RESUMO
Experimental autoimmune myasthenia gravis (EAMG) is an animal model of human myasthenia gravis (MG). In mice, EAMG is induced by immunization with Torpedo californica acetylcholine receptor (AChR) in complete Freund's adjuvant (CFA). However, the role of cytokines in the pathogenesis of EAMG is not clear. Because EAMG is an antibody-mediated disease, it is of the prevailing notion that Th2 but not Th1 cytokines play a role in the pathogenesis of this disease. To test the hypothesis that the Th1 cytokine, interferon (IFN)-gamma, plays a role in the development of EAMG, we immunized IFN-gamma knockout (IFN-gko) (-/-) mice and wild-type (WT) (+/+) mice of H-2(b) haplotype with AChR in CFA. We observed that AChR-primed lymph node cells from IFN-gko mice proliferated normally to AChR and to its dominant pathogenic alpha146-162 sequence when compared with these cells from the WT mice. However, the IFN-gko mice had no signs of muscle weakness and remained resistant to clinical EAMG at a time when the WT mice exhibited severe muscle weakness and some died. The resistance of IFN-gko mice was associated with greatly reduced levels of circulating anti-AChR antibody levels compared with those in the WT mice. Comparatively, immune sera from IFN-gko mice showed a dramatic reduction in mouse AChR-specific IgG1 and IgG2a antibodies. However, keyhole limpet hemocyanin (KLH)-priming of IFN-gko mice readily elicited both T cell and antibody responses, suggesting that IFN-gamma regulates the humoral immune response distinctly to self (AChR) versus foreign (KLH) antigens. We conclude that IFN-gamma is required for the generation of a pathogenic anti-AChR humoral immune response and for conferring susceptibility of mice to clinical EAMG.
Assuntos
Interferon gama/fisiologia , Miastenia Gravis/etiologia , Miastenia Gravis/imunologia , Receptores Colinérgicos/fisiologia , Animais , Autoanticorpos/biossíntese , Autoanticorpos/sangue , Deleção de Genes , Epitopos Imunodominantes/química , Epitopos Imunodominantes/fisiologia , Isotipos de Imunoglobulinas/biossíntese , Isotipos de Imunoglobulinas/sangue , Ativação Linfocitária/genética , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Camundongos Knockout , Miastenia Gravis/genética , Receptores Colinérgicos/química , Receptores Colinérgicos/imunologiaRESUMO
Myasthenia gravis (MG) is an autoimmune neuromuscular disease manifested by muscle weakness and fatiguability. The primary pathology in MG is antibody and complement-mediated destruction of muscle acetylcholine receptor (AChR). Like other autoimmune diseases, MG is associated with certain HLA antigens, particularly HLA-B8 and DR3 in Caucasians. Also, certain GM antigens and complotypes are associated with MG. Therefore, it is crucial to study the immunogenetic aspect of MG in animal models to evaluate disease etiopathogenesis and eventual strategy for specific therapy. In the introduction of this review article, I focus on the association of HLA and GM antigens in MG and emphasize the mouse model of experimental autoimmune myasthenia gravis (EAMG) as an ideal model to study the immunogenetic aspect of MG. The following sections deal with the role of (1) major histocompatibility complex (MHC), (2) immune response gene, (3) the IA molecule, (4) the Igl locus, (5) the complement genes, and (6) non-MHC genes on EAMG pathogenesis. The review concludes with future immunogenetic analysis and eventual strategy for specific therapy from an immunogeneticist's point of view.
Assuntos
Doenças Autoimunes , Miastenia Gravis , Animais , Doenças Autoimunes/genética , Doenças Autoimunes/imunologia , Modelos Animais de Doenças , Humanos , Imunogenética , Linfocinas/genética , Linfocinas/metabolismo , Complexo Principal de Histocompatibilidade , Camundongos , Miastenia Gravis/genética , Miastenia Gravis/imunologia , Polimorfismo Genético , Receptores Colinérgicos/genética , Receptores Colinérgicos/imunologiaRESUMO
Muscle-specific tyrosine kinase (MuSK) autoantibodies are the hallmark of a form of myasthenia gravis (MG) that can challenge the neurologist and the experimentalist. The clinical disease can be difficult to treat effectively. MuSK autoantibodies affect the neuromuscular junction in several ways. When added to muscle cells in culture, MuSK antibodies disperse acetylcholine receptor clusters. Experimental animals actively immunized with MuSK develop MuSK autoantibodies and muscle weakness. Weakness is associated with reduced postsynaptic acetylcholine receptor numbers, reduced amplitudes of miniature endplate potentials and endplate potentials, and failure of neuromuscular transmission. Similar impairments have been found in mice injected with IgG from MG patients positive for MuSK autoantibody (MuSK-MG). The active and passive models have begun to reveal the mechanisms by which MuSK antibodies disrupt synaptic function at the neuromuscular junction, and should be valuable in developing therapies for MuSK-MG. However, translation into new and improved treatments for patients requires procedures that are not too cumbersome but suitable for examining different aspects of MuSK function and the effects of potential therapies. Study design, conduct and analysis should be carefully considered and transparently reported. Here we review what has been learnt from animal and culture models of MuSK-MG, and offer guidelines for experimental design and conduct of studies, including sample size determination, randomization, outcome parameters and precautions for objective data analysis. These principles may also be relevant to the increasing number of other antibody-mediated diseases that are now recognized.
Assuntos
Miastenia Gravis Autoimune Experimental , Miastenia Gravis , Projetos de Pesquisa/normas , Animais , Autoanticorpos/imunologia , Guias como Assunto , Humanos , Receptores Proteína Tirosina Quinases/imunologia , Receptores Colinérgicos/imunologiaRESUMO
An extensive analysis of the relationship between immunological parameters and clinical responses and biochemical loss of muscle acetylcholine receptors (AChR) was performed in murine experimental autoimmune myasthenia gravis. The onset of clinical muscle weakness correlated strongly with the onset of significant muscle AChR loss. Mice with clinical muscle weakness had greater amount of muscle AChR loss. There was no correlation between the concentration of anti-AChR antibodies and the presence of clinical muscle weakness or amount of muscle AChR loss. However, the kinetics of autoantibody response correlated well with that of muscle AChR loss.
Assuntos
Músculos/imunologia , Miastenia Gravis/imunologia , Receptores Colinérgicos/imunologia , Autoanticorpos/imunologia , Humanos , Imunidade Celular , Imunização , Ativação Linfocitária , Músculos/fisiopatologia , Miastenia Gravis/fisiopatologiaRESUMO
To analyze the role of interleukin-10 (IL-10) in experimental autoimmune myasthenia gravis (EAMG) pathogenesis, we induced clinical EAMG in C57BL/6 and IL-10 gene-knockout (KO) mice. IL-10 KO mice had a lower incidence and severity of EAMG, with less muscle acetylcholine receptor (AChR) loss. AChR-immunized IL-10 KO mice showed a significantly higher AChR-specific proliferative response, altered cytokine response, lower number of class II-positive cells and B-cells, but a greater CD5(+)CD19(+) population than C57BL/6 mice. The lower clinical incidence in IL-10 KO could be explained not by a reduction of the quantity, but by a possible difference in the pathogenicity of anti-AChR antibodies.
Assuntos
Linfócitos B/imunologia , Interleucina-10/genética , Interleucina-10/imunologia , Miastenia Gravis Autoimune Experimental/genética , Miastenia Gravis Autoimune Experimental/imunologia , Receptores Colinérgicos/imunologia , Adjuvantes Imunológicos/genética , Animais , Antígenos CD19/análise , Autoanticorpos/sangue , Linfócitos B/química , Linfócitos B/citologia , Proteínas Sanguíneas/imunologia , Antígenos CD5/análise , Divisão Celular/imunologia , Linhagem Celular , Citotoxinas/imunologia , Epitopos/imunologia , Antígenos de Histocompatibilidade Classe II/biossíntese , Antígenos de Histocompatibilidade Classe II/imunologia , Imunização , Epitopos Imunodominantes/imunologia , Técnicas In Vitro , Interferon gama/biossíntese , Interferon gama/imunologia , Interleucina-6/biossíntese , Interleucina-6/imunologia , Contagem de Linfócitos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Músculo Esquelético/química , Músculo Esquelético/imunologia , Receptores Colinérgicos/genética , Fator de Necrose Tumoral alfa/biossíntese , Fator de Necrose Tumoral alfa/imunologiaRESUMO
A complete prevention of clinical experimental autoimmune myasthenia gravis (EAMG) was observed in lymphotoxin (LT)-alpha deficient (LT-alpha(-/-)) mice compared to LT-alpha(+/+) mice when immunized with acetylcholine receptor. However, only a partial prevention of clinical EAMG incidence was observed in LT-beta(-/-) mice compared to LT-beta(+/+) mice. LT-alpha(-/-)and LT-beta(-/-) mice had lower mean titers of total IgG, IgG(1), IgG(2a) and IgG(2b) and higher or equal mean titers of IgM anti-AChR antibodies compared to controls. Therefore, LT-alpha(-/-)and LT-beta(-/-) AChR immunized mice are capable of mounting a primary (IgM) humoral immune response to AChR, but are less capable of switching to the pathogenic anti-AChR IgG isotypes. LT could play a significant role in the pathogenesis of myasthenia gravis.
Assuntos
Linfotoxina-alfa/genética , Linfotoxina-alfa/imunologia , Miastenia Gravis Autoimune Experimental/imunologia , Receptores Colinérgicos/imunologia , Animais , Antígenos CD/genética , Antígenos CD/imunologia , Autoanticorpos/sangue , Antígeno B7-2 , Expressão Gênica/imunologia , Epitopos Imunodominantes/imunologia , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores do Fator de Necrose Tumoral/imunologia , Baço/citologia , Baço/imunologiaRESUMO
Evidence that human susceptibility to myasthenia gravis (MG) might be determined genetically is suggested by clinical surveys showing an association of MG with an increased frequency of certain histocompatibility antigens. We have studied the experimental autoimmune model of MG in mice to investigate whether or not major histocompatibility complex (MHC) gene products play a role in determining susceptibility to EAMG. When MHC congenic and recombinant strains of mice were inoculated with Torpedo acetylcholine receptor (AChR) and adjuvants, the magnitude of autoantibody responses to muscle AChR and of the defect of neuromuscular transmission (i.e., reduction in MEPP amplitude) closely paralleled in vitro lymphocyte proliferative responses to torpedo AChR. Reduction in MEPP amplitude correlated strikingly with the degree to which autologous muscle AChR was complexed with antibody. Lymphocyte responses to Torpedo AChR, antibody responses to mouse muscle AChR, and susceptibility to EAMG are controlled by gene(s) at the I-A subregion of the H-2 complex. Backcross studies confirmed that lymphocyte proliferative responses to AChR are controlled by a Mendelian dominant gene linked to H-2, probably at the I-A subregion. Mutation at the I-A subregion in the B6 strain, which resulted in structural alteration of the Ia molecule, converted high responsiveness to low responsiveness. Lymphocyte responses were eliminated by blocking Ia antigens on lymph node cell surfaces with specific anti-I-A alloantisera. Cellular immune responses to AChR are dependent on Lyt 1+23- cells and adherent cells. These data implicate a macrophage-associated Ia molecular in induction of autoimmune responses to AChR, probably in the presentation of AChR to helper (Lyt 1+23-) T-lymphocytes, which thereby help B-lymphocytes to differentiate into anti-AChR antibody forming cells.
Assuntos
Autoanticorpos/análise , Antígenos de Histocompatibilidade Classe II/imunologia , Miastenia Gravis/imunologia , Receptores Colinérgicos/imunologia , Potenciais de Ação , Animais , Genes MHC da Classe II , Antígenos H-2/genética , Haploidia , Ativação Linfocitária , Complexo Principal de Histocompatibilidade , Camundongos , Camundongos Endogâmicos , Junção Neuromuscular/fisiologia , Receptores Colinérgicos/genéticaAssuntos
Adjuvante de Freund/imunologia , Imunização/efeitos adversos , Miastenia Gravis/imunologia , Receptores Colinérgicos/imunologia , Animais , Modelos Animais de Doenças , Genes MHC Classe I , Antígenos de Histocompatibilidade Classe II/imunologia , Humanos , Camundongos , Miastenia Gravis/genética , Fragmentos de Peptídeos/imunologiaAssuntos
Animais Recém-Nascidos/imunologia , Doenças Autoimunes/terapia , Antígenos de Histocompatibilidade Classe II/imunologia , Tolerância Imunológica , Epitopos Imunodominantes/imunologia , Terapia de Imunossupressão , Miastenia Gravis/prevenção & controle , Receptores Nicotínicos/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Sequência de Aminoácidos , Animais , Autoanticorpos/sangue , Doenças Autoimunes/imunologia , Suscetibilidade a Doenças/imunologia , Feminino , Conversão Gênica , Predisposição Genética para Doença , Antígenos de Histocompatibilidade Classe II/genética , Humanos , Imunização , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Miastenia Gravis/imunologia , Fragmentos de Peptídeos/administração & dosagem , Fragmentos de Peptídeos/imunologia , Método Simples-Cego , Especificidade da Espécie , Torpedo/imunologiaRESUMO
The influence of the C5 gene and C5 deficiency on murine experimental autoimmune myasthenia gravis (EAMG) susceptibility was evaluated. Two co-isogenic strains, B10.D2/nSn (C5 sufficient) and B10.D2/oSn (C5 deficient), which are genetically identical except for the C5 gene locus, were immunized with acetylcholine receptors (AChR) in CFA to induce myasthenia gravis. Both strains had equivalent concentration of serum autoantibodies to muscle AChR and antibodies bound to muscle AChR. C5-sufficient B10.D2/nSn, but not C5-deficient B10.D2/oSn, demonstrated increased incidence of clinical disease and death and lost significant amounts of muscle AChR. Therefore, C5 deficiency in B10.D2/oSn prevented EAMG. C5 gene, which codes for C component C5, may influence EAMG pathogenesis through activation of the terminal lytic C sequence (C5 to C9) required for muscle AChR destruction, which is the primary pathology.
Assuntos
Doenças Autoimunes/genética , Complemento C5/genética , Miastenia Gravis/genética , Animais , Autoanticorpos/imunologia , Doenças Autoimunes/imunologia , Complemento C5/deficiência , Complemento C5/imunologia , Modelos Animais de Doenças , Suscetibilidade a Doenças , Camundongos , Camundongos Endogâmicos/genética , Camundongos Endogâmicos/imunologia , Camundongos Mutantes/imunologia , Músculos/imunologia , Miastenia Gravis/imunologia , Receptores Colinérgicos/imunologiaRESUMO
To induce autoimmune diseases in animals, the auto-antigen has to be emulsified in adjuvants (e.g., complete Freund's adjuvant) containing microbial products such as Mycobacterium tuberculosis. But these powerful immunoadjuvants are not without undesirable immune response to the microbial proteins and induction of adjuvant arthritis, which could interfere with the antigen specific autoimmune response to be tested. This study was performed to evaluate the requirement of microbial products in the induction of experimental autoimmune diseases, and to identify an adjuvant without unwanted immune responses. C57BL/6 mice were inoculated with Torpedo acetylcholine receptors (T-AChR) emulsified in Titermax (TM), an adjuvant containing nonionic block copolymer and no microbial products, and evaluated for experimental autoimmune myasthenia gravis (EAMG) susceptibility. Mice immunized with T-AChR in TM demonstrated characteristic myasthenic muscle weakness with electrophysiological defect, elevated serum anti-AChR antibodies, and muscle AChR loss. None of the mice that received TM alone had muscle weakness, serum anti-AChR antibodies or muscle AChR loss. The data imply that microbial products are not critical in the induction of autoimmune diseases like myasthenia gravis in mice. Further, nonionic block copolymer could be an ideal adjuvant in the induction of autoimmune diseases in animals.
Assuntos
Adjuvantes Imunológicos , Autoantígenos/imunologia , Doenças Autoimunes/etiologia , Miastenia Gravis/etiologia , Receptores Colinérgicos/imunologia , Animais , Complexo Antígeno-Anticorpo/imunologia , Autoanticorpos/sangue , Autoanticorpos/imunologia , Autoantígenos/administração & dosagem , Doenças Autoimunes/tratamento farmacológico , Doenças Autoimunes/imunologia , Emulsões , Imunização , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Musculares/análise , Miastenia Gravis/tratamento farmacológico , Miastenia Gravis/imunologia , Neostigmina/uso terapêutico , Receptores Colinérgicos/análise , TorpedoRESUMO
Myasthenia gravis (MG) is an antibody-mediated, autoimmune neuromuscular disease. Animal models of experimental autoimmune myasthenia gravis (EAMG) can be induced in vertebrates by immunization with Torpedo californica acetylcholine receptors (AChR) in complete Freund's adjuvant. The MHC class II genes influence the cellular and humoral immune response to AChR and are involved in the development of clinical EAMG in mice. A dominant epitope within the AChR alpha146-162 region activates MHC class II-restricted CD4 cells and is involved in the production of pathogenic anti-AChR antibodies by B cells. Neonatal or adult tolerance to this T-cell epitope could prevent EAMG. During an immune response to AChR in vivo, multiple TCR genes are used. The CD28-B7 and CD40L-CD40 interaction is required during the primary immune response to AChR. However, CTLA-4 blockade augmented T- and B-cell immune response to AChR and disease. Cytokines IFN-gamma and IL-12 upregulate, while IFN-alpha downregulates, EAMG pathogenesis. However, the Th2 cytokine IL-4 fails to play a significant role in the development of antibody-mediated EAMG. Systemic or mucosal tolerance to AChR or its dominant peptide(s) has prevented EAMG in an antigen-specific manner. Antigen-specific tolerance and downregulation of pathogenic cytokines could achieve effective therapy of EAMG and probably MG.
Assuntos
Modelos Animais de Doenças , Miastenia Gravis Autoimune Experimental , Miastenia Gravis , Animais , Autoanticorpos/sangue , Antígenos CD4/imunologia , Citocinas/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Humanos , Camundongos , Miastenia Gravis/imunologia , Miastenia Gravis/patologia , Miastenia Gravis/terapia , Miastenia Gravis Autoimune Experimental/imunologia , Miastenia Gravis Autoimune Experimental/patologia , Miastenia Gravis Autoimune Experimental/terapia , Receptores Colinérgicos/imunologiaRESUMO
In vivo therapy with monoclonal antibody (mAb) GK1.5, which recognizes a glycoprotein antigen designated L3T4 on murine helper T lymphocytes, either prevented or suppressed the development of murine lupus, autoimmune encephalomyelitis, and collagen arthritis. The L3T4 antigen in the mouse is analogous to the human Leu-3/T4 antigen expressed on helper T lymphocytes, because they both participate in the T cell response to class II major histocompatibility complex (MHC) antigens. Class II MHC genes and I-A antigens mediate murine experimental autoimmune myasthenia gravis (EAMG) induced by acetylcholine receptor (AChR) autoimmunity. We studied the efficacy of mAb GK1.5 as an immunotherapeutic agent for murine EAMG. Therapy with mAb GK1.5 not only suppressed established autoimmunity to AChR but also prevented loss of muscle AChR in mice with EAMG. Moreover, permanent remission of clinical muscle weakness was induced if mAb GK1.5 therapy was initiated after the onset of clinical disease. Because the function of the Leu-3/T4 determinant on human helper T lymphocytes is analogous to the murine L3T4 determinant, use of antibody to the Leu-3/T4 determinant as an immunotherapeutic agent may provide a way to control the progression of human MG.
Assuntos
Imunização Passiva/métodos , Miastenia Gravis/terapia , Animais , Anticorpos Monoclonais/fisiologia , Anticorpos Monoclonais/uso terapêutico , Antígenos de Diferenciação de Linfócitos T , Antígenos de Superfície/imunologia , Autoanticorpos/análise , Autoanticorpos/biossíntese , Doenças Autoimunes/imunologia , Doenças Autoimunes/terapia , Modelos Animais de Doenças , Epitopos , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Miastenia Gravis/imunologia , Receptores Colinérgicos/imunologiaRESUMO
New compounds with a greater potency than cyclosporin A (CyA) for thwarting host rejection of organ transplantation are being sought. Suramin sodium may be a novel drug to prevent or delay graft rejection and graft-vs-host disease (GVHD), because of its in vitro and in vivo immunosuppressive properties. Since the allogeneic mixed lymphocyte reaction (MLR) is considered to be the in vitro counterpart of the initial T-lymphocyte recognition and response to allogeneic histocompatibility antigens on grafted tissue or organ and to GVHD, we initially evaluated the in vitro suppressive effect of suramin in the allogeneic MLR. Suramin inhibited the H-2- and HLA-incompatible MLR in a dose-dependent manner. The suppressive effect was observed both in the primary and in the secondary MLR. The suppression of the MLR by suramin is due predominantly to the inhibition of interleukin-2 (IL-2) production by the responding T cells.
Assuntos
Interleucina-2/antagonistas & inibidores , Linfócitos/imunologia , Suramina/farmacologia , Animais , Ligação Competitiva/imunologia , Citotoxicidade Imunológica/imunologia , Antígenos H-2/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Humanos , Ativação Linfocitária/imunologia , Teste de Cultura Mista de Linfócitos , Camundongos , Camundongos Endogâmicos , Baço/imunologia , Linfócitos T/imunologiaRESUMO
Myasthenia gravis (MG) is a T cell-dependent antibody-mediated autoimmune neuromuscular disease. Antibodies to the nicotinic acetylcholine receptor (AChR) destroy the AChR, thus leading to defective neuromuscular transmission of electrical impulse and to muscle weakness. This unit is a practical guide to the induction and evaluation of experimental autoimmune myasthenia gravis (EAMG) in the mouse, the animal model for MG. Protocols are provided for the extraction and purification of AChR from the electric organs of Torpedo californica, or eel. The purified receptor is used as an immunogen to induce autoimmunity to AChR, thus causing EAMG. The defect in neuromuscular transmission can also be measured quantitatively by electromyography, as described here. In addition, EAMG is frequently characterized by the presence of antibodies to AChR, which are measured by radioimmunoassay and by a marked antibody-mediated reduction in the number of muscle AChRs. AChR extracted from mouse muscle is used in measuring serum antibody levels and for quantifying muscle AChR content.
Assuntos
Modelos Animais de Doenças , Miastenia Gravis Autoimune Experimental/imunologia , Receptores Nicotínicos/imunologia , Animais , Anticorpos/imunologia , Cromatografia de Afinidade/instrumentação , Cromatografia de Afinidade/métodos , Eletromiografia/instrumentação , Eletromiografia/métodos , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurotoxinas/química , Radioimunoensaio/métodos , Receptores Nicotínicos/isolamento & purificação , Sefarose/químicaRESUMO
Myasthenia gravis (MG) is an autoimmune neuromuscular disease, characterized by muscle weakness and electrophysiological abnormality. No treatment which would reliably induce permanent clinical remission of MG is yet available. The therapeutic efficacy and toxic effect of daunomycin (Dm), an antibiotic of the rhodomycin group, was evaluated in murine experimental autoimmune MG. Low dosage Dm treatment effectively prevented the development of muscle weakness and its associated electrophysiological abnormality, without inducing detectable toxicity and global immunosuppression.
Assuntos
Doenças Autoimunes/prevenção & controle , Daunorrubicina/uso terapêutico , Miastenia Gravis/prevenção & controle , Animais , Autoanticorpos/análise , Peso Corporal/efeitos dos fármacos , Ativação Linfocitária/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Tamanho do Órgão/efeitos dos fármacos , Receptores Colinérgicos/imunologiaRESUMO
The cellular mechanisms of high dose systemic acetylcholine receptor (AChR) T cell epitope, alpha 146--162 peptide-induced tolerance in experimental myasthenia gravis were examined. CD4 cells are the prime target for alpha 146--162 peptide-induced tolerance. The expression of CD69, Fas, and B7.2 molecules on AChR-immune lymphocytes was enhanced within 4--12 h after tolerance induction. A high dose of alpha 146--162 peptide in IFA failed to suppress T cell proliferation and/or clinical myasthenia gravis in lpr and gld mice deficient in Fas and Fas ligand, respectively. A high dose of alpha 146--162 peptide in IFA in AChR-immunized mice induced apoptosis of BV6 cells. Further, reconstitution of IL-2 in vitro-recovered alpha 146--162 peptide tolerized T cell proliferation, IFN-gamma, and IL-10 production. The findings implicate the possible role of Fas-/Fas ligand-mediated apoptosis and the resulting clonal anergy as the mechanisms of high dose AChR alpha 146--162 peptide-induced tolerance on CD4 cells.
Assuntos
Apoptose/imunologia , Anergia Clonal/imunologia , Epitopos de Linfócito T/imunologia , Glicoproteínas de Membrana/fisiologia , Receptores Colinérgicos/imunologia , Transdução de Sinais/imunologia , Receptor fas/fisiologia , Adjuvantes Imunológicos/administração & dosagem , Sequência de Aminoácidos , Animais , Antígenos CD/biossíntese , Antígenos de Diferenciação de Linfócitos T/biossíntese , Apoptose/genética , Autoanticorpos/biossíntese , Antígeno B7-2 , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Anergia Clonal/genética , Citocinas/biossíntese , Relação Dose-Resposta Imunológica , Esquema de Medicação , Proteína Ligante Fas , Adjuvante de Freund/administração & dosagem , Adjuvante de Freund/imunologia , Injeções Intraperitoneais , Injeções Subcutâneas , Cinética , Lectinas Tipo C , Ligantes , Linfonodos/citologia , Linfonodos/imunologia , Linfonodos/metabolismo , Ativação Linfocitária/genética , Glicoproteínas de Membrana/biossíntese , Glicoproteínas de Membrana/deficiência , Glicoproteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos MRL lpr , Camundongos Knockout , Dados de Sequência Molecular , Miastenia Gravis Autoimune Experimental/genética , Miastenia Gravis Autoimune Experimental/imunologia , Miastenia Gravis Autoimune Experimental/prevenção & controle , Fragmentos de Peptídeos/administração & dosagem , Fragmentos de Peptídeos/imunologia , Receptores de Antígenos de Linfócitos T alfa-beta/biossíntese , Receptores Colinérgicos/administração & dosagem , Transdução de Sinais/genética , Especificidade da Espécie , Subpopulações de Linfócitos T/citologia , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Células Th1/imunologia , Células Th1/metabolismo , Células Th2/imunologiaRESUMO
One of the dominant T cell epitopes in the acetylcholine receptor (AChR) alpha chain lies within the region 146-162 and has been implicated in the pathogenesis of experimental autoimmune myasthenia gravis (EAMG) in C57BL6 (B6) mice. To directly examine the pathogenic potential of alpha 146-162 in EAMG, B6 mice were primed with AChR in complete Freunds adjuvant (CFA) and subsequently boosted twice with either alpha 146-162 or a control peptide in CFA. Seventy percent of the mice boosted with alpha 146-162 developed muscle weakness characteristic of EAMG, while none of the mice boosted with the control peptide showed any clinical signs of the disease. Thus, the data provided evidence for epitope within AChR alpha 146-162 as one of the EAMG-inducing pathogenic epitopes in B6 mice.
Assuntos
Miastenia Gravis/imunologia , Receptores Nicotínicos/imunologia , Sequência de Aminoácidos , Animais , Autoanticorpos/imunologia , Eletromiografia , Mapeamento de Epitopos , Ativação Linfocitária , Masculino , Camundongos , Camundongos Endogâmicos , Dados de Sequência Molecular , Miastenia Gravis/fisiopatologia , Peptídeos/síntese química , Peptídeos/imunologiaRESUMO
Gene(s) at the I-A subregion of the murine major histocompatibility complex influence susceptibility to experimental autoimmune myasthenia gravis. C57Bl/6 mice immunized with acetylcholine receptors (AChR) in complete Freund's adjuvant demonstrated cellular and humoral immune responses to AChR. They developed muscle weakness characteristic of myasthenia gravis and demonstrated a reduction in the muscle AChR content. The kinetics of AChR-specific lymphocyte proliferation generally correlate with anti-AChR antibody response. AChR-specific lymphocyte proliferation was also observed in C57Bl/6 splenocytes after secondary immunization with AChR. The in vitro cellular reactivity to AChR in experimental autoimmune myasthenia gravis (EAMG) mice (C57Bl/6) was suppressed by monoclonal anti-I-Ab antibodies directed against private (Ia20) or public (Ia8) specificities, suggesting a critical role for these Ia determinants in the cellular immune response to AChR in murine EAMG.