Search results for "Immunoregulation"

The balance of HSPs expression during pregnancy: the role of placenta

2009

Disrupting immune regulation incurs transient costs in male reproductive function.

2014

9 pages; International audience; BACKGROUND: Immune protection against pathogenic organisms has been shown to incur costs. Previous studies investigating the cost of immunity have mostly focused on the metabolic requirements of immune maintenance and activation. In addition to these metabolic costs, the immune system can induce damage to the host if the immune response is mis-targeted or over-expressed. Given its non-specific nature, an over-expressed inflammatory response is often associated with substantial damage for the host. Here, we investigated the cost of an over-expressed inflammatory response in the reproductive function of male mice. METHODOLOGY/PRINCIPAL FINDINGS: We experimenta…

Metabolism via arginase or nitric oxide synthase: two competing arginine pathways in macrophages

2014

Macrophages play a major role in the immune system, both as antimicrobial effector cells and as immunoregulatory cells, which induce, suppress or modulate adaptive immune responses. These key aspects of macrophage biology are fundamentally driven by the phenotype of macrophage arginine metabolism that is prevalent in an evolving or ongoing immune response. M1 macrophages express the enzyme nitric oxide synthase (NOS), which metabolizes arginine to nitric oxide (NO) and citrulline. NO can be metabolized to further downstream reactive nitrogen species, while citrulline might be reused for efficient NO synthesis via the citrulline-NO cycle. M2 macrophages are characterized by expression of the…

Budesonide increases TLR4 and TLR2 expression in Treg lymphocytes of allergic asthmatics

2015

Abstract Background Reduced innate immunity responses as well as reduced T regulatory activities characterise bronchial asthma. Objectives In this study the effect of budesonide on the expression of TLR4 and TLR2 in T regulatory lymphocyte sub-population was assessed. Methods TLR4 and TLR2 expression in total peripheral blood mononuclear cells (PBMC), in CD4+/CD25+ and in CD4+/CD25− was evaluated, by flow cytometric analysis, in mild intermittent asthmatics (n = 14) and in controls (n = 11). The in vitro effects of budesonide in modulating: TLR4 and TLR2 expression in controls and in asthmatics; IL-10 expression and cytokine release (IL-6 and TNF-α selected by a multiplex assay) in asthmati…

Immune Modulating Effects of NKT Cells in a Physiologically Low Dose Leishmania major Infection Model after αGalCer Analog PBS57 Stimulation

2014

Leishmaniasis is a parasitic infection affecting ∼12 million people worldwide, mostly in developing countries. Treatment options are limited and no effective vaccines exist to date. Natural Killer T (NKT) cells are a conserved innate-like lymphocyte population with immunomodulating effects in various settings. A number of reports state a role of NKT cells in different models of Leishmania infection. Here, we investigated the effect of NKT cells in a physiologically relevant, intradermal low dose infection model. After inoculation of 103 infectious-stage L. major, comparable numbers of skin-immigrating NKT cells in both susceptible BALB/c mice and resistant C57BL/6 mice were noted. Compared …

Cytotoxicity of tumor antigen specific human T cells is unimpaired by arginine depletion.

2013

Tumor-growth is often associated with the expansion of myeloid derived suppressor cells that lead to local or systemic arginine depletion via the enzyme arginase. It is generally assumed that this arginine deficiency induces a global shut-down of T cell activation with ensuing tumor immune escape. While the impact of arginine depletion on polyclonal T cell proliferation and cytokine secretion is well documented, its influence on chemotaxis, cytotoxicity and antigen specific activation of human T cells has not been demonstrated so far. We show here that chemotaxis and early calcium signaling of human T cells are unimpaired in the absence of arginine. We then analyzed CD8(+) T cell activation…

Phosphatidylinositol-3-kinase activity during in vitro dendritic cell generation determines suppressive or stimulatory capacity.

2011

Modulating PI3K at different stages of dendritic cells (DC) generation could be a novel means to balance the generation of immunosuppressive versus immunostimulatory DC. We show that PI3K inhibition during mouse DC generation in vitro results in cells that are potently immunosuppressive and characteristic of CD8alpha- CD11c+ CD11b+ DC. These DC exhibited low surface class I and class II MHC, CD40, and CD86 and did not produce TNF-alpha. In allogeneic MLR, these DC were suppressive. Although in these mixed cultures, there was no increase in the frequency of CD4+ CD25+ Foxp3+ cells, the Foxp3 content on a per cell basis was significantly increased. Sustained TLR9 signaling in the presence of …

Editorial: Current concepts of cellular and biological drugs to modulate regulatory T cell activity in the clinic

2016

The Editorial on the Research Topic Current Concepts of Cellular and Biological Drugs to Modulate Regulatory T Cell Activity in the Clinic Regulatory T (Treg) cells are essential for the maintenance of peripheral tolerance and prevent the development of autoimmunity and allergy. While on the one hand being indispensable for the perpetuation of tolerance to harmless antigens or self-antigens, Treg cells contribute to cancer pathogenesis and progression (1). Hence, the potential to treat a multitude of different human diseases by pharmacological modulation of Treg cells is enormous. Consequently, this T cell population is in the focus of biomedical research and development. Currently, isolate…

Human limbal fibroblast-like stem cells induce immune-tolerance in autoreactive T lymphocytes from female patients with Hashimoto’s thyroiditis

2017

Background Due to their “natural immune privilege” and immunoregulatory properties human fibroblast-like limbal stem cells (f-LSCs) have acquired great interest as a potential tool for achieving immunotolerance. Hashimoto’s thyroiditis (HT) is the most common thyroid autoimmune disease and cause of hypothyroidism. To date, conventional hormone replacement therapy and unspecific immunosuppressive regimens cannot provide a definitive cure for HT subjects. We explored the immunosuppressant potential of human f-LSCs on circulating lymphomonocytes (PBMCs) collected from healthy donors and female HT patients. Methods We assessed the immunophenotyping of f-LSCs, both untreated and after 48 h of pr…

Interferon-α Abrogates Tolerance Induction by Human Tolerogenic Dendritic Cells

2011

Background Administration of interferon-α (IFN-α) represents an approved adjuvant therapy as reported for malignancies like melanoma and several viral infections. In malignant diseases, tolerance processes are critically involved in tumor progression. In this study, the effect of IFN-α on tolerance induction by human tolerogenic dendritic cells (DC) was analyzed. We focussed on tolerogenic IL-10-modulated DC (IL-10 DC) that are known to induce anergic regulatory T cells (iTregs). Methodology/Principal Findings IFN-α promoted an enhanced maturation of IL-10 DC as demonstrated by upregulation of the differentiation marker CD83 as well as costimulatory molecules. IFN-α treatment resulted in an…