392 research outputs found

    Selective blockade of the inhibitory Fcγ receptor (FcγRIIB) in human dendritic cells and monocytes induces a type I interferon response program

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    The ability of dendritic cells (DCs) to activate immunity is linked to their maturation status. In prior studies, we have shown that selective antibody-mediated blockade of inhibitory FcγRIIB receptor on human DCs in the presence of activating immunoglobulin (Ig) ligands leads to DC maturation and enhanced immunity to antibody-coated tumor cells. We show that Fcγ receptor (FcγR)-mediated activation of human monocytes and monocyte-derived DCs is associated with a distinct gene expression pattern, including several inflammationassociated chemokines, as well as type 1 interferon (IFN) response genes, including the activation of signal transducer and activator of transcription 1 (STAT1). FcγR-mediated STAT1 activation is rapid and requires activating FcγRs. However, this IFN response is observed without a detectable increase in the expression of type I IFNs themselves or the need to add exogenous IFNs. Induction of IFN response genes plays an important role in FcγR-mediated effects on DCs, as suppression of STAT1 by RNA interference inhibited FcγR-mediated DC maturation. These data suggest that the balance of activating/inhibitory FcγRs may regulate IFN signaling in myeloid cells. Manipulation of FcγR balance on DCs and monocytes may provide a novel approach to regulating IFN-mediated pathways in autoimmunity and human cancer

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    [No abstract available

    Persistence of Natural Killer (NK) cell lymphocytosis with hyposplenism without development of leukaemia

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    BACKGROUND: Natural killer (NK) cell lymphocytosis usually has an indolent course and can progress into massive lymphocytosis with development of cytopenias and neoplastic diseases. NK-cells usually express one or more "NK-associated" antigens (CD16, CD56, CD57). Reactive expansions are seen in autoimmune diseases, viral infections, solid tumours and non-Hodgkin's lymphoma. CASE PRESENTATION: We report a lady with a benign clinical course over 10 years and persistent CD8+/CD3-/CD57+/CD16+ LGL proliferation with presence of Howell-Jolly bodies (functional hyposplenism), an association not previously described. CONCLUSION: We discuss the possible causes of clonal expansion and conclude that this may be part of the spectrum of immune dysregulation associated with NK-cell lymphocytosis

    Life cycle assessment comparison of point-of-use water treatment technologies: solar water disinfection (SODIS), boiling water, and chlorination

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    Numerous different point-of-use (POU) water treatment technologies exist that can remove, reduce or inactivate microbial pathogens present in untreated drinking water. However, there have been uncertainties as to which technology is best suited to rural populations. Environmental impacts of these technologies can bring further threats to rural communities, so the life cycle assessment (LCA) approach is frequently used to compare different POU water treatment technologies. The present study uses LCA to compare three treatment options: solar water disinfection (SODIS) using a Transparent Jerrycan (TJC), boiling, and chlorination. A life cycle inventory database is created for each stage, calculating the embodied energy and transportation energy considering daily reliance for all the technologies. Direct carbon dioxide emission at the point of use of energy/fuel, particulate matter formation and smog formation analysis can help to implement the most appropriate technology. The life-cycle assessment in this study indicates that when considering the environmental impact associated with providing sufficient safe drinking water for a family of six over a period of 6 months, SODIS has been found to have better sustainability credentials as a water treatment technology (6.0 kg CO2e per functional unit) with low contribution in all the three impact categories, followed by chlorination (9.8 kg CO2 e per functional unit) and boiling water (6808 kg CO2e per functional unit)

    CD1d-Expressing Breast Cancer Cells Modulate NKT Cell-Mediated Antitumor Immunity in a Murine Model of Breast Cancer Metastasis

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    Tumor tolerance and immune suppression remain formidable obstacles to the efficacy of immunotherapies that harness the immune system to eradicate breast cancer. A novel syngeneic mouse model of breast cancer metastasis was developed in our lab to investigate mechanisms of immune regulation of breast cancer. Comparative analysis of low-metastatic vs. highly metastatic tumor cells isolated from these mice revealed several important genetic alterations related to immune control of cancer, including a significant downregulation of cd1d1 in the highly metastatic tumor cells. The cd1d1 gene in mice encodes the MHC class I-like molecule CD1d, which presents glycolipid antigens to a specialized subset of T cells known as natural killer T (NKT) cells. We hypothesize that breast cancer cells, through downregulation of CD1d and subsequent evasion of NKT-mediated antitumor immunity, gain increased potential for metastatic tumor progression.In this study, we demonstrate in a mouse model of breast cancer metastasis that tumor downregulation of CD1d inhibits iNKT-mediated antitumor immunity and promotes metastatic breast cancer progression in a CD1d-dependent manner in vitro and in vivo. Using NKT-deficient transgenic mouse models, we demonstrate important differences between type I and type II NKT cells in their ability to regulate antitumor immunity of CD1d-expressing breast tumors.The results of this study emphasize the importance of determining the CD1d expression status of the tumor when tailoring NKT-based immunotherapies for the prevention and treatment of metastatic breast cancer

    Polymeric human Fc-fusion proteins with modified effector functions

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    The success of Fc-fusion bio-therapeutics has spurred the development of other Fc-fusion products for treating and/or vaccinating against a range of diseases. We describe a method to modulate their function by converting them into well-defined stable polymers. This strategy resulted in cylindrical hexameric structures revealed by tapping mode atomic force microscopy (AFM). Polymeric Fc-fusions were significantly less immunogenic than their dimeric or monomeric counterparts, a result partly owing to their reduced ability to interact with critical Fc-receptors. However, in the absence of the fusion partner, polymeric IgG1-Fc molecules were capable of binding selectively to FcγRs, with significantly increased affinity owing to their increased valency, suggesting that these reagents may prove of immediate utility in the development of well-defined replacements for intravenous immunoglobulin (IVIG) therapy. Overall, these findings establish an effective IgG Fc-fusion based polymeric platform with which the therapeutic and vaccination applications of Fc-fusion immune-complexes can now be explored

    Temozolomide in paediatric high-grade glioma: a key for combination therapy?

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    This report describes a single-centre study with temozolomide (TMZ) (200 mg m(-2) day(-1) x 5 per cycle of 28 days) in children with ( recurrent) high-grade glioma. Magnetic resonance imaging was performed every two cycles. In all, 20 patients were treated between 1998 and 2001 after the UKCCSG/SFOP TMZ phase II trial. All patients had measurable disease. Totally, 15 patients had a relapse after surgery+/-radiotherapy+/-chemotherapy. Overall, five patients received TMZ after surgery or biopsy, awaiting radiotherapy. There were one clinically malignant grade II glioma, II grade III and eight grade IV gliomas. Seven tumours had oligodendroglial features. Mean age at start of TMZ was 12.0 years (range 3-20.5 years). In total, eight patients had >8 cycles (range 3-30). One VGPR (currently in CR after surgery), three PRs (with a PFS of 4, 4 and 11 months, respectively) and one MR (PFS 14 months) were observed. Three out of five responses occurred after >4 courses. The overall response rate was 20%. Median progression-free survival (PFS) was 2.0 months (range 3 weeks-34(+) months). PFS rate was 20% after 6 months. Median overall survival ( OS) was 10 months. Nine patients showed a clinical improvement. Three patients vomitted shortly after TMZ administration, eight patients ( 13 cycles) experienced grade III/IV thrombocytopenia, occurring predominantly during the fourth week of the first two cycles. Five patients experienced neutropenia, and three patients febrile neutropenia. TMZ is a well-tolerated ambulatory treatment for children with malignant glial tumours. This drug warrants further study in these highly chemoresistant tumours and should be studied either as upfront therapy or in combination therap
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