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)

The influence of experimental autoimmune encephalomyelitis (EAE) on the course and outcome of pregnancy, and the effect of pregnancy on EAE development, was investigated in rabbits and rats. Animals were immunized with encephalitogenic antigen in complete Freund's adjuvant (CFA) either before or during pregnancy. Abortion or fetal resorption was observed in most of the rabbits immunized before or during pregnancy, but not in pregnant rabbits injected with CFA or saline alone. Fetal loss was higher in those rabbits that developed clinical EAE. In rats, fetal loss occurred only when immunization was carried out during the first half of pregnancy. The appearance of EAE in pregnant rabbits, but not in rats, was delayed until after abortion or termination of pregnancy. The incidence of EAE in rabbits was lower, with milder severity and longer duration. Serum antibody levels to myelin basic protein, the autoantigen of EAE, was lower in pregnant rabbits, but not in rats, as compared to non pregnant animals. These results indicate that in species where pregnancy has a suppressive influence on the development of experimental autoimmune demyelinating disease, immunization with the neuroantigen induces a high rate of fetal loss.
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PMID:Effect of experimental autoimmune encephalomyelitis on pregnancy: studies in rabbits and rats. 170 40

Autoimmune diseases occur when T lymphocytes become activated on recognizing self antigen linked to the autologous class II molecule of the major histocompatibility complex (MHC). The resulting complex of antigen MHC T-cell receptor could be a target for treatment of autoimmune diseases. Studies in which each component is blocked separately might be limited by interference in non-relevant immune responses that either use the same set of T-cell-receptor V gene segments or are linked to the same MHC. We report here an attack by a specific antibody on the unique antigenic site formed by the binding of two components of the trimolecular complex, the autoantigen bound to the self MHC. We tested its effect in experimental allergic encephalomyelitis, an acute neurological autoimmune disease which is widely regarded as a model for autoimmune disorders and which is mediated by CD4+ T cells recognizing myelin basic protein (BP), or its peptides, in association with self Ia. We made monoclonal antibodies which bound only the complex of BP and I-As. These antibodies blocked the proliferative response in vitro to the encephalitogenic determinant of BP and reduced the response to intact BP, without affecting the response to a nonrelevant antigen-purified protein derivative of tuberculin presented on syngeneic macrophages. They also inhibited experimental allergic encephalomyelitis in H-2s mice. Hence, antibodies directed specifically to the autoantigen-Ia complex, may offer a highly selective and effective treatment in autoimmune diseases.
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PMID:Immunomodulation of experimental allergic encephalomyelitis by antibodies to the antigen-Ia complex. 170 49

Peptide binding and lymph node T cell activation studies have been used to characterize T cell recognition of an encephalitogenic T cell autoantigen from myelin basic protein in mice of the H-2u haplotype. An important role for MHC class II molecules in "determinant selection" is revealed. Amino acids which determine interactions with either the restriction element of the major histocompatibility complex (MHC) or the encephalitogenic T cell receptor are defined. This information enables the design of peptides which bind MHC yet do not crossreact with the autoantigen. Two such peptides compete with the autoantigen for binding to the disease associated class II molecule and inhibit induction of experimental autoimmune encephalomyelitis in H-2u mice. Prospects for peptide mediated therapy are discussed.
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PMID:T cell recognition in experimental autoimmune encephalomyelitis: prospects for immune intervention with synthetic peptides. 171 75

Experimental allergic encephalomyelitis is a T-cell-mediated, major histocompatibility complex (MHC) class II gene-linked autoimmune demyelinating disease of the central nervous system. To develop therapies that will specifically inactivate only the autoantigen-reactive T cells, mice were treated with soluble MHC class II molecules that had been complexed with encephalitogenic peptides. Intravenous injections of 300 micrograms of complexes consisting of encephalitogenic peptide 91-103 of myelin basic protein plus I-As protein on day 0, 4, and 7 were effective in preventing experimental allergic encephalomyelitis. Similarly, administration of 45 micrograms of I-As protein complexed to peptide 139-151 from proteolipoprotein on day 1, 4, and 7 prevented mortality and significantly reduced paralysis induced by immunization with the encephalitogenic proteolipoprotein peptide. Histological examination of sections of animal brains revealed that treatment with I-As protein plus myelin basic protein 91-103 peptide prevents the development of inflammatory lesions characteristic of experimental allergic encephalomyelitis. Thus, treatment with MHC-self-peptide complexes could serve as a highly specific therapeutic modality in treating autoimmune disease when the putative autoantigen and the MHC restricting elements are known.
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PMID:Antigen-specific therapy of experimental allergic encephalomyelitis by soluble class II major histocompatibility complex-peptide complexes. 172 35

Immunization protocols that induce high levels of delayed-type hypersensitivity are often associated with low levels of antibody production, whereas alternative immunization strategies can produce the opposite effect. This reciprocal relationship appears to depend, at least in part, on the fact that T cell-derived lymphokines that are predominantly involved in one type of response inhibit the development of those T cells that promote the alternative one. Such a regulatory mechanism is likely to be bistable in that whenever one form of response is established, spontaneous development of the alternative one will be inhibited. We have applied this concept to the control of a cell-mediated autoimmune disease in rats. By covalently linking the autoantigen to anti-IgD antibody, we have targeted it to B cells for presentation to antigen-specific T cells. This form of presentation favors antibody production and may be expected to antagonize the cell-mediated disease-inducing response to the same antigen. To test this hypothesis, use was made of the fact that experimental allergic encephalomyelitis (EAE), when induced with the encephalitogenic peptide of guinea pig myelin basic protein, is purely a cell-mediated disease. The experiments show that Lewis rats, immunized with the peptide in its encephalitogenic form, were protected from disease when simultaneously injected with the peptide coupled to anti-IgD monoclonal antibodies. Control experiments showed that neither peptide nor anti-IgD alone were protective, and the peptide covalently coupled to irrelevant antibodies also failed to protect. Spleen cells from animals protected from disease by the anti-IgD-peptide conjugate, when activated in vitro with the encephalitogen, were able to transfer EAE to naive recipients. The results demonstrate that a cell-mediated immune response can be controlled by appropriate targeting of the specific antigen without inducing T cell anergy and suggest a potential strategy for preventing autoimmune diseases that are essentially cell-mediated in type.
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PMID:Targeting autoantigen to B cells prevents the induction of a cell-mediated autoimmune disease in rats. 174 Jun 60

Recent advances in understanding antigen recognition at the level of the trimolecular complex have provided new approaches for selective immunotherapy. Many of these approaches have been applied successfully to the animal model experimental autoimmune encephalomyelitis, and some are being tested in the human disease multiple sclerosis. In addition, new approaches utilizing nonspecific modulation of immune function are being explored in animals and humans. Immunospecific therapy in autoimmune diseases will ultimately be based on understanding how the normal immune system maintains unresponsiveness to self and how this state of self-tolerance is broken. Strategies for specific immune intervention in human diseases based on components of the trimolecular complex will have to take into account the polymorphism of the major histocompatibility complex in humans and the degree of heterogeneity among autoimmune T cells that react with an autoantigen.
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PMID:Tolerance and suppressor mechanisms in experimental autoimmune encephalomyelitis: implications for immunotherapy of human autoimmune diseases. 186 80

The transforming growth factors (TGF) type beta 1 and beta 2 are regulatory cytokines strongly affecting rat astrocyte immune functions. Both cytokines suppressed presentation of autoantigen by astrocytes: highly encephalitogenic T cells cocultured with TGF-beta-treated astrocytes in the presence of myelin basic protein did not become activated to transfer experimental allergic encephalomyelitis, a central nervous system (CNS) autoimmune disease. Furthermore, TGF-beta 1 and -beta 2 antagonized hyperinduction of astrocyte major histocompatibility complex (MHC) class II antigen expression by interferon-gamma and tumor necrosis factor-alpha. Thus, TGF-beta might be a potential regulator of CNS inflammation.
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PMID:Transforming growth factors type beta 1 and beta 2 suppress rat astrocyte autoantigen presentation and antagonize hyperinduction of class II major histocompatibility complex antigen expression by interferon-gamma and tumor necrosis factor-alpha. 210 88

MS and CIP are inflammatory diseases of the CNS and PNS that are characterized by focal demyelination. Both disorders are thought to involve autoimmune processes. The factors that lead to a chronic inflammatory process have not been completely defined, but the immune system is thought to play a prominent role as has been discussed in this chapter. The role of a persistent or recurrent viral exposure has not been reviewed here but may well be a contributing factor. Since chronic relapsing experimental encephalomyelitis in animal models is a T-cell-mediated disease that pathologically resembles MS, T cells are postulated to be of primary importance in human demyelinating diseases. Oligoclonal T-cell populations can be found in the CSF of MS patients, even though their antigenic specificity is not known. HLA associations (HLA Dw2 and HLA DR2 in MS and HLA Dw3 in chronic inflammatory neuropathy) might relate to the proposed immunopathogenesis, as class II antigens encoded by these loci might serve as restriction elements for T-cell recognition of an autoantigen by encephalitogenic cell populations. Humoral factors are thought to play an important role in the pathogenesis of CIP, as plasma exchange has been shown to be beneficial. Experimental work with an antimyelin glycoprotein monoclonal antibody demonstrates the in vivo demyelinating activity of antibodies as well as the importance of cellular elements in the demyelinating process. Finally, a number of immunoregulatory abnormalities have been demonstrated in MS patients that point to defects in immunoregulation, in particular in the generation of suppression. Decreases in AMLR in active MS might be of importance, as the AMLR is a reaction against self MHC determinants during which suppression is generated. Defects in suppression might allow self-reactive cells to escape regulation and cause inflammatory lesions in the nervous system.
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PMID:Immunologic mechanisms in chronic demyelinating diseases of the central and peripheral nervous system. 215 31

T lymphocytes specific for myelin basic protein (MBP) are responsible for the cellular events leading to autoimmune disease within the central (CNS) and peripheral (PNS) nervous systems. Both in actively induced and T-cell transfer versions of experimental autoimmune encephalomyelitis (EAE) and neuritis (EAN), the autoaggressive T cells are activated outside the nervous system and reach their target tissue via the blood circulation. The target specificity of the autoaggressive T cells is impressive; T-cell lines specific for MBP predominantly home to and affect the white matter of the CNS whereas T cells specific for PNS myelin protein P2 exclusively infiltrate peripheral nerves. Having penetrated the tight blood tissue barriers, the lymphocytes seem to interact with local cells expressing the relevant autoantigen in an immunogenic form. Although the exact mechanism of target finding and destruction is unknown, studies from our laboratory have shown that astrocytes, a main component of the normal CNS glia, can actively present antigen to specific T cells. This observation suggests that astrocytes are involved in natural immune reactivity within the CNS, and that they may be involved in pathological aberrations, such as in the development of autoimmune lesions. Having studied astrocyte/T-cell interactions in more detail, we discovered that encephalitogenic T-cell lines recognizing MBP on astrocytes will subsequently proceed to kill the presenting cells. Here we report that astrocyte killing follows the rules governing 'classical' T-cell-mediated cytolysis; it is antigen-specific, restricted by antigens of the major histocompatibility complex (MHC) and apparently contact-dependent. Our data suggest that the nature of the recognized antigenic epitope determines whether or not antigen recognition is followed by killing; moreover, killing of antigen-presenting astrocytes seems to be correlated with the capacity to transfer encephalomyelitis to normal syngeneic rats.
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PMID:Ia-restricted encephalitogenic T lymphocytes mediating EAE lyse autoantigen-presenting astrocytes. 241 64

The essential requirement for adoptive transfer of autoimmune diseases such as experimental allergic encephalomyelitis (EAE) by T lymphoblasts from established T cell lines, is a prior activation of these cells by autoantigen or mitogen. We have investigated the possibility of modulating this activation process by using monoclonal antibodies directed against rat leukocyte differentiation antigens. We report here that antigen-driven activation of autoimmune, encephalitogenic T cells from established myelin basic protein (MBP)-specific rat T cell lines can be inhibited by some, but not all, antibodies against RT1.B Class II restriction elements. In addition, monoclonal antibodies with specificity for rat leukocyte common antigen (OX-1) and T cell differentiation antigens W3/13 and W3/25 are inhibitory, while monoclonal antibody OX-8 with specificity for T cytotoxic/suppressor cells has no effect. We also observed that concanavalin A-induced activation of the T cells is more resistant to the inhibitory effect of monoclonal antibodies, and can be blocked effectively only by antibody OX-1. This demonstration that autoimmune T cell function can be inhibited by monoclonal antibodies points the way in suggesting cellular targets for immunotherapeutic purposes.
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PMID:Inhibition of rat autoimmune T cell activation by monoclonal antibodies. 242 53


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