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Myeloid-derived Suppressor Cells (myeloid-derived + suppressor_cell)
Selected AbstractsMyeloid-derived suppressor cells in inflammation: Uncovering cell subsets with enhanced immunosuppressive functionsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 10 2009Vincenzo Bronte Abstract Although originally described in tumor-bearing hosts, myeloid-derived suppressor cells (MDSC) have been detected under numerous pathological situations that cause enhanced demand of myeloid cells. Thus, MDSC might be part of a conserved response to different endogenous and exogenous stress signals, including inflammation. Two processes are fundamental for MDSC biology: differentiation from myeloid progenitors and full activation of their immune regulatory program by factors released from activated T cells or present in the microenvironment conditioned by either tumor growth or inflammation. How these two processes are controlled and linked is still an open question. In this issue of the European Journal of Immunology, a paper demonstrates that a combination of the known inflammatory molecules, IFN-, and LPS, sustains MDSC expansion and activation while suppressing differentiation of DC from bone marrow precursors. Moreover, this paper contributes to defining the cell subsets that possess immunoregulatory properties within the broad population of CD11b+Gr-1+ cells, often altogether referred to as MDSC. [source] From phagocyte diversity and activation to probiotics: Back to MetchnikoffEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 12 2008Alberto Mantovani Abstract In this issue of the European Journal of Immunology, Siamon Gordon gives a detailed account of Metchnikoff's life and his achievements (Eur. J. Immunol. 2008. 38: 3257,3264). Looking back at the roots of innate immunity stimulates reflections on open issues in the field. Here, I give a personal view of some of these issues, including myeloid-derived suppressor cells, macrophage polarization and adaptive responses of mononuclear phagocytes. [source] Endotoxin-Induced Myeloid-Derived Suppressor Cells Inhibit Alloimmune Responses via Heme Oxygenase-1AMERICAN JOURNAL OF TRANSPLANTATION, Issue 9 2009V. De Wilde Inflammation and cancer are associated with impairment of T-cell responses by a heterogeneous population of myeloid-derived suppressor cells (MDSCs) coexpressing CD11b and GR-1 antigens. MDSCs have been recently implicated in costimulation blockade-induced transplantation tolerance in rats, which was under the control of inducible NO synthase (iNOS). Herein, we describe CD11b+GR-1+MDSC-compatible cells appearing after repetitive injections of lipopolysaccharide (LPS) using a unique mechanism of suppression. These cells suppressed T-cell proliferation and Th1 and Th2 cytokine production in both mixed lymphocyte reaction and polyclonal stimulation assays. Transfer of CD11b+ cells from LPS-treated mice in untreated recipients significantly prolonged skin allograft survival. They produced large amounts of IL-10 and expressed heme oxygenase-1 (HO-1), a stress-responsive enzyme endowed with immunoregulatory and cytoprotective properties not previously associated with MDSC activity. HO-1 inhibition by the specific inhibitor, SnPP, completely abolished T-cell suppression and IL-10 production. In contrast, neither iNOS nor arginase 1 inhibition did affect suppression. Importantly, HO-1 inhibition before CD11b+ cell transfer prevented the delay of allograft rejection revealing a new MDSC-associated suppressor mechanism relevant for transplantation. [source] | ||||||||||