Localization and Properties of an Acid‐Solubl'e Muscle Antigen Reacting with Antibodies in Myasthenia Gravis Sera

Sera from patients with myasthenia gravis contain antibodies to a citric acid extractable antigen present in heart and skeletal muscle. This antigen is located in the sarcolemmal/subsarcolemmal region of the muscle fibres. The antigen is resistant to pH changes between 2 and 10, but is inactivated by treatment at 56° C for 60 min or at 70° C for 30 min. The antigenic determinant is of protein nature.