Search results for "IL-2"
showing 10 items of 267 documents
Interleukin 1 stimulates T lymphocytes to produce granulocyte-monocyte colony-stimulating factor.
1988
T lymphocytes are thought to cooperatively interact with monocytes to produce colony-stimulating factors (CSF). However, little is known about monocyte-mediated signals leading to CSF-secretion by T lymphocytes, although soluble monocyte products have been implicated. We have employed monoclonal antibody anti-T3B covalently coupled to CnBr-activated Sepharose 4B beads, to show that multimeric ligation of T cell antigen receptor leads to T cell receptiveness to interleukin 1 (IL-1), as indicated by T cell production of CSF, which induces growth of myeloid progenitor cells into neutrophil, eosinophil, and monocyte colonies. To investigate the molecular basis of these findings, total RNA was e…
The mitochondrial protein TCAIM regulates activation of T cells and thereby promotes tolerance induction of allogeneic transplants.
2013
Primary T cell activation and effector cell differentiation is required for rejection of allogeneic grafts in naive recipients. It has become evident, that mitochondria play an important role for T cell activation. Expression of several mitochondrial proteins such as TCAIM (T cell activation inhibitor, mitochondrial) is down-regulated upon T cell receptor triggering. Here we report that TCAIM inhibited spontaneous development of memory and effector T cells. CD4(+) T cells from Tcaim knock-in (KI) mice showed reduced activation, cytokine secretion and proliferation in vitro. Tcaim KI T cells tolerated allogeneic skin grafts upon transfer into Rag-1 KO mice. CD4(+) and CD8(+) T cells from the…
Tonic T cell signalling and T cell tolerance as opposite effects of self-recognition on dendritic cells.
2010
Naive T cells spend most of their time scanning the surface of dendritic cells (DCs), indicating that self-MHC/T cell receptor (TCR) interactions between these immune cells occur routinely in peripheral organs during the steady state. Peripheral self-MHC recognition on DCs drives seemingly opposing effects in the absence of inflammatory stimuli such as deletion of certain self-reactive T cells as well as maintenance of the T cell responsiveness to antigen, both of which shape the T cell repertoire and regulate T cell responses. Here we review recent data on the role of self-MHC recognition on steady-state DCs in the periphery and propose that interactions between T cells and steady-state DC…
With a little help from my old T cell: Memory follicular T helper cells driving autoimmunity?
2014
It has long been known that the B cell repertoire includes cells that are capable of producing autoantibodies and that these cells can be found in humans and also in wild type strains of laboratory mice; however, normally, these B cells do not give rise to plasma cells, and thus do not fulfil their autoimmune potential. In this issue of the European Journal of Immunology, Nusser et al. [Eur. J. Immunol. 2014. 44: 2893–2902] dissect the mechanism by which these B cells are activated and autoantibodies are produced. The authors demonstrate that T cells, most likely antigen-specific, which accumulate with age or as a result of homeostatic proliferation, provide essential help to these autoreac…
An innate cell-mediated, murine ulcerative colitis-like syndrome in the absence of nuclear factor of activated T cells.
2004
Abstract Background & Aims: Nuclear factor of activated T cells transcription factors plays a central role in immunity by regulating the expression of multiple cytokines and other regulatory molecules, many of which have been heavily implicated in the pathogenesis of inflammatory bowel disease. However, few studies have directly investigated the nuclear factor of activated T cells proteins in inflammatory bowel disease. We describe here a specific role for nuclear factor of activated T cells c2 in the pathogenesis of murine inflammatory bowel disease. Methods: Mice deficient for nuclear factor of activated T cells c2, recombinase activating gene-2, or both and transgenic or nontransgenic fo…
Unexpected Modulation of Recall B and T Cell Responses after Immunization with Rotavirus-like Particles in the Presence of LT-R192G
2010
LT-R192G, a mutant of the thermolabile enterotoxin of E. coli, is a potent adjuvant of immunization. Immune responses are generally analyzed at the end of protocols including at least 2 administrations, but rarely after a prime. To investigate this point, we compared B and T cell responses in mice after one and two intrarectal immunizations with 2/6 rotavirus-like particles (2/6-VLP) and LT-R192G. After a boost, we found, an unexpected lower B cell expansion measured by flow cytometry, despite a secondary antibody response. We then analyzed CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) and CD4(+)CD25(+)Foxp3(-) helper T cells after in vitro (re)stimulation of mesenteric lymph node cells …
Tolerance without clonal expansion: self-antigen-expressing B cells program self-reactive T cells for future deletion.
2008
Abstract B cells have been shown in various animal models to induce immunological tolerance leading to reduced immune responses and protection from autoimmunity. We show that interaction of B cells with naive T cells results in T cell triggering accompanied by the expression of negative costimulatory molecules such as PD-1, CTLA-4, B and T lymphocyte attenuator, and CD5. Following interaction with B cells, T cells were not induced to proliferate, in a process that was dependent on their expression of PD-1 and CTLA-4, but not CD5. In contrast, the T cells became sensitive to Ag-induced cell death. Our results demonstrate that B cells participate in the homeostasis of the immune system by abl…
T Cells Integrate Local and Global Cues to Discriminate between Structurally Similar Antigens
2015
International audience; T lymphocytes' ability to discriminate between structurally related antigens has been attributed to the unique signaling properties of the T cell receptor. However, recent studies have suggested that the output of this discrimination process is conditioned by environmental cues. Here, we demonstrate how the IL-2 cytokine, collectively generated by strongly activated T cell clones, can induce weaker T cell clones to proliferate. We identify the PI3K pathway as being critical for integrating the antigen and cytokine responses and for controlling cell-cycle entry. We build a hybrid stochastic/deterministic computational model that accounts for such signal synergism and …
Infectious Tolerance
2002
Regulatory CD4(+)CD25(+) T cells (Treg) are mandatory for maintaining immunologic self-tolerance. We demonstrate that the cell-cell contact-mediated suppression of conventional CD4(+) T cells by human CD25(+) Treg cells is fixation resistant, independent from membrane-bound TGF-beta but requires activation and protein synthesis of CD25(+) Treg cells. Coactivation of CD25(+) Treg cells with Treg cell-depleted CD4(+) T cells results in anergized CD4(+) T cells that in turn inhibit the activation of conventional, freshly isolated CD4(+) T helper (Th) cells. This infectious suppressive activity, transferred from CD25(+) Treg cells via cell contact, is cell contact-independent and partially medi…
Perpetual proliferation of LYT-1 cells requires repetitive signals for IL-2 receptor induction by antigen-presenting cells.
1984
Abstract T cell lines with specificity for bovine insulin and ovalbumin were maintained by serial stimulation with antigen presented on irradiated syngeneic spleen cells, alternating 3 days later with subculture in IL-2 containing medium (CM). When the cultures were repetitively split in CM, with concomitant dilution of antigen-presenting cells, a gradual loss of proliferative capacity of the cells in the presence of CM was observed. Absorption studies revealed a 20-fold reduction of IL-2 receptors on the surface of T blasts assayed 12 days after antigenic stimulation as compared with day 5 blasts. This decrement in the number of IL-2 acceptor sites reflected an actual decrease in cell surf…