Search results for "Immune system"
showing 10 items of 2885 documents
A Critical Regulatory Role of Leucin Zipper Transcription Factor c-Maf in Th1-Mediated Experimental Colitis
2004
Abstract In this study, we investigated the role of c-Maf, a transcription factor known to induce IL-4 production, in inflammatory bowel diseases and experimental colitis. Although Crohn′s disease (CD) is associated with low IL-4 production by T-bet-expressing Th1 cells in the lamina propria, surprisingly a higher expression of c-Maf in these cells was found as compared with control patients. The relevance of this finding was further evaluated in an animal model of CD induced by adoptive transfer of CD4+CD62L+ T cells in RAG-deficient mice. In this Th1-mediated model, an increase of c-Maf-expressing T lymphocytes in the lamina propria over time was observed. Interestingly, adoptive transfer…
IL-21 regulates experimental colitis by modulating the balance between Treg and Th17 cells
2007
Regulatory T (T(reg)) cells play a key role in the maintenance of the immune system homeostasis. T(reg) cells can be generated in the periphery under control of TGF-beta, a cytokine involved in the negative control of the immune system. However, TGF-beta cooperates with IL-6 in the generation of Th17 cells, a novel class of effector cells involved in numerous inflammatory diseases, including colitis. Therefore, TGF-beta emerges as a mediator of both anti-inflammatory and pro-inflammatory processes, depending on the local cytokine milieu. Here we demonstrate that IL-21, a type-1 cytokine produced by T cells and involved in the pathogenesis of immune-mediated diseases, prevents the TGF-beta-d…
Interleukin-7 or Interleukin-15 Enhances Survival ofMycobacterium tuberculosis-Infected Mice
2000
ABSTRACTBoth antigen-presenting cells and immune effector cells are required to effectively eradicate or containMycobacterium tuberculosis-infected cells. A variety of cytokines are involved to ensure productive “cross talk” between macrophages and T lymphocytes. For instance, infection of macrophages with mycobacteria leads to effective interleukin-7 (IL-7) and IL-15 secretion, and both cytokines are able to maintain strong cellular immune responses of α/β and γ/δ T cells. Here we show that either cytokine is able to enhance survival ofM. tuberculosis-infected BALB/c mice significantly compared to application of IL-2, IL-4, or phosphate-buffered saline (as a control). Enhanced survival cou…
CD4+CD25+ Regulatory T Cells and TGF-Beta in Mucosal Inflammation
2008
Transforming growth factor-beta (TGF-beta) is an anti-inflammatory cytokine which plays a key role in the maintenance of the immune system homeostasis. Indeed the abrogation of the TGF-beta signaling in immune cells leads to autoimmunity and inflammation in several organs including the gut. TGF-beta acts at multiple levels to maintain the immune system in check. However, TGF-beta has been recently shown to play a key role in the peripheral generation and function of CD4+CD25+ regulatory T cells, a subset of suppressive lymphocytes involved in the control of effector T cell activation and proliferation. Consistently abrogation of Tregs maturation as observed in different systems leads to a p…
Physiological Interactions between Microglia and Neural Stem Cells in the Adult Subependymal Niche
2018
Microglia are the prototypical innate immune cells of the central nervous system. They constitute a unique type of tissue-resident mononuclear phagocytes which act as glial cells. Elegant experiments in the last few years have revealed the origin, extraordinary molecular diversity, and phenotypic plasticity of these cells and how their potential relates to both immune and non-immune actions in the normal and diseased brain. Microglial cells originate in the yolk sac and colonize the brain during embryogenesis, playing a role in neural development and later in adult brain function. Neurogenesis continues after birth in discrete areas of the mammalian brain sustained by the postnatal persiste…
Recurrent episodes of skin angioedema and severe attacks of abdominal pain induced by oral contraceptives or hormone replacement therapy
2003
Abstract Purpose Recurrent angioedema, characterized by skin swelling, colicky attacks of abdominal pain, and life-threatening laryngeal edema, can be either hereditary or acquired. According to anecdotal reports, it may be associated with use of oral contraceptives and hormone replacement therapy. We investigated potential interactions between these medications and various types of recurrent angioedema in a large cohort of women. Methods Women with recurrent angioedema (n = 516) underwent a thorough medical evaluation. They were then classified by type of angioedema, using standard criteria. Results Of the 516 women, 228 (44%) had used oral contraceptives or hormone replacement therapy, in…
Interferon-Beta Therapy of Multiple Sclerosis Patients Improves the Responsiveness of T Cells for Immune Suppression by Regulatory T Cells
2015
Multiple sclerosis (MS) is an inflammatory autoimmune disease characterized by imbalanced immune regulatory networks, and MS patient-derived T effector cells are inefficiently suppressed through regulatory T cells (Treg), a phenomenon known as Treg resistance. In the current study we investigated T cell function in MS patients before and after interferon-beta therapy. We compared cytokine profile, responsiveness for Treg-mediated suppression ex vivo and evaluated reactivity of T cells in vivo using a humanized mouse model. We found that CD4+ and CD8+ T cells of therapy-naive MS patients were resistant to Treg-mediated suppression. Treg resistance is associated with an augmented IL-6 product…
Ophthalmic manifestations in IgG4-related disease
2017
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A double-negative (IgD−CD27−) B cell population is increased in the peripheral blood of elderly people
2009
The T cell branch of the immune system has been extensively studied in the elderly and it is known that the elderly have impaired immune function, mainly due to the chronic antigenic load that ultimately causes shrinkage of the T cell repertoire and filling of the immunologic space with memory T cells. In the present paper, we describe the IgD(-)CD27(-) double-negative B cell population which (as we have recently described) is higher in the elderly. Most of these cells were IgG(+). Evaluation of the telomere length and expression of the ABCB1 transporter and anti-apoptotic molecule, Bcl2, shows that they have the markers of memory B cells. We also show that these cells do not act as antigen…
Trafficking phenotype and production of granzyme B by double negative B cells (IgG(+)IgD(-)CD27(-)) in the elderly.
2013
The impairment of humoral immune response in elderly humans has been extensively demonstrated. We have reported the increase of memory B cells (IgG(+)IgD(-)CD27(-), double negative, DN) population in the elderly, in which there is also a typical inflammatory micro-environment. In order to evaluate whether this pro-inflammatory status could influence the trafficking phenotype of naïve/memory B cells, we have assessed the expression of CCR7, CCR6, CXCR3, CXCR4, CXCR5 and CD62L on naïve/memory B cell subpopulations in young and elderly subjects. Moreover, the combination of pro-inflammatory interleukin-21 (IL-21) and B cell receptor (BCR) stimulation enables B cells to produce and secrete gran…