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)

Members of the Theiler's murine encephalomyelitis virus GDVII subgroup, which includes GDVII strain, are highly neurovirulent and induce a rapidly fatal polioencephalomyelitis. By contrast, Theiler's original subgroup members, which includes DA strain, are not as neurovirulent, and produce a chronic, demyelinating disease with virus persistence. We investigated the importance of the carboxyl region of the capsid protein VP1 in TMEV-induced disease since a trypsin-cleavable immunodominant neutralization epitope is situated in the VP1 carboxyl region, and since this region is believed to lie adjacent to the putative receptor binding site. The present studies support the role of DA VP1 residue 268 (and the aligned GDVII VP1 270) in Theiler's murine encephalomyelitis virus-induced CNS disease; however, the effect of this residue varies depending on its context: mutation of DA VP1 268 attenuates demyelination; mutation of GDVII VP1 270 in a GDVII/DA recombinant virus has no effect on demyelination but reduces early deaths (neurovirulence); mutation of GDVII VP1 270 in GDVII virus has no effect on neurovirulence. These data suggest that DA VP1 268/GDVII VP1 270 are not functionally equivalent and that a residue in recombinant viruses can differ in function from the same residue situated in a parental strain. Additional mutagenesis studies suggest that: the trypsin cleavage site of TMEV, which affects virus viability, is located at the lysine at DA VP1 261 (GDVII VP1 263); GDVII VP1 276, the predicted carboxyl terminus of VP1, affects VP1/2A processing and virus infectivity.
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PMID:The effect of Theiler's murine encephalomyelitis virus (TMEV) VP1 carboxyl region on the virus-induced central nervous system disease. 922 46

Previous studies examining the effect of nitric oxide synthase (NOS) inhibition on the course of experimental allergic encephalomyelitis (EAE) have yielded conflicting results. This may relate to the use of nonspecific inhibitors and to differences between active and adoptive EAE. We examined the effect of treatment with L-N-(1-iminoethyl)lysine (L-NIL), a selective inhibitor of the cytokine-inducible isoform of NOS, on the clinical course of active and adoptive EAE in Lewis rats. We find that while L-NIL treatment of recipients is protective in adoptive EAE, treatment of active EAE with L-NIL leads to a marked accentuation of disease expression. In L-NIL-treated animals treated with myelin basic protein/complete Freund's adjuvant (MBP/CFA), disease onset is accelerated and clinical symptoms are more severe. Accentuation of integrated disease scores is seen even if L-NIL treatment is started 5 days following immunization. The histological findings in involved spinal cords from L-NIL-treated animals with active EAE are similar to those from untreated animals with similar clinical scores. L-NIL treatment of MBP/CFA-immunized animals does not prevent recovery from clinical symptoms, nor does it allow for reinduction of disease in animals previously immunized with MBP/CFA. Treatment of F344 rats, a strain which is relatively nonsusceptible for EAE, with L-NIL results in consistent evidence of EAE following immunization with MBP/CFA. These findings, together with our previous work on interstitial nephritis, support a role for endogenously generated NO in immunoregulation of T cell responses following immunization with antigen in CFA, and suggest that inducibility of NOS expression may be an important susceptibility factor for autoimmunity.
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PMID:Nitric oxide and the immunomodulation of experimental allergic encephalomyelitis. 939 11

Experimental autoimmune encephalomyelitis (EAE) serves as a rodent model of the autoimmune disease multiple sclerosis. In mice, EAE is induced by immunizing with spinal cord homogenate, components of the myelin sheath, such as myelin basic protein (MBP) or proteolipid protein (PLP), or peptides derived from these components. EAE can be induced in H-2u or (H-2u x H-2s)F1 mice with the N-terminal peptide of MBP, Ac1-11. Coimmunization with Ac1-11 and Ac1-11[4A], an analog in which lysine at position four is substituted with alanine, prevents EAE. The mechanism of inhibition has not been elucidated, but probably does not work through MHC blockade, T cell anergy or clonal elimination of encephalitogenic T cells. We have isolated T cell clones and hybridomas from (PL/J x SJL/J)F1 mice immunized with either Ac1-11 alone or Ac1-11 and Ac1-11[4A] and analysed these cells for differences in their T cell receptor repertoire and in vitro response. Although T cells elicited by coinjection of Ac1-11 and Ac1-11[4A] expressed TCR that used V alpha and Vbeta gene elements similar to those elicited by Ac1-11 alone, they differed in the sequences of the junctional region of the alpha chain. Most of these T cells also responded less well to Ac1-11 in vitro, suggesting that coinjection of Ac1-11 and Ac1-11[4A] preferentially activates T cells bearing TCR of different affinity for Ac1-11 bound to I-A(u), and which may therefore be less encephalitogenic. Furthermore, our results show that a more diverse repertoire of V alpha and Vbeta genes are elicited by Ac1-11 in (PL/J x SJL/J)F1 mice compared to PL/J and B10.PL mice, providing further evidence that a restricted TCR repertoire is not required for the development of autoimmune disease.
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PMID:Induction of a heterogeneous TCR repertoire in (PL/JXSJL/J)F1 mice by myelin basic protein peptide Ac1-11 and its analog Ac1-11[4A]. 944 77

Theiler's murine encephalomyelitis virus (TMEV) induces immune-mediated demyelination after intracerebral inoculation of the virus into susceptible mouse strains. We isolated from a TMEV BeAn 8386 viral stock, a low-pathogenic variant which requires greater than a 10,000-fold increase in viral inoculation for the manifestation of detectable clinical signs. Intracerebral inoculation of this variant virus induced a strong, long-lasting, protective immunity from the demyelinating disease caused by pathogenic TMEV. The levels of antibodies to the whole virus as well as to the major linear epitopes were similar in mice infected with either the variant or wild-type virus. However, persistence of the variant virus in the central nervous system (CNS) of mice was significantly lower than that of the pathogenic virus. In addition, the T-cell response to the predominant VP1 (VP1(233-250)) epitope in mice infected with the variant virus was significantly weaker than that in mice infected with the parent virus, while similar T-cell responses were induced against another predominant epitope (VP2(74-86)). Further analyses indicated that a change of lysine to arginine at position 244 of VP1, which is the only amino acid difference in the P1 region, is responsible for such differential T-cell recognition. Thus, the difference in the T-cell reactivity to this VP1 region as well as the low level of viral persistence in the CNS may account for the low pathogenicity of this spontaneous variant virus.
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PMID:A spontaneous low-pathogenic variant of Theiler's virus contains an amino acid substitution within the predominant VP1(233-250) T-cell epitope. 944 95

The NH2-terminal peptide of myelin basic protein (MBP) bound to the class II major histocompatibility complex (MHC) protein I-Au is an immunodominant epitope in experimental autoimmune encephalomyelitis, a murine model of multiple sclerosis. However, the MBP-I-Au complex is very unstable. To investigate this, we performed site-directed mutagenesis of the I-Au MHC protein and the MBP peptide. Biochemical, T cell activation, and molecular modeling studies of mutant complexes demonstrate that the MBP peptide's key residue for MHC binding, lysine 4, is buried in the P6 pocket of I-Au, which is predominantly hydrophobic. This implies that the MBP-I-Au complex differs from more stable complexes in two respects: (a) the peptide leaves the NH2-terminal region of the MHC peptide-binding cleft unoccupied; (b) the peptide is not anchored by typical favorable interactions between peptide side chains and MHC pockets. To test these hypotheses, a modified MBP peptide was designed based on molecular modeling, with the aim of producing strong I-Au binding. Extension of the NH2 terminus of MBP with six amino acids from the ova peptide, and replacement of the lysine side chain in the P6 pocket with an aromatic anchor, results in >1,000-fold increased binding stability. These results provide an explanation for the unusual peptide-MHC-binding kinetics of MBP, and should facilitate an understanding of why mice are not tolerant to this self-peptide- MHC complex.
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PMID:Evidence that the autoimmune antigen myelin basic protein (MBP) Ac1-9 binds towards one end of the major histocompatibility complex (MHC) cleft. 956 42

Copolymer 1 (Cop 1) is a random synthetic amino acid copolymer of L-alanine, L-glutamic acid, L-lysine, and L-tyrosine, effective both in suppression of experimental allergic encephalomyelitis and in the treatment of relapsing forms of multiple sclerosis. Cop 1 binds promiscuously and very efficiently to living APCs of various HLA haplotypes. In the present study, a substantial part of the whole mixture of random polypeptides that compose Cop 1 was shown to bind to purified human HLA-DR1, DR2, and DR4 with high affinity in a temperature- and time (and, in the case of DR4, pH)-dependent manner, and was competitively inhibited by DR-restricted peptides, but not by peptide derivatives that bind with low affinity. Bacterial superantigens inhibited Cop 1 binding only at very high concentrations. The formation of the Cop 1-DR1 complex was also shown by SDS-PAGE. These findings represent the first direct evidence for interactions of Cop 1 with purified DR molecules, and suggest that its effectiveness in experimental allergic encephalomyelitis and multiple sclerosis may be directly related to its binding in the groove of HLA-DR proteins.
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PMID:Promiscuous binding of synthetic copolymer 1 to purified HLA-DR molecules. 957 43

Copolymer 1 [poly(Y,E,A,K)] is a random synthetic amino acid copolymer of L-tyrosine, L-glutamic acid, L-alanine, and L-lysine that is effective both in suppression of experimental allergic encephalomyelitis and in the treatment of relapsing forms of multiple sclerosis. Copolymer 1 binds promiscuously and very efficiently to purified HLA-DR molecules within the peptide-binding groove. In the present study, YEAK and YEAK-related copolymers and type II collagen (CII) peptide 261-273, a candidate autoantigen in rheumatoid arthritis (RA), competed for binding to RA-associated HLA-DR molecules encoded by DRB1*0101 and DRB1*0401. Moreover, these copolymers (particularly YEAK, YAK, and YEK) inhibited the response of DR1- and DR4-restricted T cell clones to the CII epitope 261-273 by >50%. This direct evidence both for competitive interactions of these copolymers and CII peptide with RA-associated HLA-DR molecules and for inhibition of CII-specific T cell responses suggests that these compounds should be evaluated in animal models for rheumatoid arthritis.
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PMID:Synthetic amino acid copolymers that bind to HLA-DR proteins and inhibit type II collagen-reactive T cell clones. 977 May 19

The N-terminal peptide Ac1-11 of myelin basic protein induces experimental autoimmune encephalomyelitis in H-2(u) and (H-2(u) x H-2(s)) mice but does not in H-2(s) mice. Ac1-11 binds weakly to the class II major histocompatibility complex (MHC) molecule I-Au but not at all to I-As. We have studied the interaction of Ac1-11 and I-Au as a model system for therapeutic intervention in the autoimmune response seen in experimental autoimmune encephalomyelitis. Two polymorphic residues that differ between I-Au and I-As, Y26beta and T28beta, and one conserved residue, E74beta, confer specific binding of Ac1-11 to I-Au. A fourth residue, R70beta in I-Au, affects both peptide binding and T cell recognition. These results are consistent with a model that places arginine at position five of Ac1-11 in pockets 4 and 7 of the MHC groove, which is formed in part by residues 26, 28, 70, and 74 of Abetau and places lysine at position four of Ac1-11, previously shown to be a major MHC contact, in hydrophobic pocket 6. The data indicate that the primary region of I-Au that confers specific binding of Ac1-11 lies in the center of the peptide binding groove rather than in the region that contacts the N terminus of the peptide, as has been shown for HLA DR and the homologous I-E molecules.
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PMID:A small number of residues in the class II molecule I-Au confer the ability to bind the myelin basic protein peptide Ac1-11. 987 95

Copolymer 1 [Cop 1, poly(Y,E,A,K)] is a random synthetic amino acid copolymer of L-tyrosine, L-glutamic acid, L-alanine and L-lysine, effective both in suppression of experimental allergic encephalomyelitis and in the treatment of relapsing forms of multiple sclerosis. Cop 1 binds promiscuously and very efficiently to purified human HLA-DR molecules within the peptide-binding groove. In the present study the binding of copolymers composed of three of the four amino acids found in poly(Y,E,A,K) to purified class II MHC molecules was examined. Poly(Y,A,K) and poly(Y,E,A,K) bound to purified human HLA-DR1 or -DR4 molecules with affinity higher than poly(Y,E,A), poly(E,A,K) or poly(Y,E,K), whereas poly(Y,E,A,K) and poly(E,A,K) were the better binders of HLA-DR2 molecules. On the other hand, poly(Y,E,A) and poly(Y,A,K) inhibited the binding of biotinylated poly(Y,E,A,K) to these molecules 10-fold more efficiently than poly(Y,E,K). Finally, poly(Y,E,A), poly(Y,A,K) and poly(E,A,K) were cross-reactive with poly(Y,E,A,K) using YEAK-specific T cell lines and clones of mouse or human origin.
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PMID:Binding of random copolymers of three amino acids to class II MHC molecules. 1033 Feb 69

Copolymer 1 (COP), a standardized mixture of synthetic polypeptides consisting of l-glutamic acid, l-lysine, l-alanine, and l-tyrosine, has beneficial effects in multiple sclerosis and experimental autoimmune encephalomyelitis. We selected a panel of 721 COP-reactive T cell lines (TCL) from the blood of COP-treated and untreated multiple sclerosis patients and from healthy donors by using the split-well cloning technique. All TCL selected with COP proliferated in response to COP but not to myelin basic protein (MBP). Conversely, 31 control TCL selected with MBP proliferated in response to MBP but not to COP. We used intracellular double-immunofluorescence flow cytometry for quantitative analysis of cytokine production (IL-4, IFN-gamma) by the TCL. The majority of the COP-reactive TCL from untreated multiple sclerosis patients and normal donors predominantly produced IFN-gamma and, accordingly, were classified as T helper 1 cells (TH1). In contrast, the majority of the COP-reactive TCL from COP-treated patients predominantly (but not exclusively) produced IL-4-i.e., were TH2 (P < 0.05 as assessed by using a suitable preference intensity index). Longitudinal analyses revealed that the cytokine profile of COP-reactive TCL tends to shift from TH1 to TH2 during treatment. Interestingly, although there was no proliferative cross-reaction, about 10% of the COP-reactive TCL responded to MBP by secretion of small amounts of IL-4 or IFN-gamma, depending on the cytokine profile of the TCL. These results are consistent with a protective effect of COP-reactive TH2 cells. It is hypothesized that these cells are activated by COP in the periphery, migrate into the central nervous system, and produce immunomodulatory cytokines after local recognition of MBP.
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PMID:Multiple sclerosis: comparison of copolymer-1- reactive T cell lines from treated and untreated subjects reveals cytokine shift from T helper 1 to T helper 2 cells. 1086 Oct 11


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