Search results for "Lymphocyte Activation"
showing 10 items of 414 documents
Activation of phenotypically heterogeneous murine T cell receptor gamma delta + dendritic epidermal T cells by self-antigen(s).
1995
Adult murine epidermis contains a population of Thy-1+, CD45+, CD3+, CD4- and CD8- in situ primarily T cell receptor (TCR) V gamma 3+/V delta 1+ dendritic epidermal T cells (DETC). In the present study, cell surface phenotypes as well as functional properties of DETC were characterized by using in vitro mitogen-stimulated short-term- (10 days) and cloned long-term-cultured (1 year) DETC lines. Phenotypic characterization revealed that80% of the short-term-cultured cells were routinely TCR gamma delta +, CD4-, CD8-. The majority expressed the V gamma 3 TCR. Seventy-five percent of the lines contained detectable numbers of V gamma 2+ (5-7%) and V gamma 2-3- cells (2-3%). Four different types …
Allergen-induced IgE-dependent gut inflammation in a human PBMC-engrafted murine model of allergy.
2011
Background Humanized murine models comprise a new tool to analyze novel therapeutic strategies for allergic diseases of the intestine. Objective In this study we developed a human PBMC–engrafted murine model of allergen-driven gut inflammation and analyzed the underlying immunologic mechanisms. Methods Nonobese diabetic (NOD)– scid -γc −/− mice were injected intraperitoneally with human PBMCs from allergic donors together with the respective allergen or not. Three weeks later, mice were challenged with the allergen orally or rectally, and gut inflammation was monitored with a high-resolution video miniendoscopic system, as well as histologically. Results Using the aeroallergens birch or gra…
Tumor-specific T cell activation by recombinant immunoreceptors: CD3 zeta signaling and CD28 costimulation are simultaneously required for efficient …
2001
Abstract Recombinant immunoreceptors with specificity for the carcinoembryonic Ag (CEA) can redirect grafted T cells to a MHC/Ag-independent antitumor response. To analyze receptor-mediated cellular activation in the context of CD28 costimulation, we generated: 1) CEA+ colorectal tumor cells that express simultaneously B7-1 and B7-2, and 2) CEA-specific immunoreceptors that harbor intracellularly the signaling moities either of CD28 (BW431/26-scFv-Fc-CD28), CD3ζ (BW431/26-scFv-Fc-CD3ζ), or FcεRIγ (BW431/26-scFv-Fc-γ). By retroviral gene transfer, we grafted activated T cells from the peripheral blood with these immunoreceptors. T cells that express the FcεRIγ or CD3ζ signaling receptor lyse…
MHC class II-expressing hepatocytes function as antigen-presenting cells and activate specific CD4 T lymphocyutes.
2003
The ability to activate CD4 T cells is restricted to antigen-presenting cells that express major histocompatibility complex (MHC) class II molecules. Parenchymal cells normally do not express MHC class II molecules; however, in clinical hepatitis, viral or autoimmune, hepatocytes often exhibit aberrant MHC class II expression. It is not known whether MHC class II-expressing hepatocytes can function as antigen-presenting cells, but it has been suggested that aberrant MHC class II expression by parenchymal cells may cause autoimmune disease. Therefore, we generated transgenic mice that specifically overexpress class II transactivator molecules in hepatocytes. Hepatocytes from these mice exhib…
Measurement of T Cell Activation After 16‐hr In Vitro Stimulation with Concanavalin A
2010
A flow cytometry assay that can be used to directly determine the proportion of activated T lymphocytes in human whole blood samples after stimulation with concanavalin A is presented here. Human whole blood is incubated with fluorescently labeled antibodies (against CD3, CD4, CD8, and CD69), erythrocytes are then lysed, and the samples are analyzed using a flow cytometer. The assay presented is able to differentiate between CD4+ and CD8+ T lymphocytes. Thus, it is possible to quantify both lymphocyte populations in parallel, as well as the respective proportions of activated T lymphocytes, all from one sample. An additional advantage of this assay is that it was developed to assay whole bl…
Timing of activation of CD4+ memory cells as a possible marker to establish the efficacy of vaccines against contagious agalactia in sheep
2013
Mycoplasma agalactiae is a major pathogen of sheep and goats in many areas of the world and particularly in Mediterranean countries. It causes contagious agalactia, an infectious disease primarily affecting mammary glands. Many vaccines against the pathogen are currently under development. The aim of the study was to investigate the involvement of T cell-mediated immunity during vaccination and challenge experiments against Mycoplasma agalactiae. A comparison of the antigen-specific expansion of interferon gamma positive T cell memory and naïve subsets was performed between vaccinated and non-vaccinated sheep to identify cellular subsets whose activation was different between protected and …
The role of CD8+ T cells and their local interaction with CD4+ T cells in myelin oligodendrocyte glycoprotein35-55-induced experimental autoimmune en…
2013
Abstract T cells have an essential role in the induction of multiple sclerosis and its animal model experimental autoimmune encephalomyelitis (EAE). Although for CD4+ T cells it is well established that they contribute to the disease, less is known about the role of CD8+ T cells. Our aim was to determine the individual contribution of CD4+ and CD8+ T cells in myelin oligodendrocyte glycoprotein (MOG)35–55–induced EAE. We investigated MOG35–55–activated CD8+ T cells to clarify their potential to induce or attenuate EAE. We monitored the behavior of CD8+ T cells and their interaction with CD4+ T cells directly at the site of inflammation in the CNS using intravital imaging of the brainstem of…
In vitro model for the activation of CD4 and CD8 T cell receptors.
2008
Previously, most models that sought to explain the misregulation of immune cell function assumed molecular similarities between the disease-causing pathogens and the host's proteins. In recent time several different models have been proposed and in this study, these concepts are compared to a new hypothesis proposing another explanation for this immune dysregulation: the possibility that the mislocalization of proteins may be responsible for autoimmune activity. Based on this hypothesis, proteins are recognized as self or non-self depending on where they appear in sufficiently high concentrations. To examine this new idea, the intracellular human proteins beta-actin, GAPDH, and hemoglobin a…
Characterization of lung γδ T cells following intranasal infection with Mycobacterium bovis bacillus Calmette-Guérin
2002
The lungs are considered to have an impaired capacity to contain infection by pathogenic mycobacteria, even in the presence of effective systemic immunity. In an attempt to understand the underlying cellular mechanisms, we characterized the gammadelta T cell population following intranasal infection with Mycobacterium bovis bacillus Calmette-Guerin (BCG). The peak of gammadelta T cell expansion at 7 days postinfection preceded the 30 day peak of alphabeta T cell expansion and bacterial count. The expanded population of gammadelta T cells in the lungs of BCG-infected mice represents an expansion of the resident Vgamma2 T cell subset as well as an influx of Vgamma1 and of four different Vdelt…
Mage-3 and influenza-matrix peptide-specific cytotoxic T cells are inducible in terminal stage HLA-A2.1+ melanoma patients by mature monocyte-derived…
2000
Abstract Dendritic cell (DC) vaccination, albeit still in an early stage, is a promising strategy to induce immunity to cancer. We explored whether DC can expand Ag-specific CD8+ T cells even in far-advanced stage IV melanoma patients. We found that three to five biweekly vaccinations of mature, monocyte-derived DC (three vaccinations of 6 × 106 s.c. followed by two i.v. ones of 6 and 12 × 106, respectively) pulsed with Mage-3A2.1 tumor and influenza matrix A2.1-positive control peptides as well as the recall Ag tetanus toxoid (in three of eight patients) generated in all eight patients Ag-specific effector CD8+ T cells that were detectable in blood directly ex vivo. This is the first time …