Reduction of acetylcholine sensitivity of chick muscle in culture by myasthenia gravis serum

Abstract

Sera from seven patients with myasthenia gravis and from six control subjects were tested for the presence of anti-acetylcholine receptor antibodies and for the ability to reduce acetylcholine sensitivity of embryonic chick skeletal muscle cells in culture. Anti-receptor antibodies were found in all but one of the myasthenic samples and in none of the control samples. The average reduction in sensitivity caused by the myasthenic sera was 89±4%, compared with an average reduction of 15±7% caused by the control sera. A sample taken from a patient during myasthenic crisis was found to have less blocking activity and less anti-receptor antibody than a sample from the same patient after recovery.