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Query: UMLS:C0014070 (encephalomyelitis)
 13,017 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this report we detail a procedure for the cloning of a rat encephalitogenic T cell line and show that the methods normally employed for other species may not always be applicable. The two important differences to be described are, (i) that in these experiments where the parent T cell lines were generated with thymocytes as presenting cells, splenocytes were not suitable as a source of antigen-presenting or stimulator cells and (ii) semipurified forms of IL-2, specifically that derived from EL4 lymphoma cells, resulted in a much reduced cloning frequency and rate of T cell growth compared with cruder mixtures such as that derived from mitogen-stimulated splenocytes. Functional studies with clones derived from a strongly encephalitogenic (experimental autoimmune encephalomyelitis (EAE)-inducing) T cell line revealed that the clones had a reduced capacity to mediate EAE in recipient rats but were otherwise comparable to the parent line in terms of surface phenotype and fine antigen specificity. In an attempt to begin to identify the type of CD4+ T cells that may induce EAE we tested the clones and lines for secreted interferon-gamma by a sensitive ELISA, and showed that all clones secreted high levels of this factor.
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PMID:Isolation of encephalitogenic CD4+ T cell clones in the rat. Cloning methodology and interferon-gamma secretion. 247 12

We have examined the responses of brain endothelium from different rat strains to interferon-gamma (IFN-gamma) which induces expression of MHC class II molecules. There is a marked difference between the strains in the sensitivity of their endothelium to MHC induction. LEW and DA rats, which are susceptible to experimental allergic encephalomyelitis (EAE) can be induced to express higher levels of class II molecules than EAE-resistant strains. In both the EAE-susceptible and -resistant strains, RT-1B locus-encoded molecules occur at higher surface densities than RT-1D locus molecules. These findings support the theory that genes controlling the induction of MHC expression affect disease susceptibility.
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PMID:Induction of Ia molecules on brain endothelium is related to susceptibility to experimental allergic encephalomyelitis. 249 52

We found that the course of the chemiluminescence activity (CL-A) of peripheral blood monocytes of Lewis rats with acute experimental autoimmune encephalomyelitis (EAE) correlates well with the clinical course of this autoimmune disease and that only a reduction in T helper cells caused a reduction in CL-A. However, in multiple sclerosis (MS) patients the CL-A increased when clinical improvement started. The serum of these patients contained at least two stimulatory substances. More than 50% of the stimulatory effect could be blocked by antibodies to interferon-gamma.
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PMID:The significance of the inflammatory reactions for the development of clinical signs in multiple sclerosis and acute experimental autoimmune encephalomyelitis as assessed by means of the spontaneous chemiluminescence activity of peripheral blood monocytes. 314 41

The vertebrate central nervous system (CNS) has been traditionally thought to be inaccessible for the passenger lymphocytes of the immune system. This does not seem to be the case: activated T-lymphocytes can readily cross the endothelial blood-brain barrier (BBB) and some glial cells, notably the astrocytes, seem to be programmed to act as most efficient and complex partners for antigen-specific T-lymphocytes. We used myelin basic protein (MBP) specific permanent rat T-lymphocyte lines as probes to assess the immune status of the CNS. These cells, upon activation in vitro, are able to transfer lethal, experimentally induced autoimmune-encephalomyelitis (EAE) to normal syngeneic recipients. Activated T-lymphocytes, but not resting ones, can break through the BBB irrespective of their antigen specificity. Immune surveillance of the CNS thus seems to be executed by activated T-lymphocytes. Having crossed the BBB, the activated T-cells interact with local glial cells by releasing factors, including interferon-gamma, which induced astrocytes to synthesize and express, on their membranes, class II major histocompatibility antigens (Ia determinants), which are critically required for immunogenic presentation of antigens to T-cells. Indeed, Ia-induced astrocytes of the CNS (and the Schwann cells of peripheral nerves) are efficient antigen presenter cells, which are able strongly to up-regulate antigen-reactive T-lymphocytes. In addition, it has recently been shown that at least some astrocytes are able to down-regulate immune cells. Some, but not all, astrocytes are capable of suppressing activation of T-cells. This suppression can be modulated by interferon-gamma, and is sensitive to irradiation. The question of whether suppression is mediated by direct cell-to-cell contact or via soluble mediators (e.g. apolipoprotein E) is under investigation. Astrocytes have been found to be most subtle regulators of immuno-competent T-cells. Most probably they are centrally involved in physiological immune reactivity of the CNS, and it will be tempting to learn how far glial cells are involved in transmitting regulatory signals between the immune and nervous systems.
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PMID:Immune reactivity in the nervous system: modulation of T-lymphocyte activation by glial cells. 332 5

Major histocompatibility complex (MHC) class II genes are the strongest susceptibility markers for many human autoimmune diseases. A perplexing aspect of this is that HLA alleles can confer either susceptibility or dominant protection. In nonobese diabetic (NOD) mice, the strongest known diabetes susceptibility locus is within the MHC and is presumed to be the H-2Ag7 product. When NOD mice carry a transgenic E alpha d molecule allowing expression of an H-2E heterodimer, diabetes is prevented. We investigated whether, as in human autoimmunity, a single class II heterodimer might protect from some autoimmune diseases while predisposing to others. NOD mice are susceptible to experimental autoimmune encephalomyelitis (EAE) induced by the proteolipoprotein (PLP) epitope 56-70. Susceptibility to EAE was analyzed in NOD mice which either have or lack transgenic H-2E expression. We found that H-2E expression in NOD mice has converse effects on diabetes and EAE: while diabetes is prevented, EAE is greatly exacerbated and leads to demyelination. Although PLP 56-70 could be presented both in the context of H-2A and H-2E, increased disease severity in H-2E transgenic mice could not be attributed either to an enhanced T cell proliferative response to PLP or to differences in determinant spread. However, cytokine analysis of the response revealed important differences between NOD mice and their H-2E transgenic counterparts: H-2E expression was associated with reduced interleukin-4 secretion and enhanced interferon-gamma (IFN-gamma) secretion by lymph node cells, while the response of central nervous system infiltrating T cells displayed a markedly enhanced IFN-gamma response. Thus, whether a particular class II molecule confers resistance or susceptibility to an autoimmune disease may depend on differential cytokine profiles elicited by particular class II/autoantigen complexes.
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PMID:Exacerbated autoimmunity associated with a T helper-1 cytokine profile shift in H-2E-transgenic mice. 748 54

We previously reported that the CD4+ suppressor cells (Ts) that regulate recovery of Lewis rats from experimental autoimmune encephalomyelitis (EAE) produce transforming growth factor-beta (TGF-beta). We also reported that TGF-beta downregulates interferon-gamma (IFN-gamma), but not interleukin-2 (IL-2) production, by the CD4+ effector T cells (Te) that mediate EAE. We now report that TGF-beta also inhibits the production of tumor necrosis factor/lymphotoxin (TNF/LT) by EAE effector cells. When activated in vitro with myelin basic protein (MBP), Te produced TNF/LT, as measured using a WEHI 164 cytotoxicity assay. The specificity of cytokine action was demonstrated using neutralizing antibodies to TNF/LT. When added to the Te+MBP cultures, TGF-beta inhibited TNF/LT production in a dose-dependent fashion. Moreover, neutralizing anti-TGF-beta antibodies augmented TNF/LT production in the Te+MBP cultures. We also confirm that TGF-beta inhibits adoptive transfer of EAE. In contrast, murine IL-10 only partially inhibited TNF/LT and IFN-gamma production by Te. We conclude that TGF-beta production by Ts plays a major role in recovery from EAE in the Lewis rat by inhibiting TNF/LT and IFN-gamma production by the effector cells that mediate EAE.
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PMID:Transforming growth factor-beta 1 inhibits tumor necrosis factor-alpha/lymphotoxin production and adoptive transfer of disease by effector cells of autoimmune encephalomyelitis. 751 80

Experimental allergic encephalomyelitis (EAE) is an autoimmune disease mediated by myelin protein-specific CD4+ T lymphocytes of the T(h)1-like phenotype. In rats, the disease is characterized by a monophasic clinical manifestation, followed by a subsequent spontaneous remission and the establishment of life-long resistance to reinduction of disease. Recent data indicate that intracerebral cytokine production, in particular synthesis of interleukin(IL)-10, is selectively up-regulated during the recovery phase of disease. This led us to assess the effects of IL-10 on different rat lymphoid cell functions in vitro and to consider the possibility of an IL-10-mediated treatment to prevent the induction of central nervous system (CNS) autoimmune disease in vivo. Human recombinant IL-10 suppressed interferon-gamma induced major histocompatibility complex class II up-regulation in rat peritoneal macrophages, exhibited pleiotropic effects on thymocytes and totally abrogated tumor necrosis factor production of encephalitogenic T lymphocytes in vitro, without simultaneously affecting proliferative responses of the cells. Upon systemic administration during the initiation phase of disease, IL-10 was effective in markedly suppressing the subsequent induction of EAE in Lewis rats. This suppression of clinical disease coincided with a significant and specific elevation of myelin basic protein-specific autoantibody production, a sustained T cell proliferative response to myelin basic protein and a diminution of CNS infiltrations and thymic involutions in diseased animals. These data implicate IL-10 as a possible candidate for treatment of T(h)1-mediated CNS (auto-) immune diseases.
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PMID:Interleukin-10 prevents experimental allergic encephalomyelitis in rats. 751 15

Increasing evidence indicates that the cytokines, tumor necrosis factor (TNF), interleukin-1, and/or interferon-gamma, may play a crucial role in the pathogenesis of multiple sclerosis. Several reports demonstrated that inhibition of TNF is highly protective in experimental allergic encephalomyelitis (EAE) when sensitization is accomplished by the passive transfer of myelin basic protein (MBP) sensitized lymphocytes. However, successful protection has not been reported in EAE that is induced by active immunization with MBP. We examined the effects of a TNF inhibitor, dimeric polyethylene glycol linked form of the type I soluble receptor of TNF, PEG-(rsTNF-RI)2, on actively acquired EAE. Treatment with PEG-(rsTNF-RI)2 at 0.3-3 mg/kg every other day or every third day starting on Day 9 postimmunization with MBP during the effector phase of EAE significantly inhibited clinical signs in a dose-dependent manner. Histological examination of the central nervous system indicated that the administration of PEG-(rsTNF-RI)2 reduced, in part, the cellular infiltrate, particularly in the lumbar and sacral regions of the spinal cord. These studies suggest that TNF is a pivotal mediator of the inflammation resulting from the complete immune response induced by active immunization with MBP.
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PMID:Inhibition of tumor necrosis factor is protective against neurologic dysfunction after active immunization of Lewis rats with myelin basic protein. 753 20

Experimental autoimmune encephalomyelitis (EAE) is an inflammatory disease of the central nervous system (CNS) which can be induced, in susceptible strains like Lewis rats, by transfer of activated myelin basic protein (MBP)-specific CD4+ T lymphocytes. The role of cerebral endothelium in the onset of EAE, with regard to adhesion, activation and infiltration in the CNS of encephalitogenic T lymphocytes, is not fully understood. When pretreated by interferon-gamma, the immortalized Lewis rat brain microvessel endothelial (RBE4) cells expressed major histocompatibility complex class II molecules and stimulated MBP-specific proliferation and cytolytic activity of the syngeneic encephalitogenic T cell line, designated PAS. However, RBE4-stimulated PAS lymphocytes subsequently entered an unresponsive state, known as anergy. When inoculated in syngeneic animals, anergic PAS cells, although still cytotoxic, failed to induce EAE, and no cell infiltration was detectable within CNS. The addition of interleukin-1 beta (IL-1 beta) during MBP presentation by RBE4 cells prevented T cell anergy induction, and maintained T cell encephalitogenicity, although PAS cells stimulated in these conditions caused delayed and attenuated clinical signs of EAE, with only discrete inflammatory lesions in the CNS, compared with EAE induced by PAS cells fully activated by thymic cells. Altogether, our results indicate that MBP presentation by brain microvessel endothelial cells to encephalitogenic T cells induces T cell anergy and loss of pathogenicity. In addition, IL-1 beta co-stimulation of T cells prevents anergy induction in vitro and at least partially maintains encephalitogenicity in vivo.
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PMID:Anergy induction in encephalitogenic T cells by brain microvessel endothelial cells is inhibited by interleukin-1. 753 49

In multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE) the cytokines tumour necrosis factor-alpha (TNF), lymphotoxin-alpha (LT), and interferon-gamma (IFN-gamma) are of central pathogenetic importance. A therapy capable of stopping neurological deterioration in MS patients is not yet available. Here, we report that rolipram, a selective type IV phosphodiesterase inhibitor, stereospecifically suppresses the production of TNF/LT and less strongly also IFN-gamma in human and rat auto-reactive T cells. Moreover, we show that rolipram is an effective treatment for EAE. Rolipram has extensively been studied in humans for the treatment of depression, but has not yet been marketed. The data presented here identify rolipram as potential therapy for multiple sclerosis and provoke the immediate initiation of clinical trials.
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PMID:The antidepressant rolipram suppresses cytokine production and prevents autoimmune encephalomyelitis. 758 35


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