivotal role in the induction of effector T cells that control Pb infection. In this study, we showed that after Pb Infection, an important modification of lung DC receptor expression occurred. We observed an increased expression of CCR7 and CD103 on lung DC after infection, as well as MHC-II. After Pb infection, bone marrow-derived DC as well lung DC, migrate to lymph nodes. Migration of lung DC could represent an important mechanism of pathogenesis during PCM infection. In resume our data showed that Pb induced DC migration. Furthermore, we demonstrated that bone marrow-derived DC stimulated by Pb migrate to the lymph nodes and activate a T helper (Th) response. To the best of our knowledge, this is the first reported data showing that Pb induces migration of DC and activate a T helper (Th) response. PMID:21611175

  16. Epidermal Viral Immunity Induced by CD8α+ Dendritic Cells But Not by Langerhans Cells

    NASA Astrophysics Data System (ADS)

    Allan, Rhys S.; Smith, Chris M.; Belz, Gabrielle T.; van Lint, Allison L.; Wakim, Linda M.; Heath, William R.; Carbone, Francis R.

    2003-09-01

    The classical paradigm for dendritic cell function derives from the study of Langerhans cells, which predominate within skin epidermis. After an encounter with foreign agents, Langerhans cells are thought to migrate to draining lymph nodes, where they initiate T cell priming. Contrary to this, we show here that infection of murine epidermis by herpes simplex virus did not result in the priming of virus-specific cytotoxic T lymphocytes by Langerhans cells. Rather, the priming response required a distinct CD8α+ dendritic cell subset. Thus, the traditional view of Langerhans cells in epidermal immunity needs to be revisited to accommodate a requirement for other dendritic cells in this response.

  17. Lactobacillus gasseri SBT2055 induces TGF-β expression in dendritic cells and activates TLR2 signal to produce IgA in the small intestine.

    PubMed

    Sakai, Fumihiko; Hosoya, Tomohiro; Ono-Ohmachi, Aiko; Ukibe, Ken; Ogawa, Akihiro; Moriya, Tomohiro; Kadooka, Yukio; Shiozaki, Takuya; Nakagawa, Hisako; Nakayama, Yosuke; Miyazaki, Tadaaki

    2014-01-01

    Probiotic bacteria provide benefits in enhancing host immune responses and protecting against infection. Induction of IgA production by oral administration of probiotic bacteria in the intestine has been considered to be one reason for this beneficial effect, but the mechanisms of the effect are poorly understood. Lactobacillus gasseri SBT2055 (LG2055) is a probiotic bacterium with properties such as bile tolerance, ability to improve the intestinal environment, and it has preventive effects related to abdominal adiposity. In this study, we have found that oral administration of LG2055 induced IgA production and increased the rate of IgA(+) cell population in Peyer's patch and in the lamina propria of the mouse small intestine. The LG2055 markedly increased the amount of IgA in a co-culture of B cells and bone marrow derived dendritic cells (BMDC), and TLR2 signal is critical for it. In addition, it is demonstrated that LG2055 stimulates BMDC to promote the production of TGF-β, BAFF, IL-6, and IL-10, all critical for IgA production from B cells. Combined stimulation of B cells with BAFF and LG2055 enhanced the induction of IgA production. Further, TGF-β signal was shown to be critical for LG2055-induced IgA production in the B cell and BMDC co-culture system, but TGF-β did not induce IgA production in a culture of only B cells stimulated with LG2055. Furthermore, TGF-β was critical for the production of BAFF, IL-6, IL-10, and TGF-β itself from LG2055-stimulated BMDC. These results demonstrate that TGF-β was produced by BMDC stimulated with LG2055 and it has an autocrine/paracrine function essential for BMDC to induce the production of BAFF, IL-6, and IL-10.

  18. Targeting dendritic cells for improved HIV-1 vaccines.

    PubMed

    Smed-Sörensen, Anna; Loré, Karin

    2013-01-01

    As dendritic cells (DCs) have the unique capacity to activate antigen-naive T cells they likely play a critical role in eliciting immune responses to vaccines. DCs are therefore being explored as attractive targets for vaccines, but understanding the interaction of DCs and clinically relevant vaccine antigens and adjuvants is a prerequisite. The HIV-1/AIDS epidemic continues to be a significant health problem, and despite intense research efforts over the past 30 years a protective vaccine has not yet been developed. A common challenge in vaccine design is to find a vaccine formulation that best shapes the immune response to protect against and/or control the given pathogen. Here, we discuss the importance of understanding the diversity, anatomical location and function of different human DC subsets in order to identify the optimal target cells for an HIV-1 vaccine. We review human DC interactions with some of the HIV-1 vaccine antigen delivery vehicles and adjuvants currently utilized in preclinical and clinical studies. Specifically, the effects of distinctly different vaccine adjuvants in terms of activation of DCs and improving DC function and vaccine efficacy are discussed. The susceptibility and responses of DCs to recombinant adenovirus vectors are reviewed, as well as the strategy of directly targeting DCs by using DC marker-specific monoclonal antibodies coupled to an antigen.

  19. Involvement of suppressive B-lymphocytes in the mechanism of tolerogenic dendritic cell reversal of type 1 diabetes in NOD mice.

    PubMed

    Di Caro, Valentina; Phillips, Brett; Engman, Carl; Harnaha, Jo; Trucco, Massimo; Giannoukakis, Nick

    2014-01-01

    The objective of the study was to identify immune cell populations, in addition to Foxp3+ T-regulatory cells, that participate in the mechanisms of action of tolerogenic dendritic cells shown to prevent and reverse type 1 diabetes in the Non-Obese Diabetic (NOD) mouse strain. Co-culture experiments using tolerogenic dendritic cells and B-cells from NOD as well as transgenic interleukin-10 promoter-reporter mice along with transfer of tolerogenic dendritic cells and CD19+ B-cells into NOD and transgenic mice, showed that these dendritic cells increased the frequency and numbers of interleukin-10-expressing B-cells in vitro and in vivo. The expansion of these cells was a consequence of both the proliferation of pre-existing interleukin-10-expressing B-lymphocytes and the conversion of CD19+ B-lymphcytes into interleukin-10-expressing cells. The tolerogenic dendritic cells did not affect the suppressive activity of these B-cells. Furthermore, we discovered that the suppressive murine B-lymphocytes expressed receptors for retinoic acid which is produced by the tolerogenic dendritic cells. These data assist in identifying the nature of the B-cell population increased in response to the tolerogenic dendritic cells in a clinical trial and also validate very recent findings demonstrating a mechanistic link between human tolerogenic dendritic cells and immunosuppressive regulatory B-cells.

  20. Myeloid dendritic cells frequencies are increased in children with autism spectrum disorder and associated with amygdala volume and repetitive behaviors

    PubMed Central

    Breece, Elizabeth; Paciotti, Brian; Nordahl, Christine Wu; Ozonoff, Sally; Van de Water, Judy A.; Rogers, Sally J.; Amaral, David; Ashwood, Paul

    2012-01-01

    The pathophysiology of Autism Spectrum Disorder (ASD) is not yet known; however, studies suggest that dysfunction of the immune system affects many children with ASD. Increasing evidence points to dysfunction of the innate immune system including activation of microglia and perivascular macrophages, increases in inflammatory cytokines/chemokines in brain tissue and CSF, and abnormal peripheral monocyte cell function. Dendritic cells are major players in innate immunity and have important functions in the phagocytosis of pathogens or debris, antigen presentation, activation of naïve T cells, induction of tolerance and cytokine/chemokine production. In this study, we assessed circulating frequencies of myeloid dendritic cells (defined as Lin-1−BDCA1+CD11c+ and Lin-1−BDCA3+CD123−) and plasmacytoid dendritic cells (Lin-1− BDCA2+CD123+ or Lin-1−BDCA4+ CD11c−) in 57 children with ASD, and 29 typically developing controls of the same age, all of who were enrolled as part of the Autism Phenome Project (APP). The frequencies of dendritic cells and associations with behavioral assessment and MRI measurements of amygdala volume were compared in the same participants. The frequencies of myeloid dendritic cells were significantly increased in children with ASD compared to typically developing controls (p < 0.03). Elevated frequencies of myeloid dendritic cells were positively associated with abnormal right and left amygdala enlargement, severity of gastrointestinal symptoms and increased repetitive behaviors. The frequencies of plasmacytoid dendritic cells were also associated with amygdala volumes as well as developmental regression in children with ASD. Dendritic cells play key roles in modulating immune responses and differences in frequencies or functions of these cells may result in immune dysfunction in children with ASD. These data further implicate innate immune cells in the complex pathophysiology of ASD. PMID:23063420

  1. Calcitonin gene-related peptide (CGRP) stimulates purkinje cell dendrite growth in culture.

    PubMed

    D'Antoni, Simona; Zambusi, Laura; Codazzi, Franca; Zacchetti, Daniele; Grohovaz, Fabio; Provini, Luciano; Catania, Maria Vincenza; Morara, Stefano

    2010-12-01

    Previous reports described the transient expression during development of Calcitonin Gene-Related Peptide (CGRP) in rodent cerebellar climbing fibers and CGRP receptor in astrocytes. Here, mixed cerebellar cultures were used to analyze the effects of CGRP on Purkinje cells growth. Our results show that CGRP stimulated Purkinje cell dendrite growth under cell culture conditions mimicking Purkinje cell development in vivo. The stimulation was not blocked by CGRP8-37, a specific antagonist, suggesting the activation of other related receptors. CGRP did not affect survival of Purkinje cells, granule cells or astrocytes. The selective expression of Receptor Component Protein (RCP) (a component of CGRP receptor family) in astrocytes points to a role of these cells as mediators of CGRP effect. Finally, in pure cerebellar astrocyte cultures CGRP induced a transient morphological differentiation from flat, polygonal to stellate form. It is concluded that CGRP influences Purkinje cell dendrite growth in vitro, most likely through the involvement of astrocytes.

  2. Immunogenicity is preferentially induced in sparse dendritic cell cultures

    PubMed Central

    Nasi, Aikaterini; Bollampalli, Vishnu Priya; Sun, Meng; Chen, Yang; Amu, Sylvie; Nylén, Susanne; Eidsmo, Liv; Rothfuchs, Antonio Gigliotti; Réthi, Bence

    2017-01-01

    We have previously shown that human monocyte-derived dendritic cells (DCs) acquired different characteristics in dense or sparse cell cultures. Sparsity promoted the development of IL-12 producing migratory DCs, whereas dense cultures increased IL-10 production. Here we analysed whether the density-dependent endogenous breaks could modulate DC-based vaccines. Using murine bone marrow-derived DC models we show that sparse cultures were essential to achieve several key functions required for immunogenic DC vaccines, including mobility to draining lymph nodes, recruitment and massive proliferation of antigen-specific CD4+ T cells, in addition to their TH1 polarization. Transcription analyses confirmed higher commitment in sparse cultures towards T cell activation, whereas DCs obtained from dense cultures up-regulated immunosuppressive pathway components and genes suggesting higher differentiation plasticity towards osteoclasts. Interestingly, we detected a striking up-regulation of fatty acid and cholesterol biosynthesis pathways in sparse cultures, suggesting an important link between DC immunogenicity and lipid homeostasis regulation. PMID:28276533

  3. Systemic IL-12 Administration Alters Hepatic Dendritic Cell Stimulation Capabilities

    PubMed Central

    Chan, Tim; Back, Timothy C.; Subleski, Jeffrey J.; Weiss, Jonathan M.; Ortaldo, John R.; Wiltrout, Robert H.

    2012-01-01

    The liver is an immunologically unique organ containing tolerogenic dendritic cells (DC) that maintain an immunosuppressive microenvironment. Although systemic IL-12 administration can improve responses to tumors, the effects of IL-12-based treatments on DC, in particular hepatic DC, remain incompletely understood. In this study, we demonstrate systemic IL-12 administration induces a 2–3 fold increase in conventional, but not plasmacytoid, DC subsets in the liver. Following IL-12 administration, hepatic DC became more phenotypically and functionally mature, resembling the function of splenic DC, but differed as compared to their splenic counterparts in the production of IL-12 following co-stimulation with toll-like receptor (TLR) agonists. Hepatic DCs from IL-12 treated mice acquired enhanced T cell proliferative capabilities similar to levels observed using splenic DCs. Furthermore, IL-12 administration preferentially increased hepatic T cell activation and IFNγ expression in the RENCA mouse model of renal cell carcinoma. Collectively, the data shows systemic IL-12 administration enables hepatic DCs to overcome at least some aspects of the inherently suppressive milieu of the hepatic environment that could have important implications for the design of IL-12-based immunotherapeutic strategies targeting hepatic malignancies and infections. PMID:22428016

  4. Slowing down light using a dendritic cell cluster metasurface waveguide

    NASA Astrophysics Data System (ADS)

    Fang, Z. H.; Chen, H.; Yang, F. S.; Luo, C. R.; Zhao, X. P.

    2016-11-01

    Slowing down or even stopping light is the first task to realising optical information transmission and storage. Theoretical studies have revealed that metamaterials can slow down or even stop light; however, the difficulty of preparing metamaterials that operate in visible light hinders progress in the research of slowing or stopping light. Metasurfaces provide a new opportunity to make progress in such research. In this paper, we propose a dendritic cell cluster metasurface consisting of dendritic structures. The simulation results show that dendritic structure can realise abnormal reflection and refraction effects. Single- and double-layer dendritic metasurfaces that respond in visible light were prepared by electrochemical deposition. Abnormal Goos-Hänchen (GH) shifts were experimentally obtained. The rainbow trapping effect was observed in a waveguide constructed using the dendritic metasurface sample. The incident white light was separated into seven colours ranging from blue to red light. The measured transmission energy in the waveguide showed that the energy escaping from the waveguide was zero at the resonant frequency of the sample under a certain amount of incident light. The proposed metasurface has a simple preparation process, functions in visible light, and can be readily extended to the infrared band and communication wavelengths.

  5. Slowing down light using a dendritic cell cluster metasurface waveguide.

    PubMed

    Fang, Z H; Chen, H; Yang, F S; Luo, C R; Zhao, X P

    2016-11-25

    Slowing down or even stopping light is the first task to realising optical information transmission and storage. Theoretical studies have revealed that metamaterials can slow down or even stop light; however, the difficulty of preparing metamaterials that operate in visible light hinders progress in the research of slowing or stopping light. Metasurfaces provide a new opportunity to make progress in such research. In this paper, we propose a dendritic cell cluster metasurface consisting of dendritic structures. The simulation results show that dendritic structure can realise abnormal reflection and refraction effects. Single- and double-layer dendritic metasurfaces that respond in visible light were prepared by electrochemical deposition. Abnormal Goos-Hänchen (GH) shifts were experimentally obtained. The rainbow trapping effect was observed in a waveguide constructed using the dendritic metasurface sample. The incident white light was separated into seven colours ranging from blue to red light. The measured transmission energy in the waveguide showed that the energy escaping from the waveguide was zero at the resonant frequency of the sample under a certain amount of incident light. The proposed metasurface has a simple preparation process, functions in visible light, and can be readily extended to the infrared band and communication wavelengths.

  6. Slowing down light using a dendritic cell cluster metasurface waveguide

    PubMed Central

    Fang, Z. H.; Chen, H.; Yang, F. S.; Luo, C. R.; Zhao, X. P.

    2016-01-01

    Slowing down or even stopping light is the first task to realising optical information transmission and storage. Theoretical studies have revealed that metamaterials can slow down or even stop light; however, the difficulty of preparing metamaterials that operate in visible light hinders progress in the research of slowing or stopping light. Metasurfaces provide a new opportunity to make progress in such research. In this paper, we propose a dendritic cell cluster metasurface consisting of dendritic structures. The simulation results show that dendritic structure can realise abnormal reflection and refraction effects. Single- and double-layer dendritic metasurfaces that respond in visible light were prepared by electrochemical deposition. Abnormal Goos-Hänchen (GH) shifts were experimentally obtained. The rainbow trapping effect was observed in a waveguide constructed using the dendritic metasurface sample. The incident white light was separated into seven colours ranging from blue to red light. The measured transmission energy in the waveguide showed that the energy escaping from the waveguide was zero at the resonant frequency of the sample under a certain amount of incident light. The proposed metasurface has a simple preparation process, functions in visible light, and can be readily extended to the infrared band and communication wavelengths. PMID:27886279

  7. Effects of inactivated porcine epidemic diarrhea virus on porcine monocyte-derived dendritic cells and intestinal dendritic cells.

    PubMed

    Gao, Qi; Zhao, Shanshan; Qin, Tao; Yin, Yinyan; Yu, Qinghua; Yang, Qian

    2016-06-01

    Porcine epidemic diarrhea (PED) is a serious infection in neonatal piglets. As the causative agent of PED, porcine epidemic diarrhea virus (PEDV) results in acute diarrhea and dehydration with high mortality rates in swine. Dendritic cells (DCs) are highly effective antigen-presenting cells to uptake and present viral antigens to T cells, which then initiate a distinct immune response. In this study, our results show that the expression of Mo-DCs surface markers such as SWC3a(+)CD1a(+), SWC3a(+)CD80/86(+) and SWC3a(+)SLA-II-DR(+) is increased after incubation with UV-PEDV for 24h. Mo-DCs incubated with UV-PEDV produce higher levels of IL-12 and INF-γ compared to mock-infected Mo-DCs. Interactions between Mo-DCs and UV-PEDV significantly stimulate T-cell proliferation in vitro. Consistent with these results, there is an enhancement in the ability of porcine intestinal DCs to activate T-cell proliferation in vivo. We conclude that UV-PEDV may be a useful and safe vaccine to trigger adaptive immunity.

  8. Dendritic web - A viable material for silicon solar cells

    NASA Technical Reports Server (NTRS)

    Seidensticker, R. G.; Scudder, L.;