Search results for "T cell"
showing 10 items of 2228 documents
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 …
Characterization of a T cell-derived lymphokine that acts synergistically with IL 3 on the growth of murine mast cells and is identical with IL4
1987
Abstract A mast cell-like cell line (SN-1) was established with the aid of growth factor(s) present in the supernatant of a Con A-stimulated L3T4 + T cell line. In analogy to other mast cell lines, IL 3 was identified as a growth factor for SN-1 cells. In addition, a second lymphokine produced by the T cells synergistically enhanced the IL 3-induced growth. This factor, originally termed mast cell growth enhancing factor (MaGEF), could be separated from IL 2, IL 3, a CSF-like activity and was purified to homogeneity. The N-terminal amino acid sequence (8 residues) and the functional properties of this lymphokine proved to be identical with those reported for BSF-1 (IL 4). Unless applied at …
Cutting Edge: A Key Pathogenic Role of IL-27 in T Cell- Mediated Hepatitis
2007
Abstract The signals driving T cell activation in T cell-mediated fulminant hepatitis are not fully understood. In this study, we identify the cytokine IL-27p28/EBI3 as a major pathogenic factor in the ConA model of T cell-mediated hepatitis. We found an up-regulation of hepatic EBI3 and p28 expression and augmented levels of IL-27 in wild-type mice after ConA administration, suggesting a potential pathogenic role of this cytokine in ConA hepatitis. Consistently, IL-27 EBI3-deficient mice were almost completely protected from ConA-induced liver damage. Such protection was associated with reduced levels of IFN-γ and its signaling proteins pSTAT-1 and T-bet. Finally, in vivo blockade of IL-27…
Shared determinants between virus-infected and trinitrophenyl-conjugated H-2-identical target cells detected in cell-mediated lympholysis
1976
Infection of H-2-identical mice with either lymphocytic choriomeningitis (LCM) virus, vaccinia virus, or paramyxo (Sendai) virus resulted in the generation of specifically sensitized cytotoxic T lymphocytes (CTL). CTL generated in vitro against 2,4,6-trinitrophenyl (TNP)-conjugated syngeneic stimulator cells were specifically cytotoxic for TNP-conjugated H-2K (D) region identical targets. Both LCM and vaccinia-induced CTL, however, were found to be strongly cytotoxic towards TNP-conjugated, H-2K(D) region-identical target cells. In contrast, Sendai virus-induced CTL did not lyse TNP-conjugated, syngeneic target cells. Inhibition experiments using cold targets suggested that shared antigenic…
Specialized subsets of innate-like T cells and dendritic cells protect from lethal pneumococcal infection in the lung
2021
SummaryInnate-like T cells, including invariant natural killer T (iNKT) cells, mucosal-associated invariant T (MAIT) cells and γδ T cells, are present in various barrier tissues, including the lung. They carry out protective responses during infections, but the mechanisms for protection are not completely understood. Here, we investigated their roles during pulmonary infection with Streptococcus pneumoniae. Following infection, innate-like T cells rapidly increased in lung tissue, in part through recruitment, but TCR activation and cytokine production occurred mostly in IL-17-producing NKT17 and γδ T cells. NKT17 cells were preferentially located outside the vasculature prior to infection, …
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…
Editorial: Activation, functions, and generation of immunological memory in γδ T lymphocytes: lessons from nonhuman primates
2014
T cells constitute an unconventional lymphocyte population with distinct functions complementary to those of CD4 and CD8 T cells. As such, they have both adaptive features, such as expression of the TCR, and innate-like functions reminiscent of NK cells, with whom they share extensive repertoires of activating and inhibitory receptors [1, 2]. Although most antigens recognized by murine T cells remain obscure, advances have been made in identifying ligands for human T cells. The majority of circulating human T lymphocytes expresses a TCR formed by the preferentially-paired V 9 and V 2 chains (here and thereafter, called V 9V 2 T cells). Instead of binding peptides associated with molecules b…
Cell Immunity in Inflammatory Vasculitis
2015
The vasculitides are a highly heterogeneous group of disorders characterized by the presence of inflammatory leukocytes in the vessel walls and reactive inflammation. Giant cell arteritis (GCA) and Takayasu’s arteritis (TA) are the two primary large-vessel vasculitides. Two distinct cellular pathways have been identified in GCA: Th17 polarization and IL-17 secretion and generation of Th1 cells which secrete IFN-γ. These two pathways may play different roles in the pathogenesis of vasculitides. The antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAVs) are small vessel vasculitis associated with antibodies directly to myeloperoxidase (MPO-ANCA) such as eosinophilic granulo…
Association between Serum Heat Shock Proteins and Gamma-Delta T Cells—An Outdated Clue or a New Direction in Searching for an Anticancer Strategy? A …
2021
HSPs demonstrate a strong association with gamma-delta (γδ) T cells. Most of the studies regarding interactions between the parameters were conducted in the 1990s. Despite promising results, the concept of targeting γδ T cells by HSPs seems to be a forgotten direction due to potent non-peptidic phosphoantigens rather than HSPs have been found to be the essential stimulatory components for human γδ cells. Currently, with greater knowledge of lymphocyte diversity, and more accurate diagnostic methods, we decided to study the correlation once again in the neoplastic condition. Twenty-one children with newly diagnosed acute lymphoblastic leukaemia (ALL) were enrolled on the study. Serum HSP90 c…
Postsurgical Paracicatricial Cutaneous Satellitosis of Giant Cell Tumour of Tendon Sheath, Localized Type.
2011
The tenosynovial giant cell tumour (localized type) is a tumour of tendon sheaths and interphalangeal joints, affecting the digits and arising from the synovium. It is characterized by a proliferation of mononuclear cells and osteoclast-like polykaryocytes. Its propagation to the skin is an exceptional event, which can take place either in localized form in the fingertips (localized type) or in the rare diffuse form called giant cell tumour of the tendon sheath, ( diffuse type ). We report here a case of giant cell tumour with cutaneous satellites, which appeared close to and around the surgical scar following the excision of the primary lesion, in a 9-year-old boy. In the cutaneous satelli…