Search results for "T Cell"
showing 10 items of 2228 documents
TLR2 and Dectin-1 Signaling in Mouse Hematopoietic Stem and Progenitor Cells Impacts the Ability of the Antigen Presenting Cells They Produce to Acti…
2020
Microbial recognition by pattern recognition receptors (PRRs) expressed on hematopoietic stem and progenitor cells (HSPCs) not only activates myelopoiesis but also programs the function of the monocytes and macrophages they produce. For instance, changes in HSPC programming modify the ability of macrophages derived from them to produce inflammatory cytokines. While HSPCs exposed to a TLR2 agonist give rise to tolerized macrophages (lower proinflammatory cytokine production), HSPCs treated with Dectin-1 ligands produce trained macrophages (higher proinflammatory cytokine production). However, nothing is known about the impact of HSPC exposure to microbes on the function of antigen presenting…
Characterization of T–cell subclasses and NK–cells in lysosomal disorders by immuno–electron microscopy
1994
Previous studies have shown that B and T lymphocytes are affected in lysosomal disorders. The aim of this study was to investigate the involvement of subclasses of T lymphocytes and natural killer cells in lysosomal diseases. CD4+, CD8+, and CD56+ cells were immunomagnetically separated from peripheral blood mononuclear cells in 10 patients with various lysosomal diseases--including one patient each with infantile, late infantile, and juvenile neuronal ceroid-lipfuscinoses, two patients with mucopolysaccharidosis (MPS) type I and four patients with MPS type III, and one patient with mucolipidosis type II; all lymphocytes were studied by light and electron microscopy. Respective vacuolar or …
Functionalized Polystyrene Nanoparticles Trigger Human Dendritic Cell Maturation Resulting in Enhanced CD4+T Cell Activation
2012
Nanoparticles (NP) represent a promising tool for biomedical applications. Here, sulfonate- and phosphonate-functionalized polystyrene NP are analyzed for their interaction with human monocyte-derived dendritic cells (DC). Immature dendritic cells (iDC) display a higher time- and dose-dependent uptake of functionalized polystyrene NP compared to mature dendritic cells (mDC). Notably, NP induce an enhanced maturation of iDC but not of mDC (upregulation of stimulatory molecules and cytokines). NP-triggered maturation results in a significantly enhanced T cell stimulatory capacity (increased CD4(+) T cell proliferation and IFN-γ production), indicating a shift to a pronounced Th1 response. Imm…
Chemokines enhance immunity by guiding naive CD8+ T cells to sites of CD4+ T cell-dendritic cell interaction.
2005
CD8+ T cells have a crucial role in resistance to pathogens and can kill malignant cells; however, some critical functions of these lymphocytes depend on helper activity provided by a distinct population of CD4+ T cells. Cooperation between these lymphocyte subsets involves recognition of antigens co-presented by the same dendritic cell, but the frequencies of such antigen-bearing cells early in an infection and of the relevant naive T cells are both low. This suggests that an active mechanism facilitates the necessary cell-cell associations. Here we demonstrate that after immunization but before antigen recognition, naive CD8+ T cells in immunogen-draining lymph nodes upregulate the chemok…
Alloreactive and leukemia-reactive T cells are preferentially derived from naive precursors in healthy donors: implications for immunotherapy with me…
2011
Background HLA mismatch antigens are major targets of alloreactive T cells in HLA-incompatible stem-cell transplantation, which can trigger severe graft- versus -host disease and reduce survival in transplant recipients. Our objective was to identify T-cell subsets with reduced in vitro reactivity to allogeneic HLA antigens. Design and Methods We sorted CD4 and CD8 T-cell subsets from peripheral blood by flow cytometry according to their expression of naive and memory markers CD45RA, CD45RO, CD62L, and CCR7. Subsets were defined by a single marker to facilitate future establishment of a clinical-grade procedure for reducing alloreactive T-cell precursors and graft- versus -host disease. T c…
Local blockade of IL-6R signaling induces lung CD4+ T cell apoptosis in a murine model of asthma via regulatory T cells.
2007
We previously reported high levels of the soluble form of the IL-6R (sIL-6R) in the airways of asthmatic subjects. Here, we analyzed the IL-6R effects on Th2 cell survival in the lung by locally antagonizing sIL-6R-mediated trans-signaling with a designer fusion protein (gp130-Fc) as well as IL-6R signaling with an antibody against the gp80 unit of the IL-6R (alphaIL-6R) in a murine model of asthma after ovalbumin peptide (OVA) sensitization and challenge. Blockade of the sIL-6R led to a significant decrease in inflammatory cells by an apoptosis-independent mechanism. In contrast, local treatment with alphaIL-6R antibodies that also block signaling via the membrane-bound IL-6R (mIL-6R) led …
Cytokine profile, HLA restriction and TCR sequence analysis of human CD4+ T clones specific for an immunodominant epitope of Mycobacterium tuberculos…
2003
SUMMARY The identification of immunodominant and universal mycobacterial peptides could be applied to vaccine design and have an employment as diagnostic reagents. In this paper we have investigated the fine specificity, clonal composition and HLA class II restriction of CD4+ T cell clones specific for an immunodominant epitope spanning amino acids 91–110 of the 16-kDa protein of Mycobacterium tuberculosis. Twenty-one of the tested 28 clones had a Th1 profile, while seven clones had a Th0 profile. None of the clones had a Th2 profile. While the TCR AV gene usage of the clones was heterogeneous, a dominant TCR BV2 gene family was used by 18 of the 28 clones. The CDR3 regions of BV2+ T cell c…
Modulation of proliferation and lymphokine secretion of murine CD4+ T cells and cloned Th1 cells by proteins of the extracellular matrix.
1997
In this study we investigated the co-stimulatory signaling capacity of diverse proteins of the extracellular matrix (ECM) for murine resting CD4+ T cells and Th1 clone cells, activated by immobilized anti-CD3 mAb. ECM proteins used in various concentrations had no effect on IL-2 production or proliferation of highly purified CD4+ T cell populations. When the preparation of CD4+ T cells contained contaminating accessory cells, IL-2 secretion and proliferation was enhanced in the presence of co-immobilized collagens or fibronectin. However, the level of proliferation attainable by added irradiated splenocytes was not reached. Using Th1 cell clone M4, enhanced production of IL-2 in the presenc…
NFATc2 and NFATc3 transcription factors play a crucial role in suppression of CD4+ T lymphocytes by CD4+ CD25+ regulatory T cells
2005
The phenotype of NFATc2(-/-) c3(-/-) (double knockout [DKO]) mice implies a disturbed regulation of T cell responses, evidenced by massive lymphadenopathy, splenomegaly, and autoaggressive phenomena. The population of CD4(+) CD25(+) T cells from DKO mice lacks regulatory capacity, except a small subpopulation that highly expresses glucocorticoid-induced tumor necrosis factor receptor family-related gene (GITR) and CD25. However, neither wild-type nor DKO CD4(+) CD25(+) regulatory T cells (T reg cells) are able to suppress proliferation of DKO CD4(+) CD25(-) T helper cells. Therefore, combined NFATc2/c3 deficiency is compatible with the development of CD4(+) CD25(+) T reg cells but renders c…
Cooperation of Human Tumor-Reactive CD4+ and CD8+ T Cells after Redirection of Their Specificity by a High-Affinity p53A2.1-Specific TCR
2004
Abstract Efficient immune attack of malignant disease requires the concerted action of both CD8 + CTL and CD4 + Th cells. We used human leukocyte antigen (HLA)-A*0201 (A2.1) transgenic mice, in which the mouse CD8 molecule cannot efficiently interact with the α3 domain of A2.1, to generate a high-affinity, CD8-independent T cell receptor (TCR) specific for a commonly expressed, tumor-associated cytotoxic T lymphocyte (CTL) epitope derived from the human p53 tumor suppressor protein. Retroviral expression of this CD8-independent, p53-specific TCR into human T cells imparted the CD8 + T lymphocytes with broad tumor-specific CTL activity and turned CD4 + T cells into potent tumor-reactive, p53…