title: Nasal tolerance in experimental autoimmune myasthenia gravis (EAMG): induction of protective tolerance in primed animals.
abstract: Nasal administration of microg doses of acetylcholine receptor (AChR) is effective in preventing the development of B cell-mediated EAMG in the Lewis rat, a model for human MG. In order to investigate whether nasal administration of AChR modulates ongoing EAMG, Lewis rats were treated nasally with AChR 2 weeks after immunization with AChR and Freund's complete adjuvant. Ten-fold higher amounts of AChR given nasally (600 microg/rat) were required to ameliorate the manifestations of EAMG compared with the amounts necessary for prevention of EAMG. In lymph node cells from rats receiving 600 microg/rat of AChR, AChR-induced proliferation and interferon-gamma (IFN-gamma) secretion were reduced compared with control EAMG rats receiving PBS only. The anti-AChR antibodies in rats treated nasally with 600 microg/rat of AChR had lower affinity, reduced proportion of IgG2b and reduced capacity to induce AChR degradation. Numbers of AChR-reactive IFN-gamma and tumour necrosis factor-alpha (TNF-alpha) mRNA-expressing lymph node cells from rats treated nasally with 600 microg/rat of AChR were suppressed, while IL-4, IL-10 and transforming growth factor-beta (TGF-beta) mRNA-expressing cells were not affected. Collectively, these data indicate that nasal administration of AChR in ongoing EAMG induced selective suppression of Th1 functions, i.e. IFN-gamma and IgG2b production, but no influence on Th2 cell functions. The impaired Th1 functions may result in the production of less myasthenic anti-AChR antibodies and contribute to the amelioration of EAMG severity in rats treated with AChR 600 microg/rat by the nasal route.
authors.affiliation: Division of Neurology, Karolinska Institute, Huddinge University Hospital, Stockholm, Sweden.
authors.forename: F D
authors.initials: FD
authors.lastname: Shi
authors.forename: X F
authors.initials: XF
authors.lastname: Bai
authors.forename: H L
authors.initials: HL
authors.lastname: Li
authors.forename: Y M
authors.initials: YM
authors.lastname: Huang
authors.forename: P H
authors.initials: PH
authors.lastname: Van der Meide
authors.forename: H
authors.initials: H
authors.lastname: Link
mesh_terms: D000281:Administration, Intranasal; D000818:Animals; D000918:Antibody Specificity; D016207:Cytokines / Q000096:biosynthesis; D004195:Disease Models, Animal; D005260:Female; D005620:Freund's Adjuvant / Q000008:administration & dosage; D007108:Immune Tolerance; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007132:Immunoglobulin Isotypes / Q000097:blood; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology; D009157:Myasthenia Gravis / Q000276:immunology* / Q000628:therapy*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew; D011950:Receptors, Cholinergic / Q000187:drug effects / Q000276:immunology*; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology; D018417:Th1 Cells / Q000187:drug effects / Q000276:immunology; D018418:Th2 Cells / Q000187:drug effects / Q000276:immunology; D014101:Torpedo
chemical_list: D016207:Cytokines; D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes; D012333:RNA, Messenger; D011950:Receptors, Cholinergic; D005620:Freund's Adjuvant