Search results for "T cell"
showing 10 items of 2228 documents
C-X-C Motif Chemokine Receptor 4 Blockade Promotes Tissue Repair After Myocardial Infarction by Enhancing Regulatory T Cell Mobilization and Immune-R…
2019
Background: Acute myocardial infarction (MI) elicits an inflammatory response that drives tissue repair and adverse cardiac remodeling. Inflammatory cell trafficking after MI is controlled by C-X-C motif chemokine ligand 12 (CXCL12) and its receptor, C-X-C motif chemokine receptor 4 (CXCR4). CXCR4 antagonists mobilize inflammatory cells and promote infarct repair, but the cellular mechanisms are unclear. Methods: We investigated the therapeutic potential and mode of action of the peptidic macrocycle CXCR4 antagonist POL5551 in mice with reperfused MI. We applied cell depletion and adoptive transfer strategies using lymphocyte-deficient Rag1 knockout mice; DEREG mice, which express a diphth…
Reduced virus specific T helper cell induction by autologous dendritic cells in patients with chronic hepatitis B-restoration by exogenous interleuki…
2002
SUMMARYInsufficient stimulatory capacities of autologous dendritic cells (DC) may contribute in part to impaired T cell stimulation and therefore viral persistence in patients with chronic hepatitis B virus (HBV) infection. In order to characterize the antigen presenting functions of DC from chronic HBV carriers and controls antigen specific T cell responses were analysed. CD34+ peripheral blood progenitor cells were differentiated to immature DC in the presence of GM-CSF, IL-6/IL-6R fusion protein and stem cell factor. Proliferative CD4+ T cell responses and specific cytokine release were analysed in co-cultures of DC pulsed with HBV surface and core antigens or tetanus toxoid and autologo…
Soluble interleukin-6 receptor (sIL-6R) makes IL-6R negative T cell line respond to IL-6: it inhibits TNF production
2000
The receptor for interleukin-6 (IL-6) consists of two subunits: a ligand specific IL-6Ralpha and gp130 that is responsible for signal-transduction. A soluble form of the ligand specific chain was described that when complexed to IL-6 is capable of binding to the membrane-bound gp130 subunit and thus can elicit signal-transduction. This soluble receptor can act on cells that express only the gp130 but not the ligand-specific subunit of the IL-6R. This phenomenon, called trans-signaling, introduced a novel aspect of cytokine action. In this study we examined the response of Jurkat cells, that are known not to express IL-6Ralpha, to IL-6, the soluble IL-6 receptor (sIL-6R) and a covalent compl…
Specific Regulation of T Helper Cell 1–mediated Murine Colitis by CEACAM1
2004
Carcinoembryonic antigen-related cellular adhesion molecule 1 (CEACAM1) is a cell surface molecule that has been proposed to negatively regulate T cell function. We have shown that CEACAM1 is associated with specific regulation of T helper cell (Th)1 pathways, T-bet–mediated Th1 cytokine signaling, and Th1-mediated immunopathology in vivo. Mice treated with anti–mouse CEACAM1-specific monoclonal antibody (mAb) CC1 during the effector phase exhibited a reduced severity of trinitrobenzene sulfonic acid colitis in association with decreased interferon (IFN)-γ production. Although oxazolone colitis has been reported as Th2 mediated, mice treated with the CC1 mAb or a CEACAM1-Fc chimeric protein…
The Tobacco mosaic virus movement protein associates with but does not integrate into biological membranes
2014
Plant positive-strand RNA viruses require association with plant cell endomembranes for viral translation and replication, as well as for intra- and intercellular movement of the viral progeny. The membrane association and RNA binding of the Tobacco mosaic virus (TMV) movement protein (MP) are vital for orchestrating the macromolecular network required for virus movement. A previously proposed topological model suggests that TMV MP is an integral membrane protein with two putative -helical transmembrane (TM) segments. Here we tested this model using an experimental system that measured the efficiency with which natural polypeptide segments were inserted into the ER membrane under conditions…
Cutting Edge: Trans-Signaling via the Soluble IL-6R Abrogates the Induction of FoxP3 in Naive CD4+CD25− T Cells
2007
Abstract Chronic inflammatory diseases may develop when regulatory T cells (Tregs) fail to control the balance between tolerance and immunity. Alternatively, activated immune cells might prevent the induction or activation of Tregs in such diseases. In this study, we demonstrate that trans-signaling into T cells via the soluble IL-6 receptor completely abrogates the de novo induction of adaptive Tregs. Mechanistically, IL-6 trans-signaling augmented the expression of the TGF-β signaling inhibitor SMAD7. Consequently, SMAD7 overexpression in T cells using newly created transgenic mice rendered CD4+CD25− T cells resistant to the induction of FoxP3. Finally, IL-6 trans-signaling inhibited Treg…
Large scale preparation of human MHC class II+ integrin beta(1)+ Tregs.
2010
Abstract The human CD4 + CD25 + FoxP3 + regulatory T cell population (Tregs) contains both MHC class II + and MHC class II − cells. MHC class II + Tregs belong to the integrin α 4 β 1 + subpopulation and exclusively execute contact-dependent suppressive activity. Here we present a method optimized for isolation of these MHC class II expressing Tregs from large leukaphereses products using magnetic microbeads that achieves a reproducible purity of more than 90% and enables the use of this small-sized Treg population in pre-clinical application and basic research.
Tumor cells convert immature myeloid dendritic cells into TGF-β–secreting cells inducing CD4+CD25+ regulatory T cell proliferation
2005
The mechanisms through which regulatory T cells accumulate in lymphoid organs of tumor-bearing hosts remain elusive. Our experiments indicate that the accumulation of CD4+CD25+ regulatory T cells (T reg cells) expressing FoxP3 and exhibiting immunosuppressive function originates from the proliferation of naturally occurring CD25+ T cells and requires signaling through transforming growth factor (TGF)–β receptor II. During tumor progression, a subset of dendritic cells (DCs) exhibiting a myeloid immature phenotype is recruited to draining lymph nodes. This DC subset selectively promotes the proliferation of T reg cells in a TGF-β–dependent manner in mice and rats. Tumor cells are necessary a…
Immunopathology of leishmaniasis: an update.
2007
Leishmaniasis represents a severe, increasing, public health problem. The perspective of its control is highly dependent on research progress, on therapeutic manipulations of the immune system, and on vaccine development. There is a correlation between the clinical outcome of Leishmania infection and the cytokine response profile. While a protective immune response against Leishmania has been clearly identified to be related to the influence of a type-1 response and IFN-γ production, the precise role of T helper (TH) 2 cytokines in non-healing infections requires further exploration. IL-4 and IL-13 (TH2 cytokines) can promote disease progression in cutaneous leishmaniasis, whereas IL-4 woul…
DRB1*0401-restricted human T cell clone specific for the major proinsulin73-90 epitope expresses a down-regulatory T helper 2 phenotype.
2006
Recently, we have identified proinsulin (P-Ins) 73-90 as an immunodominant T cell epitope of HLA-DRB1*0401 (DR4) subjects with β-islet cell autoimmunity and of HLA-DR4/CD4 double-transgenic mice immunized with human P-Ins. We have compared the fine specificities of one human CD4 T cell clone and two mouse T cell hybridoma clones recognizing this epitope, and, although these three clones all recognized the same core region (LALEGSLQK), there were major differences in how they interacted with the peptide (p)/HLA complex, reflecting the fact that human P-Ins is a foreign antigen in the mouse and an autoantigen in the type 1 diabetes patient. The human T cell clone was forkhead transcription f…