Thymomas Express Ryanodine Receptor Epitopes
Myasthenia gravis (MG) patients with thymoma have antibodies against the Ca2+release channel of striated muscle, the ryanodine receptor (RyR). Thymomas were examined for immunoreactivity with a panel of polyclonal antibodies against RyR peptides. An antibody raised against a peptide in the transmembrane segment of cardiac and skeletal muscle RyR immunostained thymoma epitehlial cells in sections of 17/23 thymomas, and detected a 40 kDa peptide in membrane fractions of thymoma. The RyR peptide was not detected in normal thymus, tonsil or carcinoma of colon. The results indicate that neoplastic thymoma cells express epitopes shared by skeletal and cardiac muscle RyR.
KeywordsRyanodine Receptor Normal Thymus Neoplastic Epithelial Cell Thymoma Patient Slow Skeletal Muscle Fiber
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