Mapping myasthenia gravis–associated T cell epitopes on human acetylcholine receptors in HLA transgenic mice
Huan Yang, … , Mathilde A. Poussin, Premkumar Christadoss
Huan Yang, … , Mathilde A. Poussin, Premkumar Christadoss
Published April 15, 2002
Citation Information: J Clin Invest. 2002;109(8):1111-1120. https://doi.org/10.1172/JCI14255.
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Article Immunology

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 DQ8×DQ6 and DQ8×DR3 F1 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 (α320-337, α304-322, and α419-437), of which the response to α320-337 was the most intense. DR3 transgenic mice also responded to this sequence very strongly. H-AChR– and α320-337 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, IgG2b, and IgG2c Ab’s and reduced IL-2 and IFN-γ secretion by H-AChR– and peptide α320-337–specific lymphocytes. Finally, we show that DQ8 imparts susceptibility to EAMG and responsiveness to an epitope within the sequence α320-337 as a dominant trait.

Authors

Huan Yang, Elzbieta Goluszko, Chella David, David K. Okita, Bianca Conti-Fine, Teh-sheng Chan, Mathilde A. Poussin, Premkumar Christadoss

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Reduced H-AChR– and α320-337 peptide–specific lymphocyte proliferative r...
Reduced H-AChR– and α320-337 peptide–specific lymphocyte proliferative response and IFN-γ and IL-2 secretion in DQ6 mice compared with DQ8, DR3, and DQ8×DR3 F1 mice. At termination of the long-term experiment (day 90), LNCs from DQ6, DQ8, DR3, and DQ8×DR3 F1 mice were cultured in vitro with H-AChR (0.5 μg/ml), peptide α320-337 (40 μg /ml), and PBS, and supernatants collected after 48, 72, and 96 hours were used for IL-2, IL-10, and IFN-γ measurement, respectively. Because of the reduced number of cells, the LNCs from two mice in one group were pooled. For the lymphocyte proliferation, total samples were six DQ6 mice and eight each of DQ8, DR3, and DQ8×DR3 F1 mice; for the supernatant cytokine test, total samples were three DQ6, seven DQ8, five DR3, and five DQ8×DR3 F1 mice. (a) Lymphocyte proliferation is measured in Δcpm (cpm with antigen minus cpm with medium). Mean cpm with medium was: DQ6, 6363; DQ8, 6218; DR3, 6795; DQ8×DR3 F1, 7567. Δcpm for T-AChR was: DQ6, 2152; DQ8, 7213; DR3, 9703; DQ8×DR3 F1, 1046.4. (b and c) Suppressed production of AChR-specific IFN-γ (b) and IL-2 (c) in DQ6 mice compared with DQ8, DR3, and DQ8×DR3 F1 mice. *P < 0.05, Student’s t test. The error bars are SE. Mean values (pg/ml) with medium for IFN-γ were: DQ6, 21.67; DQ8, 22.19; DR3, 36.07; DQ8×DR3 F1, 26.59; and for IL-2 were: DQ6, 27; DQ8, 54.18; DR3, 47.42; DQ8×DR3 F1, 574. (d) IL-10 secretion in supernatant of each strain of transgenic mice. Mean values (pg/ml) with medium were: DQ6, 27; DQ8, 21.4; DR3, 28; DQ8×DR3 F1, 21.79.