Search results for "hemic and immune systems"
showing 10 items of 340 documents
LFA-1 activity state on dendritic cells regulates contact duration with T cells and promotes T-cell priming.
2010
AbstractA key event in the successful induction of adaptive immune responses is the antigen-specific activation of T cells by dendritic cells (DCs). Although LFA-1 (lymphocyte function–associated antigen 1) on T cells is considered to be important for antigen-specific T-cell activation, the role for LFA-1 on DCs remains elusive. Using 2 different approaches to activate LFA-1 on DCs, either by deletion of the αL-integrin cytoplasmic GFFKR sequence or by silencing cytohesin-1–interacting protein, we now provide evidence that DCs are able to make use of active LFA-1 and can thereby control the contact duration with naive T cells. Enhanced duration of DC/T-cell interaction correlates inversely …
Molecular characterization of an inducible p-coumaric acid decarboxylase from Lactobacillus plantarum: gene cloning, transcriptional analysis, overex…
1997
By using degenerate primers designed from the first 19 N-terminal amino acids of Lactobacillus plantarum p-coumaric acid decarboxylase (PDC), a 56-bp fragment was amplified from L. plantarum in PCRs and used as a probe for screening an L. plantarum genomic bank. Of the 2,880 clones in the genomic bank, one was isolated by colony hybridization and contained a 519-bp open reading frame (pdc gene) followed by a putative terminator structure. The pdc gene is expressed on a monocistronic transcriptional unit, which is transcribed from promoter sequences homologous to Lactococcus promoter sequences. No mRNA from pdc and no PDC activity were detected in uninduced cell extracts, indicating that the…
Release of dendritic cells from cognate CD4 + T-cell recognition results in impaired peripheral tolerance and fatal cytotoxic T-cell mediated autoimm…
2012
Resting dendritic cells (DCs) induce tolerance of peripheral T cells that have escaped thymic negative selection and thus contribute significantly to protection against autoimmunity. We recently showed that CD4 + Foxp3 + regulatory T cells (Tregs) are important for maintaining the steady-state phenotype of DCs and their tolerizing capacity in vivo. We now provide evidence that DC activation in the absence of Tregs is a direct consequence of missing DC–Treg interactions rather than being secondary to generalized autoimmunity in Treg-less mice. We show that DCs that lack MHC class II and thus cannot make cognate interactions with CD4 + T cells are completely unable to induce peripheral CD8 +…
Interleukin-7 matures suppressive CD127(+) forkhead box P3 (FoxP3)(+) T cells into CD127(-) CD25(high) FoxP3(+) regulatory T cells.
2011
We have identified a novel interleukin (IL)-7-responsive T cell population [forkhead box P3 (FoxP3(+) ) CD4(+) CD25(+) CD127(+) ] that is comparably functionally suppressive to conventional FoxP3(+) CD4(+) CD25(+) regulatory T cells (T(regs) ). Although IL-2 is the most critical cytokine for thymic development of FoxP3(+) T(regs) , in the periphery other cytokines can be compensatory. CD25(+) CD127(+) T cells treated with IL-7 phenotypically 'matured' into the known 'classical' FoxP3(+) CD4(+) CD25(high) CD127(-) FoxP3(+) T(regs) . In freshly isolated splenocytes, the highest level of FoxP3 expression was found in CD127(+) CD25(+) T cells when compared with CD127(-) CD25(+) or CD127(+) CD25…
Mycobacterium tuberculosis secretory proteins downregulate T cell activation by interfering with proximal and downstream T cell signalling events
2015
Background Mycobacterium tuberculosis (M. tuberculosis) modulates host immune response, mainly T cell responses for its own survival leading to disease or latent infection. The molecules and mechanisms utilized to accomplish immune subversion by M. tuberculosis are not fully understood. Understanding the molecular mechanism of T cell response to M. tuberculosis is important for development of efficacious vaccine against TB. Methods Here, we investigated effect of M. tuberculosis antigens Ag85A and ESAT-6 on T cell signalling events in CD3/CD28 induced Peripheral blood mononuclear cells (PBMCs) of PPD+ve healthy individuals and pulmonary TB patients. We studied CD3 induced intracellular calc…
Plasmacytoid dendritic cells are inefficient in activation of human regulatory T cells
2011
BACKGROUND: Dendritic cells (DC) play a key role in initiation and regulation of immune responses. Plasmacytoid DC (pDC), a small subset of DC, characterized as type-I interferon producing cells, are critically involved in anti-viral immune responses, but also mediate tolerance by induction of regulatory T cells (Treg). In this study, we compared the capacity of human pDC and conventional DC (cDC) to modulate T cell activity in presence of Foxp3(+) Treg. PRINCIPAL FINDINGS: In coculture of T effector cells (Teff) and Treg, activated cDC overcome Treg anergy, abrogate their suppressive function and induce Teff proliferation. In contrast, pDC do not break Treg anergy but induce Teff prolifera…
dsRNA induces apoptosis through an atypical death complex associating TLR3 to caspase-8
2012
Toll-like receptor 3 (TLR3) is a pattern-recognition receptor known to initiate an innate immune response when stimulated by double-stranded RNA (dsRNA). Components of TLR3 signaling, including TIR domain-containing adapter inducing IFN-α (TRIF), have been demonstrated to contribute to dsRNA-induced cell death through caspase-8 and receptor interacting protein (RIP)1 in various human cancer cells. We provide here a detailed analysis of the caspase-8 activating machinery triggered in response to Poly(I:C) dsRNA. Engagement of TLR3 by dsRNA in both type I and type II lung cancer cells induces the formation of an atypical caspase-8-containing complex that is devoid of classical death receptors…
Foxp3 and gata3 polymorphisms, vitamin d3 and multiple sclerosis
2021
Background: Regulatory T cells (Tregs) alterations have been implicated in the pathogenesis of Multiple Sclerosis (MS). Recently, a crucial role of the X-Linked Forkhead Box P3 (FoxP3) for the development and the stability of Tregs has emerged, and FOXP3 gene polymorphisms have been associated with the susceptibility to autoimmune diseases. The expression of Foxp3 in Tregs is regulated by the transcription factor GATA binding-protein 3 (GATA3) and vitamin D3. The aim of this retrospective case-control study was to investigate the potential association between FOXP3 and GATA3 genetic variants, Vitamin D3, and MS risk. Methods: We analyzed two polymorphisms in the FOXP3 gene (rs3761547 and rs…
Keyhole Limpet Haemocyanin in Experimental Bladder Cancer
2000
Objectives: Keyhole limpet haemocyanin (KLH) is a high-molecular-weight protein antigen collected from the haemolymph of the sea mollusk Megathura crenulata. It i
Smad7 controls resistance of colitogenic T cells to regulatory T cell-mediated suppression.
2008
Background & Aims Foxp3-expressing regulatory T cells (Tregs) play a key role in the maintenance of the gut immune homeostasis, and an intact transforming growth factor (TGF)-β signaling is required for their function. In inflammatory bowel disease (IBD), the TGF-β signaling is impaired because of high expression of the inhibitory molecule Smad7. Although no intrinsic defects in Tregs function have been shown in IBD, it is still unknown whether colitogenic T cells are susceptible to Treg-mediated suppression. In this study, we have investigated whether IBD mucosal CD4+ T cells are resistant to Tregs and whether Smad7 is involved in this process. Methods IBD lamina propria mononuclear cells …