Serum Globulin in Myasthenia Gravis: Inhibition of α-Bungarotoxin Binding to Acetylcholine Receptors

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Science  04 Oct 1974:
Vol. 186, Issue 4158, pp. 55-57
DOI: 10.1126/science.186.4158.55


Serum factors that inhibit the binding of 125I-labeled α-bungarotoxin to the acetylcholine receptor extracted in detergent from denervated rat muscle were detected by a sensitive assay. The serum of at least 5 and possibly 11 out of 15 patients with myasthenia gravis showed inhibitory activity that was localized to the globulin fraction. No controls showed inhibitory activity. The demonstration of inhibitory globulins may help explain the involvement of the immune system in the pathophysiology of the neuromuscular junction in patients with myasthenia gravis.