title: Mapping myasthenia gravis-associated T cell epitopes on human acetylcholine receptors in HLA transgenic mice.
abstract: Susceptibility to myasthenia gravis (MG) is positively linked to expression of HLA-DQ8 and DR3 molecules and negatively linked to expression of the DQ6 molecule. To elucidate the molecular basis of this association, we have induced experimental autoimmune MG (EAMG) in mice transgenic for HLA-DQ8, DQ6, and DR3, and in DQ8xDQ6 and DQ8xDR3 F(1) transgenic mice, by immunization with human acetylcholine receptor (H-AChR) in CFA. Mice expressing transgenes for one or both of the HLA class II molecules positively associated with MG (DQ8 and DR3) developed EAMG. T cells from DQ8 transgenic mice responded well to three cytoplasmic peptide sequences of H-AChR (alpha320-337, alpha304-322, and alpha419-437), of which the response to alpha320-337 was the most intense. DR3 transgenic mice also responded to this sequence very strongly. H-AChR- and alpha320-337 peptide-specific lymphocyte responses were restricted by HLA class II molecules. Disease resistance in DQ6 transgenic mice was associated with reduced synthesis of anti-AChR IgG, IgG(2b), and IgG(2c) Ab's and reduced IL-2 and IFN-gamma secretion by H-AChR- and peptide alpha320-337-specific lymphocytes. Finally, we show that DQ8 imparts susceptibility to EAMG and responsiveness to an epitope within the sequence alpha320-337 as a dominant trait.
authors.affiliation: Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555-1070, USA.
authors.forename: Huan
authors.initials: H
authors.lastname: Yang
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Goluszko
authors.forename: Chella
authors.initials: C
authors.lastname: David
authors.forename: David K
authors.initials: DK
authors.lastname: Okita
authors.forename: Bianca
authors.initials: B
authors.lastname: Conti-Fine
authors.forename: Teh-sheng
authors.initials: TS
authors.lastname: Chan
authors.forename: Mathilde A
authors.initials: MA
authors.lastname: Poussin
authors.forename: Premkumar
authors.initials: P
authors.lastname: Christadoss
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004195:Disease Models, Animal; D018604:Epitope Mapping; D000939:Epitopes / Q000235:genetics; D006680:HLA Antigens / Q000235:genetics*; D006683:HLA-DQ Antigens / Q000235:genetics; D015803:HLA-DR3 Antigen / Q000235:genetics; D006801:Humans; D007114:Immunization; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D009157:Myasthenia Gravis / Q000235:genetics* / Q000276:immunology*; D011950:Receptors, Cholinergic / Q000235:genetics* / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000939:Epitopes; D006680:HLA Antigens; D006683:HLA-DQ Antigens; C063831:HLA-DQ6 antigen; C109756:HLA-DQ8 antigen; D015803:HLA-DR3 Antigen; D011950:Receptors, Cholinergic