Search results for "T cell"
showing 10 items of 2228 documents
A novel plasmid DNA electroporation method allows transfection of murine DC.
2007
Under steady state conditions dendritic cells (DC) exert tolerogenic function, but acquire potent immunogenic function due to strong upregulation of costimulatory molecules and proinflammatory cytokines. In numerous studies the potential of modified DC to induce tolerance or immune reactions towards a distinct antigen has been demonstrated. However, DC are refractory to transfection with plasmid DNA by non-viral methods. In this study we have tested the suitability of a newly developed electroporation device to transfect immature murine bone-marrow derived DC (BM-DC). Transfected BM-DC expressed reporter molecules at considerable extent which renders this method suitable to perform all kind…
A CD40/CD40L feedback loop drives the breakdown of CD8+T-cell tolerance following depletion of suppressive CD4+T cells
2014
Dendritic cells (DCs) are the key APCs not only for the priming of naive T cells, but also for the induction and maintenance of peripheral T-cell tolerance. We have recently shown that cognate interactions between Foxp3(+) Tregs and steady-state DCs are crucial to maintain the tolerogenic potential of DCs. Using DIETER mice, which allow the induction of antigen presentation selectively on DCs without altering their maturation status, we show here that breakdown of CD8(+) T-cell tolerance, which ensues after depletion of suppressive CD4(+) T cells, is driven by a positive feedback loop in which autoreactive CD8(+) T cells activate DCs via CD40. These data identify ligation of CD40 on DCs as …
Quantitative representation of all T cells committed to develop into cytotoxic effector cells and/or interleukin 2 activity-producing helper cells wi…
1984
A limiting dilution culture system based on stimulation with concanavalin A (Con A) has been used to study the quantitative distribution of helper and of cytotoxic precursor cells in Lyt-2-defined subpopulations of murine T cells. Virtually all of the selected Lyt-2+ and Lyt-2-T cells grow and expand to large clonal colonies within an 8-9-day culture period. Our data show that upon stimulation with Con A, 90% of the Lyt-2-T cells were capable to produce interleukin 2 (IL 2) activity. In addition, IL 2 activity is produced by 8-10% of Lyt-2+ T cells. However, at the clonal level, the average of the IL2 activity produced by Lyt-2+ T cells is about 8-fold less as compared to Lyt-2-T cells. Pre…
Role of accessory cells in cytokine production by T cells in chronic B- cell lymphocytic leukemia
1995
Abstract We investigated the production of cytokines by highly purified T helper cells from B-cell chronic lymphocytic leukemia (B-CLL) patients stimulated by different activation pathways, and we studied the influence of various accessory cell populations on the pattern of the secretion of cytokines, including interleukin (IL)-2, IL-4, interferon- gamma (IFN-gamma), and IL-10. Neither a qualitative nor a quantitative difference in cytokine production and proliferative capacity was observed in CLL-derived purified T cells compared with normal individuals, when T cells were stimulated by different pathways, including CD3, CD2, and costimulation with CD28. Addition of autologous accessory cel…
Interleukin-10–Treated Human Dendritic Cells Induce a Melanoma-Antigen–Specific Anergy in CD8+ T Cells Resulting in a Failure to Lyse Tumor Cells
1999
Abstract Dendritic cells (DC) are critically involved in the initiation of primary immune processes, including tumor rejection. In our study, we investigated the effect of interleukin-10 (IL-10)–treated human DC on the properties of CD8+ T cells that are known to be essential for the destruction of tumor cells. We show that IL-10–pretreatment of DC not only reduces their allostimulatory capacity, but also induces a state of alloantigen-specific anergy in both primed and naive (CD45RA+) CD8+ T cells. To investigate the influence of IL-10–treated DC on melanoma-associated antigen-specific T cells, we generated a tyrosinase-specific CD8+ T-cell line by several rounds of stimulation with the sp…
T helper cell populations: As flexible as the skin?
2011
T helper cells can be defined by the cytokines they produce and are divided into Th1, Th2, Th17, T(FH) or regulatory T cells. Th17 cells have been shown to produce, in addition to IL-17, IL-22. In the current issue of the European Journal of Immunology, an article by Larsen et al. (Eur. J. Immunol. 2011. 41: 2596-2605) provides evidence that human T helper cells, like murine cells, can also express IL-22 in the absence of the other T helper cell signature cytokines. Moreover, they show that these IL-22-producing cells, namely Th22 cells, can be found in the skin of psoriasis patients, where they might contribute to the pathogenesis of this inflammatory skin disease. Finally, they show that,…
T cell directives for transcriptional regulation in asthma.
2003
Allergic asthma frequently starts in childhood, and environmental factors such as viruses, allergens and occupational exposure can regulate the evolution of the disease. The development of allergen-specific Th2 lymphocytes represents the triggering event for the recruitment and activation of IgE-producing B cells and fibroblasts, followed by the release of soluble factors, thus giving rise to the inflammatory reaction observed in this disease. GATA-3 was identified as a cell lineage-specific factor selectively expressed and activated in the Th2 lineage as a consequence of STAT-6 activation. However, recent literature indicates that blockade of CTLA-4-directed inhibitory signals is sufficien…
2 Isolation of T Cells and Establishment of T-cell Lines and Clones
1998
Publisher Summary This chapter elaborates the isolation of T cells and the establishment of T-cell lines and clones. The study of human T cells is best performed using purified cells because the presence of other cell types may have indirect effects on T-cell function. For any kind of functional assay on T-cell specificity, antigen-presenting cells are necessary. T cells appear to play a major role in the development, maintenance, and also resolution of these forms of bacteria-associated arthritides. The E-rosetting technique describes a procedure for separating T cells and non-T cells from a population of MNCs. This method is based on the ability of human T cells to bind to sheep erthrocyt…
A rapid and simple multiparameter assay to quantify spike-specific CD4 and CD8 T cells after SARS-CoV-2 vaccination: A preliminary report
2021
mRNA and Adenovirus vaccines for COVID-19 are used to induce humoral and cell-mediated immunity, with the aim to generate both SARS-CoV-2 B and T memory cells. In present study, we described a simple assay to detect and quantify Spike-specific CD4+ and CD8+ T cell responses induced by vaccination in healthy donors and in subjects with B cell compart impairment, in which antibody response is absent due to primary immunodeficiencies or CD20 depleting therapy. We detect and quantified memory T cell immune responses against SARS-CoV-2 evocated by vaccination in both groups, irrespective to the humoral response. Furthermore, we identified TNF-α as the main cytokine produced by T memory cells, af…
Reconstitution of CD52-Negative CD4 T Cells after Alemtuzumab-Based T Cell Depleted Allogeneic Hematopoietic Stem Cell Transplantation
2008
Abstract The human CD52 molecule is the target of the monoclonal antibody Alemtuzumab, which is used for treating patients with chemo-refractory chronic lymphocytic leukemia as well as for T cell depletion (TCD) in the context of allogeneic hematopoietic stem cell transplantation (HSCT). The molecule is expressed on the surface of lymphocytes, dendritic cells and to a lesser extent on blood-derived monocytes. Previously, investigators have demonstrated that the surface expression of CD52 on T cells is down-regulated after in vitro incubation with Alemtuzumab. By treating purified human CD4 T cells over 4 hours with 10 μg/mL Alemtuzumab in medium supplemented with 10% human AB serum in vitro…