Search results for "T Cells"
showing 10 items of 498 documents
Editorial: Understanding Gamma Delta T Cell Multifunctionality - Towards Immunotherapeutic Applications.
2020
Introduction: gd T cells have been characterized by the expression of a gd T cell receptor (TCR).When the gd TCR and the corresponding ab TCR were first discovered it was assumed that the corresponding cell types were likely to be functionally very similar. However, some 30 years later, we have realized that they are not. Unlike ab T cells, gd T cells (i) sense target antigens independent of MHC molecules; (ii) display NK-cell like innate reactivities, including killing of infected cells as well as microbes; (iii) are able to take up large particulates, including bacteria, and (iv) can act as professional antigen presenting cells. The “stress sensing” abilities of gd T cells have led to a g…
Antiretroviral therapy abrogates association between arginase activity and HIV disease severity
2010
AbstractArginase-induced L-arginine deprivation is emerging as a key mechanism for the downregulation of immune responses. We hypothesised that arginase activity increases with disease severity in HIV-seropositive patients. Our results show that peripheral blood mononuclear cells (PBMCs) from 23 HIV-seropositive patients with low CD4+ T cell counts (≤350 cells/μl) expressed significantly more arginase compared with 21 patients with high CD4+ T cell counts. Furthermore, we found a significant association between the two principal prognostic markers used to monitor HIV disease (CD4+ T cell count and plasma viral load) and PBMC arginase activity in antiretroviral therapy naïve patients but not…
MMP-7 promoter polymorphisms do not influence CD4+ recovery and changes in plasma viral load during antiretroviral therapy for HIV-1 infection.
2005
Summary Matrix metalloproteinase-7 (MMP-7) generates soluble Fas Ligand (FasL), which is involved in the apoptotic loss of CD4+ T cells during HIV infection. We evaluated whether two polymorphisms in MMP-7 promoter could influence CD4+ recover in response to antiretroviral therapy, and found that these polymorphisms are ineffective.
Multiple steady states and the form of response functions to antigen in a model for the initiation of T cell activation
2017
The aim of this paper is to study the qualitative behaviour predicted by a mathematical model for the initial stage of T-cell activation. The state variables in the model are the concentrations of phosphorylation states of the T-cell receptor (TCR) complex and the phosphatase SHP-1 in the cell. It is shown that these quantities cannot approach zero and that the model possesses more than one positive steady state for certain values of the parameters. It can also exhibit damped oscillations. It is proved that the chemical concentration which represents the degree of activation of the cell, that of the maximally phosphorylated form of the TCR complex, is, in general, a non-monotone function of…
Identification of plant cells in black pigments of prehistoric Spanish Levantine rock art by means of a multi-analytical approach. A new method for s…
2017
We present a new multi-analytical approach to the characterization of black pigments in Spanish Levantine rock art. This new protocol seeks to identify the raw materials that were used, as well as reconstruct the different technical gestures and decision-making processes involved in the obtaining of these black pigments. For the first of these goals, the pictorial mat- ter of the black figurative motifs documented at the Les Dogues rock art shelter (Ares del Maestre, Castello ́ n, Spain) was characterized through the combination of physicochemical and archeobotanical analyses. During the first stage of our research protocol, in situ and non- destructive analyses were carried out by means of…
Transcriptional regulation of the stem cell leukemia gene by PU.1 and Elf-1.
1998
Abstract The SCL gene, also known astal-1, encodes a basic helix-loop-helix transcription factor that is pivotal for the normal development of all hematopoietic lineages. SCL is expressed in committed erythroid, mast, and megakaryocytic cells as well as in hematopoietic stem cells. Nothing is known about the regulation of SCL transcription in mast cells, and in other lineages GATA-1 is the only tissue-specific transcription factor recognized to regulate the SCL gene. We have therefore analyzed the molecular mechanisms underlyingSCL expression in mast cells. In this paper, we demonstrate that SCL promoter 1a was regulated by GATA-1 together with Sp1 and Sp3 in a manner similar to the situati…
CD4saurus Rex & HIVelociraptor vs. development of clinically useful immunological markers: a Jurassic tale of frozen evolution.
2011
Abstract One of the most neglected areas of everyday clinical practice for HIV physicians is unexpectedly represented by CD4 T cell counts when used as an aid to clinical decisions. All who care for HIV patients believe that CD4+ T cell counts are a reliable method to evaluate a patient immune status. There is however a fatalistic acceptance that besides its general usefulness, CD4+ T cell counts have relevant clincal and immunological limits. Shortcomings of CD4 counts appear in certain clinical scenarios including identification of immunological nonresponders, subsequent development of cancer on antiretroviral teatment, failure on tretment simplification. Historical and recently described…
Insufficient Antigen Presentation Due to Viral Immune Evasion Explains Lethal Cytomegalovirus Organ Disease After Allogeneic Hematopoietic Cell Trans…
2020
Reactivation of latent cytomegalovirus (CMV) poses a clinical problem in transiently immunocompromised recipients of hematopoietic cell (HC) transplantation (HCT) by viral histopathology that results in multiple organ manifestations. Compared to autologous HCT and to syngeneic HCT performed with identical twins as HC donor and recipient, lethal outcome of CMV infection is more frequent in allogeneic HCT with MHC/HLA or minor histocompatibility loci mismatch between donor and recipient. It is an open question if a graft-versus-host (GvH) reaction exacerbates CMV disease, or if CMV exacerbates GvH disease (GvHD), or if interference is mutual. Here we have used a mouse model of experimental HC…
Placenta-derived CD95 ligand causes liver damage in hemolysis, elevated liver enzymes, and low platelet count syndrome.
2004
Background & Aims: The HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome is a life-threatening complication during pregnancy. The associated liver disease may be severe, and maternal hepatic complications may progress to the point that transplantation becomes necessary. CD95 (APO-1, Fas)-mediated apoptosis of liver cells is one of the major pathogenic mechanisms during liver disease. The interaction of CD95 with its ligand, CD95L(FasL), induces apoptosis and thus the source of the death-inducing ligand is critical for understanding the pathomechanism of liver damage involving the CD95-system. Methods: Sera from HELLP patients were analyzed and used in cell culture experiment…
Immune ambivalence: The schizophrenic bleomycin.
2013
In addition to cytotoxic effects, anticancer agents can exert multiple immunomodulatory functions. We have recently described the molecular mechanisms whereby bleomycin can 1) promote endoplasmic reticulum stress, causing the immunogenic death of cancer cells and hence strengthening antitumor CD8+ T cell responses; and 2) induce the secretion of transforming growth factor β (TGFβ), which stimulates regulatory T cells. This suggests that bleomycin may be favorably combined with TGFβ-targeting strategies.