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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. Reovirus activates human dendritic cells to promote innate antitumor immunity.

    PubMed

    Errington, Fiona; Steele, Lynette; Prestwich, Robin; Harrington, Kevin J; Pandha, Hardev S; Vidal, Laura; de Bono, Johann; Selby, Peter; Coffey, Matt; Vile, Richard; Melcher, Alan

    2008-05-01

    Oncolytic viruses can exert their antitumor activity via direct oncolysis or activation of antitumor immunity. Although reovirus is currently under clinical investigation for the treatment of localized or disseminated cancer, any potential immune contribution to its efficacy has not been addressed. This is the first study to investigate the ability of reovirus to activate human dendritic cells (DC), key regulators of both innate and adaptive immune responses. Reovirus induced DC maturation and stimulated the production of the proinflammatory cytokines IFN-alpha, TNF-alpha, IL-12p70, and IL-6. Activation of DC by reovirus was not dependent on viral replication, while cytokine production (but not phenotypic maturation) was inhibited by blockade of PKR and NF-kappaB signaling. Upon coculture with autologous NK cells, reovirus-activated DC up-regulated IFN-gamma production and increased NK cytolytic activity. Moreover, short-term coculture of reovirus-activated DC with autologous T cells also enhanced T cell cytokine secretion (IL-2 and IFN-gamma) and induced non-Ag restricted tumor cell killing. These data demonstrate for the first time that reovirus directly activates human DC and that reovirus-activated DC stimulate innate killing by not only NK cells, but also T cells, suggesting a novel potential role for T cells in oncolytic virus-induced local tumor cell death. Hence reovirus recognition by DC may trigger innate effector mechanisms to complement the virus's direct cytotoxicity, potentially enhancing the efficacy of reovirus as a therapeutic agent.

  3. Ragweed subpollen particles of respirable size activate human dendritic cells.

    PubMed

    Pazmandi, Kitti; Kumar, Brahma V; Szabo, Krisztina; Boldogh, Istvan; Szoor, Arpad; Vereb, Gyorgy; Veres, Agota; Lanyi, Arpad; Rajnavolgyi, Eva; Bacsi, Attila

    2012-01-01

    Ragweed (Ambrosia artemisiifolia) pollen grains, which are generally considered too large to reach the lower respiratory tract, release subpollen particles (SPPs) of respirable size upon hydration. These SPPs contain allergenic proteins and functional NAD(P)H oxidases. In this study, we examined whether exposure to SPPs initiates the activation of human monocyte-derived dendritic cells (moDCs). We found that treatment with freshly isolated ragweed SPPs increased the intracellular levels of reactive oxygen species (ROS) in moDCs. Phagocytosis of SPPs by moDCs, as demonstrated by confocal laser-scanning microscopy, led to an up-regulation of the cell surface expression of CD40, CD80, CD86, and HLA-DQ and an increase in the production of IL-6, TNF-α, IL-8, and IL-10. Furthermore, SPP-treated moDCs had an increased capacity to stimulate the proliferation of naïve T cells. Co-culture of SPP-treated moDCs with allogeneic CD3(+) pan-T cells resulted in increased secretion of IFN-γ and IL-17 by T cells of both allergic and non-allergic subjects, but induced the production of IL-4 exclusively from the T cells of allergic individuals. Addition of exogenous NADPH further increased, while heat-inactivation or pre-treatment with diphenyleneiodonium (DPI), an inhibitor of NADPH oxidases, strongly diminished, the ability of SPPs to induce phenotypic and functional changes in moDCs, indicating that these processes were mediated, at least partly, by the intrinsic NAD(P)H oxidase activity of SPPs. Collectively, our data suggest that inhaled ragweed SPPs are fully capable of activating dendritic cells (DCs) in the airways and SPPs' NAD(P)H oxidase activity is involved in initiation of adaptive immune responses against innocuous pollen proteins.

  4. Ragweed Subpollen Particles of Respirable Size Activate Human Dendritic Cells

    PubMed Central

    Pazmandi, Kitti; Kumar, Brahma V.; Szabo, Krisztina; Boldogh, Istvan; Szoor, Arpad; Vereb, Gyorgy; Veres, Agota; Lanyi, Arpad; Rajnavolgyi, Eva; Bacsi, Attila

    2012-01-01

    Ragweed (Ambrosia artemisiifolia) pollen grains, which are generally considered too large to reach the lower respiratory tract, release subpollen particles (SPPs) of respirable size upon hydration. These SPPs contain allergenic proteins and functional NAD(P)H oxidases. In this study, we examined whether exposure to SPPs initiates the activation of human monocyte-derived dendritic cells (moDCs). We found that treatment with freshly isolated ragweed SPPs increased the intracellular levels of reactive oxygen species (ROS) in moDCs. Phagocytosis of SPPs by moDCs, as demonstrated by confocal laser-scanning microscopy, led to an up-regulation of the cell surface expression of CD40, CD80, CD86, and HLA-DQ and an increase in the production of IL-6, TNF-α, IL-8, and IL-10. Furthermore, SPP-treated moDCs had an increased capacity to stimulate the proliferation of naïve T cells. Co-culture of SPP-treated moDCs with allogeneic CD3+ pan-T cells resulted in increased secretion of IFN-γ and IL-17 by T cells of both allergic and non-allergic subjects, but induced the production of IL-4 exclusively from the T cells of allergic individuals. Addition of exogenous NADPH further increased, while heat-inactivation or pre-treatment with diphenyleneiodonium (DPI), an inhibitor of NADPH oxidases, strongly diminished, the ability of SPPs to induce phenotypic and functional changes in moDCs, indicating that these processes were mediated, at least partly, by the intrinsic NAD(P)H oxidase activity of SPPs. Collectively, our data suggest that inhaled ragweed SPPs are fully capable of activating dendritic cells (DCs) in the airways and SPPs' NAD(P)H oxidase activity is involved in initiation of adaptive immune responses against innocuous pollen proteins. PMID:23251688

  5. 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.

  6. 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

  7. Quercetin protects against atherosclerosis by inhibiting dendritic cell activation.

    PubMed

    Lin, Weiqun; Wang, Wenting; Wang, Dongliang; Ling, Wenhua

    2017-09-01

    Quercetin is a typical flavonol with atheroprotective effects, but the effect of quercetin on dendritic cell (DC) maturation in relation to atherosclerosis has not yet been clearly defined. Thus, we investigated whether quercetin can inhibit DC maturation and evaluated its potential value in atherosclerosis progression in ApoE(-/-) mice. Quercetin consumption inhibited DC activation, inflammatory response and suppressed the progression of atherosclerosis in ApoE(-/-) mice. Subsequently, quercetin treatment inhibited the phenotypic and functional maturation of DCs, as evidenced not only by downregulation of CD80, CD86, MHC-II, IL-6 and IL-12 but also by a reduction in the ability to stimulate T cell allogeneic proliferation. Finally, an in vitro study demonstrated that quercetin inhibited DC maturation via upregulation of Dabs, which then downregulated the Src/PI3K/Akt-NF-κB-inflammatory pathways. Our data indicate that quercetin attenuates atherosclerosis progression by regulating DC activation via Dab2 protein expression. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Blue light irradiation suppresses dendritic cells activation in vitro.

    PubMed

    Fischer, Michael R; Abel, Manuela; Lopez Kostka, Susanna; Rudolph, Berenice; Becker, Detlef; von Stebut, Esther

    2013-08-01

    Blue light is a UV-free irradiation suitable for treating chronic skin inflammation, for example, atopic dermatitis, psoriasis, and hand- and foot eczema. However, a better understanding of the mode of action is still missing. For this reason, we investigated whether dendritic cells (DC) are directly affected by blue light irradiation in vitro. Here, we report that irradiation neither induced apoptosis nor maturation of monocyte-derived and myeloid DC. However, subsequent DC maturation upon LPS/IFNγ stimulation was impaired in a dose-dependent manner as assessed by maturation markers and cytokine release. Moreover, the potential of this DC to induce cytokine secretion from allogeneic CD4 T cells was reduced. In conclusion, unlike UV irradiation, blue light irradiation at high and low doses only resulted in impaired DC maturation upon activation and a reduced subsequent stimulatory capacity in allogeneic MLRs with strongest effects at higher doses. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Modulation of Dendritic Cell Activation and Subsequent Th1 Cell Polarization by Lidocaine

    PubMed Central

    Chung, Yeonseok

    2015-01-01

    Dendritic cells play an essential role in bridging innate and adaptive immunity by recognizing cellular stress including pathogen- and damage-associated molecular patterns and by shaping the types of antigen-specific T cell immunity. Although lidocaine is widely used in clinical settings that trigger cellular stress, it remains unclear whether such treatment impacts the activation of innate immune cells and subsequent differentiation of T cells. Here we showed that lidocaine inhibited the production of IL–6, TNFα and IL–12 from dendritic cells in response to toll-like receptor ligands including lipopolysaccharide, poly(I:C) and R837 in a dose-dependent manner. Notably, the differentiation of Th1 cells was significantly suppressed by the addition of lidocaine while the same treatment had little effect on the differentiation of Th17, Th2 and regulatory T cells in vitro. Moreover, lidocaine suppressed the ovalbumin-specific Th1 cell responses in vivo induced by the adoptive transfer of ovalbumin-pulsed dendritic cells. These results demonstrate that lidocaine inhibits the activation of dendritic cells in response to toll-like receptor signals and subsequently suppresses the differentiation of Th1 cell responses. PMID:26445366

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. Dendritic cell type-specific HIV-1 activation in effector T cells: implications for latent HIV-1 reservoir establishment.

    PubMed

    van der Sluis, Renée M; van Capel, Toni M M; Speijer, Dave; Sanders, Rogier W; Berkhout, Ben; de Jong, Esther C; Jeeninga, Rienk E; van Montfort, Thijs

    2015-06-01

    Latent HIV type I (HIV-1) infections can frequently occur in short-lived proliferating effector T lymphocytes. These latently infected cells could revert into resting T lymphocytes and thereby contribute to the establishment of the long-lived viral reservoir. Monocyte-derived dendritic cells can revert latency in effector T cells in vitro. Here we investigated the latency activation properties of tissue-specific immune cells, including a large panel of dendritic cell subsets, to explore in which body compartments effector T cells are most likely to maintain latent HIV-1 provirus and thus potentially contribute to the long-lived reservoir. Our results demonstrate that blood or genital tract dendritic cells do not activate latent provirus in effector T cells, whereas gut or lymphoid dendritic cells induce virus production from latently infected effector T cells in our in-vitro model for latency. Toll-like receptor 3-induced interferon production by myeloid dendritic cells abolished the dendritic cells' ability to induce viral gene expression. In this study, we show that HIV-1 provirus residing in effector T cells is activated from latency by tissue-specific dendritic cell subsets and other immune cells with remarkably different efficiencies.Our new assay system points to an important, neglected aspect of HIV-1 research: the ability of other immune cells, especially dendritic cells, to differentially affect latency establishment as well as virus reactivation.

  15. Medroxyprogesterone acetate impairs human dendritic cell activation and function.

    PubMed

    Quispe Calla, N E; Ghonime, M G; Cherpes, T L; Vicetti Miguel, R D

    2015-05-01

    Does medroxyprogesterone acetate (MPA) impair human dendritic cell (DC) activation and function? In vitro MPA treatment suppressed expression of CD40 and CD80 by human primary DCs responding to Toll-like receptor 3 (TLR3) agonist stimulation (i.e. DC activation). Moreover, this MPA-mediated decrease in CD40 expression impaired DC capacity to stimulate T cell proliferation (i.e. DC function). MPA is the active molecule in Depo-Provera(®) (DMPA), a commonly used injectable hormonal contraceptive (HC). Although DMPA treatment of mice prior to viral mucosal tissue infection impaired the capacity of DCs to up-regulate CD40 and CD80 and prime virus-specific T cell proliferation, neither DC activation marker expression nor the ability of DCs to promote T cell proliferation were affected by in vitro progesterone treatment of human DCs generated from peripheral blood monocytes. This cross-sectional study examined MPA-mediated effects on the activation and function of human primary untouched peripheral blood DCs. Human DCs isolated from peripheral blood mononuclear cells by negative immunomagnetic selection were incubated for 24 h with various concentrations of MPA. After an additional 24 h incubation with the TLR3 agonist polyinosinic:polycytidylic acid (poly I:C), flow cytometry was used to evaluate DC phenotype (i.e. expression of CD40, CD80, CD86, and HLA-DR). In separate experiments, primary untouched human DCs were sequentially MPA-treated, poly I:C-activated, and incubated for 7 days with fluorescently labeled naïve allogeneic T cells. Flow cytometry was then used to quantify allogeneic T cell proliferation. Several pharmacologically relevant concentrations of MPA dramatically reduced CD40 and CD80 expression in human primary DCs responding to the immunostimulant poly I:C. In addition, MPA-treated DCs displayed a reduced capacity to promote allogeneic CD4(+) and CD8(+) T cell proliferation. In other DC: T cell co-cultures, the addition of antibody blocking the CD40

  16. 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

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

    PubMed

    Hammink, Roel; Mandal, Subhra; Eggermont, Loek J; Nooteboom, Marco; Willems, Peter H G M; Tel, Jurjen; Rowan, Alan E; Figdor, Carl G; Blank, Kerstin G

    2017-03-31

    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.

  18. [Features of functional activity of dendritic cells in tumor growth].

    PubMed

    Sennikov, S V; Obleukhova, I A; Kurilin, V V; Kulikova, E V; Khristin, A A

    2015-01-01

    During recent years much data, accumulated on biology, function and role of dendritic cells (DC) in cancer development, in a new way allow assessing their role in disease process. Identification of features of DC functional state as well as their interaction and influence on the immune cells in tumor growth can be used as a basis for a new approach to cancer therapy enhancing standard therapy efficacy. The review analyzes different mechanisms of escaping of tumor cell from immune surveillance involving DC as one of the main participants of antitumor immune response. Also the prospects of using DC for vaccination are discussed. DC can be promising target for therapeutic strategies and also can be used for formation of antitumor response and cell therapy.

  19. 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.

  20. Reconsideration of macrophage and dendritic cell classification.

    PubMed

    Kadowaki, Takeshi; Shimada, Misato; Inagawa, Hiroyuki; Kohchi, Chie; Hirashima, Mitsuomi; Soma, Gen-Ichiro

    2012-06-01

    It is well known that the activation of innate immune cells, especially antigen-presenting cells such as macrophages and dendritic cells, can ameliorate or exacerbate various diseases, including cancer. Currently, the macrophages and dendritic cells are categorized into several groups by their cell surface and intracellular molecules. However, the detailed classification of the differences between macrophages and dendritic cells has still not been established. Here, we summarized and reviewed the previous studies on the classification of macrophages and dendritic cells. In addition, the previous classification of monocytes, macrophages and dendritic cells is discussed based on our findings of macrophage activation, which has both conventional and plasmacytoid dendritic cell phenotype.

  1. Spherical Lactic Acid Bacteria Activate Plasmacytoid Dendritic Cells Immunomodulatory Function via TLR9-Dependent Crosstalk with Myeloid Dendritic Cells

    PubMed Central

    Jounai, Kenta; Ikado, Kumiko; Sugimura, Tetsu; Ano, Yasuhisa; Braun, Jonathan; Fujiwara, Daisuke

    2012-01-01

    Plasmacytoid dendritic cells (pDC) are a specialized sensor of viral and bacterial nucleic acids and a major producer of IFN-α that promotes host defense by priming both innate and acquired immune responses. Although synthetic Toll-like receptor (TLR) ligands, pathogenic bacteria and viruses activate pDC, there is limited investigation of non-pathogenic microbiota that are in wide industrial dietary use, such as lactic acid bacteria (LAB). In this study, we screened for LAB strains, which induce pDC activation and IFN-α production using murine bone marrow (BM)-derived Flt-3L induced dendritic cell culture. Microbial strains with such activity on pDC were absent in a diversity of bacillary strains, but were observed in certain spherical species (Lactococcus, Leuconostoc, Streptococcus and Pediococcus), which was correlated with their capacity for uptake by pDC. Detailed study of Lactococcus lactis subsp. lactis JCM5805 and JCM20101 revealed that the major type I and type III interferons were induced (IFN-α, -β, and λ). IFN-α induction was TLR9 and MyD88-dependent; a slight impairment was also observed in TLR4-/- cells. While these responses occurred with purified pDC, IFN-α production was synergistic upon co-culture with myeloid dendritic cells (mDC), an interaction that required direct mDC-pDC contact. L. lactis strains also stimulated expression of immunoregulatory receptors on pDC (ICOS-L and PD-L1), and accordingly augmented pDC induction of CD4+CD25+FoxP3+ Treg compared to the Lactobacillus strain. Oral administration of L. lactis JCM5805 induced significant activation of pDC resident in the intestinal draining mesenteric lymph nodes, but not in a remote lymphoid site (spleen). Taken together, certain non-pathogenic spherical LAB in wide dietary use has potent and diverse immunomodulatory effects on pDC potentially relevant to anti-viral immunity and chronic inflammatory disease. PMID:22505996

  2. A polymeric bacterial protein activates dendritic cells via TLR4.

    PubMed

    Berguer, Paula M; Mundiñano, Juliana; Piazzon, Isabel; Goldbaum, Fernando A

    2006-02-15

    The enzyme lumazine synthase from Brucella spp. (BLS) is a highly immunogenic protein that folds as a stable dimer of pentamers. It is possible to insert foreign peptides and proteins at the 10 N terminus of BLS without disrupting its general folding, and these chimeras are very efficient to elicit systemic and oral immunity without adjuvants. In this study, we show that BLS stimulates bone marrow dendritic cells from mice in vitro to up-regulate the levels of costimulatory molecules (CD40, CD80, and CD86) and major histocompatibility class II Ag. Furthermore, the mRNA levels of several chemokines are increased, and proinflammatory cytokine secretion is induced upon exposure to BLS. In vivo, BLS increases the number of dendritic cells and their expression of CD62L in the draining lymph node. All of the observed effects are dependent on TLR4, and clearly independent of LPS contamination. The described characteristics of BLS make this protein an excellent candidate for vaccine development.

  3. [Experimental study on activating antileukemic T cells by vaccination with dendritic cells pulsed with survivin].

    PubMed

    Zhang, Xiao-Hui; Xia, Ling-Hui; Liu, Zhong-Ping; Wei, Wen-Ning; Hu, Yu; Song, Shan-Jun

    2003-02-01

    The objective of this study is to investigate the effect of vaccination with dendritic cells pulsed with survivin antigen on activation of antileukemic T cells, and inhibiting proliferation of leukemic cells. The expression of survivin on acute leukemic cells were detected by cofocal microscopy and immunoprecipitation-Western blot. DCs collected from peripheral blood mononuclear cells were pulsed with survivin purified proteins. Stimulation index (SI) and antileukemia CTL induction were analyzed with (3)H-TdR incorporation and (51)Cr releasing assay, respectively. The phenotype of T cells and DCs were identified by flow cytometry. By immunofluorescence of bone marrow and peripheral blood mononuclear cells, survivin expression was detected in 16 out of 19 AML cases (84.2%). The results showed that survivin fluorescence distribution was in cytoplasm. DCs from peripheral blood mononuclear cells were successfully induced, with typical DC morphologic characteristic. The vaccination with dendritic cells pulsed with survivin antigen dramatically stimulated the proliferation of T cells. The DCs loading survivin activated T cells with higher CD4(+) T(H) ratio as compared with DCs group, T cells activated with DCs expressed CD8 and CD56. Survivin DCs significantly inhibited the growth of leukemic cells in vitro. In conclusion, survivin antigen expressed in the cytoplasm of leukemic cells, leukemic vaccination with DCs pulsed with survivin antigen in vitro inhibited the proliferation of leukemic cells, that may be a pathway for therapy of leukemia.

  4. Inhibitory effect of cepharanthine on dendritic cell activation and function.

    PubMed

    Uto, Tomofumi; Nishi, Yosuke; Toyama, Masaaki; Yoshinaga, Keisuke; Baba, Masanori

    2011-11-01

    Dendritic cells (DCs) are specialized antigen presenting cells that connect innate and adaptive immunity. DCs are considered as a major target for controlling excessive immune responses. In this study, the effect of cepharanthine (CEP), a biscoclaurine alkaloid isolated from Stephania cepharantha Hayata, on murine DCs was examined in vitro. CEP inhibited antigen uptake by DCs at a concentration between 1 and 5 μg/ml. Although CEP did not inhibit the expression of costimulatory molecules and major histocompatibility complex (MHC) class I in DCs, the compound inhibited lipopolysaccharide (LPS)-induced DC maturation determined by the expression of costimulatory molecules and MHC class I. In addition, CEP could reduce the production of interleukin-6 and tumor necrosis factor-α in LPS-stimulated DCs. DCs treated with CEP were found to be a poor stimulator of allogeneic T cell proliferation and interferon-γ production from the cells. These results suggest that CEP may have great potential as an immunoregulatory agent against various autoimmune diseases and allergy.

  5. 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

  6. 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

  7. Th17 Cells and Activated Dendritic Cells Are Increased in Vitiligo Lesions

    PubMed Central

    Fuentes-Duculan, Judilyn; Moussai, Dariush; Gulati, Nicholas; Sullivan-Whalen, Mary; Gilleaudeau, Patricia; Cohen, Jules A.; Krueger, James G.

    2011-01-01

    Background Vitiligo is a common skin disorder, characterized by progressive skin de-pigmentation due to the loss of cutaneous melanocytes. The exact cause of melanocyte loss remains unclear, but a large number of observations have pointed to the important role of cellular immunity in vitiligo pathogenesis. Methodology/Principal Findings In this study, we characterized T cell and inflammation-related dermal dendritic cell (DC) subsets in pigmented non-lesional, leading edge and depigmented lesional vitiligo skin. By immunohistochemistry staining, we observed enhanced populations of CD11c+ myeloid dermal DCs and CD207+ Langerhans cells in leading edge vitiligo biopsies. DC-LAMP+ and CD1c+ sub-populations of dermal DCs expanded significantly in leading edge and lesional vitiligo skin. We also detected elevated tissue mRNA levels of IL-17A in leading edge skin biopsies of vitiligo patients, as well as IL-17A positive T cells by immunohistochemistry and immunofluorescence. Langerhans cells with activated inflammasomes were also noted in lesional vitiligo skin, along with increased IL-1ß mRNA, which suggest the potential of Langerhans cells to drive Th17 activation in vitiligo. Conclusions/Significance These studies provided direct tissue evidence that implicates active Th17 cells in vitiligo skin lesions. We characterized new cellular immune elements, in the active margins of vitiligo lesions (e.g. populations of epidermal and dermal dendritic cells subsets), which could potentially drive the inflammatory responses. PMID:21541348

  8. 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

  9. Tenascin-C aggravates autoimmune myocarditis via dendritic cell activation and Th17 cell differentiation.

    PubMed

    Machino-Ohtsuka, Tomoko; Tajiri, Kazuko; Kimura, Taizo; Sakai, Satoshi; Sato, Akira; Yoshida, Toshimichi; Hiroe, Michiaki; Yasutomi, Yasuhiro; Aonuma, Kazutaka; Imanaka-Yoshida, Kyoko

    2014-11-05

    Tenascin-C (TN-C), an extracellular matrix glycoprotein, appears at several important steps of cardiac development in the embryo, but is sparse in the normal adult heart. TN-C re-expresses under pathological conditions including myocarditis, and is closely associated with tissue injury and inflammation in both experimental and clinical settings. However, the pathophysiological role of TN-C in the development of myocarditis is not clear. We examined how TN-C affects the initiation of experimental autoimmune myocarditis, immunologically. A model of experimental autoimmune myocarditis was established in BALB/c mice by immunization with murine α-myosin heavy chains. We found that TN-C knockout mice were protected from severe myocarditis compared to wild-type mice. TN-C induced synthesis of proinflammatory cytokines, including interleukin (IL)-6, in dendritic cells via activation of a Toll-like receptor 4, which led to T-helper (Th)17 cell differentiation and exacerbated the myocardial inflammation. In the transfer experiment, dendritic cells loaded with cardiac myosin peptide acquired the functional capacity to induce myocarditis when stimulated with TN-C; however, TN-C-stimulated dendritic cells generated from Toll-like receptor 4 knockout mice did not induce myocarditis in recipients. Our results demonstrated that TN-C aggravates autoimmune myocarditis by driving the dendritic cell activation and Th17 differentiation via Toll-like receptor 4. The blockade of Toll-like receptor 4-mediated signaling to inhibit the proinflammatory effects of TN-C could be a promising therapeutic strategy against autoimmune myocarditis. © 2014 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  10. Mast cells and dendritic cells form synapses that facilitate antigen transfer for T cell activation.

    PubMed

    Carroll-Portillo, Amanda; Cannon, Judy L; te Riet, Joost; Holmes, Anna; Kawakami, Yuko; Kawakami, Toshiaki; Cambi, Alessandra; Lidke, Diane S

    2015-08-31

    Mast cells (MCs) produce soluble mediators such as histamine and prostaglandins that are known to influence dendritic cell (DC) function by stimulating maturation and antigen processing. Whether direct cell-cell interactions are important in modulating MC/DC function is unclear. In this paper, we show that direct contact between MCs and DCs occurs and plays an important role in modulating the immune response. Activation of MCs through FcεRI cross-linking triggers the formation of stable cell-cell interactions with immature DCs that are reminiscent of the immunological synapse. Direct cellular contact differentially regulates the secreted cytokine profile, indicating that MC modulation of DC populations is influenced by the nature of their interaction. Synapse formation requires integrin engagement and facilitates the transfer of internalized MC-specific antigen from MCs to DCs. The transferred material is ultimately processed and presented by DCs and can activate T cells. The physiological outcomes of the MC-DC synapse suggest a new role for intercellular crosstalk in defining the immune response.

  11. Can dendritic cells see light?

    NASA Astrophysics Data System (ADS)

    Chen, Aaron C.-H.; Huang, Ying-Ying; Sharma, Sulbha K.; Hamblin, Michael R.

    2010-02-01

    There are many reports showing that low-level light/laser therapy (LLLT) can enhance wound healing, upregulate cell proliferation and has anti-apoptotic effects by activating intracellular protective genes. In the field of immune response study, it is not known with any certainty whether light/laser is proinflammatory or anti-inflammatory. Increasingly in recent times dendritic cells have been found to play an important role in inflammation and the immunological response. In this study, we try to look at the impact of low level near infrared light (810-nm) on murine bone-marrow derived dendritic cells. Changes in surface markers, including MHC II, CD80 and CD11c and the secretion of interleukins induced by light may provide additional evidence to reveal the mystery of how light affects the maturation of dendritic cells as well how these light-induced mature dendritic cells would affect the activation of adaptive immune response.

  12. PM10-stimulated airway epithelial cells activate primary human dendritic cells independent of uric acid: application of an in vitro model system exposing dendritic cells to airway epithelial cell-conditioned media.

    PubMed

    Hirota, Jeremy A; Alexis, Neil E; Pui, Mandy; Wong, SzeWing; Fung, Elkie; Hansbro, Phillip; Knight, Darryl A; Sin, Don D; Carlsten, Chris

    2014-08-01

    Airway epithelial cells represent the first line of defence against inhaled insults, including air pollution. Air pollution can activate innate immune signalling in airway epithelial cells leading to the production of soluble mediators that can influence downstream inflammatory cells. Our objective was to develop and validate a model of dendritic cell exposure to airway epithelial cell-conditioned media. After establishing the model, we explored how soluble mediators released from airway epithelial cells in response to air pollution influenced the phenotype of dendritic cells. Human airway epithelial cells were cultured under control and urban particulate matter (PM10) exposure conditions with or without pharmacological inhibitors of the uric acid pathway. Culture supernatants were collected for conditioned media experiments with peripheral blood mononuclear cell-derived dendritic cells analysed by flow cytometry. Monocytes derived from peripheral blood mononuclear cells cultured in interleukin-4 and granulocyte macrophage colony stimulating factor differentiated into immature dendritic cells that phenotypically differentiated into mature dendritic cells in response to conditioned media from phorbol myristate acetate-activated THP-1 monocytes. Exposure of immature dendritic cells to conditioned media from airway epithelial cells exposed to PM10 resulted in dendritic cell maturation that was independent of uric acid. We present a conditioned media model useful for interrogating the contribution of soluble mediators produced by airway epithelial cells to dendritic cell phenotype and function. Furthermore, we demonstrate that PM10 exposure induces airway epithelial cell production of soluble mediators that induce maturation of dendritic cells independent of uric acid. © 2014 Asian Pacific Society of Respirology.

  13. Dendritic cells for active anti-cancer immunotherapy: targeting activation pathways through genetic modification.

    PubMed

    Breckpot, Karine; Escors, David

    2009-12-01

    Tumour immunotherapy has become a treatment modality for cancer, harnessing the immune system to recognize and eradicate tumour cells specifically. It is based on the expression of tumour associated antigens (TAA) by the tumour cells and aims at the induction of TAA-specific effector T cell responses, whilst overruling various mechanisms that can hamper the anti-tumour immune response, e.g. regulatory T cells (Treg). (Re-) activation of effector T cells requires the completion of a carefully orchestrated series of specific steps. Particularly important is the provision of TAA presentation and strong stimulatory signals, delivered by co-stimulatory surface molecules and cytokines. These can only be delivered by professional antigen-presenting cells, in particular dendritic cells (DC). Therefore, DC need to be loaded with TAA and appropriately activated. It is not surprising that an extensive part of DC research has focused on the delivery of both TAA and activation signals to DC, developing a one step approach to obtain potent stimulatory DC. The simultaneous delivery of TAA and activation signals is therefore the topic of this review, emphasizing the role of DC in mediating T cell activation and how we can manipulate DC for the pill-pose of enhancing tumour immunotherapy. As we gain a better understanding of the molecular and cellular mechanisms that mediate induction of TAA-specific T cells, rational approaches for the activation of T cell responses can be developed for the treatment of cancer.

  14. Dendritic Cells for Active Anti-Cancer Immunotherapy: Targeting Activation Pathways Through Genetic Modification

    PubMed Central

    Breckpot, Karine; Escors, David

    2009-01-01

    Tumour immunotherapy has become a treatment modality for cancer, harnessing the immune system to recognize and eradicate tumour cells specifically. It is based on the expression of tumour associated antigens (TAA) by the tumour cells and aims at the induction of TAA-specific effector T cell responses, whilst overruling various mechanisms that can hamper the anti-tumour immune response, e.g. regulatory T cells (Treg). (Re-) activation of effector T cells requires the completion of a carefully orchestrated series of specific steps. Particularly important is the provision of TAA presentation and strong stimulatory signals, delivered by co-stimulatory surface molecules and cytokines. These can only be delivered by professional antigen-presenting cells, in particular dendritic cells (DC). Therefore, DC need to be loaded with TAA and appropriately activated. It is not surprising that an extensive part of DC research has focused on the delivery of both TAA and activation signals to DC, developing a one step approach to obtain potent stimulatory DC. The simultaneous delivery of TAA and activation signals is therefore the topic of this review, emphasizing the role of DC in mediating T cell activation and how we can manipulate DC for the pill-pose of enhancing tumour immunotherapy. As we gain a better understanding of the molecular and cellular mechanisms that mediate induction of TAA-specific T cells, rational approaches for the activation of T cell responses can be developed for the treatment of cancer. PMID:19857199

  15. 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.

  16. Extrafollicular B cell activation by marginal zone dendritic cells drives T cell–dependent antibody responses

    PubMed Central

    Draves, Kevin E.; Giltiay, Natalia V.; Clark, Edward A.

    2012-01-01

    Dendritic cells (DCs) are best known for their ability to activate naive T cells, and emerging evidence suggests that distinct DC subsets induce specialized T cell responses. However, little is known concerning the role of DC subsets in the initiation of B cell responses. We report that antigen (Ag) delivery to DC-inhibitory receptor 2 (DCIR2) found on marginal zone (MZ)–associated CD8α− DCs in mice leads to robust class-switched antibody (Ab) responses to a T cell–dependent (TD) Ag. DCIR2+ DCs induced rapid up-regulation of multiple B cell activation markers and changes in chemokine receptor expression, resulting in accumulation of Ag-specific B cells within extrafollicular splenic bridging channels as early as 24 h after immunization. Ag-specific B cells primed by DCIR2+ DCs were remarkably efficient at driving naive CD4 T cell proliferation, yet DCIR2-induced responses failed to form germinal centers or undergo affinity maturation of serum Ab unless toll-like receptor (TLR) 7 or TLR9 agonists were included at the time of immunization. These results demonstrate DCIR2+ DCs have a unique capacity to initiate extrafollicular B cell responses to TD Ag, and thus define a novel division of labor among splenic DC subsets for B cell activation during humoral immune responses. PMID:22966002

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

    USDA-ARS?s Scientific Manuscript database

    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...

  18. 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

  19. TSLP-activated dendritic cells induce human T follicular helper cell differentiation through OX40-ligand.

    PubMed

    Pattarini, Lucia; Trichot, Coline; Bogiatzi, Sofia; Grandclaudon, Maximilien; Meller, Stephan; Keuylian, Zela; Durand, Melanie; Volpe, Elisabetta; Madonna, Stefania; Cavani, Andrea; Chiricozzi, Andrea; Romanelli, Marco; Hori, Toshiyuki; Hovnanian, Alain; Homey, Bernhard; Soumelis, Vassili

    2017-05-01

    T follicular helper cells (Tfh) are important regulators of humoral responses. Human Tfh polarization pathways have been thus far associated with Th1 and Th17 polarization pathways. How human Tfh cells differentiate in Th2-skewed environments is unknown. We show that thymic stromal lymphopoietin (TSLP)-activated dendritic cells (DCs) promote human Tfh differentiation from naive CD4 T cells. We identified a novel population, distinct from Th2 cells, expressing IL-21 and TNF, suggestive of inflammatory cells. TSLP-induced T cells expressed CXCR5, CXCL13, ICOS, PD1, BCL6, BTLA, and SAP, among other Tfh markers. Functionally, TSLP-DC-polarized T cells induced IgE secretion by memory B cells, and this depended on IL-4Rα. TSLP-activated DCs stimulated circulating memory Tfh cells to produce IL-21 and CXCL13. Mechanistically, TSLP-induced Tfh differentiation depended on OX40-ligand, but not on ICOS-ligand. Our results delineate a pathway of human Tfh differentiation in Th2 environments. © 2017 Pattarini et al.

  20. 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).

  1. 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.

  2. Intravenous immunoglobulin ameliorates ITP via activating Fc gamma receptors on dendritic cells.

    PubMed

    Siragam, Vinayakumar; Crow, Andrew R; Brinc, Davor; Song, Seng; Freedman, John; Lazarus, Alan H

    2006-06-01

    Despite a more than 20-year experience of therapeutic benefit, the relevant molecular and cellular targets of intravenous immunoglobulin (IVIg) in autoimmune disease remain unclear. Contrary to the prevailing theories of IVIg action in autoimmunity, we show that IVIg drives signaling through activating Fc gamma receptors (Fc gammaR) in the amelioration of mouse immune thrombocytopenic purpura (ITP). The actual administration of IVIg was unnecessary because as few as 10(5) IVIg-treated cells could, upon adoptive transfer, ameliorate ITP. IVIg did not interact with the inhibitory Fc gammaRIIB on the initiator cell, although Fc gammaRIIB does have a role in the late phase of IVIg action. Notably, only IVIg-treated CD11c+ dendritic cells could mediate these effects. We hypothesize that IVIg forms soluble immune complexes in vivo that prime dendritic-cell regulatory activity. In conclusion, the clinical effects of IVIg in ameliorating ITP seem to involve the acute interaction of IVIg with activating Fc gammaR on dendritic cells.

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

    PubMed

    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.

  4. 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

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

    PubMed

    Ramirez, Oscar; Garza, Kristine M

    2014-11-01

    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 (Lep(ob)) 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 Lep(ob) 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 Lep(ob) sDC was similar to controls. However, Lep(ob) 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 Lep(ob) sDC activation of T cells in vivo, Lep(ob) and control mice were infected systemically with Mycobacterium avium. Lep(ob) 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 Lep(ob) 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. © The Japanese Society for Immunology. 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Chloroquine modulates HIV-1-induced plasmacytoid dendritic cell alpha interferon: implication for T-cell activation.

    PubMed

    Martinson, Jeffrey A; Montoya, Carlos J; Usuga, Xiomara; Ronquillo, Rollie; Landay, Alan L; Desai, Seema N

    2010-02-01

    Plasmacytoid dendritic cells (pDC) contribute to antiviral immunity mainly through recognition of microbial products and viruses via intracellular Toll-like receptor 7 (TLR7) or TLR9, resulting in the production of type I interferons (IFNs). Although interferons reduce the viral burden in the acute phase of infection, their role in the chronic phase is unclear. The presence of elevated plasma IFN-alpha levels in advanced HIV disease and its association with microbial translocation in chronic HIV infection lead us to hypothesize that IFN-alpha could contribute to immune activation. Blocking of IFN-alpha production using chloroquine, an endosomal inhibitor, was tested in a novel in vitro model system with the aim of characterizing the effects of chloroquine on HIV-1-mediated TLR signaling, IFN-alpha production, and T-cell activation. Our results indicate that chloroquine blocks TLR-mediated activation of pDC and MyD88 signaling, as shown by decreases in the levels of the downstream signaling molecules IRAK-4 and IRF-7 and by inhibition of IFN-alpha synthesis. Chloroquine decreased CD8 T-cell activation induced by aldrithiol-2-treated HIV-1 in peripheral blood mononuclear cell cultures. In addition to blocking pDC activation, chloroquine also blocked negative modulators of the T-cell response, such as indoleamine 2,3-dioxygenase (IDO) and programmed death ligand 1 (PDL-1). Our results indicate that TLR stimulation and production of IFN-alpha by pDC contribute to immune activation and that blocking of these pathways using chloroquine may interfere with events contributing to HIV pathogenesis. Our results suggests that a safe, well-tolerated drug such as chloroquine can be proposed as an adjuvant therapeutic candidate along with highly active antiretroviral therapy to control immune activation in HIV-1 infection.

  12. 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.

  13. Virulent Salmonella enterica Serovar Typhimurium Evades Adaptive Immunity by Preventing Dendritic Cells from Activating T Cells

    PubMed Central

    Tobar, Jaime A.; Carreño, Leandro J.; Bueno, Susan M.; González, Pablo A.; Mora, Jorge E.; Quezada, Sergio A.; Kalergis, Alexis M.

    2006-01-01

    Dendritic cells (DCs) constitute the link between innate and adaptive immunity by directly recognizing pathogen-associated molecular patterns (PAMPs) in bacteria and by presenting bacterial antigens to T cells. Recognition of PAMPs renders DCs as professional antigen-presenting cells able to prime naïve T cells and initiate adaptive immunity against bacteria. Therefore, interfering with DC function would promote bacterial survival and dissemination. Understanding the molecular mechanisms that have evolved in virulent bacteria to evade activation of adaptive immunity requires the characterization of virulence factors that interfere with DC function. Salmonella enterica serovar Typhimurium, the causative agent of typhoid-like disease in the mouse, can prevent antigen presentation to T cells by avoiding lysosomal degradation in DCs. Here, we show that this feature of virulent Salmonella applies in vivo to prevent activation of adaptive immunity. In addition, this attribute of virulent Salmonella requires functional expression of a type three secretion system (TTSS) and effector proteins encoded within the Salmonella pathogenicity island 2 (SPI-2). In contrast to wild-type virulent Salmonella, mutant strains carrying specific deletions of SPI-2 genes encoding TTSS components or effectors proteins are targeted to lysosomes and are no longer able to prevent DCs from activating T cells in vitro or in vivo. SPI-2 mutant strains are attenuated in vivo, showing reduced tissue colonization and enhanced T-cell activation, which confers protection against a challenge with wild-type virulent Salmonella. Our data suggest that impairment of DC function by the activity of SPI-2 gene products is crucial for Salmonella pathogenesis. PMID:17057096

  14. Clinical Trials Using Adenoviral Transduced hIL-12-expressing Autologous Dendritic Cells INXN-3001 Plus Activator Ligand INXN-1001

    Cancer.gov

    NCI supports clinical trials that test new and more effective ways to treat cancer. Find clinical trials studying adenoviral transduced hil-12-expressing autologous dendritic cells inxn-3001 plus activator ligand inxn-1001.

  15. 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

  16. Plasmacytoid dendritic cells protect against atherosclerosis by tuning T cell proliferation and activity

    PubMed Central

    Daissormont, Isabelle T.M.N.; Christ, Anette; Temmerman, Lieve; Millares, Stefan Sampedro; Seijkens, Tom; Rousch, Mat; Poggi, Marjorie; Boon, Louis; van der Loos, Chris; Daemen, Mat; Lutgens, Esther; Halvorsen, Bente; Aukrust, Pal; Janssen, Edith; Biessen, Erik A.L.

    2011-01-01

    Rationale Unlike conventional dendritic cells (cDC), plasmacytoid DCs (pDC) are poor in antigen presentation and critical for type I interferon response. While proposed to be present in human atherosclerotic lesions, their role in atherosclerosis remains elusive. Objective To investigate the role of pDC in atherosclerosis. Methods and Results We show that pDC are scarcely present in human atherosclerotic lesions, and almost absent in mouse plaques. Surprisingly, pDC depletion by 120G8 mAb administration was seen to promote plaque T cell accumulation and exacerbate lesion development and progression in LDLr−/− mice. PDC depletion was accompanied by increased CD4+ T cell proliferation, IFN-γ expression by splenic T cells and plasma IFN-γ levels. Lymphoid tissue pDC from atherosclerotic mice showed increased indoleamine 2,3-dioxygenase (IDO) expression and IDO blockage abrogated the pDC suppressive effect on T cell proliferation. Conclusion Our data reveal a protective role for pDC in atherosclerosis, possibly by dampening T cell proliferation and activity in peripheral lymphoid tissue, rendering pDC an interesting target for future therapeutic interventions. PMID:22021930

  17. Differential activation of dendritic cells by nerve growth factor and brain-derived neurotrophic factor.

    PubMed

    Noga, O; Peiser, M; Altenähr, M; Knieling, H; Wanner, R; Hanf, G; Grosse, R; Suttorp, N

    2007-11-01

    Neurotrophins are involved in inflammatory reactions influencing several cells in health and disease including allergy and asthma. Dendritic cells (DCs) play a major role in the induction of inflammatory processes with an increasing role in allergic diseases as well. The aim of this study was to investigate the influence of neurotrophins on DC function. Monocyte-derived dendritic cells were generated from allergic and non-allergic donors. Neurotrophin receptors were demonstrated by western blotting, flow cytometry and fluorescence microscopy. Activation of small GTPases was evaluated by pull-down assays. DCs were incubated with nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) and supernatants were collected for measurement of IL-4, IL-6, IL-10, IL-12p70, TNF-alpha and TGF-beta. Receptor proteins were detectable by western blot, fluorescence activated cell sorting analysis and fluorescence microscopy. Signalling after neurotrophin stimulation occurred in a ligand-specific pattern. NGF led to decreased RhoA and increased Rac activation, while BDNF affected RhoA and Rac activity in a reciprocal fashion. Cells of allergics released a significantly increased amount of IL-6, while for healthy subjects a significantly higher amount of IL-10 was found. These data indicate that DCs are activated by the neurotrophins NGF and BDNF by different pathways in a receptor-dependant manner. These cells then may initiate inflammatory responses based on allergic sensitization releasing preferred cytokines inducing tolerance or a T-helper type 2 response.

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. 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.

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

    PubMed Central

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

    2014-01-01

    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. PMID:25454621

  4. 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. Copyright © 2014 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.

  5. 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.

  6. 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

  7. 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

  8. 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

  9. Particulate β-glucans synergistically activate TLR4 and Dectin-1 in human dendritic cells.

    PubMed

    Sahasrabudhe, Neha M; Dokter-Fokkens, Jelleke; de Vos, Paul

    2016-11-01

    The major receptor for β(1-3)-glucans on immune cells is considered to be Dectin-1 receptor. Particulate β-glucans induce stronger immune responses than soluble β-glucans by clustering of Dectin-1 receptors. Here, it was hypothesized that activation of other pattern recognition receptors such as Toll-like receptor 4 (TLR4) can also contribute to enhanced activity of immune cells after exposure to particulate β-glucans. To test this hypothesis, reporter cell lines were designed expressing TLR4 with either Dectin-1A or Dectin-1B, that is, one of the two transcript variants of human Dectin-1 receptors. Enhanced NF-κB activation was observed after stimulation with particulate β-glucans in both Dectin-1A-TLR4 and the Dectin-1B-TLR4 cell lines. This was different with soluble β-glucans, which enhanced activation in Dectin-1A-TLR4 cell lines but not in Dectin-1B-TLR4 cells. The synergistic activation of TLR4 and Dectin-1 by particulate β-glucans was confirmed in human dendritic cells. The effects of particulate β-glucan induced TLR4 binding were regulatory as blocking TLR4 enhanced pro-inflammatory cytokine IL-23, IL-4, IL-6, and TNF-α production. These results suggest that TLR4 and Dectin-1 are synergistically activated by particulate β-glucans, wherein TLR4 activates an immune regulatory pathway in human dendritic cells. Our data suggest that β-glucan is an immune regulatory ligand for TLR4. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. 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

  11. 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.

  12. Pig skin includes dendritic cell subsets transcriptomically related to human CD1a and CD14 dendritic cells presenting different migrating behaviors and T cell activation capacities.

    PubMed

    Marquet, Florian; Vu Manh, Thien-Phong; Maisonnasse, Pauline; Elhmouzi-Younes, Jamila; Urien, Céline; Bouguyon, Edwige; Jouneau, Luc; Bourge, Mickael; Simon, Gaëlle; Ezquerra, Angel; Lecardonnel, Jérôme; Bonneau, Michel; Dalod, Marc; Schwartz-Cornil, Isabelle; Bertho, Nicolas

    2014-12-15

    Swine skin is one of the best structural models for human skin, widely used to probe drug transcutaneous passage and to test new skin vaccination devices. However, little is known about its composition in immune cells, and among them dendritic cells (DC), that are essential in the initiation of the immune response. After a first seminal work describing four different DC subpopulations in pig skin, we hereafter deepen the characterization of these cells, showing the similarities between swine DC subsets and their human counterparts. Using comparative transcriptomic study, classical phenotyping as well as in vivo and in vitro functional studies, we show that swine CD163(pos) dermal DC (DDC) are transcriptomically similar to the human CD14(pos) DDC. CD163(pos) DDC are recruited in inflamed skin, they migrate in inflamed lymph but they are not attracted toward CCL21, and they modestly activate allogeneic CD8 T cells. We also show that CD163(low) DDC are transcriptomically similar to the human CD1a(pos) DDC. CD163(low) DDC migrate toward CCL21, they activate allogeneic CD8 and CD4 T cells and, like their potential human lung counterpart, they skew CD4 T cells toward a Th17 profile. We thus conclude that swine skin is a relevant model for human skin vaccination. Copyright © 2014 by The American Association of Immunologists, Inc.

  13. Local Activation of Dendritic Cells Alters the Pathogenesis of Autoimmune Disease In the Retina1

    PubMed Central

    Heuss, Neal D.; Lehmann, Ute; Norbury, Christopher C.; McPherson, Scott W.; Gregerson, Dale S.

    2011-01-01

    Interest in the identities, properties, functions and origins of local antigen presenting cells (APC) in CNS tissues is growing. We recently reported that dendritic cells (DC) distinct from microglia were present in quiescent retina, and rapidly responded to injured neurons. In this study, the disease-promoting and regulatory contributions of these APC in experimental autoimmune uveoretinitis (EAU) were examined. Local delivery of purified, exogenous DC or monocytes from bone marrow substantially increased the incidence and severity of EAU induced by adoptive transfer of activated, autoreactive CD4 or CD8 T cells that was limited to the manipulated eye. In vitro assays of antigen presenting cell activity of DC from quiescent retina showed that they promoted generation of Foxp3+ T cells, and inhibited activation of naive T cells by splenic DC and antigen. Conversely, in vitro assays of DC purified from injured retina revealed an enhanced ability to activate T cells, and reduced induction of Foxp3+ T cells. These findings were supported by the observation that in situ activation of DC prior to adoptive transfer of β-galactosidase-specific T cells dramatically increased severity and incidence of EAU. Recruitment of T cells into retina by local delivery of antigen in vivo showed that quiescent retina promoted development of parenchymal Foxp3+ T cells, but assays of pre-injured retina did not. Together, these results demonstrated that local conditions in the retina determined APC function, and affected the pathogenesis of EAU by both CD4 and CD8 T cells. PMID:22219322

  14. A Model of Cytotoxic T Antitumor Activation Stimulated by Pulsed Dendritic Cells

    NASA Astrophysics Data System (ADS)

    Pennisi, Marzio; Pappalardo, Francesco; Chiacchio, Ferdinando; Motta, Santo

    2011-09-01

    We present a preliminary ODE model to sketch the immune response of cytotoxic T cells against cancer through the use of pulsed autologous dendritic cells. The model is partially based on data coming from experiments that are presently in progress in the wet lab of our collaborators, but it can be applied in principle to different tumors. To this end, we show the immune response of cytotoxic T cells stimulated by autologous dendritic cells for different cancers.

  15. Tolerogenic versus Inflammatory Activity of Peripheral Blood Monocytes and Dendritic Cells Subpopulations in Systemic Lupus Erythematosus

    PubMed Central

    Carvalheiro, Tiago; Rodrigues, Ana; Lopes, Ana; Inês, Luís; Velada, Isabel; Ribeiro, Andreia; Martinho, António; Silva, José A. P.; Pais, Maria L.; Paiva, Artur

    2012-01-01

    Abnormalities in monocytes and in peripheral blood dendritic cells (DC) subsets have been reported in systemic lupus erythematosus (SLE). We aim to clarify the tolerogenic or inflammatory role of these cells based on ICOSL or IFN-α and chemokine mRNA expression, respectively, after cell purification. The study included 18 SLE patients with active disease (ASLE), 25 with inactive disease (ISLE), and 30 healthy controls (HG). In purified plasmacytoid DC (pDC) was observed a lower ICOSL mRNA expression in ASLE and an increase in ISLE; similarly, a lower ICOSL mRNA expression in monocytes of ALSE patients was found. However, a higher ICOSL mRNA expression was observed in ASLE compared to HG in myeloid DCs. Interestingly, clinical parameters seem to be related with ICOSL mRNA expression. Regarding the inflammatory activity it was observed in purified monocytes and CD14−/low CD16+ DCs an increase of CCL2, CXCL9, and CXCL10 mRNA expression in ASLE compared to HG. In myeloid DC no differences were observed regarding chemokines, and IFN-α mRNA expression. In pDC, a higher IFN-α mRNA expression was observed in ASLE. Deviations in ICOSL, chemokine, and IFN-α mRNA expression in peripheral blood monocytes and dendritic cells subpopulations in SLE appear to be related to disease activity. PMID:22969819

  16. 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.

  17. 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

  18. Saccharomyces boulardii inhibits lipopolysaccharide-induced activation of human dendritic cells and T cell proliferation

    PubMed Central

    Thomas, S; Przesdzing, I; Metzke, D; Schmitz, J; Radbruch, A; Baumgart, D C

    2009-01-01

    Saccharomyces boulardii (Sb) is a probiotic yeast preparation that has demonstrated efficacy in inflammatory and infectious disorders of the gastrointestinal tract in controlled clinical trials. Although patients clearly benefit from treatment with Sb, little is known on how Sb unfolds its anti-inflammatory properties in humans. Dendritic cells (DC) balance tolerance and immunity and are involved critically in the control of T cell activation. Thus, they are believed to have a pivotal role in the initiation and perpetuation of chronic inflammatory disorders, not only in the gut. We therefore decided to investigate if Sb modulates DC function. Culture of primary (native, non-monocyte-derived) human myeloid CD1c+CD11c+CD123– DC (mDC) in the presence of Sb culture supernatant (active component molecular weight < 3 kDa, as evaluated by membrane partition chromatography) reduced significantly expression of the co-stimulatory molecules CD40 and CD80 (P < 0·01) and the DC mobilization marker CC-chemokine receptor CCR7 (CD197) (P < 0·001) induced by the prototypical microbial antigen lipopolysaccharide (LPS). Moreover, secretion of key proinflammatory cytokines such as tumour necrosis factor-α and interleukin (IL)-6 were notably reduced, while the secretion of anti-inflammatory IL-10 increased. Finally, Sb supernatant inhibited the proliferation of naive T cells in a mixed lymphocyte reaction with mDC. In summary, our data suggest that Sb may exhibit part of its anti-inflammatory potential through modulation of DC phenotype, function and migration by inhibition of their immune response to bacterial microbial surrogate antigens such as LPS. PMID:19161443

  19. 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

  20. Fluorescence Lifetime Imaging Microscopy reveals rerouting of SNARE trafficking driving dendritic cell activation.

    PubMed

    Verboogen, Daniëlle Rianne José; González Mancha, Natalia; Ter Beest, Martin; van den Bogaart, Geert

    2017-05-19

    SNARE proteins play a crucial role in intracellular trafficking by catalyzing membrane fusion, but assigning SNAREs to specific intracellular transport routes is challenging with current techniques. We developed a novel Förster resonance energy transfer-fluorescence lifetime imaging microscopy (FRET-FLIM)-based technique allowing visualization of real-time local interactions of fluorescently tagged SNARE proteins in live cells. We used FRET-FLIM to delineate the trafficking steps underlying the release of the inflammatory cytokine interleukin-6 (IL-6) from human blood-derived dendritic cells. We found that activation of dendritic cells by bacterial lipopolysaccharide leads to increased FRET of fluorescently labeled syntaxin 4 with VAMP3 specifically at the plasma membrane, indicating increased SNARE complex formation, whereas FRET with other tested SNAREs was unaltered. Our results revealed that SNARE complexing is a key regulatory step for cytokine production by immune cells and prove the applicability of FRET-FLIM for visualizing SNARE complexes in live cells with subcellular spatial resolution.

  1. 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.

  2. Human dendritic cell subsets

    PubMed Central

    Collin, Matthew; McGovern, Naomi; Haniffa, Muzlifah

    2013-01-01

    Summary Dendritic cells are highly adapted to their role of presenting antigen and directing immune responses. Developmental studies indicate that DCs originate independently from monocytes and tissue macrophages. Emerging evidence also suggests that distinct subsets of DCs have intrinsic differences that lead to functional specialisation in the generation of immunity. Comparative studies are now allowing many of these properties to be more fully understood in the context of human immunology. PMID:23621371

  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. Dendritic cell-induced activation of adaptive and innate antitumor immunity.

    PubMed

    van den Broeke, Leon T; Daschbach, Emily; Thomas, Elaine K; Andringa, Gerda; Berzofsky, Jay A

    2003-12-01

    While studying Ag-pulsed syngeneic dendritic cell (DC) immunization, we discovered that surprisingly, unpulsed DCs induced protection against tumor lung metastases resulting from i.v. injection of a syngeneic BALB/c colon carcinoma CT26 or a syngeneic C57BL/6 lung carcinoma LL/2. Splenocytes or immature splenic DCs did not protect. The protection was mediated by NK cells, in that it was abrogated by treatment with anti-asialo-GM1 but not anti-CD8, and was induced by CD1(-/-) DCs unable to stimulate NKT cells, but did not occur in beige mice lacking NK cells. Protection correlated with increased NK activity, and increased infiltration of NK but not CD8(+) cells in lungs of tumor-bearing mice. Protection depended on the presence of costimulatory molecules CD80, CD86, and CD40 on the DCs, but surprisingly did not require DCs that could make IL-12 or IL-15. Unexpectedly, protection sensitive to anti-asialo-GM1 and increased NK activity were still present 14 mo after DC injection. As NK cells lack memory, we found by depletion that CD4(+) not CD8(+) T cells were required for induction of the NK antitumor response. The role of DCs and CD4(+) T cells provides a novel mechanism for NK cell induction and innate immunity against cancer that may have potential in preventing clinical metastases.

  7. Sequential actions of immune effector cells induced by viral activation of dendritic cells to eliminate murine neuroblastoma.

    PubMed

    Kawakubo, Naonori; Tanaka, Sakura; Kinoshita, Yoshiaki; Tajiri, Tatsuro; Yonemitsu, Yoshikazu; Taguchi, Tomoaki

    2017-08-26

    In preclinical trails, we reported the antitumor effect of dendritic cells activated with Sendai virus (rSeV/DC) combined with γ-irradiation against neuroblastoma. However, what kind of effector cells for the combined therapy were used to show the antitumor effect was unclear. In this study, we performed radiation and rSeV/DC therapy in vivo and examined the effector cells involved. Dendritic cells were cultured from bone marrow cells, activated with SeV and administered intratumorally at 10(6) weekly for 3weeks. Radiation was administered at 4Gy/time × 3 times. During the treatment, CD4+ and CD8+ cells and natural killer (NK) cells were removed by antibodies. Complete remission of neuroblastoma was observed in 62.5% of individuals in the combined therapy group. By depleting the effector cells using antibodies, the tumor increased in size from an early stage of treatment in the CD4+ and NK cell-depleted group. In contrast, the tumor increased in size in the late stage of treatment in the CD8+ cell-depleted group. The combination of radiation and rSeV/DC therapy induces different effector cells, depending on the time point during treatment. V. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. 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.

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

    PubMed Central

    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

    2014-01-01

    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. PMID:24979331

  10. Suppression of dendritic cell activation by diabetes autoantigens linked to the cholera toxin B subunit.

    PubMed

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

    2011-04-01

    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

  11. 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

  12. 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

  13. Metabolic Control of Dendritic Cell Activation and Function: Recent Advances and Clinical Implications

    PubMed Central

    Everts, Bart; Pearce, Edward J.

    2014-01-01

    Dendritic cells (DCs) are key regulators of both immunity and tolerance by controlling activation and polarization of effector T helper cell and regulatory T cell responses. Therefore, there is a major focus on developing approaches to manipulate DC function for immunotherapy. It is well known that changes in cellular activation are coupled to profound changes in cellular metabolism. Over the past decade there is a growing appreciation that these metabolic changes also underlie the capacity of immune cells to perform particular functions. This has led to the concept that the manipulation of cellular metabolism can be used to shape innate and adaptive immune responses. While most of our understanding in this area has been gained from studies with T cells and macrophages, evidence is emerging that the activation and function of DCs are also dictated by the type of metabolism these cells commit to. We here discuss these new insights and explore whether targeting of metabolic pathways in DCs could hold promise as a novel approach to manipulate the functional properties of DCs for clinical purposes. PMID:24847328

  14. Curdlan induces DC-mediated Th17 polarization via Jagged1 activation in human dendritic cells.

    PubMed

    Higashi, Takehiro; Hashimoto, Kumiko; Takagi, Rie; Mizuno, Yosuke; Okazaki, Yasushi; Tanaka, Yoshiya; Matsushita, Sho

    2010-06-01

    Th17-inducing activity is carried by certain polysaccharides such as beta-glucan derived from Candia albicans. Our previous studies have shown that Th1- and Th2-inducing activities can be qualitatively evaluated by the expression patterns of Notch ligand isoforms, using human monocyte-derived dendritic cells (Mo-DCs) and some leukemic cell lines such as THP-1. The association of Th17-inducing activities with Notch ligand expression patterns has been unclear. Mo-DCs from healthy volunteers were co-cultured with HLA-DR-nonshared allogeneic CD4+ naïve T cells to induce a mixed lymphocyte reaction, in the presence of adjuvants, such as curdlan. Culture supernatants were assayed for IFNgamma, IL-5 and IL-17 by an enzyme-linked immunosorbent assay (ELISA). Notch ligand expression on Mo-DCs and THP-1 cells was evaluated by using RT-PCR. The present study shows that curdlan, one of the beta-glucans, has the ability to induce DC-mediated Th17 differentiation. It is also interesting to note that Jagged1 mRNA in Mo-DCs and THP-1 cells is up-regulated by curdlan. Furthermore, polyclonal anti-Jagged1 antibody inhibited such DC-mediated Th17 differentiation. This study suggests that curdlan induces human DC-mediated Th17 polarization via Jagged1 activation in DCs.

  15. Dendritic cell tumor killing activity and its potential applications in cancer immunotherapy.

    PubMed

    Hanke, Neale; Alizadeh, Darya; Katsanis, Emmanuel; Larmonier, Nicolas

    2013-01-01

    Universally viewed as the sentinels and messengers of the immune system and traditionally referred to as professional antigen-presenting cells, dendritic cells (DCs) play a fundamental role in antitumor immunity. DCs are uniquely equipped with the ability to acquire, process, and present to T lymphocytes tumor-derived antigens. They can drive the differentiation of naive T cells into activated tumor-specific effector lymphocytes. DCs also dictate the type and regulate the strength and duration of T-cell responses. In addition, they contribute to natural killer and natural killer T-cell antitumoral function and to B-cell-mediated immunity. Besides this cardinal role as orchestrators of innate and adaptive immune responses, many studies have provided evidence that DCs can also function as direct cytotoxic effectors against tumors. This less conventional aspect of DC function has, however, raised controversy as it relates to the origin of these cells and the induction, regulation, and mechanisms underlying their tumoricidal activity. The possible impact of the cytotoxic function of DCs on their capability to present antigens also has been the focus of intensive research. This review examines these questions and discusses the biological significance of this nontraditional property and possible strategies to exploit the killing potential of DCs in cancer immunotherapy.

  16. 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.

  17. Efficient generation of canine bone marrow-derived dendritic cells.

    PubMed

    Isotani, Mayu; Katsuma, Kensuke; Tamura, Kyoichi; Yamada, Misato; Yagihara, Hiroko; Azakami, Daigo; Ono, Kenichiro; Washizu, Tsukimi; Bonkobara, Makoto

    2006-08-01

    Because of their unsurpassed potency in presenting antigens to naive T cells, dendritic cells are considered to be an important candidate in the development of immunotherapeutic strategies. Despite the high potential of dendritic cell-based immunotherapy, as a so-called dendritic cell vaccination, few clinical approaches using dendritic cell vaccination have been performed in the dog because of very limited information regarding the generation of canine dendritic cells and their functional properties. We therefore established a protocol for the efficient generation of dendritic cells from canine bone marrow cells using recombinant feline granulocyte-macrophage colony-stimulating factor and canine interleukin-4. Dendritic cells were generated efficiently: a yield of 1-9 x 10(6) cells per approximately 0.5 ml of canine bone marrow aspiration was achieved. These dendritic cells showed features shared with mouse and human dendritic cells: dendrite morphology, expression of surface markers MHC class II and CD11c, and up-regulation of molecules related to antigen presentation (MHC class II, B7-1, and B7-2) by activation with lipopolysaccharide. Moreover, the dendritic cells demonstrated phagocytic activity, processing activity of pinocytosed proteins, and activation of allogeneic T cells far more potent than that by macrophages. Our findings suggest that the bone marrow-derived dendritic cells are functional for the capturing and processing of antigens and the initiation of T cell responses.

  18. 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

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

    PubMed

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

    2016-02-05

    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.

  20. 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

  1. Neutrophils Activate Plasmacytoid Dendritic Cells by Releasing Self-DNA–Peptide Complexes in Systemic Lupus Erythematosus

    PubMed Central

    Lande, Roberto; Ganguly, Dipyaman; Facchinetti, Valeria; Frasca, Loredana; Conrad, Curdin; Gregorio, Josh; Meller, Stephan; Chamilos, Georgios; Sebasigari, Rosalie; Riccieri, Valeria; Bassett, Roland; Amuro, Hideki; Fukuhara, Shirou; Ito, Tomoki; Liu, Yong-Jun; Gilliet, Michel

    2012-01-01

    Systemic lupus erythematosus (SLE) is a severe and incurable autoimmune disease characterized by chronic activation of plasmacytoid dendritic cells (pDCs) and production of autoantibodies against nuclear self-antigens by hyperreactive B cells. Neutrophils are also implicated in disease pathogenesis; however, the mechanisms involved are unknown. Here, we identified in the sera of SLE patients immunogenic complexes composed of neutrophil-derived antimicrobial peptides and self-DNA. These complexes were produced by activated neutrophils in the form of web-like structures known as neutrophil extracellular traps (NETs) and efficiently triggered innate pDC activation via Toll-like receptor 9 (TLR9). SLE patients were found to develop autoantibodies to both the self-DNA and antimicrobial peptides in NETs, indicating that these complexes could also serve as autoantigens to trigger B cell activation. Circulating neutrophils from SLE patients released more NETs than those from healthy donors; this was further stimulated by the antimicrobial autoantibodies, suggesting a mechanism for the chronic release of immunogenic complexes in SLE. Our data establish a link between neutrophils, pDC activation, and autoimmunity in SLE, providing new potential targets for the treatment of this devastating disease. PMID:21389263

  2. Bifidobacterium bifidum Actively Changes the Gene Expression Profile Induced by Lactobacillus acidophilus in Murine Dendritic Cells

    PubMed Central

    Weiss, Gudrun; Rasmussen, Simon; Nielsen Fink, Lisbeth; Jarmer, Hanne; Nøhr Nielsen, Birgit; Frøkiær, Hanne

    2010-01-01

    Dendritic cells (DC) play a pivotal regulatory role in activation of both the innate as well as the adaptive immune system by responding to environmental microorganisms. We have previously shown that Lactobacillus acidophilus induces a strong production of the pro-inflammatory and Th1 polarizing cytokine IL-12 in DC, whereas bifidobacteria do not induce IL-12 but inhibit the IL-12 production induced by lactobacilli. In the present study, genome-wide microarrays were used to investigate the gene expression pattern of murine DC stimulated with Lactobacillus acidophilus NCFM and Bifidobacterium bifidum Z9. L. acidophilus NCFM strongly induced expression of interferon (IFN)-β, other virus defence genes, and cytokine and chemokine genes related to the innate and the adaptive immune response. By contrast, B. bifidum Z9 up-regulated genes encoding cytokines and chemokines related to the innate immune response. Moreover, B. bifidum Z9 inhibited the expression of the Th1-promoting genes induced by L. acidophilus NCFM and had an additive effect on genes of the innate immune response and Th2 skewing genes. The gene encoding Jun dimerization protein 2 (JDP2), a transcription factor regulating the activation of JNK, was one of the few genes only induced by B. bifidum Z9. Neutralization of IFN-β abrogated L. acidophilus NCFM-induced expression of Th1-skewing genes, and blocking of the JNK pathway completely inhibited the expression of IFN-β. Our results indicate that B. bifidum Z9 actively inhibits the expression of genes related to the adaptive immune system in murine dendritic cells and that JPD2 via blocking of IFN-β plays a central role in this regulatory mechanism. PMID:20548777

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

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

    USDA-ARS?s Scientific Manuscript database

    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...

  9. Gastric cancer-derived heat shock protein-gp96 peptide complex enhances dendritic cell activation

    PubMed Central

    Lu, Wen-Wen; Zhang, Hong; Li, You-Ming; Ji, Feng

    2017-01-01

    AIM To investigate the role of heat shock protein (HSP)-glycoprotein (gp)96 in dendritic cells (DCs) and lymphocytes induction in gastric cancer (GC). METHODS Human GC cell lines KATOIII, MKN-28 and SGC-7901 were infected with adenovirus gp96 at a multiplicity of infection of 100. gp96-GC antigen peptide complexes were purified. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, lactate dehydrogenase (LDH) release assay and enzyme-linked immunosorbent assay were used to determine allo-reactive T cell stimulation, natural killer (NK) cell activity and expression of cytokines (such as interleukin (IL)-10, IL-12, interferon (IFN)-γ and tumor necrosis factor (TNF)-α), respectively. Effect of cytotoxic T lymphocyte (CTL) on DCs incubated with HSP-gp96 was also evaluated by LDH release. All assays were performed in triplicate and the average values were reported. Comparison between groups was conducted using Student’s t test. RESULTS T cells incubated with HSP-gp96 exhibited a marked increase in proliferation in a dose-dependent manner (P < 0.05). NK cell activity after gp96-GC peptide complex treatment was significantly higher than that after antigen peptide treatment (P < 0.05). The activity of CTLs incubated with DCs from three GC cells lines was obviously higher than that stimulated by GC antigen at ratios of 50: 1, 25: 1, 10: 1, and 5: 1 (P < 0.05). Furthermore, the secretion of TNF-α, IL-10, IL-12 (P70) and IFN-γ markedly increased after incubation with HSP-gp96 (P < 0.05). CONCLUSION HSP-gp96 promotes T cell response, enhances DC antigen presentation and induces cytokine secretion, as well. HSP-gp96 has potential as immunotherapy for elimination of residual GC cells. PMID:28706421

  10. 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.

  11. 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

  12. 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.

  13. 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

  14. [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.

  15. 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.

  16. 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

  17. 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.

  18. 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

  19. 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.

  20. Effect of liposomal antigens on the priming and activation of the immune system by dendritic cells.

    PubMed

    Shahum, Eliane; Thérien, Hélène-Marie

    2002-03-01

    Dendritic cells (DCs) are recognized as the sole professional antigen-presenting cells capable of priming naive T cells of the helper and cytotoxic phenotypes. This property is presently exploited with success in vaccinal strategies against pathogens or tumor cells that otherwise escape immune recognition, but the repeated infusions of ex vivo expanded and sensitized DCs are usually required to achieve protection. In this paper, we demonstrate that liposomal antigens can efficiently relay and propagate the action of DCs, inducing a strong long-term response against their associated antigen. Their effect is mainly achieved by improving the ex vivo loading of DCs and by efficiently channeling the activation stimulus into the induction of effector function. This is demonstrated by the sustained immunoglobulin production as well as by the sustained lymphoproliferation and the increased cytokine secretion that can be achieved upon restimulation of DC-primed immune cells with limited amount of liposomal antigenic material. Being well-tolerated and easily prepared, liposomal antigens could therefore be expected to significantly contribute to the efficiency and to a more general utilization of the highly promising but rather cumbersome DC-based immunotherapies.

  1. 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.

  2. 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

  3. 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

  4. 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.

  5. Recombinant Saccharomyces cerevisiae (yeast-CEA) as a potent activator of murine dendritic cells.

    PubMed

    Bernstein, Michael B; Chakraborty, Mala; Wansley, Elizabeth K; Guo, Zhimin; Franzusoff, Alex; Mostböck, Sven; Sabzevari, Helen; Schlom, Jeffrey; Hodge, James W

    2008-01-24

    Recombinant Saccharomyces cerevisiae (yeast) represents a unique and attractive vehicle to deliver antigens in vaccine immunotherapy protocols for cancer or infectious disease, in that it has been shown to be extremely safe and can be administered multiple times to hosts. In the studies reported here, we describe the effects of treatment with recombinant yeast on murine immature dendritic cells (DCs). Yeast expressing human carcinoembryonic antigen (CEA) as a model antigen was studied. Injection of mice subcutaneously with yeast-CEA resulted in rapid increases in MHC class II(+) cells and total antigen-presenting cells in draining lymph nodes. Post-treatment with yeast-CEA, DCs rapidly elevated both MHC class I and class II, numerous costimulatory molecules and other DC maturation markers, and secreted a range of Type I inflammatory cytokines. Gene expression arrays also revealed the rapid up-regulation of numerous cytokine and chemokine mRNAs, as well as genes involved in signal transduction and antigen uptake. Functional studies demonstrated enhanced allospecific reactivity of DCs following treatment with yeast-CEA or control yeast. Additionally, treatment of DCs with yeast-CEA resulted in specific activation of CEA-specific CD8(+) T cells in an MHC-restricted manner in vitro. Lastly, vaccination of CEA-transgenic mice with yeast-CEA elicited antigen-specific CD4(+) and CD8(+) immune responses in vivo. Thus, these studies taken together form a scientific rationale for the use of recombinant yeast in vaccination protocols for cancer or infectious diseases.

  6. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Inhibition of Human Dendritic Cell Activation by Hydroethanolic But Not Lipophilic Extracts of Turmeric (Curcuma longa)

    PubMed Central

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

    2015-01-01

    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. PMID:19034830

  8. 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.

  9. Models of Neocortical Layer 5b Pyramidal Cells Capturing a Wide Range of Dendritic and Perisomatic Active Properties

    PubMed Central

    Hay, Etay; Hill, Sean; Schürmann, Felix; Markram, Henry; Segev, Idan

    2011-01-01

    The thick-tufted layer 5b pyramidal cell extends its dendritic tree to all six layers of the mammalian neocortex and serves as a major building block for the cortical column. L5b pyramidal cells have been the subject of extensive experimental and modeling studies, yet conductance-based models of these cells that faithfully reproduce both their perisomatic Na+-spiking behavior as well as key dendritic active properties, including Ca2+ spikes and back-propagating action potentials, are still lacking. Based on a large body of experimental recordings from both the soma and dendrites of L5b pyramidal cells in adult rats, we characterized key features of the somatic and dendritic firing and quantified their statistics. We used these features to constrain the density of a set of ion channels over the soma and dendritic surface via multi-objective optimization with an evolutionary algorithm, thus generating a set of detailed conductance-based models that faithfully replicate the back-propagating action potential activated Ca2+ spike firing and the perisomatic firing response to current steps, as well as the experimental variability of the properties. Furthermore, we show a useful way to analyze model parameters with our sets of models, which enabled us to identify some of the mechanisms responsible for the dynamic properties of L5b pyramidal cells as well as mechanisms that are sensitive to morphological changes. This automated framework can be used to develop a database of faithful models for other neuron types. The models we present provide several experimentally-testable predictions and can serve as a powerful tool for theoretical investigations of the contribution of single-cell dynamics to network activity and its computational capabilities. PMID:21829333

  10. 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.

  11. Cholesterol crystals activate Syk and PI3 kinase in human macrophages and dendritic cells.

    PubMed

    Corr, Emma M; Cunningham, Clare C; Dunne, Aisling

    2016-08-01

    Cholesterol crystals are a key component of atherosclerotic lesions where they promote pro-inflammatory cytokine production and plaque destabilization. Antagonists of inflammatory mediators and agents that dissolve or prevent the formation of cholesterol crystals are being explored as potential therapeutics for atherothrombosis. We sought to identify signalling molecules activated following exposure of immune cells to cholesterol crystals with the view to identifying novel therapeutic targets. Human macrophages and dendritic cells (DC) were exposed to cholesterol crystals and activation of signalling molecules was assessed by immunoblotting. The role of Syk and PI3K in crystal-induced interleukin (IL)-1 production was determined by ELISA using specific kinase inhibitors. Real-time PCR was employed to examine the role of Syk/PI3K in cholesterol crystal-induced expression of S100 proteins and MMPs. Exposure of human macrophages and DC to cholesterol crystals induced robust activation of Syk and PI3K within 2-5 min. Pharmacological inhibition of Syk/PI3K reduced crystal-induced IL-1α/β production by approximately 80%. Activation of the downstream MAP kinases, MEK and ERK, was suppressed following inhibition of Syk and PI3K. Finally, inhibition of both Syk and PI3K significantly reduced cholesterol crystal-induced S100A8 and MMP1 gene expression by >70% while inhibition of PI3K also reduced S100A12 expression. Cholesterol crystals activate specific cell signalling pathways which drive the production of inflammatory cytokines and degradative enzymes known to contribute to disease initiation and progression. These molecular events are dependent on activation of Syk and PI3K, hence, they represent potential therapeutic targets for the treatment of cholesterol crystal-related pathologies. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  12. Galectin-8 activates dendritic cells and stimulates antigen-specific immune response elicitation.

    PubMed

    Carabelli, Julieta; Quattrocchi, Valeria; D'Antuono, Alejandra; Zamorano, Patricia; Tribulatti, María Virginia; Campetella, Oscar

    2017-08-15

    Galectin-8 (Gal-8) is a mammalian β-galactoside-binding lectin, endowed with proinflammatory properties. Given its capacity to enhance antigen-specific immune responses in vivo, we investigated whether Gal-8 was also able to promote APC activation to sustain T cell activation after priming. Both endogenous [dendritic cells (DCs)] and bone marrow-derived DCs (BMDCs) treated with exogenous Gal-8 exhibited a mature phenotype characterized by increased MHC class II (MHCII), CD80, and CD86 surface expression. Moreover, Gal-8-treated BMDCs (Gal-8-BMDCs) stimulated antigen-specific T cells more efficiently than immature BMDCs (iBMDCs). Proinflammatory cytokines IL-3, IL-2, IL-6, TNF, MCP-1, and MCP-5, as well as growth factor G-CSF, were augmented in Gal-8-BMDC conditioned media, with IL-6 as the most prominent. Remarkably, BMDCs from Gal-8-deficient mice (Lgals8(-/-) BMDC) displayed reduced CD86 and IL-6 expression and an impaired ability to promote antigen-specific CD4 T cell activation. To test if Gal-8-induced activation correlates with the elicitation of an effective immune response, soluble Gal-8 was coadministrated with antigen during immunization of BALB/cJ mice in the experimental foot-and-mouth disease virus (FMDV) model. When a single dose of Gal-8 was added to the antigen formulation, an increased specific and neutralizing humoral response was developed, sufficient to enhance animal protection upon viral challenge. IL-6 and IFN-γ, as well as lymphoproliferative responses, were also incremented in Gal-8/antigen-immunized animals only at 48 h after immunization, suggesting that Gal-8 induces the elicitation of an inflammatory response at an early stage. Taking together, these findings argue in favor of the use of Gal-8 as an immune-stimulator molecule to enhance the adaptive immune response. © Society for Leukocyte Biology.

  13. 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

  14. 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

  15. 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.

  16. 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.

  17. Serotonin Activates Dendritic Cell Function in the Context of Gut Inflammation

    PubMed Central

    Li, Nan; Ghia, Jean-Eric; Wang, Huaqing; McClemens, Jessica; Cote, Francine; Suehiro, Youko; Mallet, Jacques; Khan, Waliul I.

    2011-01-01

    Mucosal inflammation in the gut is characterized by infiltration of innate and adaptive immune cells and by an alteration in serotonin–producing enterochromaffin cells. We investigated the role of serotonin in the function of dendritic cells (DCs) and sequential T-cell activation in relation to generation of gut inflammation. DCs isolated from tryptophan hydroxylase-1–deficient (TPH1−/−) mice, which have reduced serotonin in the gut, and wild-type (TPH1+/+) mice with or without dextran sulfate sodium (DSS)–induced colitis were stimulated with lipopolysaccharide to assess interleukin-12 (IL-12) production. Isolated DCs from TPH1+/+ and TPH1−/− mice were also cocultured with CD4+ T cells of naive TPH1+/+ mice to assess the role of serotonin in priming T cells. In addition, serotonin-pulsed DCs were transferred to TPH1−/− mice to assess the effect on DSS-induced colitis. Consistent with a reduced severity of colitis, DCs from DSS-induced TPH1−/− mice produced less IL-12 compared with the TPH1+/+ mice. In vitro serotonin stimulation restored the cytokine production from TPH1−/− DCs and adoptive transfer of serotonin-pulsed DCs into TPH1−/− up-regulated colitis. Furthermore, CD4+ T cells primed by TPH1−/− DCs produce reduced the levels of IL-17 and interferon-γ. This study provides novel information on serotonin-mediated immune signaling and promotion of interactions between innate and adaptive immune responses in the context of gut inflammation, which may ultimately lead to improved strategies to combat gut inflammatory disorders. PMID:21281798

  18. Serotonin activates dendritic cell function in the context of gut inflammation.

    PubMed

    Li, Nan; Ghia, Jean-Eric; Wang, Huaqing; McClemens, Jessica; Cote, Francine; Suehiro, Youko; Mallet, Jacques; Khan, Waliul I

    2011-02-01

    Mucosal inflammation in the gut is characterized by infiltration of innate and adaptive immune cells and by an alteration in serotonin-producing enterochromaffin cells. We investigated the role of serotonin in the function of dendritic cells (DCs) and sequential T-cell activation in relation to generation of gut inflammation. DCs isolated from tryptophan hydroxylase-1-deficient (TPH1(-/-)) mice, which have reduced serotonin in the gut, and wild-type (TPH1(+/+)) mice with or without dextran sulfate sodium (DSS)-induced colitis were stimulated with lipopolysaccharide to assess interleukin-12 (IL-12) production. Isolated DCs from TPH1(+/+) and TPH1(-/-) mice were also cocultured with CD4(+) T cells of naive TPH1(+/+) mice to assess the role of serotonin in priming T cells. In addition, serotonin-pulsed DCs were transferred to TPH1(-/-) mice to assess the effect on DSS-induced colitis. Consistent with a reduced severity of colitis, DCs from DSS-induced TPH1(-/-) mice produced less IL-12 compared with the TPH1(+/+) mice. In vitro serotonin stimulation restored the cytokine production from TPH1(-/-) DCs and adoptive transfer of serotonin-pulsed DCs into TPH1(-/-) up-regulated colitis. Furthermore, CD4(+) T cells primed by TPH1(-/-) DCs produce reduced the levels of IL-17 and interferon-γ. This study provides novel information on serotonin-mediated immune signaling and promotion of interactions between innate and adaptive immune responses in the context of gut inflammation, which may ultimately lead to improved strategies to combat gut inflammatory disorders. Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  19. Functional and phenotypic effects of AhR activation in inflammatory dendritic cells

    SciTech Connect

    Bankoti, Jaishree; Rase, Ben; Simones, Tom; Shepherd, David M.

    2010-07-15

    Aryl hydrocarbon receptor (AhR) activation by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces immune suppression. Dendritic cells (DCs) are key antigen presenting cells governing T cell activation and differentiation. However, the consequences of AhR activation in DCs are not fully defined. We hypothesized that AhR activation alters DC differentiation and generates dysfunctional DCs. To test this hypothesis, inflammatory bone marrow-derived DCs (BMDCs) from C57Bl/6 mice were generated in the presence of vehicle or TCDD. TCDD decreased CD11c expression but increased MHC class II, CD86 and CD25 expression on the BMDCs. The effects of TCDD were strictly AhR-dependent but not exclusively DRE-mediated. Similar effects were observed with two natural AhR ligands, 6-formylindolo[3,2-b]carbazole (FICZ) and 2-(1H-Indol-3-ylcarbonyl)-4-thiazolecarboxylic acid (ITE). TCDD increased LPS- and CpG-induced IL-6 and TNF-{alpha} production by BMDCs but decreased their NO production. TCDD decreased CpG-induced IL-12p70 production by BMDCs but did not affect their secretion of IL-10. TCDD downregulated LPS- and CpG-induced NF-kB p65 levels and induced a trend towards upregulation of RelB levels in the BMDCs. AhR activation by TCDD modulated BMDC uptake of both soluble and particulate antigens. Induction of indoleamine-2,3-dioxygenase (IDO) and TGF-{beta}3 has been implicated in the generation of regulatory T cells following AhR activation. TCDD increased IDO1, IDO2 and TGF-{beta}3 mRNA levels in BMDCs as compared to vehicle. Despite the induction of regulatory mediators, TCDD-treated BMDCs failed to suppress antigen-specific T cell activation. Thus, AhR activation can directly alter the differentiation and innate functions of inflammatory DCs without affecting their ability to successfully interact with T cells.

  20. DC-SIGN promotes allergen uptake and activation of dendritic cells in patients with atopic dermatitis.

    PubMed

    Zhang, Y; Luo, Y; Li, W; Liu, J; Chen, M; Gu, H; Wang, B; Yao, X

    2016-11-01

    Atopic dermatitis (AD) is a common inflammatory skin disease, concomitant with allergic reactions to allergens. However, the exact mechanisms of allergen-induced immune responses in AD are not clear. The aim of this study is to explore the role of DC-SIGN in capturing and processing glycan-containing allergens and in the subsequent DC activation and T helper cell polarization in AD patients. DC-SIGN expression on DCs from AD patients was analysed by confocal microscopy and flow cytometry. DC-SIGN binding to common allergens was determined by ELISA. Activation of monocyte-derived dendritic cells (Mo-DCs) by allergens was analysed by evaluation of pro-inflammatory cytokines production, and their impact on T-cell responses was investigated by a DC-T cell coculture. DC-SIGN expression was higher on DCs in the lesional skin of AD patients compared with that of healthy controls and was correlated with disease severity. DC-SIGN could bind to many common allergens including house dust mite allergen (Der p2) and egg white allergen (Gal d2). Mo-DCs showed measurable expression of DC-SIGN and a concentration-dependent uptake of Der p2 and Gal d2, which was inhibited by mannan and anti-DC-SIGN Abs. Der p2 and Gal d2 induced the production of pro-inflammatory cytokines, including TNF-α and IL-6, by DCs from AD patients and facilitated Th2 and Th22 cell polarization. Binding of common allergens by DC-SIGN on DCs may initiate allergen sensitization of AD or provoke the relapse of AD. Regulating the allergen-DC-SIGN interaction might be a promising strategy to prevent or intervene in the progress of AD. Copyright © 2016 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

  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. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

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

    PubMed Central

    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

    2015-01-01

    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. PMID:25637353

  8. 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.

  9. 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.

  10. Asthmatic bronchial epithelium activated by the proteolytic allergen Der p 1 increases selective dendritic cell recruitment.

    PubMed

    Pichavant, Muriel; Charbonnier, Anne-Sophie; Taront, Solenne; Brichet, Anne; Wallaert, Benoît; Pestel, Joel; Tonnel, André-Bernard; Gosset, Philippe

    2005-04-01

    Airway dendritic cells (DCs) are crucial for allergen-induced sensitization and inflammation in allergic asthma. After allergen challenge, an increased number of DCs is observed in airway epithelium from patients with allergy. Because Der p 1, a cysteine protease allergen from Dermatophagoides pteronyssinus , induces chemokine production by bronchial epithelial cells (BECs), the purpose of this investigation was to evaluate the capacity of BEC exposed to Der p 1 to recruit DCs. Chemotactic activity of BEAS-2B, a bronchial epithelial cell line, and BECs from nonatopic controls and patients with allergic asthma was evaluated on the migration of precursors, immature and mature monocyte-derived DCs (MDDCs), and CD34 + -derived Langerhans cells (LCs). C-C chemokine ligand (CCL)-2, CCL5, and C-X-C chemokine ligand 10 production by BEAS-2B and BEC was increased after Der p 1 exposure, whereas the proenzyme proDer p 1 devoid of enzymatic activity had no effect. Der p 1 stimulation of BEAS-2B and BEC from both groups increased significantly the recruitment of MDDC precursors, depending on CCL2, CCL5, and C-X-C chemokine ligand 10 production. In a reconstituted polarized epithelium, apical application of Der p 1 enhanced MDDC precursor migration into the epithelial layer. Moreover, Der p 1 stimulation of BEC from patients with asthma but not from controls increased the migration of LC precursors, mainly dependent on CCL20 secretion. No migration of immature and mature DCs was observed. These data confirmed that BECs participate in the homeostasis of the DC network present within the bronchial epithelium through the secretion of chemokines. In allergic asthma, upregulation of CCL20 production induced LC recruitment, the role of which remains to be determined.

  11. Aerosol Delivery of Functionalized Gold Nanoparticles Target and Activate Dendritic Cells in a 3D Lung Cellular Model.

    PubMed

    Fytianos, Kleanthis; Chortarea, Savvina; Rodriguez-Lorenzo, Laura; Blank, Fabian; von Garnier, Christophe; Petri-Fink, Alke; Rothen-Rutishauser, Barbara

    2017-01-24

    Nanocarrier design combined with pulmonary drug delivery holds great promise for the treatment of respiratory tract disorders. In particular, targeting of dendritic cells that are key immune cells to enhance or suppress an immune response in the lung is a promising approach for the treatment of allergic diseases. Fluorescently encoded poly(vinyl alcohol) (PVA)-coated gold nanoparticles, functionalized with either negative (-COO(-)) or positive (-NH3(+)) surface charges, were functionalized with a DC-SIGN antibody on the particle surface, enabling binding to a dendritic cell surface receptor. A 3D coculture model consisting of epithelial and immune cells (macrophages and dendritic cells) mimicking the human lung epithelial tissue barrier was employed to assess the effects of aerosolized AuNPs. PVA-NH2 AuNPs showed higher uptake compared to that of their -COOH counterparts, with the highest uptake recorded in macrophages, as shown by flow cytometry. None of the AuNPs induced cytotoxicity or necrosis or increased cytokine secretion, whereas only PVA-NH2 AuNPs induced higher apoptosis levels. DC-SIGN AuNPs showed significantly increased uptake by monocyte-derived dendritic cells (MDDCs) with subsequent activation compared to non-antibody-conjugated control AuNPs, independent of surface charge. Our results show that DC-SIGN conjugation to the AuNPs enhanced MDDC targeting and activation in a complex 3D lung cell model. These findings highlight the potential of immunoengineering approaches to the targeting and activation of immune cells in the lung by nanocarriers.

  12. Dendritic cell activation is influenced by cyclic mechanical strain when cultured on adhesive substrates

    PubMed Central

    Lewis, Jamal S.; Dolgova, Natalia; Chancellor, T.J.; Acharya, Abhinav P.; Karpiak, Jerome V.; Lele, Tanmay P.; Keselowsky, Benjamin G.

    2014-01-01

    Dendritic cells (DCs), key regulators of tolerance and immunity, have been found to reside in mechanically active tissues such as the interior layers of the arterial wall, which experience cyclic radial wall strain due to pulsatile blood flow. Although experimentally difficult to determine in vivo, it is reasonable to postulate DCs experience the mechanical forces in such mechanically active tissues. However, it is currently unknown how DCs respond to cyclic mechanical strain. In order to explore the hypothesis that DCs are responsive to mechanical strain, DCs were cultured in vitro on pre-adsorbed adhesive proteins (e.g., laminin, collagen, fibrinogen) and 1 Hz cyclic strain was applied for various durations and strain magnitudes. It was determined that a strain magnitude of 10% and 24 h duration adversely affected DC viability compared to no-strain controls, but culture on certain adhesive substrates provided modest protection of viability under this harsh strain regime. In contrast, application of 1 h of 1 Hz cyclic 3% strain did not affect DC viability and this strain regime was used for the remaining experiments for quantifying DC activation and T-cell priming capability. Application of 3% strain increased expression of stimulatory (MHC-II) and co-stimulatory molecules (CD86, CD40), and this effect was generally increased by culture on pre-coated adhesive substrates. Interestingly, the cytokine secretion profile of DCs was not significantly affected by strain. Lastly, strained DCs demonstrated increased stimulation of allogeneic T cell proliferation, in a manner that was independent of the adhesive substrate. These observations indicate generation of a DC consistent with what has been described as a semi-mature phenotype. This work begins elucidating a potential role for DCs in tissue environments exposed to cyclic mechanical forces. PMID:24008042

  13. Enhanced activation of dendritic cells by autologous apoptotic microvesicles in MRL/lpr mice.

    PubMed

    Dieker, Jürgen; Hilbrands, Luuk; Thielen, Astrid; Dijkman, Henry; Berden, Jo H; van der Vlag, Johan

    2015-04-16

    Systemic lupus erythematosus is associated with a persistent circulation of modified autoantigen-containing apoptotic debris that might be capable of breaking tolerance. We aimed to evaluate apoptotic microvesicles obtained from lupus or control mice for the presence of apoptosis-associated chromatin modifications and for their capacity to stimulate dendritic cells (DC) from lupus and control mice. Apoptotic microvesicles were in vitro generated from splenocytes, and ex vivo isolated from plasma of both MRL/lpr lupus mice and normal BALB/c mice. Microvesicles were analyzed using flow cytometry. Bone marrow-derived (BM)-DC cultured from MRL/lpr or BALB/c mice were incubated with microvesicles and CD40 expression and cytokine production were determined as measure of activation. Microvesicles derived from apoptotic splenocytes or plasma of MRL/lpr mice contained more modified chromatin compared to microvesicles of BALB/c mice, and showed enhanced activation of DC, either from MRL/lpr or BALB/c mice, and consecutively an enhanced DC-mediated activation of splenocytes. The content of apoptosis-modified chromatin in microvesicles of apoptotic splenocytes correlated with their potency to induce interleukin-6 (IL-6) production by DC. Microvesicle-activated MRL/lpr DC showed a significant higher production of IL-6 and tumor growth factor-β (TGF-β) compared to BALB/c DC, and were more potent in the activation of splenocytes. Apoptotic microvesicles from MRL/lpr mice are more potent activators of DC, and DC from MRL/lpr mice appear relatively more sensitive to activation by apoptotic microvesicles. Our findings indicate that aberrations at the level of apoptotic microvesicles and possibly DC contribute to the autoimmune response against chromatin in MRL/lpr mice.

  14. Attraction and activation of dendritic cells at the site of tumor elicits potent antitumor immunity.

    PubMed

    Lapteva, Natalia; Aldrich, Melissa; Rollins, Lisa; Ren, Wenhong; Goltsova, Tatiana; Chen, Si-Yi; Huang, Xue F

    2009-09-01

    Tumor cells harbor unique genetic mutations, which lead to the generation of immunologically foreign antigenic peptide repertoire with the potential to induce individual tumor-specific immune responses. Here, we developed an in situ tumor vaccine with the ability to elicit antitumor immunity. This vaccine comprised an E1B-deleted oncolytic adenovirus expressing beta-defensin-2 (Ad-BD2-E1A) for releasing tumor antigens, recruiting and activating plasmacytoid dendritic cells (pDCs). Intratumoral injections of Ad-BD2-E1A vaccine inhibited primary breast tumor growth and blocked naturally occurring metastasis in mice. Ad-BD2-E1A vaccination induced potent tumor-specific T-cell responses. Splenic and intratumoral DCs isolated from Ad-BD2-E1A-immunized mice were able to stimulate or promote the differentiation of naive T cells into tumor-specific cytotoxic T cells. We further found that the increased numbers of mature CD45RA(+)CD8alpha(+)CD40(+) pDCs infiltrated into Ad-BD2-E1A-treated tumors. The antitumor effect of Ad-BD2-E1A vaccination was abrogated in toll-like receptor 4 (TLR4) deficient mice, suggesting the critical role of TLR4 in the induction of antitumor immunity by Ad-BD2-E1A. The results of this study indicate that in situ vaccination with the oncolytic BD2-expressing adenovirus preferentially attracts pDCs and promotes their maturation, and thus elicits potent tumor-specific immunity. This vaccine represents an attractive therapeutic strategy for the induction of individualized antitumor immunity.

  15. Activation of dendritic cell function by soypeptide lunasin as a novel vaccine adjuvant.

    PubMed

    Tung, Chun-Yu; Lewis, David E; Han, Ling; Jaja, Morayo; Yao, Shuyu; Li, Fang; Robertson, Michael J; Zhou, Baohua; Sun, Jie; Chang, Hua-Chen

    2014-09-22

    The addition of an appropriate adjuvant that activates the innate immunity is essential to subsequent development of the adaptive immunity specific to the vaccine antigens. Thus, any innovation capable of improving the immune responses may lead to a more efficacious vaccine. We recently identified a novel immune modulator using a naturally occurring seed peptide called lunasin. Lunasin was originally isolated from soybeans, and it is a small peptide containing 43 amino acids. Our studies revealed stimulatory effects of lunasin on innate immune cells by regulating expression of a number of genes that are important for immune responses. The objective was to define the effectiveness of lunasin as an adjuvant that enhances immune responses. The immune modulating functions of lunasin were characterized in dendritic cells (DCs) from human peripheral blood mononuclear cells (PBMCs). Lunasin-treated conventional DCs (cDCs) not only expressed elevated levels of co-stimulatory molecules (CD86, CD40) but also exhibited up-regulation of cytokines (IL1B, IL6) and chemokines (CCL3, CCL4). Lunasin-treated cDCs induced higher proliferation of allogeneic CD4+ T cells when comparing with medium control treatment in the mixed leukocyte reaction (MLR). Immunization of mice with ovalbumin (OVA) and lunasin inhibited the growth of OVA-expressing A20 B-lymphomas, which was correlated with OVA-specific CD8+ T cells. In addition, lunasin was an effective adjuvant for immunization with OVA, which together improved animal survival against lethal challenge with influenza virus expressing the MHC class I OVA peptide SIINFEKL (PR8-OTI). These results suggest that lunasin may function as a vaccine adjuvant by promoting DC maturation, which in turn enhances the development of protective immune responses to the vaccine antigens. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. 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.

  17. Foal Monocyte-Derived Dendritic Cells Become Activated upon Rhodococcus equi Infection▿ †

    PubMed Central

    Flaminio, M. Julia B. F.; Nydam, Daryl V.; Marquis, Hélène; Matychak, Mary Beth; Giguère, Steeve

    2009-01-01

    Susceptibility of foals to Rhodococcus equi pneumonia is exclusive to the first few months of life. The objective of this study was to investigate the immediate immunologic response of foal and adult horse antigen-presenting cells (APCs) upon infection with R. equi. We measured the activation of the antigen-presenting major histocompatibility complex (MHC) class II molecule, costimulatory molecules CD40 and CD86, the cytokine interleukin-12 (IL-12), and the transcriptional factor interferon regulatory factor 1 (IRF-1) in monocyte-derived macrophages (mMOs) and dendritic cells (mDCs) of adult horses and foals of different ages (from birth to 3 months of age) infected with virulent R. equi or its avirulent, plasmid-cured derivative. Infection with virulent or avirulent R. equi induced (P ≤ 0.01) the expression of IL-12p35 and IL-12p40 mRNAs in foal mMOs and mDCs at different ages. This response was likely mediated by the higher (P = 0.008) expression of IRF-1 in foal mDCs at birth than in adult horse mDCs. R. equi infection promoted comparable expression of costimulatory molecules CD86 and CD40 in foal and adult horse cells. The cytokine and costimulatory response by foal mDCs was not accompanied by robust MHC class II molecule expression. These data suggest that foal APCs detect the presence of R. equi and respond with the expression of the Th1-inducing cytokine IL-12. Nevertheless, there seems to be a limitation to MHC class II molecule expression which we hypothesize may compromise the efficient priming of naïve effector cells in early life. PMID:19109450

  18. 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.

  19. 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

  20. TLR7/TLR8 Activation Restores Defective Cytokine Secretion by Myeloid Dendritic Cells but Not by Plasmacytoid Dendritic Cells in HIV-Infected Pregnant Women and Newborns

    PubMed Central

    Cardoso, Elaine Cristina; Pereira, Nátalli Zanete; Mitsunari, Gabrielle Eimi; Oliveira, Luanda Mara da Silva; Ruocco, Rosa Maria S. A.; Francisco, Rossana Pulcineli Vieira; Zugaib, Marcelo; da Silva Duarte, Alberto José; Sato, Maria Notomi

    2013-01-01

    Mother-to-child transmission (MTCT) of HIV-1 has been significantly reduced with the use of antiretroviral therapies, resulting in an increased number of HIV-exposed uninfected infants. The consequences of HIV infection on the innate immune system of both mother-newborn are not well understood. In this study, we analyzed peripheral blood and umbilical cord blood (CB) collected from HIV-1-infected and uninfected pregnant women. We measured TNF-α, IL-10 and IFN-α secretion after the stimulation of the cells with agonists of both extracellular Toll-like receptors (TLRs) (TLR2, TLR4 and TLR5) and intracellular TLRs (TLR7, TLR7/8 and TLR9). Moreover, as an indicator of the innate immune response, we evaluated the responsiveness of myeloid dendritic cells (mDCs) and plasmacytoid DCs (pDCs) to TLRs that are associated with the antiviral response. Our results showed that peripheral blood mononuclear cells (PBMCs) from HIV-1-infected mothers and CB were defective in TNF-α production after activation by TLR2, TLR5, TLR3 and TLR7. However, the TNF-α response was preserved after TLR7/8 (CL097) stimulation, mainly in the neonatal cells. Furthermore, only CL097 activation was able to induce IL-10 and IFN-α secretion in both maternal and CB cells in the infected group. An increase in IFN-α secretion was observed in CL097-treated CB from HIV-infected mothers compared with control mothers. The effectiveness of CL097 stimulation was confirmed by observation of similar mRNA levels of interferon regulatory factor-7 (IRF-7), IFN-α and TNF-α in PBMCs of both groups. The function of both mDCs and pDCs was markedly compromised in the HIV-infected group, and although TLR7/TLR8 activation overcame the impairment in TNF-α secretion by mDCs, such stimulation was unable to reverse the dysfunctional type I IFN response by pDCs in the HIV-infected samples. Our findings highlight the dysfunction of innate immunity in HIV-infected mother-newborn pairs. The activation of the TLR7/8 pathway

  1. Dendritic morphology, synaptic transmission, and activity of mature granule cells born following pilocarpine-induced status epilepticus in the rat

    PubMed Central

    Gao, Fei; Song, Xueying; Zhu, Dexiao; Wang, Xiaochen; Hao, Aijun; Nadler, J. Victor; Zhan, Ren-Zhi

    2015-01-01

    To understand the potential role of enhanced hippocampal neurogenesis after pilocarpine-induced status epilepticus (SE) in the development of epilepsy, we quantitatively analyzed the geometry of apical dendrites, synaptic transmission, and activation levels of normotopically distributed mature newborn granule cells in the rat. SE in male Sprague-Dawley rats (between 6 and 7 weeks old) lasting for more than 2 h was induced by an intraperitoneal injection of pilocarpine. The complexity, spine density, miniature post-synaptic currents, and activity-regulated cytoskeleton-associated protein (Arc) expression of granule cells born 5 days after SE were studied between 10 and 17 weeks after CAG-GFP retroviral vector-mediated labeling. Mature granule cells born after SE had dendritic complexity similar to that of granule cells born naturally, but with denser mushroom-like spines in dendritic segments located in the outer molecular layer. Miniature inhibitory post-synaptic currents (mIPSCs) were similar between the controls and rats subjected to SE; however, smaller miniature excitatory post-synaptic current (mEPSC) amplitude with a trend toward less frequent was found in mature granule cells born after SE. After maturation, granule cells born after SE did not show denser Arc expression in the resting condition or 2 h after being activated by pentylenetetrazol-induced transient seizure activity than vicinal GFP-unlabeled granule cells. Thus our results suggest that normotopic granule cells born after pilocarpine-induced SE are no more active when mature than age-matched, naturally born granule cells. PMID:26500490

  2. 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

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. 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.

  10. 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

  11. 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

  12. 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

    Ngo, V N; Tang, H L; Cyster, J G

    1998-07-06

    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/MIP3beta) 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.

  13. 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.

  14. Dendritic cells process synthetic long peptides better than whole protein, improving antigen presentation and T-cell activation.

    PubMed

    Rosalia, Rodney A; Quakkelaar, Esther D; Redeker, Anke; Khan, Selina; Camps, Marcel; Drijfhout, Jan W; Silva, Ana Luisa; Jiskoot, Wim; van Hall, Thorbald; van Veelen, Peter A; Janssen, George; Franken, Kees; Cruz, Luis J; Tromp, Angelino; Oostendorp, Jaap; van der Burg, Sjoerd H; Ossendorp, Ferry; Melief, Cornelis J M

    2013-10-01

    The efficiency of antigen (Ag) processing by dendritic cells (DCs) is vital for the strength of the ensuing T-cell responses. Previously, we and others have shown that in comparison to protein vaccines, vaccination with synthetic long peptides (SLPs) has shown more promising (pre-)clinical results. Here, we studied the unknown mechanisms underlying the observed vaccine efficacy of SLPs. We report an in vitro processing analysis of SLPs for MHC class I and class II presentation by murine DCs and human monocyte-derived DCs. Compared to protein, SLPs were rapidly and much more efficiently processed by DCs, resulting in an increased presentation to CD4⁺ and CD8⁺ T cells. The mechanism of access to MHC class I loading appeared to differ between the two forms of Ag. Whereas whole soluble protein Ag ended up largely in endolysosomes, SLPs were detected very rapidly outside the endolysosomes after internalization by DCs, followed by proteasome- and transporter associated with Ag processing-dependent MHC class I presentation. Compared to the slower processing route taken by whole protein Ags, our results indicate that the efficient internalization of SLPs, accomplished by DCs but not by B or T cells and characterized by a different and faster intracellular routing, leads to enhanced CD8⁺ T-cell activation. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. 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.

  16. Activity-dependent accumulation of calcium in Purkinje cell dendritic spines

    SciTech Connect

    Andrews, S.B.; Leapman, R.D.; Landis, D.M.; Reese, T.S.

    1988-03-01

    The calcium content of synapses of parallel fibers on Purkinje cell dendritic spines was determined by electron probe x-ray microanalysis of freeze-dried cryosections from directly frozen slices of mouse cerebellar cortex. In fresh slices frozen within 20-30 sec of excision, calcium concentrations ranging from 0.8 to 18.6 mmol/kg of dry weight were measured in cisterns of smooth endoplasmic reticulum within Purkinje cell dendritic spines. The average calcium content of spine cisterns in rapidly excised slices (6.7 +/- 0.6 mmol/kg of dry weight +/- SEM) was higher than the average calcium content of spine cisterns in brain slices incubated without stimulation for 1-2 hr before direct freezing (2.5 +/- 0.4 mmol/kg of dry weight). Depolarization of incubated cerebellar slices by isotonic 55 mM KCl resulted in the accumulation within spine cisterns of very high amounts of calcium or isotonically substituted strontium, both derived from the extracellular fluid. These results suggest that one function of spine cisterns is to sequester free calcium that enters the spine through ligand-gated or voltage-gated channels during synaptic transmission.

  17. 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

  18. HIV-1 gp120 impairs the induction of B cell responses by TLR9-activated plasmacytoid dendritic cells.

    PubMed

    Chung, Nancy P Y; Matthews, Katie; Klasse, Per Johan; Sanders, Rogier W; Moore, John P

    2012-12-01

    Plasmacytoid dendritic cells (pDCs) play a central role in innate and adaptive immune responses to viral infections, including HIV type 1 (HIV-1). pDCs produce substantial quantities of type I IFN and proinflammatory cytokines upon stimulation via TLRs, specifically TLR7 or TLR9. The HIV-1 envelope glycoproteins, exemplified by the gp120 monomer, are the focus of vaccines aimed at inducing B cell responses. We have studied how the interactions of gp120 with various receptors on human pDCs affect the activation of these cells via TLR9 and their subsequent ability to stimulate B cells. We observed that IFN-α production by pDCs in response to TLR9, but not TLR7, stimulation was reduced by exposure to gp120. Specifically, gp120 inhibited the CpG-induced maturation of pDCs and their expression of TNF-α, IL-6, TLR9, IFN regulatory factor 7, and BAFF. Receptor-blocking and cross-linking studies showed that these inhibitory effects of gp120 were mediated by interactions with CD4 and mannose-binding C-type lectin receptors, but not with the chemokine receptors CCR5 and CXCR4. Of note is that gp120 inhibited the activation of B cells by TLR9-stimulated pDCs. Taken together, our data show that HIV-1 gp120 impairs pDC functions, including activation of B cell responses, and imply that TLR9 ligands may not be good adjuvants to use in combination with envelope glycoprotein vaccines.

  19. TLR-Induced Murine Dendritic Cell (DC) Activation Requires DC-Intrinsic Complement.

    PubMed

    Sheen, Joong-Hyuk; Strainic, Michael G; Liu, Jinbo; Zhang, Weijia; Yi, Zhengzi; Medof, M Edward; Heeger, Peter S

    2017-07-01

    Induction of proinflammatory T cell immunity is augmented by innate dendritic cell (DC) maturation commonly initiated by TLR signaling. We demonstrate that ligation of TLR3, TLR4, and TLR9 induces murine DC production of complement components and local production of the anaphylatoxin C5a. In vitro, ex vivo, and in vivo analyses show that TLR-induced DC maturation, as assessed by surface phenotype, expression profiling by gene array, and functional ability to stimulate T cell responses, requires autocrine C3a receptor and C5a receptor (C3ar1/C5ar1) signaling. Studies using bone marrow chimeric animals and Foxp3-GFP/ERT2-Cre/dTomato fate-mapping mice show that TLR-initiated DC autocrine C3ar1/C5ar1 signaling causes expansion of effector T cells and instability of regulatory T cells and contributes to T cell-dependent transplant rejection. Together, our data position immune cell-derived complement production and autocrine/paracrine C3ar1/C5ar1 signaling as crucial intermediary processes that link TLR stimulation to DC maturation and the subsequent development of effector T cell responses. Copyright © 2017 by The American Association of Immunologists, Inc.

  20. [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.

  1. DlgR2 knockdown boosts dendritic cell activity and inhibits hepatocellular carcinoma tumor in-situ growth.

    PubMed

    Lu, Zhen; Xia, Yun-Hong; Zhao, Min; Zhang, Bing; Dai, Wen-Ting; Ding, Lu; Hu, Li-Xia; Bi, Jin-Ling; Jiang, Guo-Lin

    2017-08-15

    Tumor-specific hepatic stellate cells (tHSCs) positively participate in human hepatocellular carcinoma (HCC) tumorigenesis and progression. Our previous studies have shown that tHSCs co-culture with dendritic cells (DCs) induced DIgR2 (dendritic cell-derived immunoglobulin receptor 2) expression. The latter is a member of IgSF inhibitory receptor suppressing DCs-initiated antigen-specific T-cell responses. In the current study, we show that hepatic artery injection of DlgR2 siRNA significantly inhibited in-situ HCC xenograft growth in rat livers. Further, 5-FU-medied inhibition of in-situ HCC growth was dramatically sensitized with DlgR2 silence. DlgR2 siRNA injection indeed downregulated DlgR2 in ex-vivo cultured tumor-derived DCs (tDCs). More importantly, tDCs activity was boosted following DlgR2 siRNA. These cells presented with upregulated CD80, CD86 and MHC-II. Production of interleukin-12 and tumor necrosis factor-α was also increased in the DlgR2-silenced tDCs. We propose that DlgR2 knockdown likely boosts the activity of tumor-associated DCs, and inhibits growth of in-situ HCC xenografts.

  2. Dendritic cells that phagocytose apoptotic macrophages loaded with mycobacterial antigens activate CD8 T cells via cross-presentation.

    PubMed

    Espinosa-Cueto, Patricia; Magallanes-Puebla, Alejandro; Castellanos, Carlos; Mancilla, Raul

    2017-01-01

    While homeostatic apoptosis is immunologically silent, macrophage apoptosis during Mycobacterium tuberculosis infection can potentially induce an immune response against the mycobacteria. To examine the role of dendritic cells in this response, macrophage apoptosis was induced by incubating the macrophage with cell wall extracts of mycobacteria expressing LpqH. The apoptogenic proteins of the cell wall extracts were engulfed by the macrophage and then were translocated from the cytosol to the nuclei of the dying cells. Dendritic cells that engulfed the apoptotic macrophages acquired an immunogenic phenotype that included upregulation of MHC-I, increased expression of the costimulatory molecules, CD40, CD80, and CD86, and increased production of IL-12, IL-10, TNF-α, and TGF-β. In addition, the dendritic cells triggered a proliferative response of CD8+ T cells with IFN-γ production via cross-presentation. Taken together, these findings support a model in which phagocytosis of whole apoptotic cells carrying mycobacterial antigens promotes a potentially protective immune response.

  3. Dendritic cells that phagocytose apoptotic macrophages loaded with mycobacterial antigens activate CD8 T cells via cross-presentation

    PubMed Central

    Espinosa-Cueto, Patricia; Magallanes-Puebla, Alejandro; Castellanos, Carlos

    2017-01-01

    While homeostatic apoptosis is immunologically silent, macrophage apoptosis during Mycobacterium tuberculosis infection can potentially induce an immune response against the mycobacteria. To examine the role of dendritic cells in this response, macrophage apoptosis was induced by incubating the macrophage with cell wall extracts of mycobacteria expressing LpqH. The apoptogenic proteins of the cell wall extracts were engulfed by the macrophage and then were translocated from the cytosol to the nuclei of the dying cells. Dendritic cells that engulfed the apoptotic macrophages acquired an immunogenic phenotype that included upregulation of MHC-I, increased expression of the costimulatory molecules, CD40, CD80, and CD86, and increased production of IL-12, IL-10, TNF-α, and TGF-β. In addition, the dendritic cells triggered a proliferative response of CD8+ T cells with IFN-γ production via cross-presentation. Taken together, these findings support a model in which phagocytosis of whole apoptotic cells carrying mycobacterial antigens promotes a potentially protective immune response. PMID:28767693

  4. 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

  5. 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

  6. Replication-Independent Activation of Human Plasmacytoid Dendritic Cells by the Paramyxovirus SV5 Requires TLR7 and Autophagy Pathways

    PubMed Central

    Manuse, Mary J.; Briggs, Caitlin M.; Parks, Griffith D.

    2010-01-01

    The paramyxovirus Simian Virus 5 (SV5) is a poor inducer of interferon (IFN) secretion in all cell types tested so far, including primary epithelial cells and primary human myeloid dendritic cells. SV5 is hypothesized to limit induction of antiviral responses through control of viral gene expression and production of the V protein antagonist. Plasmacytoid dendritic cells (pDCs) are known to uniquely express toll-like receptor (TLR)-7 and are a main producer of IFN-alpha among peripheral blood mononuclear cells in response to many viruses. Here, we tested whether SV5 would remain a poor inducer of IFN in primary human pDCs. The efficiency of SV5 infection of pDCs could be increased by an increasing multiplicity of infection. pDCs infected by both live and UV-inactivated SV5 induced large amounts of IFN-alpha secretion and resulted in upregulation of maturation markers CD80 and CD86. However, IL-6 secretion was not induced by SV5 infection. When TLR7 signaling was inhibited, SV5 induced less IFN secretion and CD80 expression, and there was a corresponding increase in number of infected cells. Similar effects were seen with inhibitors of cellular autophagy pathways, suggesting that the SV5 activation of pDC requires access to the cytoplasm and autophagic sampling of cytoplasmic contents. These results have implications for control of SV5 infections in vivo and for development of SV5 as a vaccine vector. PMID:20605567

  7. 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.

  8. Lpa2 is a negative regulator of dendritic cell activation and murine models of allergic lung inflammation

    PubMed Central

    Emo, Jason; Meednu, Nida; Chapman, Timothy J.; Rezaee, Fariba; Balys, Marlene; Randall, Troy; Rangasamy, Tirumalai; Georas, Steve N.

    2012-01-01

    Negative regulation of innate immune responses is essential in order to prevent excess inflammation and tissue injury and promote homeostasis. Lysophosphatidic acid (LPA) is a pleiotropic lipid that regulates cell growth, migration and activation, and is constitutively produced at low levels in tissues and in serum. Extracellular LPA binds to specific G-protein coupled receptors, the function of which in regulating innate or adaptive immune responses remains poorly understood. Of the classical LPA receptors belonging to the Edg family, lpa2 (edg4) is expressed by dendritic cells (DC) and other innate immune cells. Here we show that DC from lpa2−/− mice are hyperactive compared to their wild-type counterparts, and are also less susceptible to inhibition by different LPA species. In transient transfection assays, we found that lpa2-overexpression inhibits NF-κB-driven gene transcription. Using an adoptive transfer approach, we found that allergen-pulsed lpa2−/− DC induced substantially more lung inflammation than wild-type DC after inhaled allergen challenge. Finally, lpa2−/− mice develop greater allergen-driven lung inflammation than their wild-type counterparts in models of allergic asthma involving both systemic and mucosal sensitization. Taken together, these findings identify LPA acting via lpa2 as a novel negative regulatory pathway that inhibits dendritic cell activation and allergic airway inflammation. PMID:22427635

  9. 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.

  10. Genomewide effects of peroxisome proliferator-activated receptor gamma in macrophages and dendritic cells--revealing complexity through systems biology.

    PubMed

    Cuaranta-Monroy, Ixchelt; Kiss, Mate; Simandi, Zoltan; Nagy, Laszlo

    2015-09-01

    Systems biology approaches have become indispensable tools in biomedical and basic research. These data integrating bioinformatic methods gained prominence after high-throughput technologies became available to investigate complex cellular processes, such as transcriptional regulation and protein-protein interactions, on a scale that had not been studied before. Immunology is one of the medical fields that systems biology impacted profoundly due to the plasticity of cell types involved and the accessibility of a wide range of experimental models. In this review, we summarize the most important recent genomewide studies exploring the function of peroxisome proliferator-activated receptor γ in macrophages and dendritic cells. PPARγ ChIP-seq experiments were performed in adipocytes derived from embryonic stem cells to complement the existing data sets and to provide comparators to macrophage data. Finally, lists of regulated genes generated from such experiments were analysed with bioinformatics and system biology approaches. We show that genomewide studies utilizing high-throughput data acquisition methods made it possible to gain deeper insights into the role of PPARγ in these immune cell types. We also demonstrate that analysis and visualization of data using network-based approaches can be used to identify novel genes and functions regulated by the receptor. The example of PPARγ in macrophages and dendritic cells highlights the crucial importance of systems biology approaches in establishing novel cellular functions for long-known signaling pathways. © 2015 Stichting European Society for Clinical Investigation Journal Foundation.

  11. 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.

  12. 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.

  13. Caspase-8 acts as a molecular rheostat to limit RIPK1- and MyD88-mediated dendritic cell activation.

    PubMed

    Cuda, Carla M; Misharin, Alexander V; Gierut, Angelica K; Saber, Rana; Haines, G Kenneth; Hutcheson, Jack; Hedrick, Stephen M; Mohan, Chandra; Budinger, G Scott; Stehlik, Christian; Perlman, Harris

    2014-06-15

    Caspase-8, an executioner enzyme in the death receptor pathway, was shown to initiate apoptosis and suppress necroptosis. In this study, we identify a novel, cell death-independent role for caspase-8 in dendritic cells (DCs): DC-specific expression of caspase-8 prevents the onset of systemic autoimmunity. Failure to express caspase-8 has no effect on the lifespan of DCs but instead leads to an enhanced intrinsic activation and, subsequently, more mature and autoreactive lymphocytes. Uncontrolled TLR activation in a RIPK1-dependent manner is responsible for the enhanced functionality of caspase-8-deficient DCs, because deletion of the TLR-signaling mediator, MyD88, ameliorates systemic autoimmunity induced by caspase-8 deficiency. Taken together, these data demonstrate that caspase-8 functions in a cell type-specific manner and acts uniquely in DCs to maintain tolerance. Copyright © 2014 by The American Association of Immunologists, Inc.

  14. 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.

  15. Indoor pollutant hexabromocyclododecane enhances house dust mite-induced activation of human monocyte-derived dendritic cells.

    PubMed

    Canbaz, Derya; Lebre, M Cristina; Logiantara, Adrian; van Ree, Ronald; van Rijt, Leonie S

    2016-11-01

    The indoor pollutant hexabromocyclododecane (HBCD) has been added as flame retardant to many consumer products but detaches and accumulates in house dust. Inhalation of house dust leads to exposure to house dust mite (HDM) allergens in the presence of HBCD. Activation of dendritic cells is crucial in the sensitization to HDM allergens. The current study examined whether exposure to HBCD affected activation/maturation of HDM-exposed human dendritic cells (DC). Human monocyte-derived DC (moDC) were exposed simultaneously to HDM and a concentration range of HBCD (0.1-20 μM) in vitro. HDM exposure of moDC induced expression of co-stimulatory molecule CD80 and production of pro-inflammatory cytokines interleukin (IL)-6, IL-8, and tumor necrosis factor (TNF)-α. However, simultaneous exposure of moDC to HBCD and HDM enhanced the expression of antigen presenting molecule HLA-DR, co-stimulatory molecule CD86 and pro-inflammatory cytokine IL-8 depending on the dose of HBCD. Our results indicate that simultaneous exposure of HDM and HBCD can enhance the antigen presentation and maturation/activation of DC.

  16. Infected dendritic cells are sufficient to mediate the adjuvant activity generated by Venezuelan equine encephalitis virus replicon particles

    PubMed Central

    Tonkin, Daniel R; Whitmore, Alan; Johnston, Robert E; Barro, Mario

    2012-01-01

    Replicon particles derived from Venezuelan equine encephalitis virus (VEE) are infectious non-propagating particles which act as a safe and potent systemic, mucosal, and cellular adjuvant when delivered with antigen. VEE and VEE replicon particles (VRP) can target multiple cell types including dendritic cells (DCs). The role of these cell types in VRP adjuvant activity has not been previously evaluated, and for these studies we focused on the contribution of DCs to the response to VRP. By analysis of VRP targeting in the draining lymph node, we found that VRP induced rapid recruitment of TNF-secreting monocyte-derived inflammatory dendritic cells. VRP preferentially infected these inflammatory DCs as well as classical DCs and macrophages, with less efficient infection of other cell types. DC depletion suggested that the interaction of VRP with classical DCs was required for recruitment of inflammatory DCs, induction of high levels of many cytokines, and for stable transport of VRP to the draining lymph node. Additionally, in vitro-infected DCs enhanced antigen-specific responses by CD4 and CD8 T cells. By transfer of VRP-infected DCs into mice we showed that these DCs generated an inflammatory state in the draining lymph node similar to that achieved by VRP injection. Most importantly, VRP-infected DCs were sufficient to establish robust adjuvant activity in mice comparable to that produced by VRP injection. These findings indicate that VRP infect, recruit and activate both classical and inflammatory DCs, and those DCs become mediators of the VRP adjuvant activity. PMID:22531556

  17. Infected dendritic cells are sufficient to mediate the adjuvant activity generated by Venezuelan equine encephalitis virus replicon particles.

    PubMed

    Tonkin, Daniel R; Whitmore, Alan; Johnston, Robert E; Barro, Mario

    2012-06-22

    Replicon particles derived from Venezuelan equine encephalitis virus (VEE) are infectious non-propagating particles which act as a safe and potent systemic, mucosal, and cellular adjuvant when delivered with antigen. VEE and VEE replicon particles (VRP) can target multiple cell types including dendritic cells (DCs). The role of these cell types in VRP adjuvant activity has not been previously evaluated, and for these studies we focused on the contribution of DCs to the response to VRP. By analysis of VRP targeting in the draining lymph node, we found that VRP induced rapid recruitment of TNF-secreting monocyte-derived inflammatory dendritic cells. VRP preferentially infected these inflammatory DCs as well as classical DCs and macrophages, with less efficient infection of other cell types. DC depletion suggested that the interaction of VRP with classical DCs was required for recruitment of inflammatory DCs, induction of high levels of many cytokines, and for stable transport of VRP to the draining lymph node. Additionally, in vitro-infected DCs enhanced antigen-specific responses by CD4 and CD8 T cells. By transfer of VRP-infected DCs into mice we showed that these DCs generated an inflammatory state in the draining lymph node similar to that achieved by VRP injection. Most importantly, VRP-infected DCs were sufficient to establish robust adjuvant activity in mice comparable to that produced by VRP injection. These findings indicate that VRP infect, recruit and activate both classical and inflammatory DCs, and those DCs become mediators of the VRP adjuvant activity. Published by Elsevier Ltd.

  18. Dendritic cells are required for optimal activation of natural killer functions following primary infection with herpes simplex virus type 1.

    PubMed

    Kassim, Sadik H; Rajasagi, Naveen K; Ritz, Barry W; Pruett, Stephen B; Gardner, Elizabeth M; Chervenak, Robert; Jennings, Stephen R

    2009-04-01

    Natural killer (NK) cells play an important role in the optimal clearance of herpes simplex virus type 1 (HSV-1) infection in mice. Activated NK cells function via cytokine secretion or direct cytolysis of target cells; dendritic cells (DCs) are thought to make critical contributions in the activation of both of these functions. Yet, the magnitude and physiological relevance of DC-mediated NK cell activation in vivo is not completely understood. To examine the contribution of DC help in regulating NK cell functions after infection with HSV-1, we utilized a transgenic mouse model that allows the transient ablation of DCs. Using this approach, it was found that the gamma interferon (IFN-gamma) expression potential of NK cells is quantitatively and qualitatively impaired in the absence of DCs. With regard to priming of NK cytolytic functions, the ablation of DCs did not significantly affect cytotoxic protein expression by NK cells. An in vivo cytolytic assay did, however, reveal impairments in the magnitude of NK cell cytotoxicity. Overall, this study provides direct evidence that functional DCs are required for optimal IFN-gamma expression and cytolytic function by NK cells following infection with HSV-1.

  19. West Nile virus-infected human dendritic cells fail to fully activate invariant natural killer T cells.

    PubMed

    Kovats, S; Turner, S; Simmons, A; Powe, T; Chakravarty, E; Alberola-Ila, J

    2016-11-01

    West Nile virus (WNV) infection is a mosquito-borne zoonosis with increasing prevalence in the United States. WNV infection begins in the skin, and the virus replicates initially in keratinocytes and dendritic cells (DCs). In the skin and cutaneous lymph nodes, infected DCs are likely to interact with invariant natural killer T cells (iNKTs). Bidirectional interactions between DCs and iNKTs amplify the innate immune response to viral infections, thus controlling viral load and regulating adaptive immunity. iNKTs are stimulated by CD1d-bound lipid antigens or activated indirectly by inflammatory cytokines. We exposed human monocyte-derived DCs to WNV Kunjin and determined their ability to activate isolated blood iNKTs. DCs became infected as judged by synthesis of viral mRNA and Envelope and NS-1 proteins, but did not undergo significant apoptosis. Infected DCs up-regulated the co-stimulatory molecules CD86 and CD40, but showed decreased expression of CD1d. WNV infection induced DC secretion of type I interferon (IFN), but no or minimal interleukin (IL)-12, IL-23, IL-18 or IL-10. Unexpectedly, we found that the WNV-infected DCs stimulated human iNKTs to up-regulate CD69 and produce low amounts of IL-10, but not proinflammatory cytokines such as IFN-γ or tumour necrosis factor (TNF)-α. Both CD1d and IFNAR blockade partially abrogated this iNKT response, suggesting involvement of a T cell receptor (TCR)-CD1d interaction and type I interferon receptor (IFNAR) signalling. Thus, WNV infection interferes with DC-iNKT interactions by preventing the production of proinflammatory cytokines. iNKTs may be a source of IL-10 observed in human flavivirus infections and initiate an anti-inflammatory innate response that limits adaptive immunity and immune pathology upon WNV infection. © 2016 British Society for Immunology.

  20. 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

  1. CD40-directed scFv-TRAIL fusion proteins induce CD40-restricted tumor cell death and activate dendritic cells

    PubMed Central

    El-Mesery, M; Trebing, J; Schäfer, V; Weisenberger, D; Siegmund, D; Wajant, H

    2013-01-01

    Targeted cancer therapy concepts often aim at the induction of adjuvant antitumor immunity or stimulation of tumor cell apoptosis. There is further evidence that combined application of immune stimulating and tumor apoptosis-inducing compounds elicits a synergistic antitumor effect. Here, we describe the development and characterization of bifunctional fusion proteins consisting of a single-chain variable fragment (scFv) domain derived from the CD40-specific monoclonal antibody G28-5 that is fused to the N-terminus of stabilized trimeric soluble variants of the death ligand TNF-related apoptosis-inducing ligand (TRAIL). As shown before by us and others for other cell surface antigen-targeted scFv-TRAIL fusion proteins, scFv:G28-TRAIL displayed an enhanced capacity to induce apoptosis upon CD40 binding. Studies with scFv:G28 fusion proteins of TRAIL mutants that discriminate between the two TRAIL death receptors, TRAILR1 and TRAILR2, further revealed that the CD40 binding-dependent mode of apoptosis induction of scFv:G28-TRAIL is operable with each of the two TRAIL death receptors. Binding of scFv:G28-TRAIL fusion proteins to CD40 not only result in enhanced TRAIL death receptor signaling but also in activation of the targeted CD40 molecule. In accordance with the latter, the scFv:G28-TRAIL fusion proteins triggered strong CD40-mediated maturation of dendritic cells. The CD40-targeted TRAIL fusion proteins described in this study therefore represent a novel type of bifunctional fusion proteins that couple stimulation of antigen presenting cells and apoptosis induction. PMID:24232092

  2. 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.

  3. 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

  4. 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

  5. Plasmacytoid dendritic cells and myeloid cells differently contribute to B-cell-activating factor belonging to the tumor necrosis factor superfamily overexpression during primary HIV infection.

    PubMed

    Borhis, Gwenoline; Burelout, Chantal; Chaoul, Nada; Smith, Nikaïa; Goujard, Cecile; Meyer, Laurence; Paul, Stephane; Saoudin, Henia; Hosmalin, Anne; Gilbert, Caroline; Herbeuval, Jean-Philippe; Richard, Yolande

    2016-01-28

    After describing heightened levels of circulating B-cell-activating factor belonging to the tumor necrosis factor superfamily (BAFF) as well as changes in B-cell phenotype and functions during acute infection by simian immunodeficiency virus, we wanted to determine whether and by which cells BAFF was over-expressed in primary HIV-infected (PHI) patients. We simultaneously examined circulating BAFF levels by ELISA and membrane-bound BAFF (mBAFF) expression by flow cytometry in peripheral blood mononuclear cells of healthy donors and PHI patients followed for 6 months. We also examined whether HIV-1 modifies BAFF expression or release in various myeloid cells and plasmacytoid dendritic cells (pDC) in vitro. Circulating BAFF levels were transiently increased at enrolment. They positively correlated with CXCL10 levels and inversely with B-cell counts. Whereas mBAFF was expressed by most pDC and on a fraction of intermediate monocytes in healthy donors, the frequency of mBAFF cells significantly increased among nonclassical monocytes and CD1c dendritic cells but decreased among pDC in PHI patients. In contrast to myeloid cells, pDC never released BAFF upon stimulation. Their mBAFF expression was enhanced by HIV-1, independently of type I IFN. Our findings reveal that the pattern of BAFF expression by myeloid cells and pDC is altered in PHI patients and constitutes a valuable marker of immune activation whose circulating levels correlate with CXCL10 levels. Due to their homing in different tissue areas, pDC and myeloid cells might target different B-cell subsets through their mBAFF expression or soluble BAFF release.

  6. 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.

  7. 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.

  8. Elevated CD1c+ Myeloid Dendritic Cell Proportions Associate With Clinical Activity and Predict Disease Reactivation in Noninfectious Uveitis

    PubMed Central

    Chen, Ping; Urzua, Cristhian A.; Knickelbein, Jared E.; Kim, Jane S.; Li, Zhiyu; Hannes, Susan; Kuo, David; Chaigne-Delalande, Benjamin; Armbrust, Karen; Tucker, William; Liu, Baoying; Agrón, Elvira; Sen, H. Nida; Nussenblatt, Robert B.

    2016-01-01

    Purpose To test the association between elevated proportions of CD1c+ myeloid dendritic cells (mDCs) and disease activation/reactivation in noninfectious uveitis. Methods Noninfectious uveitis patients (n = 89) and healthy controls (n = 111) were recruited. The proportion of CD1c+ mDCs in the total dendritic cell (DC) population of peripheral blood was measured by flow cytometry (CD1c+ mDCs gated on Lineage 1+HLADR+ DCs). Disease activity was assessed per Standardization of Uveitis Nomenclature criteria. Uveitis reactivation was ascribed to clinically quiescent patients who developed reactivation of intraocular inflammation within 6 months. Results The proportions of CD1c+ mDCs were increased in noninfectious uveitis patients, especially in active disease, compared to healthy controls. This CD1c+ mDC elevation was not associated with underlying systemic diseases, anatomic locations of uveitis, medications, or demographic factors. Longitudinal data showed that the dynamics of CD1c+ mDC levels were correlated with disease activity. The average proportion of CD1c+ mDCs in active uveitis patients was 60% so we set this as the cutoff between high and low CD1c+ mDC levels. Although 74% of quiescent patients had low proportions of CD1c+ mDCs, 26% still had high proportions. Quiescent patients with high CD1c+ mDC proportions showed increased risk of disease reactivation, compared to quiescent patients with low CD1c+ mDC proportions. Conclusions Increased proportions of CD1c+ mDCs were associated with clinical activity, and quiescent patients with elevated CD1c+ mDCs were more likely to undergo reactivation. This suggests that CD1c+ mDC proportion may be a potential biomarker for assessing clinical activation and reactivation in noninfectious uveitis. PMID:27070110

  9. Elevated CD1c+ Myeloid Dendritic Cell Proportions Associate With Clinical Activity and Predict Disease Reactivation in Noninfectious Uveitis.

    PubMed

    Chen, Ping; Urzua, Cristhian A; Knickelbein, Jared E; Kim, Jane S; Li, Zhiyu; Hannes, Susan; Kuo, David; Chaigne-Delalande, Benjamin; Armbrust, Karen; Tucker, William; Liu, Baoying; Agrón, Elvira; Sen, H Nida; Nussenblatt, Robert B

    2016-04-01

    To test the association between elevated proportions of CD1c+ myeloid dendritic cells (mDCs) and disease activation/reactivation in noninfectious uveitis. Noninfectious uveitis patients (n = 89) and healthy controls (n = 111) were recruited. The proportion of CD1c+ mDCs in the total dendritic cell (DC) population of peripheral blood was measured by flow cytometry (CD1c+ mDCs gated on Lineage 1+HLADR+ DCs). Disease activity was assessed per Standardization of Uveitis Nomenclature criteria. Uveitis reactivation was ascribed to clinically quiescent patients who developed reactivation of intraocular inflammation within 6 months. The proportions of CD1c+ mDCs were increased in noninfectious uveitis patients, especially in active disease, compared to healthy controls. This CD1c+ mDC elevation was not associated with underlying systemic diseases, anatomic locations of uveitis, medications, or demographic factors. Longitudinal data showed that the dynamics of CD1c+ mDC levels were correlated with disease activity. The average proportion of CD1c+ mDCs in active uveitis patients was 60% so we set this as the cutoff between high and low CD1c+ mDC levels. Although 74% of quiescent patients had low proportions of CD1c+ mDCs, 26% still had high proportions. Quiescent patients with high CD1c+ mDC proportions showed increased risk of disease reactivation, compared to quiescent patients with low CD1c+ mDC proportions. Increased proportions of CD1c+ mDCs were associated with clinical activity, and quiescent patients with elevated CD1c+ mDCs were more likely to undergo reactivation. This suggests that CD1c+ mDC proportion may be a potential biomarker for assessing clinical activation and reactivation in noninfectious uveitis.

  10. 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

  11. 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.

  12. 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

  13. 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

  14. Bioactive grape proanthocyanidins enhance immune reactivity in UV-irradiated skin through functional activation of dendritic cells in mice

    PubMed Central

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

    2013-01-01

    Ultraviolet (UV) radiation-induced immunosuppression has been implicated in skin carcinogenesis. Grape seed proanthocyanidins (GSPs) have anti-skin carcinogenic effects in mice and GSPs-fed mice exhibit a reduction in UV-induced suppression of allergic contact hypersensitivity (CHS), a prototypic T cell-mediated response. Here, we report that dietary GSPs did not inhibit UVB-induced suppression of CHS in xeroderma pigmentosum complementation group A (XPA)-deficient mice, which lack nucleotide excision repair mechanisms. GSPs enhanced repair of UVB-induced DNA damage (cyclobutane pyrimidine dimers) in wild-type, but not XPA-deficient, dendritic cells (DCs). Co-culture of CD4+ T cells with DCs from UVB-irradiated wild-type mice resulted in suppression of T-cell proliferation and secretion of Th-1 type cytokines that was ameliorated when the DCs were obtained from GSPs-fed mice; whereas, DCs obtained from GSPs-fed XPA-KO mice failed to restore T-cell proliferation. In adoptive transfer experiments, donor DCs were positively selected from the draining lymph nodes of UVB-exposed donor mice that were sensitized to 2,4, dinitrofluorobenzene were transferred into naïve recipient mice and the CHS response assessed. Naïve recipients that received DCs from UVB-exposed wild-type donors that had been fed GSPs exhibited a full CHS response, whereas no significant CHS was observed in mice that received DCs from XPA-KO mice fed GSPs. These results suggest that GSPs prevent UVB-induced immunosuppression through DNA repair-dependent functional activation of dendritic cells in mice. PMID:23321928

  15. Bioactive grape proanthocyanidins enhance immune reactivity in UV-irradiated skin through functional activation of dendritic cells in mice.

    PubMed

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

    2013-03-01

    Ultraviolet (UV) radiation-induced immunosuppression has been implicated in skin carcinogenesis. Grape seed proanthocyanidins (GSPs) have anti-skin carcinogenic effects in mice and GSPs-fed mice exhibit a reduction in UV-induced suppression of allergic contact hypersensitivity (CHS), a prototypic T-cell-mediated response. Here, we report that dietary GSPs did not inhibit UVB-induced suppression of CHS in xeroderma pigmentosum complementation group A (XPA)-deficient mice, which lack nucleotide excision repair mechanisms. GSPs enhanced repair of UVB-induced DNA damage (cyclobutane pyrimidine dimers) in wild-type, but not XPA-deficient, dendritic cells (DC). Co-culture of CD4(+) T cells with DCs from UVB-irradiated wild-type mice resulted in suppression of T-cell proliferation and secretion of T-helper (TH) 1-type cytokines that was ameliorated when the DCs were obtained from GSP-fed mice, whereas DCs obtained from GSP-fed XPA-KO mice failed to restore T-cell proliferation. In adoptive transfer experiments, donor DCs were positively selected from the draining lymph nodes of UVB-exposed donor mice that were sensitized to 2,4,-dinitrofluorobenzene were transferred into naïve recipient mice and the CHS response assessed. Naïve recipients that received DCs from UVB-exposed wild-type donors that had been fed GSPs exhibited a full CHS response, whereas no significant CHS was observed in mice that received DCs from XPA-KO mice fed GSPs. These results suggest that GSPs prevent UVB-induced immunosuppression through DNA repair-dependent functional activation of dendritic cells in mice. Cancer Prev Res; 6(3); 242-52. ©2013 AACR. ©2013 AACR.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. Endothelial cell-derived microparticles induce plasmacytoid dendritic cell maturation: potential implications in inflammatory diseases

    PubMed Central

    Angelot, Fanny; Seillès, Estelle; Biichlé, Sabeha; Berda, Yael; Gaugler, Béatrice; Plumas, Joel; Chaperot, Laurence; Dignat-George, Françoise; Tiberghien, Pierre; Saas, Philippe; Garnache-Ottou, Francine

    2009-01-01

    Background Increased circulating endothelial microparticles, resulting from vascular endothelium dysfunction, and plasmacytoid dendritic cell activation are both encountered in common inflammatory disorders. The aim of our study was to determine whether interactions between endothelial microparticles and plasmacytoid dendritic cells could contribute to such pathologies. Design and Methods Microparticles generated from endothelial cell lines, platelets or activated T cells were incubated with human plasmacytoid dendritic cells sorted from healthy donor blood or with monocyte-derived dendritic cells. Dendritic cell maturation was evaluated by flow cytometry, cytokine secretion as well as naive T-cell activation and polarization. Labeled microparticles were also used to study cellular interactions. Results Endothelial microparticles induced plasmacytoid dendritic cell maturation. In contrast, conventional dendritic cells were resistant to endothelial microparticle-induced maturation. In addition to upregulation of co-stimulatory molecules, endothelial microparticle-matured plasmacytoid dendritic cells secreted inflammatory cytokines (interleukins 6 and 8, but no interferon-α) and also induced allogeneic naive CD4+ T cells to proliferate and to produce type 1 cytokines such as interferon-γ and tumor necrosis factor-α. Endothelial microparticle endocytosis by plasmacytoid dendritic cells appeared to be required for plasmacytoid dendritic cell maturation. Importantly, the ability of endothelial microparticles to induce plasmacytoid dendritic cells to mature was specific as microparticles derived from activated T cells or platelets (the major source of circulating microparticules in healthy subjects) did not induce such plasmacytoid dendritic cell maturation. Conclusions Our data show that endothelial microparticles specifically induce plasmacytoid dendritic cell maturation and production of inflammatory cytokines. This novel activation pathway may be implicated in

  1. 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.

  2. 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

  3. 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

  4. Dendritic cell-targeted lentiviral vector immunization uses pseudotransduction and DNA-mediated STING and cGAS activation.

    PubMed

    Kim, Jocelyn T; Liu, Yarong; Kulkarni, Rajan P; Lee, Kevin K; Dai, Bingbing; Lovely, Geoffrey; Ouyang, Yong; Wang, Pin; Yang, Lili; Baltimore, David

    2017-07-21

    Dendritic cell (DC) activation and antigen presentation are critical for efficient priming of T cell responses. Here, we study how lentiviral vectors (LVs) deliver antigen and activate DCs to generate T cell immunization in vivo. We report that antigenic proteins delivered in vector particles via pseudotransduction were sufficient to stimulate an antigen-specific immune response. The delivery of the viral genome encoding the antigen increased the magnitude of this response in vivo but was irrelevant in vitro. Activation of DCs by LVs was independent of MyD88, TRIF, and MAVS, ruling out an involvement of Toll-like receptor or RIG-I-like receptor signaling. Cellular DNA packaged in LV preparations induced DC activation by the host STING (stimulator of interferon genes) and cGAS (cyclic guanosine monophosphate-adenosine monophosphate synthase) pathway. Envelope-mediated viral fusion also activated DCs in a phosphoinositide 3-kinase-dependent but STING-independent process. Pseudotransduction, transduction, viral fusion, and delivery of cellular DNA collaborate to make the DC-targeted LV preparation an effective immunogen. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  5. Stimulatory effect of Echinacea purpurea extract on the trafficking activity of mouse dendritic cells: revealed by genomic and proteomic analyses.

    PubMed

    Yin, Shu-Yi; Wang, Wen-Hsin; Wang, Bi-Xue; Aravindaram, Kandan; Hwang, Pei-Ing; Wu, Han-Ming; Yang, Ning-Sun

    2010-11-01

    Several Echinacea species have been used as nutraceuticals or botanical drugs for "immunostimulation", but scientific evidence supporting their therapeutic use is still controversial. In this study, a phytocompound mixture extracted from the butanol fraction (BF) of a stem and leaf (S+L) extract of E. purpurea ([BF/S+L/Ep]) containing stringently defined bioactive phytocompounds was obtained using standardized and published procedures. The transcriptomic and proteomic effects of this phytoextract on mouse bone marrow-derived dendritic cells (BMDCs) were analyzed using primary cultures. Treatment of BMDCs with [BF/S+L/Ep] did not significantly influence the phenotypic maturation activity of dendritic cells (DCs). Affymetrix DNA microarray and bioinformatics analyses of genes differentially expressed in DCs treated with [BF/S+L/Ep] for 4 or 12 h revealed that the majority of responsive genes were related to cell adhesion or motility (Cdh10, Itga6, Cdh1, Gja1 and Mmp8), or were chemokines (Cxcl2, Cxcl7) or signaling molecules (Nrxn1, Pkce and Acss1). TRANSPATH database analyses of gene expression and related signaling pathways in treated-DCs predicted the JNK, PP2C-α, AKT, ERK1/2 or MAPKAPK pathways as the putative targets of [BF/S+L/Ep]. In parallel, proteomic analysis showed that the expressions of metabolic-, cytoskeleton- or NF-κB signaling-related proteins were regulated by treatment with [BF/S+L/Ep]. In vitro flow cytometry analysis of chemotaxis-related receptors and in vivo cell trafficking assay further showed that DCs treated with [BF/S+L/Ep] were able to migrate more effectively to peripheral lymph node and spleen tissues than DCs treated as control groups. Results from this study suggest that [BF/S+L/Ep] modulates DC mobility and related cellular physiology in the mouse immune system. Moreover, the signaling networks and molecules highlighted here are potential targets for nutritional or clinical application of Echinacea or other candidate medicinal

  6. 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.

  7. Lung dendritic cells and the inflammatory response.

    PubMed

    Grayson, Mitchell H

    2006-05-01

    To discuss the role of conventional and plasmacytoid dendritic cells in inducing and modulating immune responses in the lung. The primary literature and selected review articles studying the role of dendritic cells in both rodent and human lungs as identified via a PubMed/MEDLINE search using the keywords dendritic cell, antigen-presenting cell, viral airway disease, asthma, allergy, and atopy. The author's knowledge of the field was used to identify studies that were relevant to the stated objective. Dendritic cells are well positioned in the respiratory tract and other mucosal surfaces to respond to any foreign protein. These cells are crucial to the initiation of the adaptive immune response through induction of antigen specific T-cell responses. These cells also play an important role in the regulation of developing and ongoing immune responses, an area that is currently under intense investigation. This review discusses the various subsets of human and rodent dendritic cells and the pathways involved in antigen processing and subsequent immune regulation by dendritic cells in the lung using both viral and nonviral allergenic protein exposure as examples. Conventional and plasmacytoid dendritic cells are uniquely situated in the immune cascade to not only initiate but also modulate immune responses. Therapeutic interventions in allergic and asthmatic diseases will likely be developed to take advantage of this exclusive position of the dendritic cell.

  8. 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.

  9. Enhanced activation of human dendritic cells by inducible CD40 and Toll-like receptor-4 ligation.

    PubMed

    Lapteva, Natalia; Seethammagari, Mamatha R; Hanks, Brent A; Jiang, Jianghong; Levitt, Jonathan M; Slawin, Kevin M; Spencer, David M

    2007-11-01

    Despite the potency of dendritic cells (DC) as antigen-presenting cells for priming adaptive immunity, DC-based cancer vaccines have been largely insufficient to effectively reduce tumor burden or prevent tumor progression in most patients. To enhance DC-based vaccines, we used the combination of a synthetic ligand-inducible CD40 receptor (iCD40) along with Toll-like receptor-4 (TLR-4) ligation in human monocyte-derived DCs. The iCD40 receptor permits targeted, reversible activation of CD40 in vivo, potentially bypassing the essential role of CD4(+) T cells for activation of DCs. As a rigorous preclinical study of this approach, we evaluated key parameters of DC activation and function. Whereas neither iCD40 nor TLR-4 signaling alone led to high levels of interleukin (IL)-12p70 and IL-6, using iCD40 in combination with lipopolysaccharide (LPS) or monophosphoryl lipid A led to strongly synergistic production of both. Furthermore, this approach led to high expression of DC maturation markers, epitope-specific CTL and T helper 1 responses, as well as DC migration in vitro and in vivo. Moreover, use of iCD40-modified and LPS-stimulated DCs led to targeted expansion of autologous T cells against tumor-associated antigens, including prostate-specific membrane antigen, and elimination of preestablished tumors, supporting this technology as a potent strategy for DC-based cancer immunotherapy.

  10. [Disseminated interdigitating dendritic cell sarcoma].

    PubMed

    Santarelli, Ignacio M; Veltri, Mariano; Manzella, Diego J; Avagnina, María Alejandra; Pereyra, Pablo M; Chavín, Hernán C

    2017-01-01

    A 70 year-old woman was admitted to our hospital with a 3-month history of abdominal pain, weight loss and night sweats. On physical examination, she presented with a 5 cm diameter abdominal mass extended from epigastrium to the left flank, and at least three bilateral supraclavicular adenopathies. A disseminated interdigitating dendritic cell sarcoma was diagnosed through a biopsy of the abdominal mass. After that, a CHOP regime (cyclophosphamide, doxorubicin, vincristine and prednisone) was iniciated. She died after completion of the first cycle of treatment, six months after diagnosis.

  11. Laricitrin ameliorates lung cancer-mediated dendritic cell suppression by inhibiting signal transducer and activator of transcription 3.

    PubMed

    Chang, Wei-An; Hung, Jen-Yu; Jian, Shu-Fang; Lin, Yi-Shiuan; Wu, Cheng-Ying; Hsu, Ya-Ling; Kuo, Po-Lin

    2016-12-20

    Natural polyphenolic compounds of grapes and their seeds are thought to be therapeutic adjuvants in a variety of diseases, including cancer prevention. This study was carried out to investigate the effect of grape phenolic compounds on the regulation of cancer-mediated immune suppression. Laricitrin exhibits the greatest potential to ameliorate the suppressive effects of lung cancer on dendritic cells' (DCs') differentiation, maturation and function. Human lung cancer A549 and CL1-5 cells change the phenotype of DCs that express to high levels of IL-10 and prime T cells towards an immune suppression type-2 response (Th2). Laricitrin treatment stimulated DC differentiation and maturation in the condition media of cancer cells, a finding supported by monocyte marker CD14's disappearance and DC marker CD1a's upregulation. Laricitrin decreases expression of IL-10 in cancer-conditioned DCs, and subsequently switches CD4+ T cell response from Th2 to Th1 in vitro and in vivo. Reversal of laricitrin on lung cancer-induced DCs' paralysis was via inhibiting the phosphorylation of signal transducer and activator of transcription 3 (STAT3). Laricitrin also potentiated the anticancer activity of cisplatin in mouse models. Thus, laricitrin could be an efficacious immunoadjuvant and have a synergistic effect when combined with chemotherapy.

  12. 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.

  13. 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

  14. 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.

  15. 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

  16. 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

  17. Direct Activation of Human Dendritic Cells by Particle-Bound but Not Soluble MHC Class II Ligand

    PubMed Central

    Baleeiro, Renato B.; Wiesmüller, Karl-Heinz; Dähne, Lars; Lademann, Jürgen; Barbuto, José A.; Walden, Peter

    2013-01-01

    Dendritic cells (DCs) are key activators of cellular immune responses through their capacity to induce naïve T cells and sustained effector T cell responses. This capacity is a function of their superior efficiency of antigen presentation via MHC class I and class II molecules, and the expression of co-stimulatory cell surface molecules and cytokines. Maturation of DCs is induced by microbial factors via pattern recognition receptors such as Toll-like receptors, pro-inflammatory cytokines or cognate interaction with CD4+ T cells. Here we show that, unexpectedly, the PanDR helper T cell epitope PADRE, a generic T helper cell antigen presented by a large fraction of HLA-DR alleles, when delivered in particle-bound form induced maturation of human DCs. The DCs that received the particle-bound PADRE displayed all features of fully mature DCs, such as high expression of the co-stimulatory molecules CD80, CD86, CD83, the MHC-II molecule HLA-DR, secretion of high levels of the biologically active IL-12 (IL-12p70) and induction of vigorous proliferation of naïve CD4+ T cells. Furthermore, the maturation of DCs induced by particle-bound PADRE was shown to involve sphingosine kinase, calcium signaling from internal sources and downstream signaling through the MAP kinase and the p72syk pathways, and finally activation of the transcription factor NF-κB. Based on our findings, we propose that particle-bound PADRE may be used as a DC activator in DC-based vaccines. PMID:23658796

  18. 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

  19. Lactate Dehydrogenase-Elevating Virus Induces Systemic Lymphocyte Activation via TLR7-Dependent IFNα Responses by Plasmacytoid Dendritic Cells

    PubMed Central

    Ammann, Christoph G.; Messer, Ronald J.; Peterson, Karin E.; Hasenkrug, Kim J.

    2009-01-01

    Background Lactate dehydrogenase-elevating virus (LDV) is a natural infectious agent of mice. Like several other viruses, LDV causes widespread and very rapid but transient activation of both B cells and T cells in lymphoid tissues and the blood. The mechanism of this activation has not been fully described and is the focus of the current studies. Principal Findings A known inducer of early lymphocyte activation is IFNα, a cytokine strongly induced by LDV infection. Neutralization of IFNα in the plasma from infected mice ablated its ability to activate lymphocytes in vitro. Since the primary source of virus-induced IFNα in vivo is often plasmacytoid dendritic cells (pDC's), we depleted these cells prior to LDV infection and tested for lymphocyte activation. Depletion of pDC's in vivo eradicated both the LDV-induced IFNα response and lymphocyte activation. A primary receptor in pDC's for single stranded RNA viruses such as LDV is the toll-like receptor 7 (TLR7) pattern recognition receptor. Infection of TLR7-knockout mice revealed that both the IFNα response and lymphocyte activation were dependent on TLR7 signaling in vivo. Interestingly, virus levels in both TLR7 knockout mice and pDC-depleted mice were indistinguishable from controls indicating that LDV is largely resistant to the systemic IFNα response. Conclusion Results indicate that LDV-induced activation of lymphocytes is due to recognition of LDV nucleic acid by TLR7 pattern recognition receptors in pDC's that respond with a lymphocyte-inducing IFNα response. PMID:19568424

  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. 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.

  2. 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

  3. Efficient monocyte-derived dendritic cell generation in patients with acute myeloid leukemia after chemotherapy treatment: application to active immunotherapy.

    PubMed

    Royer, Pierre-Joseph; Bougras, Gwenola; Ebstein, Frederic; Leveque, Lucie; Tanguy-Royer, Severine; Simon, Thomas; Juge-Morineau, Nadine; Chevallier, Patrice; Harousseau, Jean-Luc; Gregoire, Marc

    2008-03-01

    While complete remission in acute myeloid leukemia (AML) can be achieved after chemotherapy (CT), relapses occur for the majority of patients, underlying the need to eliminate residual disease. Based on dendritic cell (DC) vaccination, the triggering of an immune response against residual leukemia cells after CT could maintain patients in remission. The aim of our study was to assess, for vaccine preparation, generation of monocyte-derived DCs in AML patients after CT. We evaluated efficiency of the production, yields, maturation, and functional properties of DCs from 22 AML patients at different CT stages compared to those from 15 healthy donors. We demonstrated that monocyte-derived DC production is successful later than 3 weeks after the last CT cycle, whatever the CT was. Immature DCs demonstrated functional phagocytic activity. Mature DCs displayed migratory, T-cell stimulatory and Th1-activation capacities. Our results also suggest a favorable period from 20 to 60 days after CT for potent monocyte-derived DC production and immune activation. In defining patient-sampling conditions, this preclinical study has direct implications for AML DC-based immunotherapy.

  4. [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.

  5. Nimotuzumab Induces NK Cell Activation, Cytotoxicity, Dendritic Cell Maturation and Expansion of EGFR-Specific T Cells in Head and Neck Cancer Patients.

    PubMed

    Mazorra, Zaima; Lavastida, Anabel; Concha-Benavente, Fernando; Valdés, Anet; Srivastava, Raghvendra M; García-Bates, Tatiana M; Hechavarría, Esperanza; González, Zuyen; González, Amnely; Lugiollo, Martha; Cuevas, Iván; Frómeta, Carlos; Mestre, Braulio F; Barroso, Maria C; Crombet, Tania; Ferris, Robert L

    2017-01-01

    Survival benefit and long-term duration of clinical response have been seen using the epidermal growth factor receptor (EGFR)-targeted monoclonal antibody (mAb) nimotuzumab. Blocking EGFR signaling may not be the only mechanism of action underlying its efficacy. As an IgG1 isotype mAb, nimotuzumab's capacity of killing tumor cells by antibody dependent cellular cytotoxicity (ADCC) and to induce an immune response in cancer patients have not been studied. ADCC-induced by nimotuzumab was determined using a (51)Cr release assay. The in vitro effect of nimotuzumab on natural killer (NK) cell activation and dendritic cell (DC) maturation and the in vivo frequency of circulating regulatory T cells (Tregs) and NK cells were assessed by flow cytometry. Cytokine levels in supernatants were determined by ELISA. ELISpot was carried out to quantify EGFR-specific T cells in nimotuzumab-treated head and neck cancer (HNSCC) patients. Nimotuzumab was able to kill EGFR+ tumor cells by NK cell-mediated ADCC. Nimotuzumab-activated NK cells promoted DC maturation and EGFR-specific CD8+ T cell priming. Interestingly, nimotuzumab led to upregulation of some immune checkpoint molecules on NK cells (TIM-3) and DC (PD-L1), to a lower extent than another EGFR mAb, cetuximab. Furthermore, circulating EGFR-specific T cells were identified in nimotuzumab-treated HNSCC patients. Notably, nimotuzumab combined with cisplatin-based chemotherapy and radiation increased the frequency of peripheral CD4+CD39+FOXP3+Tregs which otherwise were decreased to baseline values when nimotuzumab was used as monotherapy. The frequency of circulating NK cells remained constant during treatment. Nimotuzumab-induced, NK cell-mediated DC priming led to induction of anti-EGFR specific T cells in HNSCC patients. The association between EGFR-specific T cells and patient clinical benefit with nimotuzumab treatment should be investigated.

  6. Nimotuzumab Induces NK Cell Activation, Cytotoxicity, Dendritic Cell Maturation and Expansion of EGFR-Specific T Cells in Head and Neck Cancer Patients

    PubMed Central

    Mazorra, Zaima; Lavastida, Anabel; Concha-Benavente, Fernando; Valdés, Anet; Srivastava, Raghvendra M.; García-Bates, Tatiana M.; Hechavarría, Esperanza; González, Zuyen; González, Amnely; Lugiollo, Martha; Cuevas, Iván; Frómeta, Carlos; Mestre, Braulio F.; Barroso, Maria C.; Crombet, Tania; Ferris, Robert L.

    2017-01-01

    Survival benefit and long-term duration of clinical response have been seen using the epidermal growth factor receptor (EGFR)-targeted monoclonal antibody (mAb) nimotuzumab. Blocking EGFR signaling may not be the only mechanism of action underlying its efficacy. As an IgG1 isotype mAb, nimotuzumab’s capacity of killing tumor cells by antibody dependent cellular cytotoxicity (ADCC) and to induce an immune response in cancer patients have not been studied. ADCC-induced by nimotuzumab was determined using a 51Cr release assay. The in vitro effect of nimotuzumab on natural killer (NK) cell activation and dendritic cell (DC) maturation and the in vivo frequency of circulating regulatory T cells (Tregs) and NK cells were assessed by flow cytometry. Cytokine levels in supernatants were determined by ELISA. ELISpot was carried out to quantify EGFR-specific T cells in nimotuzumab-treated head and neck cancer (HNSCC) patients. Nimotuzumab was able to kill EGFR+ tumor cells by NK cell-mediated ADCC. Nimotuzumab-activated NK cells promoted DC maturation and EGFR-specific CD8+ T cell priming. Interestingly, nimotuzumab led to upregulation of some immune checkpoint molecules on NK cells (TIM-3) and DC (PD-L1), to a lower extent than another EGFR mAb, cetuximab. Furthermore, circulating EGFR-specific T cells were identified in nimotuzumab-treated HNSCC patients. Notably, nimotuzumab combined with cisplatin-based chemotherapy and radiation increased the frequency of peripheral CD4+CD39+FOXP3+Tregs which otherwise were decreased to baseline values when nimotuzumab was used as monotherapy. The frequency of circulating NK cells remained constant during treatment. Nimotuzumab-induced, NK cell-mediated DC priming led to induction of anti-EGFR specific T cells in HNSCC patients. The association between EGFR-specific T cells and patient clinical benefit with nimotuzumab treatment should be investigated. PMID:28674498

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. Plasmacytoid dendritic cells are recruited to the colorectum and contribute to immune activation during pathogenic SIV infection in rhesus macaques

    PubMed Central

    Kwa, Suefen; Kannanganat, Sunil; Nigam, Pragati; Siddiqui, Mariam; Shetty, Ravi Dyavar; Armstrong, Wendy; Ansari, Aftab; Bosinger, Steven E.; Silvestri, Guido

    2011-01-01

    In SIV/HIV infection, the gastrointestinal tissue dominates as an important site because of the impact of massive mucosal CD4 depletion and immune activation-induced tissue pathology. Unlike AIDS-susceptible rhesus macaques, natural hosts do not progress to AIDS and resolve immune activation earlier. Here, we examine the role of dendritic cells (DCs) in mediating immune activation and disease progression. We demonstrate that plasmacytoid DCs (pDCs) in the blood up-regulate β7-integrin and are rapidly recruited to the colorectum after a pathogenic SIV infection in rhesus macaques. These pDCs were capable of producing proinflammatory cytokines and primed a T cytotoxic 1 response in vitro. Consistent with the up-regulation of β7-integrin on pDCs, in vivo blockade of α4β7-integrin dampened pDC recruitment to the colorectum and resulted in reduced immune activation. The up-regulation of β7-integrin expression on pDCs in the blood also was observed in HIV-infected humans but not in chronically SIV-infected sooty mangabeys that show low levels of immune activation. Our results uncover a new mechanism by which pDCs influence immune activation in colorectal tissue after pathogenic immunodeficiency virus infections. PMID:21693759

  14. 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

  15. 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

  16. Lpa2 is a negative regulator of both dendritic cell activation and murine models of allergic lung inflammation.

    PubMed

    Emo, Jason; Meednu, Nida; Chapman, Timothy J; Rezaee, Fariba; Balys, Marlene; Randall, Troy; Rangasamy, Tirumalai; Georas, Steve N

    2012-04-15

    Negative regulation of innate immune responses is essential to prevent excess inflammation and tissue injury and promote homeostasis. Lysophosphatidic acid (LPA) is a pleiotropic lipid that regulates cell growth, migration, and activation and is constitutively produced at low levels in tissues and in serum. Extracellular LPA binds to specific G protein-coupled receptors, whose function in regulating innate or adaptive immune responses remains poorly understood. Of the classical LPA receptors belonging to the Edg family, lpa2 (edg4) is expressed by dendritic cells (DC) and other innate immune cells. In this article, we show that DC from lpa2(-/-) mice are hyperactive compared with their wild-type counterparts and are less susceptible to inhibition by different LPA species. In transient-transfection assays, we found that lpa2 overexpression inhibits NF-κB-driven gene transcription. Using an adoptive-transfer approach, we found that allergen-pulsed lpa2(-/-) DC induced substantially more lung inflammation than did wild-type DC after inhaled allergen challenge. Finally, lpa2(-/-) mice develop greater allergen-driven lung inflammation than do their wild-type counterparts in models of allergic asthma involving both systemic and mucosal sensitization. Taken together, these findings identify LPA acting via lpa2 as a novel negative regulatory pathway that inhibits DC activation and allergic airway inflammation.

  17. The mechanisms of up-regulation of dendritic cell activity by oxidative stress

    PubMed Central

    Batal, Ibrahim; Azzi, Jamil; Mounayar, Marwan; Abdoli, Rozita; Moore, Robert; Lee, Jack Y.; Rosetti, Florencia; Wang, Chang; Fiorina, Paolo; Sackstein, Robert; Ichimura, Takaharu; Abdi, Reza

    2014-01-01

    Whereas DC have increasingly been recognized for their role in activating the inflammatory cascades during IRIs, the mechanisms by which oxidative stress enhances DC activation remain to be explored. We examined the role of oxidative stress on two important features of DC: T cell activation and trafficking. Bone marrow-derived OS-DC were compared with untreated DC. DC exposed to oxidative stress augmented allogeneic T cell proliferation and showed increased migration in a chemotaxis chamber. These results were confirmed by using hypoxanthine and xanthine oxidase as another inducer of oxidative stress. We used OT-II and OT-I mice to assess the effect of oxidative stress on DC activation of OVA-specific CD4+ and CD8+ T cells, respectively. Oxidative stress increased DC capacity to promote OVA-specific CD4+ T cell activity, demonstrated by an increase in their proliferation and production of IFN-γ, IL-6, and IL-2 proinflammatory cytokines. Whereas oxidative stress increased the DC ability to stimulate IFN-γ production by OVA-specific CD8+ T cells, cellular proliferation and cytotoxicity were not affected. Compared with untreated DC, oxidative stress significantly reduced the capacity of DC to generate Tregs, which were restored by using anti-IL-6. With regard to DC trafficking, whereas oxidative stress increased DC expression of p-Akt and p-NF-κB, targeting PI3Kγ and NF-κB pathways abrogated the observed increase in DC migration. Our data propose novel insights on the activation of DC by oxidative stress and provide rationales for targeted therapies, which can potentially attenuate IRI. PMID:24676276

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

    PubMed

    Mason, Lauren M K; 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.

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. Dendritic cells during Epstein Barr virus infection

    PubMed Central

    Christian, Münz

    2014-01-01

    Epstein Barr virus (EBV) causes persistent infection in more than 90% of the human adult population and is associated with 2% of all tumors in humans. This γ-herpes virus infects primarily human B and epithelial cells, but it has been reported to be sensed by dendritic cells (DCs) during primary infection. These activated DCs are thought to contribute to innate restriction of EBV infection and initiate EBV-specific adaptive immune responses via cross-priming. The respective evidence and their potential importance for EBV-specific vaccine development will be discussed in this review. PMID:24999343

  4. 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

  5. Dendritic cells in hematological malignancies.

    PubMed

    Galati, Domenico; Corazzelli, Gaetano; De Filippi, Rosaria; Pinto, Antonio

    2016-12-01

    Dendritic cells (DCs) are bone-marrow-derived immune cells accounted for a crucial role in initiating and modulating the adaptive immune response and supporting the innate immune response independently from T cells. While functioning as the most effective antigen-presenting cells within the immune system, DCs can otherwise induce tolerance in central and peripheral lymphoid organs acting therefore as suppressors rather than stimulators of the immune response. Within mechanisms regulating antitumor immunity, DCs can capture antigens from viable or damaged tumor cells and present the processed peptides to T-cells to prompt the generation and maintenance of an effective tumor-specific T-cell response. Upon a complex cross-talk with other cellular components of the tumor microenvironment, DCs can, on the other hand, exert a potent antigen-dependent and -independent tolerogenic function by favoring the process of tumor immune evasion. Due to this dual-role in balancing antitumor immunity and tolerance, possibly linked to distinct developmental stages and functional subsets, several studies have addressed the regulatory significance of DCs in different types of malignancies. This review summarizes the most significant pieces of evidence highlighting the critical relevance of bone marrow-derived DCs within the immune pathways regulating pathogenesis and progression of hemopoietic tumors. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. 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.

  7. Targeted delivery of tumor antigens to activated dendritic cells via CD11c molecules induces potent antitumor immunity in mice.

    PubMed

    Wei, Huafeng; Wang, Suhui; Zhang, Dapeng; Hou, Sheng; Qian, Weizhu; Li, Bohua; Guo, Huaizu; Kou, Geng; He, Jinqiu; Wang, Hao; Guo, Yajun

    2009-07-15

    CD11c is an antigen receptor predominantly expressed on dendritic cells (DC), to which antigen targeting has been shown to induce robust antigen-specific immune responses. To facilitate targeted delivery of tumor antigens to DCs, we generated fusion proteins consisting of the extracellular domain of human HER or its rat homologue neu, fused to the single-chain fragment variable specific for CD11c (scFv(CD11c)-HER2/neu). Induction of cellular and humoral immune responses and antitumoral activity of the fusion proteins admixed with DC-activating CpG oligonucleotides (scFv(CD11c)-HER2/neu(CpG)) were tested in transplantable HER2/neu-expressing murine tumor models and in transgenic BALB-neuT mice developing spontaneous neu-driven mammary carcinomas. Vaccination of BALB/c mice with scFv(CD11c)-HER2(CpG) protected mice from subsequent challenge with HER2-positive, but not HER2-negative, murine breast tumor cells, accompanied by induction of strong HER2-specific T-cell and antibody responses. In a therapeutic setting, injection of scFv(CD11c)-HER2(CpG) caused rejection of established HER2-positive tumors. Importantly, antitumoral activity of such a fusion protein vaccine could be reproduced in immunotolerant BALB-neuT mice, where scFv(CD11c)-neu(CpG) vaccination significantly protected against a subsequent challenge with neu-expressing murine breast tumor cells and markedly delayed the onset of spontaneous mammary carcinomas. CD11c-targeted protein vaccines for in vivo delivery of tumor antigens to DCs induce potent immune responses and antitumoral activities and provide a rationale for further development of this approach for cancer immunotherapy.

  8. 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.

  9. 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

  10. Rabies Virus Expressing Dendritic Cell-Activating Molecules Enhances the Innate and Adaptive Immune Response to Vaccination ▿

    PubMed Central

    Wen, Yongjun; Wang, Hualei; Wu, Hua; Yang, Fuhe; Tripp, Ralph A.; Hogan, Robert J.; Fu, Zhen F.

    2011-01-01

    Our previous studies indicated that recruitment and/or activation of dendritic cells (DCs) is important in enhancing the protective immune responses against rabies virus (RABV) (L. Zhao, H. Toriumi, H. Wang, Y. Kuang, X. Guo, K. Morimoto, and Z. F. Fu, J. Virol. 84:9642-9648). To address the importance of DC activation for RABV vaccine efficacy, the genes for several DC recruitment and/or activation molecules, e.g., granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage-derived chemokine (MDC), and macrophage inflammatory protein 1α (MIP-1α), were individually cloned into RABV. The ability of these recombinant viruses to activate DCs was determined in vitro and in vivo. Infection of mouse bone marrow-derived DCs with each of the recombinant viruses resulted in DC activation, as shown by increased surface expression of CD11c and CD86 as well as an increased level of alpha interferon (IFN-α) production compared to levels observed after infection with the parent virus. Intramuscular infection of mice with each of the viruses recruited and/or activated more DCs and B cells in the periphery than infection with the parent virus, leading to the production of higher levels of virus-neutralizing antibodies. Furthermore, a single immunization with recombinant RABV expressing GM-CSF or MDC protected significantly more mice against intracerebral challenge with virulent RABV than did immunization with the parental virus. Yet, these viruses did not show more virulence than the parent virus, since direct intracerebral inoculation with each virus at up to 1 × 107 fluorescent focus units each did not induce any overt clinic symptom, such as abnormal behavior, or any neurological signs. Together, these data indicate that recombinant RABVs expressing these molecules activate/recruit DCs and enhance protective immune responses. PMID:21106736

  11. 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.

  12. 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.

  13. CD4+ T-cell activation is differentially modulated by bacteria-primed dendritic cells, but is generally down-regulated by n-3 polyunsaturated fatty acids

    PubMed Central

    Brix, Susanne; Lund, Pia; Kjaer, Tanja M R; Straarup, Ellen M; Hellgren, Lars I; Frøkiær, Hanne

    2010-01-01

    Appropriate activation of CD4+ T cells is fundamental for efficient initiation and progression of acquired immune responses. Here, we showed that CD4+ T-cell activation is dependent on changes in membrane n-3 polyunsaturated fatty acids (PUFAs) and is dynamically regulated by the type of signals provided by dendritic cells (DCs). Upon interaction with DCs primed by different concentrations and species of gut bacteria, CD4+ T cells were activated according to the type of DC stimulus. The levels of CD80 were found to correlate to the levels of expression of CD28 and to the proliferation of CD4+ T cells, while the presence of CD40 and CD86 on DCs inversely affected inducible costimulator (ICOS) and cytotoxic T-lymphocyte antigen-4 (CTLA-4) levels in CD4+ T cells. For all DC stimuli, cells high in n-3 PUFAs showed reduced ability to respond to CD28 stimulation, to proliferate, and to express ICOS and CTLA-4. Diminished T-cell receptor (TCR) and CD28 signalling was found to be responsible for n-3 PUFA effects. Thus, the dietary fatty acid composition influences the overall level of CD4+ T-cell activation induced by DCs, while the priming effect of the DC stimuli modulates CD80, CD86 and CD40 levels, thereby affecting and shaping activation of acquired immunity by differential regulation of proliferation and costimulatory molecule expression in CD4+ T cells. PMID:19909377

  14. Stimulatory effect of Echinacea purpurea extract on the trafficking activity of mouse dendritic cells: revealed by genomic and proteomic analyses

    PubMed Central

    2010-01-01

    Background Several Echinacea species have been used as nutraceuticals or botanical drugs for "immunostimulation", but scientific evidence supporting their therapeutic use is still controversial. In this study, a phytocompound mixture extracted from the butanol fraction (BF) of a stem and leaf (S+L) extract of E. purpurea ([BF/S+L/Ep]) containing stringently defined bioactive phytocompounds was obtained using standardized and published procedures. The transcriptomic and proteomic effects of this phytoextract on mouse bone marrow-derived dendritic cells (BMDCs) were analyzed using primary cultures. Results Treatment of BMDCs with [BF/S+L/Ep] did not significantly influence the phenotypic maturation activity of dendritic cells (DCs). Affymetrix DNA microarray and bioinformatics analyses of genes differentially expressed in DCs treated with [BF/S+L/Ep] for 4 or 12 h revealed that the majority of responsive genes were related to cell adhesion or motility (Cdh10, Itga6, Cdh1, Gja1 and Mmp8), or were chemokines (Cxcl2, Cxcl7) or signaling molecules (Nrxn1, Pkce and Acss1). TRANSPATH database analyses of gene expression and related signaling pathways in treated-DCs predicted the JNK, PP2C-α, AKT, ERK1/2 or MAPKAPK pathways as the putative targets of [BF/S+L/Ep]. In parallel, proteomic analysis showed that the expressions of metabolic-, cytoskeleton- or NF-κB signaling-related proteins were regulated by treatment with [BF/S+L/Ep]. In vitro flow cytometry analysis of chemotaxis-related receptors and in vivo cell trafficking assay further showed that DCs treated with [BF/S+L/Ep] were able to migrate more effectively to peripheral lymph node and spleen tissues than DCs treated as control groups. Conclusion Results from this study suggest that [BF/S+L/Ep] modulates DC mobility and related cellular physiology in the mouse immune system. Moreover, the signaling networks and molecules highlighted here are potential targets for nutritional or clinical application of Echinacea or

  15. Impulse encoding across the dendritic morphologies of retinal ganglion cells.

    PubMed

    Sheasby, B W; Fohlmeister, J F

    1999-04-01

    Na-channel density can lead to dendritic impulse initiation, this does not occur with our "standard" channel densities and is not seen experimentally. Even so, impulses initiated elsewhere do invade all except very thin dendritic processes. Impulse-encoding irregularities increase when channel conductances are reduced in the encoder region, and the F/I properties of the cells are a strong function of the calcium- and Ca-activated K-channel densities. Use of equivalent dendritic cylinders requires more soma-dendritic surface area than real dendritic trees, and the source of the discrepancy is discussed.

  16. 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

  17. [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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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).

  3. 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

  4. 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.

  5. Stochastic Ion Channel Gating in Dendritic Neurons: Morphology Dependence and Probabilistic Synaptic Activation of Dendritic Spikes

    PubMed Central

    Nolan, Matthew F.

    2010-01-01

    Neuronal activity is mediated through changes in the probability of stochastic transitions between open and closed states of ion channels. While differences in morphology define neuronal cell types and may underlie neurological disorders, very little is known about influences of stochastic ion channel gating in neurons with complex morphology. We introduce and validate new computational tools that enable efficient generation and simulation of models containing stochastic ion channels distributed across dendritic and axonal membranes. Comparison of five morphologically distinct neuronal cell types reveals that when all simulated neurons contain identical densities of stochastic ion channels, the amplitude of stochastic membrane potential fluctuations differs between cell types and depends on sub-cellular location. For typical neurons, the amplitude of membrane potential fluctuations depends on channel kinetics as well as open probability. Using a detailed model of a hippocampal CA1 pyramidal neuron, we show that when intrinsic ion channels gate stochastically, the probability of initiation of dendritic or somatic spikes by dendritic synaptic input varies continuously between zero and one, whereas when ion channels gate deterministically, the probability is either zero or one. At physiological firing rates, stochastic gating of dendritic ion channels almost completely accounts for probabilistic somatic and dendritic spikes generated by the fully stochastic model. These results suggest that the consequences of stochastic ion channel gating differ globally between neuronal cell-types and locally between neuronal compartments. Whereas dendritic neurons are often assumed to behave deterministically, our simulations suggest that a direct consequence of stochastic gating of intrinsic ion channels is that spike output may instead be a probabilistic function of patterns of synaptic input to dendrites. PMID:20711353

  6. 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.

  7. Imidazoquinoline TLR8 agonists activate human newborn monocytes and dendritic cells via adenosine-refractory and caspase-1-dependent pathways

    PubMed Central

    Philbin, Victoria J.; Dowling, David J.; Gallington, Leighanne C.; Cortés, Guadalupe; Tan, Zhen; Suter, Eugénie E.; Chi, Kevin W.; Shuckett, Ariel; Stoler-Barak, Liat; Tomai, Mark; Miller, Richard L.; Mansfield, Keith; Levy, Ofer

    2012-01-01

    Background Newborns suffer frequent infection and manifest impaired vaccine responses, motivating a search for neonatal vaccine adjuvants. Alum is a neonatal adjuvant, but may confer a Th2 bias. Toll-like receptor (TLR) agonists are candidate adjuvants, but human neonatal cord blood monocytes (Mos) demonstrate impaired Th1-polarizing responses to many TLR agonists due to plasma adenosine acting via cAMP. TLR8 agonists, including imidazoquinolines (IMQs) such as the small synthetic 3M-002, induce adult-level TNF from neonatal Mos, but the scope and mechanisms of IMQ-induced activation of neonatal Mos and Mo-derived dendritic cells (MoDCs) have not been reported. Objectives To characterize IMQ-induced activation of neonatal Mos and MoDCs. Methods Neonatal cord and adult peripheral blood Mos and MoDCs were cultured in autologous plasma; Alum- and TLR agonist-induced cytokines and co-stimulatory molecules were measured. TLR8 and inflammasome function were assayed using siRNA and western blotting/caspase-1 inhibitory peptide, respectively. The ontogeny of TLR8 agonist–induced cytokine responses was defined in Rhesus macaque whole blood ex vivo. Results IMQs were more potent and effective than Alum at inducing TNF and IL-1β from Mos. 3M-002 induced robust TLR pathway transcriptome activation and Th1-polarizing cytokine production in neonatal and adult Mos and MoDCs, signaling via TLR8 in an adenosine/cAMP- refractory manner. Newborn MoDCs displayed impaired LPS/ATP-induced caspase-1-mediated IL-1β production, but robust 3M-002-induced caspase-1-mediated inflammasome activation independent of exogenous ATP. TLR8-IMQs induced robust TNF and IL-1β in whole blood of Rhesus macaques at birth and infancy. Conclusions IMQ TLR8 agonists engage adenosine-refractory TLR8 and inflammasome pathways to induce robust Mo and MoDC activation and represent promising neonatal adjuvants. PMID:22521247

  8. Isolation and characterization of dendritic cells from adenoids of children with otitis media with effusion.

    PubMed Central

    van Nieuwkerk, E B; van der Baan, S; Richters, C D; Kamperdijk, E W

    1992-01-01

    Dendritic cells were enriched from adenoids of children with otitis media with effusion (OME) by density gradient centrifugation and culture techniques. An enrichment of 40-140-fold was obtained for dendritic cells. These cells were identified using morphology, enzyme cytochemistry, immunocytochemistry and functional criteria. Dendritic cells could be easily distinguished from macrophages. It appeared that the MoAb EBM11 (CD68) discriminated between dendritic cells and macrophages; in dendritic cells this activity was localized in a spot, whereas in macrophages it was found throughout the whole cytoplasm. The fractions enriched with dendritic cells showed a strong stimulatory effect on allogeneic T cells. These responses were MHC class II dependent since they could be blocked by anti-HLA-DR/DQ MoAbs. The data clearly show that dendritic cells from adenoids of children with OME still have functional capacities. Images Fig. 1 Fig. 2 Fig. 3 PMID:1572100

  9. 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

  10. 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.

  11. Dendritic cells activation is associated with sustained virological response to telaprevir treatment of HCV-infected patients.

    PubMed

    Sacchi, Alessandra; Tumino, Nicola; Turchi, Federica; Refolo, Giulia; Fimia, GianMaria; Ciccosanti, Fabiola; Montalbano, Marzia; Lionetti, Raffaella; Taibi, Chiara; D'Offizi, Gianpiero; Casetti, Rita; Bordoni, Veronica; Cimini, Eleonora; Martini, Federico; Agrati, Chiara

    2017-07-20

    First anti-HCV treatments, that include protease inhibitors in conjunction with IFN-α and Ribavirin, increase the sustained virological response (SVR) up to 80% in patients infected with HCV genotype 1. The effects of triple therapies on dendritic cell (DC) compartment have not been investigated. In this study we evaluated the effect of telaprevir-based triple therapy on DC phenotype and function, and their possible association with treatment outcome. HCV+ patients eligible for telaprevir-based therapy were enrolled, and circulating DC frequency, phenotype, and function were evaluated by flow-cytometry. The antiviral activity of plasmacytoid DC was also tested. In SVR patients, myeloid DC frequency transiently decreased, and returned to baseline level when telaprevir was stopped. Moreover, an up-regulation of CD80 and CD86 on mDC was observed in SVR patients as well as an improvement of IFN-α production by plasmacytoid DC, able to inhibit in vitro HCV replication. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Effect of Tinospora cordifolia on the antitumor activity of tumor-associated macrophages-derived dendritic cells.

    PubMed

    Singh, Nisha; Singh, Sukh Mahendra; Shrivastava, Pratima

    2005-01-01

    We and others previously have reported that extract prepared from medicinal plant Tinospora cordifolia shows a wide spectrum of immunoaugmentary effects. Tinospora cordifolia was shown to upregulate antitumor activity of tumor-associated macrophages (TAM). In this article we present evidence to show that an alcoholic extract of Tinospora cordifolia (ALTC) enhances the differentiation of TAM to dendritic cells (DC) in response to granulocyte/macrophage-colony-stimulating factor, interleukin-4, and tumor necrosis factor. DC differentiated in vitro from TAM that were harvested from tumor-bearing mice after i.p. administration of ALTC (200 mg/kg body weight) 2 days posttumor transplantation shows an enhanced tumor cytotoxicity and production of tumoricidal soluble molecules like TNF, IL-1, and NO. Adoptive transfer of these TAM-derived DC to Dalton's lymphoma-bearing mice resulted in prolongation of survival of tumor-bearing mice. This is the first report regarding the differentiation and antitumor functions of TAM-derived DC obtained from tumor-bearing host administered with ALTC. The possible mechanisms involved also are discussed.

  13. 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

  14. 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

  15. 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

  16. 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

  17. Role of Wnt3a expressed by dendritic cells in the activation of canonical Wnt signaling and generation of memory T cells during primary immune responses.

    PubMed

    Luo, Lei; Li, Zhengyu; Luo, Guangheng; Zhao, Yingting; Yang, Jing; Chen, Hui

    2016-12-01

    The presence of memory T cells (TMs) hinders transplant survival. Dendritic cells (DCs) induce the generation of TMs during primary immune responses. However, the specific mechanisms are unclear. In this study, we constructed a Wnt3a-expressing adenovirus and used small interfering RNA (siRNA) targeting Wnt3a to investigate the influence of Wnt3a expression in DCs on the generation of TMs during primary immune responses. Our results demonstrated that the Wnt3a expression levels in DCs influenced the generation of TMs after 5days in co-culture with naïve T cells through activation of the Wnt canonical pathway. Interleukin-7 secretion levels in supernatants of DC/TNs co-cultures showed a similar pattern of Wnt3a expression levels in DCs. These findings provide a better understanding of TMs generation mechanisms that might be useful to improve transplant outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

  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. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  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. 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

  11. Interaction of Mycoplasma hominis PG21 with Human Dendritic Cells: Interleukin-23-Inducing Mycoplasmal Lipoproteins and Inflammasome Activation of the Cell.

    PubMed

    Goret, J; Béven, L; Faustin, B; Contin-Bordes, C; Le Roy, C; Claverol, S; Renaudin, H; Bébéar, C; Pereyre, S

    2017-08-01

    Mycoplasma hominis lacks a cell wall, and lipoproteins anchored to the extracellular side of the plasma membrane are in direct contact with the host components. A Triton X-114 extract of M. hominis enriched with lipoproteins was shown to stimulate the production of interleukin-23 (IL-23) by human dendritic cells (hDCs). The inflammasome activation of the host cell has never been reported upon M. hominis infection. We studied here the interaction between M. hominis PG21 and hDCs by analyzing both the inflammation-inducing mycoplasmal lipoproteins and the inflammasome activation of the host cell. IL-23-inducing lipoproteins were determined using a sequential extraction strategy with two nondenaturing detergents, Sarkosyl and Triton X-114, followed by SDS-PAGE separation and mass spectrometry identification. The activation of the hDC inflammasome was assessed using PCR array and enzyme-linked immunosorbent assay (ELISA). We defined a list of 24 lipoproteins that could induce the secretion of IL-23 by hDCs, 5 with a molecular mass between 20 and 35 kDa and 19 with a molecular mass between 40 and 100 kDa. Among them, lipoprotein MHO_4720 was identified as potentially bioactive, and a synthetic lipopeptide corresponding to the N-terminal part of the lipoprotein was subsequently shown to induce IL-23 release by hDCs. Regarding the hDC innate immune response, inflammasome activation with caspase-dependent production of IL-1β was observed. After 24 h of coincubation of hDCs with M. hominis, downregulation of the NLRP3-encoding gene and of the adaptor PYCARD-encoding gene was noticed. Overall, this study provides insight into both protagonists of the interaction of M. hominis and hDCs.IMPORTANCEMycoplasma hominis is a human urogenital pathogen involved in gynecologic and opportunistic infections. M. hominis lacks a cell wall, and its membrane contains many lipoproteins that are anchored to the extracellular side of the plasma membrane. In the present study, we focused on

  12. Purified Dendritic Cell-Tumor Fusion Hybrids Supplemented with Non-Adherent Dendritic Cells Fraction Are Superior Activators of Antitumor Immunity

    PubMed Central

    Wang, Yucai; Liu, Yunyan; Zheng, Lianhe

    2014-01-01

    Background Strong evidence supports the DC-tumor fusion hybrid vaccination strategy, but the best fusion product components to use remains controversial. Fusion products contain DC-tumor fusion hybrids, unfused DCs and unfused tumor cells. Various fractions have been used in previous studies, including purified hybrids, the adherent cell fraction or the whole fusion mixture. The extent to which the hybrids themselves or other components are responsible for antitumor immunity or which components should be used to maximize the antitumor immunity remains unknown. Methods Patient-derived breast tumor cells and DCs were electro-fused and purified. The antitumor immune responses induced by the purified hybrids and the other components were compared. Results Except for DC-tumor hybrids, the non-adherent cell fraction containing mainly unfused DCs also contributed a lot in antitumor immunity. Purified hybrids supplemented with the non-adherent cell population elicited the most powerful antitumor immune response. After irradiation and electro-fusion, tumor cells underwent necrosis, and the unfused DCs phagocytosed the necrotic tumor cells or tumor debris, which resulted in significant DC maturation. This may be the immunogenicity mechanism of the non-adherent unfused DCs fraction. Conclusions The non-adherent cell fraction (containing mainly unfused DCs) from total DC/tumor fusion products had enhanced immunogenicity that resulted from apoptotic/necrotic tumor cell phagocytosis and increased DC maturation. Purified fusion hybrids supplemented with the non-adherent cell population enhanced the antitumor immune responses, avoiding unnecessary use of the tumor cell fraction, which has many drawbacks. Purified hybrids supplemented with the non-adherent cell fraction may represent a better approach to the DC-tumor fusion hybrid vaccination strategy. PMID:24466232

  13. Soluble helminth products suppress clinical signs in murine experimental autoimmune encephalomyelitis and differentially modulate human dendritic cell activation.

    PubMed

    Kuijk, Loes M; Klaver, Elsenoor J; Kooij, Gijs; van der Pol, Susanne M A; Heijnen, Priscilla; Bruijns, Sven C M; Kringel, Helene; Pinelli, Elena; Kraal, Georg; de Vries, Helga E; Dijkstra, Christine D; Bouma, Gerd; van Die, Irma

    2012-06-01

    The increased incidence of auto-inflammatory and autoimmune diseases in the developed countries seems to be caused by an imbalance of the immune system due to the lack of proper regulation. Helminth parasites are well known modulators of the immune system and as such are of great interest for the treatment of these disorders. Clinical studies showed that administration of eggs of the pig nematode Trichuris suis to patients with inflammatory bowel disease reduces the disease severity. Here we demonstrate that treatment with soluble products from the nematodes T. suis and Trichinella spiralis induces significant suppression of symptoms in murine experimental autoimmune encephalomyelitis, a validated animal model for multiple sclerosis. These data show that infection with live nematodes is not a prerequisite for suppression of inflammation. To translate these results to the human system, the effects of soluble products of T. suis, T. spiralis and Schistosoma mansoni on the phenotype and function of human dendritic cells (DCs) were compared. Our data show that soluble products of T. suis, S. mansoni and T. spiralis suppress TNF-α and IL-12 secretion by TLR-activated human DCs, and that T. suis and S. mansoni, but not T. spiralis, strongly enhance expression of OX40L. Furthermore, helminth-primed human DCs differentially suppress the development of Th1 and/or Th17 cells. In conclusion, our data demonstrate that soluble helminth products have strong immunomodulatory capacities, but might exert their effects through different mechanisms. The suppressed secretion of pro-inflammatory cytokines together with an upregulation of OX40L expression on human DCs might contribute to achieve this modulation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Identification and isolation of synovial dendritic cells.

    PubMed

    Pettit, Allison R; Cavanagh, Lois; Boyce, Amanda; Padmanabha, Jagadish; Peng, Judy; Thomas, Ranjeny

    2007-01-01

    In rheumatoid arthritis patients, three compartments need to be considered: peripheral blood, synovial fluid, and synovial tissue. Dendritic cells characterized from each compartment have different properties. The methods given are based on cell sorting for isolation of cells, and flow cytometry and immunohistochemical staining for analysis of cells in these compartments.

  15. The mouse dendritic cell marker CD11c is down-regulated upon cell activation through Toll-like receptor triggering.

    PubMed

    Singh-Jasuja, Harpreet; Thiolat, Allan; Ribon, Matthieu; Boissier, Marie-Christophe; Bessis, Natacha; Rammensee, Hans-Georg; Decker, Patrice

    2013-01-01

    Dendritic cells (DC) play a key role in regulating immune responses and are the best professional antigen-presenting cells. Two major DC populations are defined in part according to cell surface CD11c expression levels. Unexpectedly, we observed that mouse DC strongly down-regulate the typical DC marker CD11c upon activation. To better characterize DC responses, we have analyzed CD11c expression on mouse and human myeloid DC after Toll-like receptor (TLR) triggering. Here we show that mouse bone marrow-derived DC (BMDC) as well as spleen DC down-regulate cell surface CD11c upon activation by TLR3/4/9 agonists. In all cases, full DC activation was reached, as determined by cytokine secretion, cell stimulation in mixed leukocyte reactions (MLR), and CD40/CD86/major histocompatibility complex (MHC) up-regulation. Interestingly, membrane CD11c down-regulation correlated with increased cytoplasmic pools of CD11c. In contrast to the up-regulation of CD40 and MHC class II molecules, lipopolysaccharide (LPS)-induced CD11c down-regulation was MyD88-dependent. Polyinosinic-polycytidylic acid (poly I:C), which does not signal through MyD88, also induced cell surface CD11c down-regulation. Notably, CD11c down-regulation was not observed upon activation of human DC, either through TLR-dependent or -independent cell activation. Thus, activated mouse DC may be transiently CD11c-negative in vivo, hampering the identification of those cells. On the other hand, cell surface CD11c down-regulation may serve as a new activation marker for mouse DC. Copyright © 2012 Elsevier GmbH. All rights reserved.

  16. Role of heterogeneous cell population on modulation of dendritic cell phenotype and activation of CD8 T cells for use in cell-based immunotherapies.

    PubMed

    Frizzell, Hannah; Park, Jaehyung; Comandante Lou, Natacha; Woodrow, Kim A

    2017-01-01

    Dendritic cell (DC)-based immunotherapies have much utility in their ability to prime antigen-specific adaptive immune responses. However, there does not yet exist a consensus standard to how DCs should be primed. In this study, we aimed to determine the role of heterogeneous co-cultures, composed of both CD11c+ (DCs) and CD11c- cells, in combination with monophosphoryl lipid A (MPLA) stimulation on DC phenotype and function. Upon DC priming in different co-culture ratios, we observed reduced expression of MHCII and CD86 and increased antigen uptake among CD11c+ cells in a CD11c- dependent manner. DCs from all culture conditions were induced to mature by MPLA treatment, as determined by secretion of pro-inflammatory cytokines IL-12 and TNF-α. Antigen-specific stimulation of CD4+ T cells was not modulated by co-culture composition, in terms of proliferation nor levels of IFN-γ. However, the presence of CD11c- cells enhanced cross-presentation to CD8+ T cells compared to purified CD11c+ cells, resulting in increased cell proliferation along with higher IFN-γ production. These findings demonstrate the impact of cell populations present during DC priming, and point to the use of heterogeneous cultures of DCs and innate immune cells to enhance cell-mediated immunity. Copyright © 2016 Elsevier Inc. All rights reserved.

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

    PubMed

    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.

  18. 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

  19. 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

  20. HIV-1 gp120 activates the STAT3/interleukin-6 axis in primary human monocyte-derived dendritic cells.

    PubMed

    Del Cornò, Manuela; Donninelli, Gloria; Varano, Barbara; Da Sacco, Letizia; Masotti, Andrea; Gessani, Sandra

    2014-10-01

    Dendritic cells (DCs) are fundamental for the initiation of immune responses and are important players in AIDS immunopathogenesis. The modulation of DC functional activities represents a strategic mechanism for HIV-1 to evade immune surveillance. Impairment of DC function may result from bystander effects of HIV-1 envelope proteins independently of direct HIV-1 infection. In this study, we report that exposure of immature monocyte-derived DCs (MDDCs) to HIV-1 R5 gp120 resulted in the CCR5-dependent production of interleukin-6 (IL-6) via mitogen-activated protein kinase (MAPK)/NF-κB pathways. IL-6 in turn activated STAT3 by an autocrine loop. Concomitantly, gp120 promoted an early activation of STAT3 that further contributed to IL-6 induction. This activation paralleled a concomitant upregulation of the STAT3 inhibitor PIAS3. Notably, STAT3/IL-6 pathway activation was not affected by the CCR5-specific ligand CCL4. These results identify STAT3 as a key signaling intermediate activated by gp120 in MDDCs and highlight the existence of a virus-induced dysregulation of the IL-6/STAT3 axis. HIV-1 gp120 signaling through STAT3 may provide an explanation for the impairment of DC function observed upon HIV exposure. This study provides new evidence for the molecular mechanisms and signaling pathways triggered by HIV-1 gp120 in human DCs in the absence of productive infection, emphasizing a role of aberrant signaling in early virus-host interaction, contributing to viral pathogenesis. We identified STAT3 as a key component in the gp120-mediated signaling cascade involving MAPK and NF-κB components and ultimately leading to IL-6 secretion. STAT3 now is recognized as a key regulator of DC functions. Thus, the identification of this transcription factor as a signaling molecule mediating some of gp120's biological effects unveils a new mechanism by which HIV-1 may deregulate DC functions and contribute to AIDS pathogenesis. Copyright © 2014, American Society for Microbiology

  1. 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.

  2. 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.

  3. Leishmania donovani Isolates with Antimony-Resistant but Not -Sensitive Phenotype Inhibit Sodium Antimony Gluconate-Induced Dendritic Cell Activation

    PubMed Central

    Singhal, Eshu; Bisht, Kamlesh Kumar; Singh, Alpana; Bhaumik, Suniti; Basu, Rajatava; Sen, Pradip; Roy, Syamal

    2010-01-01

    The inability of sodium antimony gluconate (SAG)-unresponsive kala-azar patients to clear Leishmania donovani (LD) infection despite SAG therapy is partly due to an ill-defined immune-dysfunction. Since dendritic cells (DCs) typically initiate anti-leishmanial immunity, a role for DCs in aberrant LD clearance was investigated. Accordingly, regulation of SAG-induced activation of murine DCs following infection with LD isolates exhibiting two distinct phenotypes such as antimony-resistant (SbRLD) and antimony-sensitive (SbSLD) was compared in vitro. Unlike SbSLD, infection of DCs with SbRLD induced more IL-10 production and inhibited SAG-induced secretion of proinflammatory cytokines, up-regulation of co-stimulatory molecules and leishmanicidal effects. SbRLD inhibited these effects of SAG by blocking activation of PI3K/AKT and NF-κB pathways. In contrast, SbSLD failed to block activation of SAG (20 µg/ml)-induced PI3K/AKT pathway; which continued to stimulate NF-κB signaling, induce leishmanicidal effects and promote DC activation. Notably, prolonged incubation of DCs with SbSLD also inhibited SAG (20 µg/ml)-induced activation of PI3K/AKT and NF-κB pathways and leishmanicidal effects, which was restored by increasing the dose of SAG to 40 µg/ml. In contrast, SbRLD inhibited these SAG-induced events regardless of duration of DC exposure to SbRLD or dose of SAG. Interestingly, the inhibitory effects of isogenic SbSLD expressing ATP-binding cassette (ABC) transporter MRPA on SAG-induced leishmanicidal effects mimicked that of SbRLD to some extent, although antimony resistance in clinical LD isolates is known to be multifactorial. Furthermore, NF-κB was found to transcriptionally regulate expression of murine γglutamylcysteine synthetase heavy-chain (mγGCShc) gene, presumably an important regulator of antimony resistance. Importantly, SbRLD but not SbSLD blocked SAG-induced mγGCS expression in DCs by preventing NF-κB binding to the mγGCShc promoter. Our

  4. 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

  5. Helicobacter pylori susceptible/resistant to antibiotic eradication therapy differ in the maturation and activation of dendritic cells.

    PubMed

    Kopitar, Andreja N; Skvarc, Miha; Tepes, Bojan; Kos, Janko; Ihan, Alojz

    2013-12-01

    The natural course of Helicobacter pylori infection, as well as the success of antibiotic eradication is determined by the immune response to bacteria. The aim of the study is to investigate how different Helicobacter pylori isolates influence the dendritic cells maturation and antigen-presenting function in order to elucidate the differences between Helicobacter pylori strains, isolated from the patients with successful antibiotic eradication therapy or repeated eradication failure. Dendritic cells maturation and antigen presentation were monitored by flow cytometry analysis of the major histocompatibility complex class II (MHC-II), Toll-like receptor (TLR) and costimulatory molecules expression, and by determining cytokine secretion. Dendritic cells stimulated with Helicobacter pylori isolated from patients with repeated antibiotic eradication failure expressed less human leukocyte antigen (HLA-DR), CD86, TLR-2, and interleukin-8 (IL-8) compared to Helicobacter pylori strains susceptible to antibiotic therapy; the latter expressed lower production of IL-10. Polymyxin B inhibition of lipopolysaccharide reduces IL-8 secretion in the group of Helicobacter pylori strains susceptible to antibiotic therapy. The differences in IL-8 secretion between both groups are lipopolysaccharide dependent, while the differences in secretion of IL-10 remain unchanged after lipopolysaccharide inhibition. Inhibitor of cathepsin X Mab 2F12 reduced the secretion of IL-6, and the secretion was significantly lower in the group of Helicobacter pylori strains isolated from patients with repeated antibiotic eradication failure. Helicobacter pylori strains, susceptible/resistant to antibiotic eradication therapy, differ in their capability to induce DCs maturation and antigen-presenting function. © 2013 John Wiley & Sons Ltd.

  6. 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

  7. Changes in T Cell and Dendritic Cell Phenotype from Mid to Late Pregnancy Are Indicative of a Shift from Immune Tolerance to Immune Activation

    PubMed Central

    Shah, Nishel Mohan; Herasimtschuk, Anna A.; Boasso, Adriano; Benlahrech, Adel; Fuchs, Dietmar; Imami, Nesrina; Johnson, Mark R.

    2017-01-01

    During pregnancy, the mother allows the immunologically distinct fetoplacental unit to develop and grow. Opinions are divided as to whether this represents a state of fetal-specific tolerance or of a generalized suppression of the maternal immune system. We hypothesized that antigen-specific T cell responses are modulated by an inhibitory T cell phenotype and modified dendritic cell (DC) phenotype in a gestation-dependent manner. We analyzed changes in surface markers of peripheral blood T cells, ex vivo antigen-specific T cell responses, indoleamine 2,3-dioxygenase (IDO) activity (kynurenine/tryptophan ratio, KTR), plasma neopterin concentration, and the in vitro expression of progesterone-induced blocking factor (PIBF) in response to peripheral blood mononuclear cell culture with progesterone. We found that mid gestation is characterized by reduced antigen-specific T cell responses associated with (1) predominance of effector memory over other T cell subsets; (2) upregulation of inhibitory markers (programmed death ligand 1); (3) heightened response to progesterone (PIBF); and (4) reduced proportions of myeloid DC and concurrent IDO activity (KTR). Conversely, antigen-specific T cell responses normalized in late pregnancy and were associated with increased markers of T cell activation (CD38, neopterin). However, these changes occur with a simultaneous upregulation of immune suppressive mechanisms including apoptosis (CD95), coinhibition (TIM-3), and immune regulation (IL-10) through the course of pregnancy. Together, our data suggest that immune tolerance dominates in the second trimester and that it is gradually reversed in the third trimester in association with immune activation as the end of pregnancy approaches. PMID:28966619

  8. Changes in T Cell and Dendritic Cell Phenotype from Mid to Late Pregnancy Are Indicative of a Shift from Immune Tolerance to Immune Activation.

    PubMed

    Shah, Nishel Mohan; Herasimtschuk, Anna A; Boasso, Adriano; Benlahrech, Adel; Fuchs, Dietmar; Imami, Nesrina; Johnson, Mark R

    2017-01-01

    During pregnancy, the mother allows the immunologically distinct fetoplacental unit to develop and grow. Opinions are divided as to whether this represents a state of fetal-specific tolerance or of a generalized suppression of the maternal immune system. We hypothesized that antigen-specific T cell responses are modulated by an inhibitory T cell phenotype and modified dendritic cell (DC) phenotype in a gestation-dependent manner. We analyzed changes in surface markers of peripheral blood T cells, ex vivo antigen-specific T cell responses, indoleamine 2,3-dioxygenase (IDO) activity (kynurenine/tryptophan ratio, KTR), plasma neopterin concentration, and the in vitro expression of progesterone-induced blocking factor (PIBF) in response to peripheral blood mononuclear cell culture with progesterone. We found that mid gestation is characterized by reduced antigen-specific T cell responses associated with (1) predominance of effector memory over other T cell subsets; (2) upregulation of inhibitory markers (programmed death ligand 1); (3) heightened response to progesterone (PIBF); and (4) reduced proportions of myeloid DC and concurrent IDO activity (KTR). Conversely, antigen-specific T cell responses normalized in late pregnancy and were associated with increased markers of T cell activation (CD38, neopterin). However, these changes occur with a simultaneous upregulation of immune suppressive mechanisms including apoptosis (CD95), coinhibition (TIM-3), and immune regulation (IL-10) through the course of pregnancy. Together, our data suggest that immune tolerance dominates in the second trimester and that it is gradually reversed in the third trimester in association with immune activation as the end of pregnancy approaches.

  9. 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.

  10. 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

  11. Direct regulatory immune activity of lactic acid bacteria on Der p 1-pulsed dendritic cells from allergic patients.

    PubMed

    Pochard, Pierre; Hammad, Hamida; Ratajczak, Céline; Charbonnier-Hatzfeld, Anne-Sophie; Just, Nicolas; Tonnel, André-Bernard; Pestel, Joël

    2005-07-01

    Lactic acid bacteria (LAB) are suggested to play a regulatory role in the development of allergic reactions. However, their potential effects on dendritic cells (DCs) directing the immune polarization remain unclear. The immunologic effect of Lactobacillus plantarum NCIMB 8826 (LAB1) on monocyte-derived dendritic cells (MD-DCs) from patients allergic to house dust mite was evaluated. MD-DCs were stimulated for 24 hours with the related allergen Der p 1 in the presence or absence of LAB1. Cell-surface markers were assessed by means of FACS analysis, and the key polarizing cytokines IL-12 and IL-10 were quantified. The subsequent regulatory effect of pulsed MD-DCs on naive or memory T cells was evaluated by determining the T-cell cytokine profile. LAB1 induced the maturation of MD-DCs, even if pulsed with Der p 1. Interestingly, after incubation with LAB1 and Der p 1, MD-DCs produced higher amounts of IL-12 than Der p 1-pulsed DCs. Indeed, the T H 2 cytokine (IL-4 and IL-5) production observed when naive or memory autologous T cells were cocultured with Der p 1-pulsed MD-DCs was highly reduced in the presence of LAB1. Finally, in contrast to naive or memory T cells exposed once to Der p 1-pulsed DCs, T cells stimulated by MD-DCs pulsed with Der p 1 and LAB1 failed to produce T H 2 cytokines in response to a new stimulation with Der p 1-pulsed DCs. Thus in the presence of LAB1, MD-DCs from allergic patients tend to reorientate the T-cell response toward a beneficial T H 1 profile.

  12. Propolis modulates miRNAs involved in TLR-4 pathway, NF-κB activation, cytokine production and in the bactericidal activity of human dendritic cells.

    PubMed

    Conti, Bruno J; Santiago, Karina B; Cardoso, Eliza O; Freire, Paula P; Carvalho, Robson F; Golim, Marjorie A; Sforcin, José M

    2016-12-01

    Dendritic cells (DCs) are antigen-presenting cells, essential for recognition and presentation of pathogens to T cells. Propolis, a resinous material produced by bees from various plants, exhibits numerous biological properties, highlighting its immunomodulatory action. Here, we assayed the effects of propolis on the maturation and function of human DCs. DCs were generated from human monocytes and incubated with propolis and LPS. NF-κB and cytokines production were determined by ELISA. microRNA's expression was analysed by RT-qPCR and cell markers detection by flow cytometry. Colony-forming units were obtained to assess the bactericidal activity of propolis-treated DCs. Propolis activated DCs in the presence of LPS, inducing NF-kB, TNF-α, IL-6 and IL-10 production. The inhibition of hsa-miR-148a and hsa-miR-148b abolished the inhibitory effects on HLA-DR and pro-inflammatory cytokines. The increased expression of hsa-miR-155 may be correlated to the increase in TLR-4 and CD86 expression, maintaining LPS-induced expression of HLA-DR and CD40. Such parameters may be involved in the increased bactericidal activity of DCs against Streptococcus mutans. Propolis modulated the maturation and function of DCs and may be useful in the initial steps of the immune response, providing a novel approach to the development of DC-based strategies and for the discovery of new immunomodulators. © 2016 Royal Pharmaceutical Society.

  13. 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

  14. Acetylcorynoline Impairs the Maturation of Mouse Bone Marrow-Derived Dendritic Cells via Suppression of IκB Kinase and Mitogen-Activated Protein Kinase Activities

    PubMed Central

    Fu, Ru-Huei; Wang, Yu-Chi; Liu, Shih-Ping; Chu, Ching-Liang; Tsai, Rong-Tzong; Ho, Yu-Chen; Chang, Wen-Lin; Chiu, Shao-Chih; Harn, Horng-Jyh; Shyu, Woei-Cherng; Lin, Shinn-Zong

    2013-01-01

    Background Dendritic cells (DCs) are major modulators in the immune system. One active field of research is the manipulation of DCs as pharmacological targets to screen novel biological modifiers for the treatment of inflammatory and autoimmune disorders. Acetylcorynoline is the major alkaloid component derived from Corydalis bungeana herbs. We assessed the capability of acetylcorynoline to regulate lipopolysaccharide (LPS)-stimulated activation of mouse bone marrow-derived DCs. Methodology/Principal Findings Our experimental data showed that treatment with up to 20 µM acetylcorynoline does not cause cytotoxicity in cells. Acetylcorynoline significantly inhibited the secretion of tumor necrosis factor-α, interleukin-6, and interleukin-12p70 by LPS-stimulated DCs. The expression of LPS-induced major histocompatibility complex class II, CD40, and CD86 on DCs was also decreased by acetylcorynoline, and the endocytic capacity of LPS-stimulated DCs was restored by acetylcorynoline. In addition, LPS-stimulated DC-elicited allogeneic T-cell proliferation was blocked by acetylcorynoline, and the migratory ability of LPS-stimulated DCs was reduced by acetylcorynoline. Moreover, acetylcorynoline significantly inhibits LPS-induced activation of IκB kinase and mitogen-activated protein kinase. Importantly, administration of acetylcorynoline significantly attenuates 2,4-dinitro-1-fluorobenzene-induced delayed-type hypersensitivity. Conclusions/Significance Acetylcorynoline may be one of the potent immunosuppressive agents through the blockage of DC maturation and function. PMID:23472193

  15. Salidroside liposome formulation enhances the activity of dendritic cells and immune responses.

    PubMed

    Zhao, Xiaojuan; Lu, Yu; Tao, Yang; Huang, Yee; Wang, Deyun; Hu, Yuanliang; Liu, Jiaguo; Wu, Yi; Yu, Yun; Liu, Cui

    2013-12-01

    Salidroside, the important composition, of Rhodiola rosea L. has been reported to have various pharmacological properties. Liposome is known to be effective as drug carriers and immune adjuvant. Therefore, the aim of this study is to investigate immunological adjuvant activity of salidroside liposome. Here we reported the preparation, the effect on DCs in vitro and the immune response in vivo. The immunological adjuvant activity of salidroside liposome formulation was compared with that of salidroside and liposome. The result showed that salidroside liposome formulation not only could promote the maturation of DCs, the stimulation of DCs on MLR proliferation and the antigen presenting ability, but also induced the sustained cellular immune and humoral immune response. Overall, the results showed that salidroside liposome formulation had the potential to act as effective sustained release vaccine delivery systems. © 2013.

  16. 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.

  17. 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

  18. 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

  19. Urban particulate matter suppresses priming of T helper type 1 cells by granulocyte/macrophage colony-stimulating factor-activated human dendritic cells.

    PubMed

    Matthews, Nick C; Faith, Alex; Pfeffer, Paul; Lu, Haw; Kelly, Frank J; Hawrylowicz, Catherine M; Lee, Tak H

    2014-02-01

    Urban particulate matter (UPM) exacerbates asthmatic lung inflammation and depresses lung immunity. Lung dendritic cells (DCs) react to airway particulates, and have a critical role in linking innate and adaptive immunity, but the direct effects of UPM on DCs, that have been activated by granulocyte/macrophage colony-stimulating factor (GM-CSF), a product of stimulated normal human bronchial epithelial cells, has not been investigated. Human blood CD1c(+) DCs were purified and activated with UPM in the presence or absence of GM-CSF with and without LPS, and DC maturation was assessed by flow cytometry. DC stimulatory capacity and priming of 5-(and -6)-carboxyfluorescein diacetate succinimidyl ester-labeled naive CD4 T cells was investigated using the allogeneic mixed lymphocyte reaction. T cell proliferation and effector function were assessed using flow cytometry and secreted cytokines were measured by combined bead array. UPM enhanced DC maturation in an LPS-independent manner. DCs activated by UPM plus GM-CSF (UPM + GM-CSF DCs) induced higher naive CD4 T cell proliferation in the allogeneic mixed lymphocyte reaction than DCs pretreated by GM-CSF alone (GM-CSF DCs), and elicited both substantially lower levels of IFN-γ, IL-13, and IL-5 secretion, and lower frequencies of alloantigen-specific T helper (Th) type 1 effector cells than naive CD4 T cells primed by GM-CSF DCs. UPM-stimulated DCs produced IL-6 and TNF-α. Neutralization of IL-6 decreased naive CD4 T cell proliferation stimulated by UPM + GM-CSF DCs, and significantly increased the frequency of alloantigen-specific Th1 effector cells, but did not reverse UPM-induced inhibition of IFN-γ secretion. We conclude that UPM enhances GM-CSF-induced DC maturation and stimulatory capacity, but inhibits the generation of Th1 cells. Thus, UPM exposure may impair Th1 responses to pulmonary pathogens.

  20. Engineering Dendritic Cells to Enhance Cancer Immunotherapy

    PubMed Central

    Boudreau, Jeanette E; Bonehill, Aude; Thielemans, Kris; Wan, Yonghong

    2011-01-01

    Cancer immunotherapy aims to establish immune-mediated control of tumor growth by priming T-cell responses to target tumor-associated antigens. Three signals are required for T-cell activation: (i) presentation of cognate antigen in self MHC molecules; (ii) costimulation by membrane-bound receptor-ligand pairs; and (iii) soluble factors to direct polarization of the ensuing immune response. The ability of dendritic cells (DCs) to provide all three signals required for T-cell activation makes them an ideal cancer vaccine platform. Several strategies have been developed to enhance and control antigen presentation, costimulation, and cytokine production. In this review, we discuss progress toward developing DC-based cancer vaccines by genetic modification using RNA, DNA, and recombinant viruses. Furthermore, the ability of DC-based vaccines to activate natural killer (NK) and B-cells, and the impact of gene modification strategies on these populations is described. Clinical trials using gene-modified DCs have shown modest results, therefore, further considerations for DC manipulation to enhance their clinical efficacy are also discussed. PMID:21468005

  1. 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

  2. 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

  3. The ATP-binding cassette transporter A1 regulates phosphoantigen release and Vγ9Vδ2 T cell activation by dendritic cells

    PubMed Central

    Castella, Barbara; Kopecka, Joanna; Sciancalepore, Patrizia; Mandili, Giorgia; Foglietta, Myriam; Mitro, Nico; Caruso, Donatella; Novelli, Francesco; Riganti, Chiara; Massaia, Massimo

    2017-01-01

    Vγ9Vδ2 T cells are activated by phosphoantigens, such as isopentenyl pyrophosphate (IPP), which is generated in the mevalonate pathway of antigen-presenting cells. IPP is released in the extracellular microenvironment via unknown mechanisms. Here we show that the ATP-binding cassette transporter A1 (ABCA1) mediates extracellular IPP release from dendritic cells (DC) in cooperation with apolipoprotein A-I (apoA-I) and butyrophilin-3A1. IPP concentrations in the supernatants are sufficient to induce Vγ9Vδ2 T cell proliferation after DC mevalonate pathway inhibition with zoledronic acid (ZA). ZA treatment increases ABCA1 and apoA-I expression via IPP-dependent LXRα nuclear translocation and PI3K/Akt/mTOR pathway inhibition. These results close the mechanistic gap in our understanding of extracellular IPP release from DC and provide a framework to fine-tune Vγ9Vδ2 T cell activation via mevalonate and PI3K/Akt/mTOR pathway modulation. PMID:28580927

  4. Critical role of dendritic cell-derived IL-27 in antitumor immunity through regulating the recruitment and activation of NK and NKT cells.

    PubMed

    Wei, Jun; Xia, Siyuan; Sun, Huayan; Zhang, Song; Wang, Jingya; Zhao, Huiyuan; Wu, Xiaoli; Chen, Xi; Hao, Jianlei; Zhou, Xinglong; Zhu, Zhengmao; Gao, Xiang; Gao, Jian-xin; Wang, Puyue; Wu, Zhenzhou; Zhao, Liqing; Yin, Zhinan

    2013-07-01

    Critical roles of IL-27 in autoimmune diseases and infections have been reported; however, the contribution of endogenous IL-27 to tumor progression remains elusive. In this study, by using IL-27p28 conditional knockout mice, we demonstrate that IL-27 is critical in protective immune response against methyl-cholanthrene-induced fibrosarcoma and transplanted B16 melanoma, and dendritic cells (DCs) are the primary source. DC-derived IL-27 is required for shaping tumor microenvironment by inducing CXCL-10 expression in myeloid-derived suppressor cells and regulating IL-12 production from DCs, which lead to the recruitment and activation of NK and NKT cells resulting in immunological control of tumors. Indeed, reconstitution of IL-27 or CXCL-10 in tumor site significantly inhibits tumor growth and restores the number and activation of NK and NKT cells. In summary, our study identifies a previous unknown critical role of DC-derived IL-27 in NK and NKT cell-dependent antitumor immunity through shaping tumor microenvironment, and sheds light on developing novel therapeutic approaches based on IL-27.

  5. 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

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. Pimecrolimus inhibits up-regulation of OX40 and synthesis of inflammatory cytokines upon secondary T cell activation by allogeneic dendritic cells

    PubMed Central

    KALTHOFF, F S; CHUNG, J; STUETZ, A

    2002-01-01

    Pimecrolimus is a new non-steroidal inhibitor of T cell and mast cell activation. In the present study, we compared the potency of pimecrolimus and cyclosporin A (CyA) to inhibit cytokine synthesis of alloantigen-primed T cells and the expression of CD134 (OX40), an inducible co-receptor molecule thought to be critical for the survival and expansion of inflammation-mediating T cells. To mimic the physiological situation of recurrent antigenic stimulation, we have used dendritic cells (DC) as stimulators of purified CD4+ T cells in the primary and secondary allogeneic mixed lymphocyte culture (allo-MLC). Pimecrolimus inhibited surface expression of OX40 and prevented the up-regulation of CD25 and CD54 with a 10-fold higher potency compared to CyA. Similarly, 50% inhibition of allo-DC-mediated T cell proliferation by pimecrolimus was obtained at 0·55 nm, compared to about 12 nm for CyA. Furthermore, pimecrolimus blocked the increase of OX40 on primed T cells restimulated on day 10 in secondary allo-MLC. Allo-DC-primed T cells showed a restricted cytokine profile characterized by the production of TNF-α, IFN-γ and IL-2 but low to undetectable levels of IL-4 and IL-10. The synthesis of TNF-α and IFN-γ and the up-regulation of OX40 on T cells after secondary allogeneic stimulation were almost entirely blocked by 10 nm pimecrolimus. Taken together, pimecrolimus inhibits T cell proliferation and Th1 cytokine synthesis and also prevents the up-regulation of the OX40 co-receptor on primed T cells indicating its potential in the therapy of chronic inflammation and autoimmunity. PMID:12296857

  11. ISOLATION OF CHICKEN FOLLICULAR DENDRITIC CELLS

    USDA-ARS?s Scientific Manuscript database

    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...

  12. Engagement of Toll-like receptor 2 enhances interleukin (IL)-17(+) autoreactive T cell responses via p38 mitogen-activated protein kinase signalling in dendritic cells.

    PubMed

    Wei, R; Dong, L; Xiao, Q; Sun, D; Li, X; Nian, H

    2014-11-01

    Functional analysis of single Toll-like receptors (TLRs) in vivo is necessary to understand how they shape the ocular inflammation involved in uveitis. In this study we explored the role and mechanisms of TLR-2 agonists on the autoreactive T helper type 17 (Th17) response in experimental autoimmune uveitis (EAU). Treatment by peptidoglycan (PGN), a specific TLR-2 agonist, remarkably increased mRNA levels of Th17-lineage genes interleukin (IL)-17A, IL-21 and RAR-related orphan receptor (ROR)γt and promoted antigen-specific Th17 response in EAU mice. A mixture of PGN and interphotoreceptor retinoid-binding protein peptide (IRBP161-180 ) could effectively induce EAU in the absence of complete Freund's adjuvant (CFA). PGN treatment also enhanced the pathogenic activities of activated antigen-specific Th17 cells in vivo. PGN significantly increased the production of IL-1β, IL-6 and IL-23 of dendritic cells (DCs) and enhanced their ability to promote IL-17(+) uveitogenic T cells. Enhanced immunostimulatory activities of PGN-DCs depend upon p38 activation. Inhibition of p38 mitogen-activated protein kinase (MAPK) activity dramatically decreased IL-17 gene expression and antigen-specific Th17 responses stimulated by PGN-DCs. Our findings suggest that PGN treatment dramatically promotes the IL-17(+) uveitogenic T cell responses via enhancing the immunostimulatory activities of DCs. This effect may be mediated, at least in part, by activation of the p38 signalling pathway in DCs. © 2014 British Society for Immunology.

  13. 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.

  14. 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.

  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. Cutting Edge: LL-37-Mediated Formyl Peptide Receptor-2 Signaling in Follicular Dendritic Cells Contributes to B Cell Activation in Peyer's Patch Germinal Centers.

    PubMed

    Kim, Sae-Hae; Kim, Yu Na; Jang, Yong-Suk

    2017-01-15

    Peyer's patches (PPs) are the major mucosal immune-inductive site, and germinal centers (GCs) in PPs determine the quality of the Abs produced. PP GCs are continuously induced by the gut microbiota, and their maintenance contributes to the induction of strong IgA responses to Ags. In this study, we investigated the role of formyl peptide receptor (FPR)-mediated signaling in the maintenance of PP GCs, because FPRs recognize the microbiota and initiate an innate immune response by chemotaxis. We found that follicular dendritic cells (FDCs), a key organizer of B cell follicles and GCs in mucosal immunity, express Fpr2. Additionally, Fpr2-mediated signaling in PP FDCs promoted Cxcl13 and B cell activating factor expression, as well as B cell proliferation and activation. Therefore, we suggest that Fpr2-mediated signaling in FDCs plays a key role in GC maintenance in PPs and results in an Ag-specific IgA response in the gut mucosal immune compartment. Copyright © 2017 by The American Association of Immunologists, Inc.

  17. 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.

  18. DOWN-REGULATION OF SIGNAL TRANSDUCER AND ACTIVATOR OF TRANSCRIPTION 3 IMPROVES HUMAN ACUTE MYELOID LEUKEMIA-DERIVED DENDRITIC CELL FUNCTION

    PubMed Central

    Brady, Michael T.; Miller, Austin; Sait, Sheila N.; Ford, Laurie A.; Minderman, Hans; Wang, Eunice S.; Lee, Kelvin P.; Baumann, Heinz; Wetzler, Meir

    2013-01-01

    Signal transducer and activator of transcription (STAT) 3 inhibits dendritic cell (DC) differentiation and is constitutively activated in blasts of approximately half of AML patients. We investigated the correlation between STAT3 activity, DC maturation and the ability to stimulate T-cells in primary acute myeloid leukemia (AML)-derived DCs. STAT3 knock-down by shRNAmir increased the ability of AML-DCs to stimulate T-cells. Treatment of AML-DC with arsenic trioxide, but not AG490, JSI-124 or NSC-74859, led to a more mature phenotype and enhanced T-cell stimulation, while having minimal effect on normal DC. We conclude that AML-DCs have improved immunogenicity after reducing STAT3. PMID:23628554

  19. Leukotrienes modulate cytokine release from dendritic cells.

    PubMed

    Jozefowski, Szczepan; Biedroń, Rafał; Bobek, Malgorzata; Marcinkiewicz, Janusz

    2005-12-01

    Leukotriene B(4) (LTB(4)) and cysteinyl leukotrienes (CysLTs) are known as potent mediators of inflammation, whereas their role in the regulation of adaptive immunity remains poorly characterized. Dendritic cells (DCs) are specialized antigen-presenting cells, uniquely capable to initiate primary immune responses. We have found that zymosan, but not lipopolysaccharide (LPS) stimulates murine bone marrow-derived dendritic cells (BM-DCs) to produce large amounts of CysLTs and LTB(4) from endogenous substrates. A selective inhibitor of leukotriene synthesis MK886 as well as an antagonist of the high affinity LTB(4) receptor (BLT(1)) U-75302 slightly inhibited zymosan-, but not LPS-stimulated interleukin (IL)-10 release from BM-DCs. In contrast, U-75302 increased zymosan-stimulated release of IL-12 p40 by approximately 23%. Pre-treatment with transforming growth factor-beta1 enhanced both stimulated leukotriene synthesis and the inhibitory effect of U-75302 and MK886 on IL-10 release from DCs. Consistent with the effects of leukotriene antagonists, exogenous LTB(4) enhanced LPS-stimulated IL-10 release by approximately 39% and inhibited IL-12 p40 release by approximately 22%. Both effects were mediated by the BLT(1) receptor. Ligands of the high affinity CysLTs receptor (CysLT(1)), MK-571 and LTD(4) had little or no effect on cytokine release. Agonists of the nuclear LTB(4) receptor peroxisome proliferator-activated receptor-alpha, 8(S)-hydroxyeicosatetraenoic acid and 5,8,11,14-eicosatetraynoic acid, inhibited release of both IL-12 p40 and IL-10. Our results indicate that both autocrine and paracrine leukotrienes may modulate cytokine release from DCs, in a manner that is consistent with previously reported T helper 2-polarizing effects of leukotrienes.

  20. Leukotrienes modulate cytokine release from dendritic cells

    PubMed Central

    Jozefowski, Szczepan; Biedroń, Rafał; Bobek, Malgorzata; Marcinkiewicz, Janusz

    2005-01-01

    Leukotriene B4 (LTB4) and cysteinyl leukotrienes (CysLTs) are known as potent mediators of inflammation, whereas their role in the regulation of adaptive immunity remains poorly characterized. Dendritic cells (DCs) are specialized antigen-presenting cells, uniquely capable to initiate primary immune responses. We have found that zymosan, but not lipopolysaccharide (LPS) stimulates murine bone marrow-derived dendritic cells (BM-DCs) to produce large amounts of CysLTs and LTB4 from endogenous substrates. A selective inhibitor of leukotriene synthesis MK886 as well as an antagonist of the high affinity LTB4 receptor (BLT1) U-75302 slightly inhibited zymosan-, but not LPS-stimulated interleukin (IL)-10 release from BM-DCs. In contrast, U-75302 increased zymosan-stimulated release of IL-12 p40 by ∼23%. Pre-treatment with transforming growth factor-β1 enhanced both stimulated leukotriene synthesis and the inhibitory effect of U-75302 and MK886 on IL-10 release from DCs. Consistent with the effects of leukotriene antagonists, exogenous LTB4 enhanced LPS-stimulated IL-10 release by ∼39% and inhibited IL-12 p40 release by ∼22%. Both effects were mediated by the BLT1 receptor. Ligands of the high affinity CysLTs receptor (CysLT1), MK-571 and LTD4 had little or no effect on cytokine release. Agonists of the nuclear LTB4 receptor peroxisome proliferator-activated receptor-α, 8(S)-hydroxyeicosatetraenoic acid and 5,8,11,14-eicosatetraynoic acid, inhibited release of both IL-12 p40 and IL-10. Our results indicate that both autocrine and paracrine leukotrienes may modulate cytokine release from DCs, in a manner that is consistent with previously reported T helper 2-polarizing effects of leukotrienes. PMID:16313356

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. Suppression of zinc dendrites in zinc electrode power cells

    NASA Technical Reports Server (NTRS)

    Damjanovic, A.; Diggle, J. W.

    1970-01-01

    Addition of various tetraalkyl quarternary ammonium salts, to alkaline zincate electrolyte of cell, prevents formation of zinc dendrites during charging of zinc electrode. Electrode capacity is not impaired and elimination of dendrites prolongs cell life.

  6. 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

  7. Inhibition of JAK/STAT pathway restrains TSLP-activated dendritic cells mediated inflammatory T helper type 2 cell response in allergic rhinitis.

    PubMed

    Shi, Zhaohui; Jiang, Weihong; Wang, Min; Wang, Xiaocheng; Li, Xiaoyuan; Chen, Xiaodong; Qiao, Li

    2017-06-01

    Thymic stromal lymphopoietin (TSLP) has recently been implicated as a key molecule for initiating allergic rhinitis (AR) at the cell-dendritic cell (DC) interface. Previous studies demonstrated that TSLP activated DCs to express more OX40 ligand (OX40L), which is associated with the initiation of T helper type 2 (Th2) cell responses. STAT phosphorylation has been reported to be promoted by TSLP. Thus, we investigated if the JAK/STAT pathway inhibitor CYT387 could affect TSLP-DC-mediated Th2 cell response in naive T cell and AR mice model. Western blot showed that the levels of phosphorylated JAK1, JAK2, STAT1, STAT3, and STAT5 were increased in TSLP-DCs, which can be offset by CYT387. Flow cytometry indicated that CYT387 had obviously down-regulated the surface maturation co-stimulatory molecules (CD11c, CD80, CD86, and MHCII) in DCs, which were increased by TSLP. Moreover, CYT387 markedly reduced the ability of TSLP-DCs to promote the differentiation of naive CD4(+) T cells into IL-4-expressing Th2 cells. The histological examination showed that the CYT387-treated group showed less epithelial disruption, epithelial cell proliferation, and reduced eosinophil infiltration compared with AR group. Western blot and RT-PCR demonstrated that the expression of OX40L was increased in AR mice, but that it was decreased by CYT387. Furthermore, CYT387 treatment resulted in the reduction of IL-4 and IL-5 expression and increased IFN-γ level in AR mice, which was consistent with the levels of intracellular cytokine in Th2 cell. In conclusion, we suggest that blockading the JAK/STAT pathway restrains inflammatory Th2 cell response induced by TSLP-DCs in AR.

  8. 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.

  9. 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

  10. TLR3 is required for survival following Coxsackievirus B3 infection by driving T lymphocyte activation and polarization: The role of dendritic cells.

    PubMed

    Sesti-Costa, Renata; Françozo, Marcela Cristina Santiago; Silva, Grace Kelly; Proenca-Modena, José Luiz; Silva, João Santana

    2017-01-01

    Type B coxsackievirus (CVB) is a common cause of acute and chronic myocarditis, meningitis and pancreatitis, often leading to heart failure and pancreatic deficiency. The polarization of CD4+ T lymphocytes and their cytokine milieu are key factors in the outcome of CVB-induced diseases. Thus, sensing the virus and driving the adaptive immune response are essential for the establishment of a protective immune response. TLR3 is a crucial virus recognition receptor that confers the host with resistance to CVB infection. In the current study, we found that TLR3 expression in dendritic cells plays a role in their activation upon CVB3 infection in vitro, as TLR3-deficient dendritic cells up-regulate CD80 and CD86 to a less degree than WT cells. Instead, they up-regulated the inhibitory molecule PD-L1 and secreted considerably lower levels of TNF-α and IL-10 and a higher level of IL-23. T lymphocyte proliferation in co-culture with CVB3-infected dendritic cells was increased by TLR3-expressing DCs and other cells. Furthermore, in the absence of TLR3, the T lymphocyte response was shifted toward a Th17 profile, which was previously reported to be deleterious for the host. TLR3-deficient mice were very susceptible to CVB3 infection, with increased pancreatic injury and extensive inflammatory infiltrate in the heart that was associated with uncontrolled viral replication. Adoptive transfer of TLR3+ dendritic cells slightly improved the survival of TLR-deficient mice following CVB3 infection. Therefore, our findings highlight the importance of TLR3 signaling in DCs and in other cells to induce activation and polarization of the CD4+ T lymphocyte response toward a Th1 profile and consequently for a better outcome of CVB3 infection. These data provide new insight into the immune-mediated mechanisms by which CVBs are recognized and cleared in order to prevent the development of myocarditis and pancreatitis and may contribute to the design of therapies for enteroviral infections.

  11. 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.

  12. Aqueous extracts from Menyanthes trifoliate and Achillea millefolium affect maturation of human dendritic cells and their activation of allogeneic CD4+ T cells in vitro.

    PubMed

    Jonsdottir, Gudbjorg; Omarsdottir, Sesselja; Vikingsson, Arnor; Hardardottir, Ingibjorg; Freysdottir, Jona

    2011-06-14

    Menyanthes trifoliate and Achillea millefolium have been used in traditional medicine to ameliorate chronic inflammatory conditions. The aim of this study was to identify the effects of ethanol and aqueous extracts of Menyanthes trifoliate and Achillea millefolium on maturation of dendritic cells (DCs) and their ability to activate allogeneic CD4(+) T cells. Human monocyte-derived DCs were matured in the absence or presence of lyophilised aqoueous or ethanol extracts from Menyanthes trifoliate or Achillea millefolium and their expression of surface molecules analysed with flow cytometry and cytokine secretion measured by ELISA. DCs matured in the presence of aqueous extracts from Menyanthes trifoliate and Achillea millefolium were co-cultured with allogeneic CD4(+) T cells and the expression of surface molecules by T cells and their cytokine secretion and cell proliferation determined. Maturation of DCs in the presence of aqueous extracts from Menyanthes trifoliate or Achillea millefolium did not affect expression of the surface molecules examined but reduced the ratio of secreted IL-12p40/IL-10, compared with that by DCs matured in the absence of extracts. Allogeneic CD4(+) T cells co-cultured with DCs matured in the presence of aqueous extract from Menyanthes trifoliate secreted less IFN-γ, IL-10 and IL-17 than CD4(+) T cells co-cultured with DCs matured without an extract. Maturation of DCs in the presence of aqueous extract from Achillea millefolium decreased IL-17 secretion but did not affect IFN-γ and IL-10 secretion by allogeneic CD4(+) T cells. Aqueous extract from Menyanthes trifoliate induces a suppressive phenotype of DCs that has reduced capacity to induce Th1 and Th17 stimulation of allogeneic CD4(+) T cells, whereas aqueous extract from Achillea millefolium reduces the capacity of DCs to induce a Th17 response. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  13. Travelling waves in a model of quasi-active dendrites with active spines

    NASA Astrophysics Data System (ADS)

    Timofeeva, Y.

    2010-05-01

    Dendrites, the major components of neurons, have many different types of branching structures and are involved in receiving and integrating thousands of synaptic inputs from other neurons. Dendritic spines with excitable channels can be present in large densities on the dendrites of many cells. The recently proposed Spike-Diffuse-Spike (SDS) model that is described by a system of point hot-spots (with an integrate-and-fire process) embedded throughout a passive tree has been shown to provide a reasonable caricature of a dendritic tree with supra-threshold dynamics. Interestingly, real dendrites equipped with voltage-gated ion channels can exhibit not only supra-threshold responses, but also sub-threshold dynamics. This sub-threshold resonant-like oscillatory behaviour has already been shown to be adequately described by a quasi-active membrane. In this paper we introduce a mathematical model of a branched dendritic tree based upon a generalisation of the SDS model where the active spines are assumed to be distributed along a quasi-active dendritic structure. We demonstrate how solitary and periodic travelling wave solutions can be constructed for both continuous and discrete spine distributions. In both cases the speed of such waves is calculated as a function of system parameters. We also illustrate that the model can be naturally generalised to an arbitrary branched dendritic geometry whilst remaining computationally simple. The spatio-temporal patterns of neuronal activity are shown to be significantly influenced by the properties of the quasi-active membrane. Active (sub- and supra-threshold) properties of dendrites are known to vary considerably among cell types and animal species, and this theoretical framework can be used in studying the combined role of complex dendritic morphologies and active conductances in rich neuronal dynamics.

  14. Anti-inflammatory activity on LPS-stimulated dendritic cells of lupanetype triterpenoids from the leaves of Acanthopanax koreanum.

    PubMed

    Nhiem, Nguyen Xuan; Kiem, Phan Van; Minh, Chau Van; Tai, Bui Huu; Quang, Tran Hong; Soung, Kwang Su; Koo, Jung-Eun; Koh, Young-Sang; Kim, Young Ho

    2011-10-01

    Acanthopanax koreanum is well known herb in traditional Korean, Chinese, and Japanese anti-inflammatory action without any adverse effects. In the current study, we investigated the inhibitory effects of isolated compounds 1-13 from the leaves of A. koreanum on the lipopolysaccharide-stimulated production of pro-inflammatory cytokines in bone marrow-derived dendritic cells. Of these lupane-type triterpenoids, 1 exhibited particularly high inhibitory effect on lipopolysaccharide-stimulated TNF-α, IL-6, and IL-12 production with the values ranging from 45.0 to 84.5% at a concentration of 50 μM. These results warrant further studies concerning the potential anti-inflammatory benefits of medicinal foods containing the leaves of A. koreanum.

  15. Cetuximab-activated natural killer and dendritic cells collaborate to trigger tumor antigen-specific T-cell immunity in head and neck cancer patients.

    PubMed

    Srivastava, Raghvendra M; Lee, Steve C; Andrade Filho, Pedro A; Lord, Christopher A; Jie, Hyun-Bae; Davidson, H Carter; López-Albaitero, Andrés; Gibson, Sandra P; Gooding, William E; Ferrone, Soldano; Ferris, Robert L

    2013-04-01

    Tumor antigen-specific monoclonal antibodies (mAb) block oncogenic signaling and induce Fcγ receptor (FcγR)-mediated cytotoxicity. However, the role of CD8(+) CTL and FcγR in initiating innate and adaptive immune responses in mAb-treated human patients with cancer is still emerging. FcγRIIIa codon 158 polymorphism was correlated with survival in 107 cetuximab-treated patients with head and neck cancer (HNC). Flow cytometry was carried out to quantify EGF receptor (EGFR)-specific T cells in cetuximab-treated patients with HNC. The effect of cetuximab on natural killer (NK) cell, dendritic cell (DC), and T-cell activation was measured using IFN-γ release assays and flow cytometry. FcγRIIIa polymorphism did not predict clinical outcome in cetuximab-treated patients with HNC; however, elevated circulating EGFR(853-861)-specific CD8(+) T cells were found in cetuximab-treated patients with HNC (P < 0.005). Cetuximab promoted EGFR-specific cellular immunity through the interaction of EGFR(+) tumor cells and FcγRIIIa on NK cells but not on the polymorphism per se. Cetuximab-activated NK cells induced IFN-γ-dependent expression of DC maturation markers, antigen processing machinery components such as TAP-1/2 and T-helper cell (T(H)1) chemokines through NKG2D/MICA binding. Cetuximab initiated adaptive immune responses via NK cell-induced DC maturation, which enhanced cross-presentation to CTL specific for EGFR as well as another tumor antigen, MAGE-3. Cetuximab-activated NK cells promote DC maturation and CD8(+) T-cell priming, leading to tumor antigen spreading and TH1 cytokine release through "NK-DC cross-talk." FcγRIIIa polymorphism did not predict clinical response to cetuximab but was necessary for NK-DC interaction and mAb-induced cross-presentation. EGFR-specific T cells in cetuximab-treated patients with HNC may contribute to clinical response. ©2013 AACR.

  16. 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

  17. Characterization of a novel maitake (Grifola frondosa) protein that activates natural killer and dendritic cells and enhances antitumor immunity in mice.

    PubMed

    Tsao, Yao-Wei; Kuan, Yen-Chou; Wang, Jia-Lin; Sheu, Fuu

    2013-10-16

    Grifola frondosa, also known as maitake, is a culinary mushroom with immune-enhancing and antitumor effects. Numerous studies have investigated the activity of maitake polysaccharide extracts, but studies of maitake proteins are scarce. In this study, we purified and characterized a new G. frondosa protein, GFP, from maitake fruiting bodies. GFP is a nonglucan heterodimeric 83 kDa protein that consists of two 41 kDa subunits. GFP induced interferon-γ secretion by murine splenocytes and natural killer cells and activated the maturation of bone marrow-derived dendritic cells (BMDCs) via a TLR4-dependent mechanism. GFP-treated BMDCs promoted a Th1 response and exhibited significant antitumor activity when transferred into tumor-bearing mice. In conclusion, we are the first to reveal the critical role of GFP in modulating the immune response and to link the immune-enhancing effects of maitake to its antitumor activities.

  18. 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.

  19. 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.

  20. 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.

  1. Characterization of chicken dendritic cell markers

    USDA-ARS?s Scientific Manuscript database

    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 ...

  2. 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

  3. 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.

  4. 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

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

    PubMed

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

    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.

  6. 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

  7. 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.

  8. Phase I trial of active specific immunotherapy with autologous dendritic cells pulsed with autologous irradiated tumor stem cells in hepatitis B-positive patients with hepatocellular carcinoma.

    PubMed

    Wang, Xiaojin; Bayer, Michael E; Chen, Xiaosong; Fredrickson, Craig; Cornforth, Andrew N; Liang, Greg; Cannon, Jessica; He, Jia; Fu, Qingchun; Liu, Jia; Nistor, Gabriel I; Cao, Wei; Chen, Chengwei; Dillman, Robert O

    2015-06-01

    Hepatocellular carcinoma (HCC) is often associated with chronic hepatitis due to hepatitis-B or -C viruses. Active specific immunotherapy (ASI) with autologous dendritic cells (DC) presenting antigens from autologous tumor stem cell (TC) lines is associated with promising long-term survival in metastatic cancer, but hepatitis patients were excluded. ASI might benefit high-risk primary HCC patients following surgical resection, but first it is important to show that ASI does not exacerbate hepatitis. Previously untreated HCC patients with a solitary lesion > 5 cm, or three lesions with at least one > 3 cm, or more than three lesions, underwent surgical resection from which autologous TC lines were established. Irradiated TC were incubated with autologous DC to create DC-TC. After one course of trans-arterial chemoembolization therapy (TACE), three weekly subcutaneous injections of DC-TC suspended in granulocyte-macrophage colony stimulating factor were administered. Patients were monitored for eight weeks. HCC cell lines were established within five weeks for 15/15 patients. Eight patients, all with chronic hepatitis B, were treated. There was no increase in hepatic transaminases, hepatitis B antigens, or viral DNA. Autologous DC-TC did not exacerbate HBV in these HCC patients. A phase II efficacy trial is being planned. © 2015 Wiley Periodicals, Inc.

  9. Toxoplasma gondii triggers phosphorylation and nuclear translocation of dendritic cell STAT1 while simultaneously blocking IFNγ-induced STAT1 transcriptional activity.

    PubMed

    Schneider, Anne G; Abi Abdallah, Delbert S; Butcher, Barbara A; Denkers, Eric Y

    2013-01-01

    The protozoan Toxoplasma gondii actively modulates cytokine-induced JAK/STAT signaling pathways to facilitate survival within the host, including blocking IFNγ-mediated STAT1-dependent proinflammatory gene expression. We sought to further characterize inhibition of STAT1 signaling in infected murine dendritic cells (DC) because this cell type has not previously been examined, yet is known to serve as an early target of in vivo infection. Unexpectedly, we discovered that T. gondii infection alone induced sustained STAT1 phosphorylation and nuclear translocation in DC in a parasite strain-independent manner. Maintenance of STAT1 phosphorylation required active invasion but intracellular parasite replication was dispensable. The parasite rhoptry protein ROP16, recently shown to mediate STAT3 and STAT6 phosphorylation, was not required for STAT1 phosphorylation. In combination with IFNγ, T. gondii induced synergistic STAT1 phosphorylation and binding of aberrant STAT1-containing complexes to IFNγ consensus sequence oligonucleotides. Despite these findings, parasite infection blocked STAT1 binding to the native promoters of the IFNγ-inducible genes Irf-1 and Lrg47, along with subsequent gene expression. These results reinforce the importance of parasite-mediated blockade of IFNγ responses in dendritic cells, while simultaneously showing that T. gondii alone induces STAT1 phosphorylation.

  10. [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.

  11. Caspase-8 Acts as a Molecular Rheostat to Limit RIPK1- and MyD88-Mediated Dendritic Cell Activation1

    PubMed Central

    Cuda, Carla M.; Misharin, Alexander V.; Gierut, Angelica K.; Saber, Rana; Haines, G. Kenneth; Hutcheson, Jack; Hedrick, Stephen M.; Mohan, Chandra; Budinger, G. Scott; Stehlik, Christian; Perlman, Harris

    2014-01-01

    Caspase-8, an executioner enzyme in the death receptor pathway, has previously been shown to initiate apoptosis and suppress necroptosis. Here, we identify a novel, cell death-independent role for caspase-8 in dendritic cells (DCs); namely, DC-specific expression of caspase-8 prevents the onset of systemic autoimmunity. Failure to express caspase-8 has no effect on the life-span of DCs but instead leads to an enhanced intrinsic activation and subsequently more mature and autoreactive lymphocytes. Uncontrolled toll-like receptor activation in a RIPK1-dependent manner is responsible for the enhanced functionality of caspase-8-deficient DCs, as deletion of TLR signaling mediator, MyD88, ameliorates systemic autoimmunity induced by caspase-8 deficiency. Taken together, these data demonstrate that caspase-8 functions in a cell-type-specific manner and acts uniquely in DCs to maintain tolerance. PMID:24808358

  12. 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

  13. S100-positive dendritic cells in squamous cell laryngeal cancer.

    PubMed

    Diaconescu, Daniela Eugenia; Dima, Lorena; Marinescu, Daniela Maria; Ţânţu, Marilena Monica; Rogozea, Liliana Marcela

    2014-01-01

    Dendritic cells (DC) are the most potent antigen-presenting cells, and induce antigen-specific immune responses. DC are believed to evolve into tumor-antigen pulsed cells and then to migrate to local lymph nodes, where they activate anti-tumor immune responses. This theory is supported by studies showing that high DC densities are associated with favorable prognosis in some tumor types. In the present study, we evaluated 40 primary and metastatic laryngeal carcinomas for the presence of DC, using immunohistochemistry with the anti-S100 protein antibody. We analyzed the relationship between the degree of infiltration by S100-positive (S100+) DC and prognostic factors, including histological subtype, histological grade, peritumor inflammatory infiltration, and stromal desmoplasia. The results show that in all evaluated laryngeal cancers S100-positive cells were significantly more frequent in the tumor stroma. Primary tumors with nodal metastases showed more significant differences in intraepithelial and stromal DC distribution than tumors without nodal metastases. A significant higher S100+ DC was also noticed in the desmoplasic stroma of lymph nodes. The subtype with keratinization had a significant higher S100-positive cells infiltration than the adenoid÷transitional subtype. The infiltration rate of intraepithelial S100+ DC was much higher in well-differentiated (G1) tumors. No significant correlation between S100-positive cells and peritumoral inflammatory infiltration and stromal desmoplasia was found. In conclusion, dendritic cells need multiple, much more complex investigations. This work should be regarded as a preliminary investigation.

  14. 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

  15. 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

  16. Tumor's other immune targets: dendritic cells.

    PubMed

    Esche, C; Lokshin, A; Shurin, G V; Gastman, B R; Rabinowich, H; Watkins, S C; Lotze, M T; Shurin, M R

    1999-08-01

    The induction of apoptosis in T cells is one of several mechanisms by which tumors escape immune recognition. We have investigated whether tumors induce apoptosis in dendritic cells (DC) by co-culture of murine or human DC with different tumor cell lines for 4-48 h. Analysis of DC morphological features, JAM assay, TUNEL, caspase-3-like and transglutaminase activity, Annexin V binding, and DNA fragmentation assays revealed a time- and dose-dependent induction of apoptosis in DC by tumor-derived factors. This finding is both effector and target specific. The mechanism of tumor-induced DC apoptosis involved regulation of Bcl-2 and Bax expression. Double staining of both murine and human tumor tissues confirmed that tumor-associated DC undergo apoptotic death in vivo. DC isolated from tumor tissue showed significantly higher levels of apoptosis as determined by TUNEL assay when compared with DC isolated from spleen. These findings demonstrate that tumors induce apoptosis in DC and suggest a new mechanism of tumor escape from immune recognition. DC protection from apoptosis will lead to improvement of DC-based immunotherapies for cancer and other immune diseases.

  17. 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

  18. Monocyte-derived dendritic cells from patients with dermatophytosis restrict the growth of Trichophyton rubrum and induce CD4-T cell activation.

    PubMed

    Santiago, Karla; Bomfim, Gisele Facholi; Criado, Paulo Ricardo; Almeida, Sandro Rogerio

    2014-01-01

    Dermatophytes are the most common agents of superficial mycoses that are caused by mold fungi. Trichophyton rubrum is the most common pathogen causing dermatophytosis. The immunology of dermatophytosis is currently poorly understood. Recently, our group investigated the interaction of T. rubrum conidia with peritoneal mouse macrophages. We found that macrophages phagocytose T. rubrum conidia resulted in a down-modulation of class II major histocompatibility complex (MHC) antigens and in the expression of co-stimulatory molecules. Furthermore, it induced the production of IL-10, and T. rubrum conidia differentiated into hyphae that grew and killed the macrophages after 8 hrs of culture. This work demonstrated that dendritic cells (DCs) and macrophages, from patients or normal individuals, avidly interact with pathogenic fungus T. rubrum. The dermatophyte has two major receptors on human monocyte-derived DC: DC-SIGN and mannose receptor. In contrast macrophage has only mannose receptor that participates in the phagocytosis or bound process. Another striking aspect of this study is that unlike macrophages that permit rapid growth of T. rubrum, human DC inhibited the growth and induces Th activation. The ability of DC from patients to interact and kill T. rubrum and to present Ags to T cells suggests that DC may play an important role in the host response to T. rubrum infection by coordinating the development of cellular immune response.

  19. A novel kefir product (PFT) activates dendritic cells to induce CD4+T and CD8+T cell responses in vitro.

    PubMed

    Ghoneum, Mamdooh; Felo, Nouran; Agrawal, Sudhanshu; Agrawal, Anshu

    2015-12-01

    Lactobacilli have been widely studied for their probiotic effects and have been reported to function as antiviral and anticancer agents. However, the underlying mechanisms via immune modulation are poorly understood. PFT is a freeze dried compound of Lactobacillus kefiri P-IF with a unique composition and functionality. In this study, we examined the potential stimulatory effects of two concentrations (50 µg and 100 µg/mL) of PFT on human monocyte-derived dendritic cell (DC) function in vitro. Results showed that PFT upregulated the expression of DC surface co-stimulatory and maturation markers CD80, CD86, and HLADR in a concentration dependent manner. PFT at 100 µg/mL markedly increased the secretion of IL-6, IL-10, TNF-α, and IL-1β by DCs. This concentration of PFT also stimulated the production of antiviral cytokines, IFN-α and IFN-λ(IL29) in DCs. Additionally, PFT at 100 µg/mL activated moDCs prime CD4(+)T cells and significantly increased the levels of IL-10, IFN-γ, and TNF-α by 1.7, four, three-fold, respectively. Furthermore PFT-stimulated DCs were also effective in enhancing the cytotoxic potential of CD8(+)T cells via the induction of Granzyme-B and upregulation of CD107a, and CD103 expression, a marker of resident/regulatory CD8(+)T cells. These data suggest that PFT functions as a natural adjuvant for DC activation and thus may be used in DC-based vaccine strategies against viral infections and cancer. © The Author(s) 2015.

  20. 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

  1. Lymphokine-activated killer and dendritic cell carriage enhances oncolytic reovirus therapy for ovarian cancer by overcoming antibody neutralization in ascites

    PubMed Central

    Jennings, VA; Ilett, EJ; Scott, KJ; West, EJ; Vile, R; Pandha, H; Harrington, K; Young, A; Hall, GD; Coffey, M; Selby, P; Errington-Mais, F; Melcher, AA

    2014-01-01

    Reovirus is an oncolytic virus (OV), which acts by both direct tumor cell killing and priming of antitumor immunity. A major obstacle for effective oncolytic virotherapy is effective delivery of OV to tumor cells. Ovarian cancer is often confined to the peritoneal cavity and therefore i.p. delivery of reovirus may provide the ideal locoregional delivery, avoiding systemic dissemination. However, ovarian cancer is associated with an accumulation of ascitic fluid, which may interfere with oncolytic viral therapy. Here, we investigated the effect of ascites on reovirus-induced oncolysis against primary ovarian cancer cells and ovarian cancer cell lines. In the absence of ascites, reovirus was cytotoxic against ovarian cancer cells; however, cytotoxicity was abrogated in the presence of ascitic fluid. Neutralizing antibodies (NAb) were identified as the cause of this inhibition. Loading OV onto cell carriers may facilitate virus delivery in the presence of NAb and immune cells which have their own antitumor effector activity are particularly appealing. Immature dendritic cells (iDC), Lymphokine-activated killer (LAK) cells and LAKDC cocultures were tested as potential carriers for reovirus for tumor cell killing and immune cell priming. Reovirus-loaded LAKDC, and to a lesser degree iDC, were able to: (i) protect from NAb and hand-off reovirus for tumor cell killing; (ii) induce a proinflammatory cytokine milieu (IFNɣ, IL-12, IFNα and TNFα) and (iii) generate an innate and specific antitumor adaptive immune response. Hence, LAKDC pulsed with reovirus represent a novel, clinically practical treatment for ovarian cancer to maximise both direct and innate/adaptive immune-mediated tumor cell killing. What’s new? Oncolytic viruses (OVs) specifically infect and kill tumor cells. In this study, the authors began to examine whether intraperitoneal delivery of an OV could be effective against ovarian cancer. They found that, while the virus does kill ovarian-cancer cells in

  2. 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

  3. 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.

  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. 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.

  6. 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

  7. 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

  8. Immune heterogeneity in neuroinflammation: dendritic cells in the brain.

    PubMed

    Colton, Carol A

    2013-03-01

    Dendritic cells (DC) are critical to an integrated immune response and serve as the key link between the innate and adaptive arms of the immune system. Under steady state conditions, brain DC's act as sentinels, continually sampling their local environment. They share this function with macrophages derived from the same basic hemopoietic (bone marrow-derived) precursor and with parenchymal microglia that arise from a unique non-hemopoietic origin. While multiple cells may serve as antigen presenting cells (APCs), dendritic cells present both foreign and self-proteins to naïve T cells that, in turn, carry out effector functions that serve to protect or destroy. The resulting activation of the adaptive response is a critical step to resolution of injury or infection and is key to survival. In this review we will explore the critical roles that DCs play in the brain's response to neuroinflammatory disease with emphasis on how the brain's microenvironment impacts these actions.

  9. Dendritic cells in systemic lupus erythematosus.

    PubMed

    Seitz, Heather M; Matsushima, Glenn K

    2010-04-01

    Systemic lupus erythematosus (SLE) persists as a chronic inflammatory autoimmune disease and is characterized by the production of autoantibodies and immune complexes that affect multiple organs. The underlying mechanism that triggers and sustains disease are complex and involve certain susceptibility genes and environmental factors. There have been several immune mediators linked to SLE including cytokines and chemokines that have been reviewed elsewhere [ 1-3 ]. A number of articles have reviewed the role of B cells and T cells in SLE [ 4-10 ]. Here, we focus on the role of dendritic cells (DC) and innate immune factors that may regulate autoreactive B cells.

  10. 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.

  11. 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

  12. Human dendritic cells - stars in the skin.

    PubMed

    Klechevsky, Eynav

    2013-12-01

    "A properly functioning adaptive immune system signifies the best features of life. It is diverse beyond compare, tolerant without fail, and capable of behaving appropriately with a myriad of infections and other challenges. Dendritic cells (DCs) are required to explain how this remarkable system is energized and directed." This is a quote by one of the greatest immunologists our community has ever known, and the father of dendritic cells, Ralph Steinman. Steinman's discovery of DCs in 1973 and his subsequent research opened a new field of study within immunology: DC biology and in particular the role of DCs in immune regulation in health and disease. Here, I review themes from our work and others on the complex network of dendritic cells in the skin and discuss the significance of skin DCs in understanding aspects of host defense against infections, the pathology of inflammatory skin diseases, and speculate on the future effective immune-based therapies. © 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. 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