Search results for "Class II"
showing 10 items of 194 documents
Cortical neurons selectively inhibit MHC class II induction in astrocytes but not in microglial cells.
1993
Astrocytes have been shown to act as potent accessory cells for MHC class II-restricted T cell responses in vitro after treatment with interferon-gamma. In contrast, even under conditions of severe central nervous system (CNS) inflammation, they seem to express little, if any, class II molecules in vivo. Thus the role of astroglial cells as accessory cells in immune responses in the CNS remains to be determined. We have studied neuron--glia interactions with respect to induction of MHC class II molecules. Surprisingly, in a co-culture system, viable neurons inhibited the induction of class II restriction elements on astrocytes. This effect was only observed when neurons had contact to astro…
Macrophages are dispensable for superantigen-mediated stimulation and anergy induction of peripheral T cells in vivo.
1994
Bacterial superantigens provoke T lymphocyte activation by cross-linking the variable part of the T cell receptor (TCR) beta-chain with MHC class II molecules on antigen-presenting cells. Although the molecular mechanisms of this interaction are well characterized, the in vivo accessory cell requirements for this stimulation of T lymphocytes by bacterial superantigens remain unknown. In the present study we have addressed the role of splenic macrophages in the activation of V beta 8+ peripheral T cells by staphylococcal enterotoxin B (SEB) in BALB/c mice. SEB-triggered clonal expansion and subsequent induction of unresponsiveness of both CD4+ and CD8+ T cells were investigated in naive anim…
Suppressive effects of C3b on monocyte-dependent T cell proliferation.
1987
The effect of C3b treatment of human monocytes on secondary antigen-dependent T cell response was studied. When antigen-specific T cell blasts were cultivated together with C3b-treated monocytes the proliferative response was inhibited in a dose-dependent fashion. This suppressive effect was specific for C3b because heat-inactivated C3b or buffer alone had no influence on T cell proliferation. In part, this suppressive effect is mediated through a C3b-induced decreased expression of class II antigens on the surface of treated monocytes, but another suppressive mechanism exists because the C3b pretreatment of monocytes also led to an inhibition of the proliferative response in a class II ant…
HLA-DR phenotypes and blood levels of T cell subsets
1984
Blood mononuclear cell and T cell subsets values were analyzed in 53 Sicilian individuals according to HLA-DR phenotypes. The results demonstrate that DR1-positive subjects show a significant increase of blood T cell subsets whereas DR3-positive subjects show a non-significant decrease of these values. These results suggest that gene(s) associated with HLA-DR could be one of the factors which affect blood levels of T cell subsets.
Effectiveness of interceptive treatment of class III malocclusions with skeletal anchorage: A systematic review and meta-analysis
2017
Recently, new strategies for treating class III malocclusions have appeared. Skeletal anchorage appears to reduce the dentoalveolar effects while maximising the orthopaedic effect in growing patients. The purpose of this systematic review and meta-analysis is to examine the effectiveness of bone anchorage devices for interceptive treatment of skeletal class III malocclusions. Searches were made in the Pubmed, Embase, Scopus and Cochrane databases, as well as in a grey literature database, and were complemented by hand-searching. The criteria for eligibility were: patients who had undergone orthodontic treatment with skeletal anchorage (miniplates and miniscrews). Patients with syndromes or …
Thymoma and paraneoplastic myasthenia gravis
2010
Paraneoplastic autoimmune diseases associate occasionally with small cell lung cancers and gynecologic tumors. However, myasthenia gravis (MG) occurs in at least 30% of all patients with thymomas (usually present at MG diagnosis). These epithelial neoplasms almost always have numerous admixed maturing polyclonal T cells (thymocytes). This thymopoiesis-and export of mature CD4(+)T cells-particularly associates with MG, though there are rare/puzzling exceptions in apparently pure epithelial WHO type A thymomas. Other features potentially leading to inefficient self-tolerance induction include defective epithelial expression of the autoimmune regulator (AIRE) gene and/or of major histocompatib…
Synthesis and cell surface display of class II determinants by long-term propagated rat T line cells
1987
We have investigated the capacity of the encephalitogenic BS rat T cell line bs 83 and its variant clone bs 83.III.C6 to synthesize and express RT1.B-specific class II molecule subsets defined by monoclonal antibodies (mAb) MRC-OX6 and MRC-OX3. Earlier studies had indicated that mAb MRC-OX6 recognizes three distinct molecular species: an immature oligomeric polypeptide chain complex comprised of the polymorphic subunits alpha, beta and the invariant proteins of the gamma group; a biosynthetic intermediate composed of post-translationally modified alpha, beta and gamma chain (denoted p35) and a fully glycosylated alpha, beta two-chain complex derived from the plasma membrane. MRC-OX3 was sho…
Release of dendritic cells from cognate CD4 + T-cell recognition results in impaired peripheral tolerance and fatal cytotoxic T-cell mediated autoimm…
2012
Resting dendritic cells (DCs) induce tolerance of peripheral T cells that have escaped thymic negative selection and thus contribute significantly to protection against autoimmunity. We recently showed that CD4 + Foxp3 + regulatory T cells (Tregs) are important for maintaining the steady-state phenotype of DCs and their tolerizing capacity in vivo. We now provide evidence that DC activation in the absence of Tregs is a direct consequence of missing DC–Treg interactions rather than being secondary to generalized autoimmunity in Treg-less mice. We show that DCs that lack MHC class II and thus cannot make cognate interactions with CD4 + T cells are completely unable to induce peripheral CD8 +…
The deubiquitinase USP11 is a versatile and conserved regulator of autophagy
2021
Autophagy is a major cellular quality control system responsible for the degradation of proteins and organelles in response to stress and damage to maintain homeostasis. Ubiquitination of autophagy-related proteins or regulatory components is important for the precise control of autophagy pathways. Here, we show that the deubiquitinase ubiquitin-specific protease 11 (USP11) restricts autophagy and that KO of USP11 in mammalian cells results in elevated autophagic flux. We also demonstrate that depletion of the USP11 homolog H34C03.2 in Caenorhabditis elegans triggers hyperactivation of autophagy and protects the animals against human amyloid-β peptide 42 aggregation-induced paralysis. USP11…
Analysis of Invariant Chain Processing in 3 Day Cultured Rat Langerhans Cells
1995
MHC class II molecules, critical peptide binding elements involved in the presentation of exogenous antigen to T helper cells, are expressed constitutively by Langerhans cells (LC) within their epidermal microenvironment. Several studies in mouse and man demonstrated, that short term in vitro culture of LC entails remarkable functional and penotypic alterations, including a profound increase of class II elements exposed at the LC’s surface1. Biosynthetic analysis revealed a downregulation of class II synthesis during the culture period2,3. In recent work on rat LC we described the uncoupling of the coordinately regulated biosynthesis of class II and invariant chain proteins in the course of…