Search results for "interleukin 12"
showing 10 items of 123 documents
Inhibition of anti-GD3-ganglioside antibody-induced proliferation of human CD8+ T cells by CD16+ natural killer cells
1994
The ganglioside GD3 has been described as a membrane component of human T cells which is involved in T cell growth. In the present study the activating function of GD3 for human CD4+ and CD8+ T cells was analyzed by five different monoclonal antibodies (mAb) directed against the GD3 molecule. Three mAb U5, Z21 and R24 induced strong proliferation of peripheral blood mononuclear cells and purified CD8+ and CD4+ T cells of normal donors containing less than 5% CD16+ natural killer (NK) cells. In contrast to CD4+ T cells, CD8+ T cells proliferated only weakly in the presence of 15% CD16+ NK cells. The proliferative response of purified CD4+ and CD8+ T cells (< 5% NK cells) correlated with the …
Inhibition of human allergic T-helper type 2 immune responses by induced regulatory T cells requires the combination of interleukin-10-treated dendri…
2006
Summary Background In grass pollen-allergic individuals, T cell anergy can be induced by IL-10-treated dendritic cells (IL-10-DC) resulting in the suppression of T helper type 1 (Th1) as well as Th2 cells. This study was performed to analyse whether such IL-10-DC-treated T cells are able to act as regulatory T cells (Treg) suppressing the function of other T cells in the periphery. As transforming growth factor (TGF)-β is also a potential inducer of Treg, we additionally analysed the inhibitory capacity of TGF-β-treated T cells in this system. Materials and Methods Freshly isolated CD4+ or CD4+CD25− T cells from grass pollen-allergic donors were stimulated with autologous mature monocyte-de…
Mast cells promote Th1 and Th17 responses by modulating dendritic cell maturation and function
2011
Mast cells (MCs) play an important role in the regulation of protective adaptive immune responses against pathogens. However, it is still unclear whether MCs promote such host defense responses via direct effects on T cells or rather by modifying the functions of antigen-presenting cells. To identify the underlying mechanisms of the immunoregulatory capacity of MCs, we investigated the impact of MCs on dendritic cell (DC) maturation and function. We found that murine peritoneal MCs underwent direct crosstalk with immature DCs that induced DC maturation as evidenced by enhanced expression of costimulatory molecules. Furthermore, the MC/DC interaction resulted in the release of the T-cell mod…
Cytoskeletal stabilization of inhibitory interactions in immunologic synapses of mature human dendritic cells with natural killer cells
2011
Abstract Human mature dendritic cells (DCs) can efficiently stimulate natural killer (NK)–cell responses without being targeted by their cytotoxicity. To understand this important regulatory crosstalk, we characterized the development of the immunologic synapse between mature DCs and resting NK cells. Conjugates between these 2 innate leukocyte populations formed rapidly, persisted for prolonged time periods and matured with DC-derived f-actin polymerization at the synapse. Polarization of IL-12 and IL-12R to the synapse coincided with f-actin polymerization, while other activating and inhibitory molecules were enriched at the interface between DCs and NK cells earlier. Functional assays re…
IL-15 in human visceral leishmaniasis caused byLeishmania infantum
2002
SummaryInterleukin (IL)-15 is a recently discovered cytokine with the ability to stimulate the proliferation activity of Th1 and/or Th2 lymphocytes. Here, we investigated the involvement of IL-15 in the immune response to Leishmania infantum infection by studying patients with visceral leishmaniasis (VL). We found that IL-15 is produced by leishmanial antigen (LAg)-stimulated peripheral blood mononuclear cells (PBMC) from active VL patients at a significantly higher level than those produced by cells from healed VL subjects or healthy controls. A significant increase in IL-15 serum blood levels was also observed in acute VL patients compared with healed ones. Furthermore, recombinant IL-15 …
Pathological role of IL-6 in the experimental allergic bronchial asthma in mice.
2005
Although allergic asthma was described to be associated with the presence of mucosal T helper (Th)2 cells, it is not entirely clear which factors are responsible for priming of T cells to differentiate into Th2 effector cells in this disease. Interleukin (IL)-6 has been recognized as important because it is secreted by cells of the innate immunity and induces the expansion of the Th2 effector cells, which are major players of the adaptive immune responses. Additionally, IL-6 released by dendritic cells (DCs) inhibits the suppressive function of CD4+CD25+ T regulatory cells, thus inhibiting the peripheral tolerance. The signal transduction of IL-6 has recently taught us how this cytokine inf…
Cyclosporin A mediates immunosuppression of primary cytotoxic T cell responses by impairing the release of interleukin 1 and interleukin 2
1981
The site of action of the immunosuppressive drug cyclosporin A in in vitro cytotoxic allograft responses has been localized. General cytotoxic effects of the drug on proliferating T cells became apparent at concentrations of 500-1000 ng/ml, while selective effects were observed at concentrations of 10-100 ng/ml. The selective effects included a blockade of interleukin 2 release from activated T helper cells on the one hand and inhibition of interleukin 1 release from splenic adherent cells on the other. While cyclosporin A did not interfere with the intracellular events required for the activation and subsequent clonal expansion of alloreactive T cells, the lack of interleukin 1 and interle…
Induction of Interleukin 10–Producing, Nonproliferating Cd4+ T Cells with Regulatory Properties by Repetitive Stimulation with Allogeneic Immature Hu…
2000
The functional properties of dendritic cells (DCs) are strictly dependent on their maturational state. To analyze the influence of the maturational state of DCs on priming and differentiation of T cells, immature CD83− and mature CD83+ human DCs were used for stimulation of naive, allogeneic CD4+ T cells. Repetitive stimulation with mature DCs resulted in a strong expansion of alloreactive T cells and the exclusive development of T helper type 1 (Th1) cells. In contrast, after repetitive stimulation with immature DCs the alloreactive T cells showed an irreversibly inhibited proliferation that could not be restored by restimulation with mature DCs or peripheral blood mononuclear cells, or by…
Active suppression induced by cutaneous exposure to bacterial superantigen is prevented by interleukin-12 treatmentin vivo
1998
Exposure to the bacterial superantigen staphylococcal enterotoxin B (SEB) leads to inhibition of several immune responses and the induction of regulatory cells. The aim of this study was to characterize these regulatory cells further and to investigate the effect of interleukin-12 (IL-12) on superantigen-induced suppression. For this purpose BALB/c mice were injected subcutaneously with low doses of SEB that did not deplete the SEB-reactive V beta T cells. Intravenous transfer of unseparated local-draining lymph node cells from these SEB-treated animals suppressed the proliferative response of mononuclear spleen cells of naive syngeneic recipients for at least 3 weeks. The regulatory cells …
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…