Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0014070 (encephalomyelitis)
 13,017 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In strains of mice that are susceptible to experimental autoimmune encephalomyelitis (EAE), cloned CD4+ T cells reactive with autologous myelin basic protein (MBP) have been shown to cause disease when transferred to naive syngeneic recipients. Recent reports indicate that under particular experimental conditions, 'resistant' strains of mice can also develop EAE, although cloned cells have not been isolated and characterized. An analysis of the characteristics of a panel of MBP-specific T cells and the antigen presenting capability of CNS-derived cells obtained from the resistant strain BALB/c is presented here. The data demonstrate that immunization of EAE-resistant BALB/c mice results in the activation of a heterogeneous group of T cells reactive with autologous MBP. Both peripheral antigen presenting cells, as well as microglia isolated from brains of BALB/c mice, are capable of stimulating these cloned MBP-specific T cells to proliferate. When optimally activated in vitro and then injected in vivo into syngeneic BALB/c recipients, three clones studied induced severe cachexia, resulting in loss of up to 35% of body weight before death. Two of the clones also induced clinical and histological EAE, while the third induced only occasional histological evidence of disease. Differences in epitope recognition, T cell receptor usage, cytokine profiles or regulatory mechanisms of self tolerance, may play important roles in preventing potentially destructive autoimmune reactions by these T cells capable of recognizing autologous myelin in the central nervous system.
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PMID:T cell responses to myelin basic protein in experimental autoimmune encephalomyelitis-resistant BALB/c mice. 768 53

Experimental allergic encephalomyelitis (EAE) is a prototype for CD4+ T cell-mediated autoimmune diseases. Immunization with myelin basic protein (MBP) in B10.PL mice results in EAE, and a majority of animals recover permanently from the disease. Most MBP-reactive encephalitogenic T cells recognize an immunodominant NH2-terminal peptide, Ac1-9, and predominantly use the T cell receptor (TCR) V beta 8.2 gene segment. Here we report that in mice recovering from MBP-induced EAE, peripheral T cells proliferate in response to a single immunodominant TCR peptide from the V beta 8.2 chain (amino acids 76-101), indicating natural priming during the course of the disease. Cloned T cells, specific for this TCR peptide, specifically downregulate proliferative responses to Ac1-9 in vivo and also protect mice from MBP-induced EAE. These regulatory T cells express CD4 molecules and recognize a dominant peptide from the TCR variable framework region of V beta 8.2, in the context of the major histocompatibility complex class II molecule, I-Au, and predominantly use the TCR V beta 14 gene segment. This is the first demonstration of the physiological induction of TCR peptide-specific CD4+ T cells that result from MBP immunization and that are revealed only during the recovery from disease. The downregulation of disease-causing T cells by TCR peptide-specific T cells offers a mechanism for antigen-specific, network-induced recovery from autoimmune disease.
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PMID:The involvement of T cell receptor peptide-specific regulatory CD4+ T cells in recovery from antigen-induced autoimmune disease. 768 92

Neuritogenic T cells specific for SP-26, a synthetic peptide (residue 53-78) of myelin P2 protein that causes experimental autoimmune neuritis (EAN), use the same T cell receptor (TCR) V gene family (V beta 8) that can induce experimental autoimmune encephalomyelitis (EAE) in Lewis rats. Tolerance to autoregulatory T cells may be induced in rats by intravenous (iv) administration of antigen-coupled splenocytes; however, the mechanisms that lead to altered immune reactivity are not well understood. Here we demonstrate that SP-26, when coupled to syngeneic spleen cells and administered iv, either before or after disease induction, markedly inhibited development and expression of clinical signs and histological changes of EAN. The induction of tolerance by this method was peptide-specific and MHC-restricted. We showed previously that T cells involved in EAN utilize the T cell antigen receptor V beta 8, whereas less than 5% of normal rat peripheral T cells express V beta 8. We have examined T lymphocytes from tolerized rats to determine the presence or absence of V beta 8(+)-bearing cells in order to determine the mechanism of tolerance. V beta 8 cells were undetectable by Northern blot analysis in the lymph nodes of unimmunized animals but easily detected in SP-26-primed and tolerized rats. In addition, spleen cells isolated from tolerized animals were anergic and failed to proliferate in response to SP-26, but retained responsiveness to IL-2 and Con A stimulation. Thus, the peptide-specific unresponsiveness that can be induced in rats with EAN, a T-cell-mediated process that is MHC-restricted and utilizes the T cell receptor V beta 8, occurs while V beta 8 transcripts remain readily detectable in spleen and lymph node cells. The detection of V beta 8-bearing T cells requires the development of antibodies specific for this rat surface protein.
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PMID:Induction of peripheral tolerance with peptide-specific anergy in experimental autoimmune neuritis. 769 Mar 7

Activated CD4+ T lymphocytes specific for myelin basic protein (MBP) can cause experimental autoimmune encephalomyelitis (EAE) upon their inoculation into syngeneic recipients. In Lewis rats, most of the pathogenic T cell clones that develop following immunization with MBP are reactive against the 72-84 amino acid sequence of MBP, the major encephalitogenic region for Lewis rats. In this study, some MBP-specific T cell clones were found to be non-pathogenic, in spite of their strong reactivity against the encephalitogenic epitope. One of these non-pathogenic clones, designated Znp, and an encephalitogenic clone, Z1a-p, were derived from Z1a encephalitogenic line cells. These subclones were compared for epitope specificity, T cell receptor variable gene expression and for various functional activities, in order to delineate properties crucial for pathogenicity. The Z1a-p and Znp cells expressed comparable levels of the T cell receptor genes and shared strong reactivity against the 72-84 epitope of MBP. The pathogenic Z1a-p cells displayed MBP-specific cytolytic activity in vitro, provided an in-vivo 'help' for elicitation of MBP-specific antibodies, mediated a delayed type hypersensitivity (DTH) response to MBP, caused EAE and vaccinated against the disease, thus demonstrating that a single CD4+ T cell clone is capable of eliciting various functions. The non-pathogenic Znp cells could also carry out most of these various functions, but failed to mediate a DTH response to MBP in normal animals. However, when inoculated into sublethally (650 R) irradiated syngeneic recipients, the Znp cells became highly pathogenic and mediated DTH response to MBP. Local irradiation of the recipient facilitated a DTH response to MBP in the irradiated ear, indicating that Znp cells are equipped with the effector mechanisms required for pathogenicity, and that their failure to cause disease may be accounted for by their inability to migrate into extravascular target tissue. Similar data were obtained with an independently isolated non-pathogenic clone, LB-3, specific for the encephalitogenic epitope of MBP. The ability of these non-pathogenic cells to vaccinate against EAE mediated by pathogenic cells raises the possibility that such non-pathogenic cells may play a role in triggering downregulation of pathogenic T cells.
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PMID:Pathogenic and non-pathogenic T lymphocytes specific for the encephalitogenic epitope of myelin basic protein: functional characteristics and vaccination properties. 769 Jul 70

To determine the role of encephalitogenic T cells in the formation of lesions in the central nervous system (CNS), experimental autoimmune encephalomyelitis (EAE) was induced in Lewis rats by immunization with either myelin basic protein (MBP) or the synthetic peptide which corresponds to the 87-100 sequence of guinea pig MBP, and T cells expressing T cell receptor (TcR) V beta 8.2, V beta 8.5, V beta 10 and V beta 16 in the lymphoid organs and CNS were localized and quantified by flow cytometry (FCM) and immunohistochemistry. In normal rats, the percentage of T cells expressing these V beta phenotypes to the total number of TcR alpha beta+ T cells, as determined by FCM, ranged from 5% to 10% in the lymph node. V beta 16+ T cells were the most predominant population among the four V beta subsets tested. Essentially the same findings were obtained from the analysis of the lymphoid organs of rats with EAE which had been induced by immunization with the same two antigens. In sharp contrast, 15-20% of the T cells isolated from lesions of MBP-induced EAE expressed V beta 8.2. Thus, the percentage of V beta 8.2+ T cells in the EAE lesions was threefold higher than that in the lymph node, while the proportions of V beta 8.5+, V beta 10+ and V beta 16+ T cells were about the same in both organs. The predominance of V beta 8.2+ T cells in EAE lesions was confirmed by counts of immunohistochemically stained T cells in the spinal cord. Moreover, it was revealed that (i) the predominance of V beta 8.2+ T cells was greatest during the development of EAE and became less obvious at the recovery state, and (ii) at the peak stage of EAE, approximately 85% of V beta 8.2+ T cells were distributed in the parenchyma while 15% were in the perivascular space of the CNS vessels. These findings indicate that encephalitogenic T cells which express V beta 8.2 infiltrate the CNS at a very early stage of EAE and become the predominant population in infiltrating T cells, and further suggest that encephalitogenic T cells, not only recruit inflammatory cells in the CNS, but also cause neural tissue damage, such as demyelination.
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PMID:Preferential distribution of V beta 8.2-positive T cells in the central nervous system of rats with myelin basic protein-induced autoimmune encephalomyelitis. 769 5

We describe recent advances in understanding a mechanism of peripheral tolerance that operates through antigen-induced programmed cell death of mature T lymphocytes. A three-phase model of this process, termed propriocidal regulation, involves: (i) activation of T cells to express growth lymphokines and their receptors, (ii) lymphokine-stimulated cell-cycle progression, and (iii) T cell receptor reengagement leading to programmed cell death. Based on this model, antigen was used to treat experimental allergic encephalomyelitis and caused profound deletion of autoreactive, encephalitogenic T cells as well as dramatic clinical and pathological improvement of the disease. The potential strengths and weaknesses of this approach to the clinical treatment of T-cell-mediated diseases are discussed.
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PMID:Antigen-induced programmed T cell death as a new approach to immune therapy. 788 90

A number of endogenous mouse mammary tumor virus (MMTV) proviruses encode superantigen that have the ability to stimulate T cells with a certain T cell receptor (TCR) beta-chain variable region (V beta) and to mediate the V beta-specific clonal deletion. The tumorigenic milk-borne MMTV carried by C3H and GR mice also have superantigenic properties in vivo. In the present study we identified and characterized a novel V beta 8.2-specific superantigen of exogenous MMTV carried by FM mice. The open reading frame (ORF) in the 3' long terminal repeat of the MMTV was cloned by polymerase chain reaction with primers corresponding to conserved regions spanning the ORF coding region. Sequence analysis of the ORF revealed that there is no sequence identical to those in other known MMTV in the carboxy terminus implicated in TCR V beta recognition. Subcutaneous injection of the virus into adult BALB/c mice induced an approximately three- to fourfold enlargement of draining lymph nodes and a substantial increase of V beta 8.2+ CD4+ T cells in the lymph nodes within 6 days. The exposure of newborn BALB/c mice to the virus by foster nursing resulted in a marked deletion of V beta 8.2+ cells both in CD4+ and CD8+ T cells. Thus, a novel milk-borne MMTV in FM mice expresses strong superantigenic properties capable of stimulating V beta 8.2+ T cells. V beta 8.2+ T cells have been demonstrated to be frequently involved in recognition of conventional antigens and responsible for autoimmune diseases such as experimental allergic encephalomyelitis. Therefore, the MMTV (FM) may provide a new mouse model system for inducing immunodeficiency or autoimmune disease by retroviral infection.
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PMID:A V beta 8.2-specific superantigen from exogenous mouse mammary tumor virus carried by FM mice. 791 38

Experimental autoimmune encephalomyelitis (EAE) is induced by myelin-specific autoimmune T cells that are characterized by a limited T cell receptor (TCR) heterogeneity. Recent studies demonstrate that regulatory T cells recognizing EAE-associated idiotopes and ergotope are involved in the auto-regulation of EAE. Anti-idiotypic T cells are rapidly induced after T cell vaccination or TCR peptide immunization, indicating that the anti-TCR response is a recall response and that natural anti-idiotypic network is established in the normal T cell repertoire. Anti-idiotypic T cells are induced not only by vaccination but as the consequence of EAE. In this review, I stress that prevention and treatment of autoimmune disease should aim at the re-organization of anti-idiotypic network.
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PMID:[Regulatory T cell network]. 799 72

Superantigens (SA) bind to major histocompatibility complex (MHC) class II antigens and activate T cells through a specific interaction between the V beta region of the T cell receptor and the toxin. Therefore, it has been postulated that SA may trigger or modulate the development of autoimmune diseases caused by T cells. In this report, the effects of SA on the development of experimental and human neurological autoimmune diseases are reviewed and the possibility of the involvement of retroviral SA in the development of human diseases is discussed. In experimental autoimmune encephalomyelitis (EAE), administration of SA prior to antigen challenge protects animals from EAE, whereas the same treatment after antigen challenge augments EAE development. These findings suggest either that 1) exposure of individuals to bacterial toxins during infection stimulates a few potentially autoreactive T cells that have escaped from the process of tolerance to expand above a threshold level, permitting autoattack, or that 2) the toxin suppresses autoreactive T cells which have the capability of inducing autoimmune diseases. In human neuroimmunological diseases such as multiple sclerosis, circumstantial evidence suggests that retroviral SA might be associated with disease development, but no direct proof has been presented so far. The possible reasons for this are also discussed.
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PMID:[Effect of superantigens on the development of neuroimmunological disorders]. 799 82

The cause of multiple sclerosis (MS) is unknown, but an immunopathological process with both endogenous and exogenous factors contributing to disease seems likely. Considerable recent attention, triggered predominantly by findings in the animal model, experimental allergic encephalomyelitis (EAE), which resembles MS, has focused on the role of T cells in MS. Findings in the animal model have raised the possibility that demyelination could be produced by CD4+ T cells specific for myelin proteins and expressing a limited set of T cell receptor (TCR) molecules. Thus, specific therapies targeting T cells or more specifically the TCR could represent an effective treatment of MS as has been demonstrated in EAE. However, current studies of patients with MS indicate that the immunological mechanisms in MS are considerably more complicated than in EAE. The evidence for a pivotal role for T cells in MS and the characteristics of these T cells particularly with respect to TCR usage and potential for therapies directed at the TCR will be examined in this review.
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PMID:The role of T cells in multiple sclerosis: implications for therapies targeting the T cell receptor. 802 8


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