Differences in the interaction of acetylcholine receptor antibodies with receptor from normal, denervated and myasthenic human muscle.

The interaction of acetylcholine receptor antibodies with different kinds of human skeletal muscle receptor was investigated. The reaction of most receptor antibodies was strongest with receptor from a patient with myasthenia gravis and with receptor from denervated muscle. Results obtained with these receptors were well correlated. The binding of most receptor antibodies to receptor from functionally normal muscle was much weaker and also qualitatively different. In a few patients with moderate and severe clinical symptoms the existence of acetylcholine receptor antibodies was revealed only by their reaction with receptor from myasthenic muscle. One patient had a clone of receptor antibodies reacting exclusively with receptor from her own muscle.