title: Thymomas express epitopes shared by the ryanodine receptor.
abstract: Myasthenia gravis (MG) patients with thymoma have antibodies against ryanodine receptor (RyR) of skeletal and heart muscle. In this study, thymomas were examined for reactivity with a panel of polyclonal rabbit antibodies against various short peptides of RyR. An antibody against peptide C2 in the transmembrane region of RyR stained thymoma epithelial cells in cryosections of 17/23 thymomas, and detected a 40-kDa peptide in Western blotting of a thymoma membrane fraction. The other RyR antibodies did not react with thymoma tissue. The anti-C2 RyR antibody did not react with normal thymus, tonsil or carcinoma of colon. The results strongly indicate that epithelial thymoma cells express an epitope shared by the transmembrane region of skeletal and cardiac muscle RyR.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000918:Antibody Specificity; D015153:Blotting, Western; D015220:Calcium Channels / Q000276:immunology*; D002148:Calmodulin-Binding Proteins / Q000276:immunology*; D002675:Child, Preschool; D000939:Epitopes / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000276:immunology*; D009157:Myasthenia Gravis / Q000276:immunology; D011817:Rabbits; D019837:Ryanodine Receptor Calcium Release Channel; D013601:T-Lymphocytes / Q000276:immunology; D013945:Thymoma / Q000276:immunology* / Q000648:ultrastructure
chemical_list: D015220:Calcium Channels; D002148:Calmodulin-Binding Proteins; D000939:Epitopes; D009124:Muscle Proteins; D019837:Ryanodine Receptor Calcium Release Channel