Autoantibodies, neurotoxins and the nervous system.

Myasthenia gravis, the Lambert-Eaton myasthenic syndrome, and acquired neuromyotonia are three disorders of the neuromuscular junction or motor nerve that are caused by autoantibodies to ion channel proteins: acetylcholine receptors, voltage-gated calcium channels and voltage-gated potassium channels, respectively. The antibody titres can be measured using the relevant 125I-neurotoxins to label the extracted channels. Other disorders of the peripheral motor nerve are associated with antibodies to gangliosides. Sera with raised levels of anti-ganglioside antibodies have direct effects on the function of the distal motor nerve and motor nerve terminal. These conditions can be improved by therapies designed to reduce circulating antibodies. Antibodies that bind to neuronal surface antigens are proving to be of great clinical importance and interest in neurological disorders.