Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Transforming growth factor-beta (TGF-beta) had a profound effect on the in vitro phenotypic development of Ag-activated Th cells and enhanced the in vivo effector function of these cells upon adoptive transfer. Previous studies have shown that there are two types of Th cell populations found in unimmunized animals, naive helper cells, which are short-lived and express low levels of CD44 and high levels of CD45R and Mel-14, and memory helper cells, which have a long life span and express high levels of CD44 and low levels of CD45R and Mel-14. Culturing of Ag-specific murine Th cell lines and clones in the presence of TGF-beta greatly enhanced both the memory phenotype of the cultured cells and the effector function upon adoptive transfer in experimental autoimmune encephalomyelitis. Histologic evaluation of spinal cords from recipients receiving passively transferred murine T cell lines cultured with TGF-beta revealed large demyelinated plaques (multiple sclerosis-like) that were not present in animals receiving cells cultured with Ag alone. TGF-beta also enhanced the capability of myelin basic protein-specific Lewis rat T cell lines to transfer experimental autoimmune encephalomyelitis and potentiated a purified protein derivative-specific rat helper cell line to transfer delayed type hypersensitivity. Thus, the effects of TGF-beta did not appear to be limited by species specificity, Ag specificity, or in vivo T cell function. This is the first study showing that TGF-beta can potentiate the development and maintenance of the Th cell memory phenotype in vitro and enhance their in vivo effector function in an animal disease model.
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PMID:Transforming growth factor-beta enhances the in vivo effector function and memory phenotype of antigen-specific T helper cells in experimental autoimmune encephalomyelitis. 134 50

In experimental allergic encephalomyelitis (EAE), autoimmune T cells infiltrate the central nervous system (CNS) and initiate demyelinating pathology. We have used flow cytometry to directly analyse the migration to the CNS of MBP-reactive CD4+ T cells labelled with a lipophilic fluorescent dye (PKH2), in SJL/J mice with passively transferred EAE. Labelled cells constituted about 45% of the CNS CD4+ population at the time of EAE onset. Almost all (greater than 90%) of the PKH2-labelled CD4+ T cells from EAE CNS were blasts and were alpha/beta T cell receptor (TCR)+, CD44(Pgp-1)high, and the majority were CD45RB(low). By contrast, most PKH2-labelled CD4+ T cells in lymph nodes, although CD44high, were CD45RBhigh cells. The cells that were transferred to induce EAE were essentially similar to antigen-primed lymph node cell populations, containing less than 15% CD44high cells, and most of them were CD45RBhigh. The CD44high CD45RB(low) phenotype is characteristic of memory/effector T cells that have been activated by antigen recognition. The difference in CD45RB expression between CNS and LN could therefore reflect differential exposure and/or response to antigen. Consistent with this, PKH2-labelled CD4+ cells isolated from the CNS were responsive to MBP in vitro, whereas PKH2+ CD4+ cells from lymph nodes showed almost undetectable responses. In control experiments in which ovalbumin (OVA)-reactive T cells were transferred, a small number of fluorescent-labelled CD4+ T cells were also detected in CNS, but there were very few blasts, and these remained CD45RBhigh. These results argue for induction of the memory/effector phenotype of CD4+ T cells, and their selective retention in the CNS, as a consequence of antigen recognition.
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PMID:Direct demonstration of the infiltration of murine central nervous system by Pgp-1/CD44high CD45RB(low) CD4+ T cells that induce experimental allergic encephalomyelitis. 138 82

The nature of inflammatory lymphocytes recruited to the CNS has been studied in a model of chronic inflammation. Injection of killed Corynebacterium parvum into the cortex of the mouse brain produces a circumscribed inflammatory cellular infiltrate around the injection site, and recruited mononuclear inflammatory cells (IC) can be isolated for flow cytometric analysis. The majority of IC were T cells. In comparison with the predominant naive population of mesenteric lymph node T cells, IC T cells express much higher levels of CD44, LFA-1 and ICAM-1, and lower levels of CD45RB, features commonly associated with memory (previously activated) cells. In addition, in contrast to the L-selectin+ alpha 6-integrinlow phenotype of naive lymph node T cells, IC T cells lacked L-selectin and were alpha 6-integrin-. Mac-1, recently proposed as another marker of memory T cell differentiation, was not displayed by IC T cells, suggesting that Mac-1 expression may be heterogeneous among memory T cell subsets. A subset of mesenteric lymph node (MLN) T cells, probably representing activated T cells undergoing the naive to memory transition, but not of IC T cells, expressed high levels of alpha 6-, beta 7- and alpha E-integrin. IC and MLN naive T cells expressed comparable levels of alpha 4-integrin, but IC T cells stain poorly with anti-beta 7 mAbs and with mAb DATK 32, specific for the alpha 4 beta 7 heterodimeric lymphocyte homing receptor for the mucosal addressin MAdCAM-1, suggesting that these inflammatory cells express more alpha 4 beta 1 than alpha 4 beta 7. Consistent with this, in in vitro adhesion assays, brain IC bound better than MLN cells to the alpha 4 beta 1 integrin ligand VCAM-1 and the LFA-1 ligand ICAM-1 but adhered very poorly to the alpha 4 beta 7 ligand MAdCAM-1. These findings are consistent with and extend previous immunohistological studies of T cells in murine experimental autoimmune encephalomyelitis, and demonstrate a distinctive phenotype for lymphocytes being present in the chronically inflamed brain.
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PMID:Lymphocytes infiltrating the CNS during inflammation display a distinctive phenotype and bind to VCAM-1 but not to MAdCAM-1. 754 Aug 64

The phenotypic and functional characteristics of activated T cells and recruited unactivated T cells at an inflammatory site were examined using a V beta 4+ myelin basic protein-specific T cell clone in a passively transferred model of experimental allergic encephalomyelitis. A high percentage of the T cells isolated from the central nervous system (CNS) were V beta 4+. This population exhibited the characteristics of activated T cells based on the proportion of cells in the blast state, their ability to proliferate in response to IL-2 or CNS Ag, and their expression of activation/memory cell markers. Activated V beta 4+ T cells were also observed in the periphery. Large numbers of V beta 4- T cells, which are entirely host-recruited, were also found in the CNS, where they demonstrated the properties of memory cells. There were differences in adhesion molecule expression between CNS V beta 4+ T cells and peripheral V beta 4+ T cells, although both populations were in activated state. V beta 4+ T cells at the site of Ag expression (the spinal cord) demonstrated higher levels of LFA-1 and CD44, but lower levels of VLA-4 and intercellular adhesion molecule-1, than did V beta 4+ T cells in the spleen. In contrast, the levels of all of these adhesion molecules on recruited V beta 4- T cells were higher in the CNS than in the periphery. This experimental model allows the detailed characterization of different T cell populations isolated from the same inflammatory site.
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PMID:Presence of T cells with activated and memory phenotypes in inflammatory spinal cord lesions. 759 58

We have derived a panel of CD4+, TCR-alpha/beta + T cell clones from SJL (H-2s) mice specific for an encephalitogenic determinant of myelin proteolipid protein (PLP) 139-151 (HSLGKWLGHPDKF). All the clones are Ag specific and IAs restricted, but they show heterogeneity in their ability to induce experimental allergic encephalomyelitis (EAE), i.e., one group induces EAE in naive mice, a second group induces disease only in mice that are pretreated with pertussis and irradiation, whereas a third group is essentially nonencephalitogenic. To determine the basis for this functional heterogeneity, the clones were tested for the expression of adhesion molecules and cytokines and for Ag-specific cytolytic activity. All of the clones expressed comparable levels of LFA-1 and CD44 but lacked expression of Mel 14. However, those clones that induced EAE only in irradiation- and pertussis-treated recipients did not express VLA4. Because pretreatment with pertussis has been suggested to increase permeability of the blood-brain barrier and facilitate migration of T cells into the central nervous system, the absence of VLA4 on this group of clones may account for the need for pretreatment to induce EAE. The nonencephalitogenic clones expressed all of the adhesion molecules tested but were not cytolytic in vitro and failed to produce one or more of the proinflammatory cytokines after Ag-specific stimulation. One nonencephalitogenic clone that did not produce many cytokines on activation with specific Ag, however, could be activated with Con A to express mRNA for most cytokines and this was accompanied by a concomitant change in the encephalitogenic potency of this clone. These results suggest that adhesion molecules and cytokines both play a critical role in the encephalitogenicity of PLP peptide-specific T cell clones. Furthermore, the nonencephalitogenicity of some clones may be related to a defect in Ag-mediated activation.
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PMID:Cytokines and adhesion molecules contribute to the ability of myelin proteolipid protein-specific T cell clones to mediate experimental allergic encephalomyelitis. 769 46

Expression of adhesion molecules in immune-mediated diseases of the central nervous system was reviewed. In multiple sclerosis and experimental allergic encephalomyelitis (EAE), endothelial cells of active lesions increase expression of the adhesion molecules such as ICAM-1, VCAM-1 and inflammatory cells including memory T cells and macrophages express high levels of adhesion molecules such as LFA-1, VLA-4. Astrocytes also express CD44, ICAM-1, VCAM-1 and E-selectin in response to cytokine stimuli. In EAE, the majority of infiltrating cells are not MBP-specific memory T cells, thus it is speculated that the up-regulation of the adhesion molecules in the endothelial cells plays a decisive role in the development of immune-mediated diseases of the central nervous system. Therapeutic potency of clinical usage of anti-adhesion molecule antibodies has been explored.
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PMID:[Adhesion molecules and immune-mediated diseases of the central nervous system]. 799 76

A novel method for the isolation of leukocytes from the spinal cords of mice during chronic relapsing experimental allergic encephalomyelitis (CREAE) was developed using discontinuous density gradients. Immunostaining of these cells, together with spinal cord sections and peripheral blood leukocytes, with a panel of monoclonal antibodies enabled a detailed profile of the kinetics and cell phenotype during CREAE to be developed. Overall, the kinetics of cell accumulation within the spinal cord correlated with disease severity. The number of cells increased from an average of 5 x 10(4) in unimmunized animals to 40 x 10(4) in paralysed animals during the initial disease episode. The cell numbers rapidly declined with clinical remission (6 x 10(4) cells/cord) and again dramatically increased during clinical relapse. Low numbers of CD3+ lymphocytes (50-150 cells) were consistently isolated from normal mice. However, the number of T cells infiltrating the spinal cord increased following immunization. The numbers of T cells, macrophages, B cells, neutrophils, and Ig-bearing cells all paralleled the clinical disease course, with T cells and macrophages (showing evidence of myelin breakdown) predominating. T cells infiltrating the spinal cord generally failed to express gamma delta T cell receptors and expressed low levels of IL-2 receptors (5% of infiltrating T cells). These cells were phenotypically dissimilar to peripheral blood leukocytes isolated in parallel, with the spinal cord having a consistently higher ratio (9:1) of CD4+ to CD8+ than the peripheral blood (7:3). The low expression of MEL-14 (L-selectin) and 16a antigen (CD45RBhigh) and the higher levels of Pgp-1 (CD44) expressed by the infiltrating T cells, compared with splenocytes, suggest a preferential recruitment/retention of distinct T cell subsets, possibly memory/primed cells, into the central nervous system from the periphery during neuroimmunological disease.
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PMID:Isolation and characterization of cells infiltrating the spinal cord during the course of chronic relapsing experimental allergic encephalomyelitis in the Biozzi AB/H mouse. 817 74

The CD44 adhesion molecule is expressed by astrocytes, glial-type cells which exhibit features of accessory cells for immune responses in the central nervous system. In primary cultures of mouse astrocytes, we have observed that surface expression and mRNA levels of CD44 are induced following stimulation with either PMA, or tumor necrosis factor alpha plus gamma interferon. Comparison of CD44 splice variants expressed by astrocytes and a T cell hybridoma shows that upon activation, both cell types express a similar pattern of CD44 transcripts. Thus, in both cell types, CD44 transcripts are produced which contain additional exons, including the exon v6 (known to be expressed by in vivo activated lymphocytes and by metastatic variants of tumor cells) as well as variants of larger size. In the autoimmune disease multiple sclerosis, activated T cells cross the blood-brain barrier and lead to inflammation in the central nervous system. Analysis of mice with experimental allergic encephalomyelitis, frequently used as an animal model of multiple sclerosis, shows that CD44 is induced in vivo on glial cells surrounding inflammatory lesions. Using an in vitro model for adhesion between T cells and astrocytes, we have found a correlation between the activation state of these cells and their adhesion potential. Dose-dependent inhibition of adhesion by hyaluronate and by anti-CD44 monoclonal antibody KM81 shows that CD44 is involved in the adhesive interactions between T cells and astrocytes.
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PMID:Activated mouse astrocytes and T cells express similar CD44 variants. Role of CD44 in astrocyte/T cell binding. 835 94

In the present study we address the question of whether distinct self-determinants can target alternative autoimmune disease patterns in experimental autoimmune encephalomyelitis (EAE), an animal model widely used for studying multiple sclerosis. We have found that the clinical course of EAE can be determined by the target peptide selected for induction of disease. In SJL/J mice, actively induced and passively transferred EAE mediated by the immunodominant PLP determinants p139-151 and p178-191 consistently produced a rapid onset of severe clinical signs. In contrast, a delayed onset of both active and passive EAE is associated with the nondominant cryptic PLP determinant p104-117. The delayed disease induced with p104-117 is not associated with any unusual peptide feature, with bystander immunoregulation, with inept class II MHC binding, or with failure to induce T cell expression of CD44, VLA-4, or IL-2 receptor upon activation. However, delayed disease is associated with innate qualities of the T cell repertoire responding to the p104-117 determinant. T cell lines responding to the cryptic p104-117 show limited TCR-V beta utilization compared to the diverse repertoire responding to the dominant p139-151 determinant. The repertoire deletions are accompanied by low level production of pathogenic Th1 cytokines (IFN gamma; IL-2) and increased production of regulatory Th2 (IL-4) cytokine in activated p104-117 primed T cells. Thus, the delayed encephalitogenicity of p104-117 may be due to TCR-V beta deletions and activation defects in the responding T cell repertoire. The development of "slow disease" mediated by autoreactivity against hidden self-determinants may have important implications in the pathogenesis of both relapsing and chronic autoimmune demyelinating disease.
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PMID:Determinant-regulated onset of experimental autoimmune encephalomyelitis: distinct epitopes of myelin proteolipid protein mediate either acute or delayed disease in SJL/J mice. 882 78

The central nervous system (CNS) in considered to be an immunological privileged site. However, inflammatory reactions in response to virus infections, in multiple sclerosis (MS) and in experimental autoimmune encephalomyelitis (EAE) suggest that there are definite connections between the CNS and the immune system. In this review, we examine evidence for afferent and efferent pathways of communication between the CNS and the immune system, the pivotal role of regional lymph nodes in T-cell mediated autoimmune disease of the CNS, and the factors involved in lymphocyte targeting of the CNS. Afferent pathways of lymphatic drainage of the brain are well established in a variety of species, especially rodents. Fluid and antigens appear to drain along perivascular spaces populated by immunocompetent perivascular cells. Drainage pathways connect directly via the cribriform plate to nasal lymphatics and cervical lymph nodes. Soluble antigens draining from the brain induce antibody production in the cervical lymph nodes. Using a model of cryolesion-enhanced EAE, we review the role of lymphatic drainage and cervical lymph nodes in the enhancement of cerebral EAE. If a brain wound in the form of a cryolesion is produced 8 days post inoculation (dpi) of antigen in the induction of acute EAE, there is a 6-fold increase in severity of cerebral EAE by 15 dpi. Removal of the cervical lymph nodes significantly reduces such enhancement of EAE. These findings suggest that drainage of antigens from the brain to the cervical lymph nodes, in the presence of activated lymphocytes in the meninges or CNS, results in an enhanced second wave of lymphocytes targeting the brain. In examining the efferent immune pathway by which lymphocytes home to the CNS, several studies have characterized the phenotype of infiltrating T lymphocytes by the use of immunocytochemistry or FACS analysis. T-cells infiltrating the CNS are recently activated/memory lymphocytes typified by their high expression of CD44, LFA-1 and ICAM-1 and low expression of CD45RB in the mouse. Following the induction of EAE in susceptible mice, ICAM-1 and VCAM-1 are dramatically upregulated on CNS vessels; lymphocytes bind to such vessels via the interaction of their known ligands, LFA-1/Mac-1 and alpha 4-integrins, at least in vitro. It appears that alpha 4-integrin plays a key role in lymphocyte recruitment across the blood-brain barrier and may be a major factor in lymphocyte targeting of the CNS. Definition of factors involved in the afferent and efferent connections between the CNS and the immune system may clarify mechanisms involved in immune privilege of the CNS and may open significant therapeutic opportunities for multiple sclerosis.
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PMID:Lymphocyte targeting of the central nervous system: a review of afferent and efferent CNS-immune pathways. 886 84


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