Abstract
Lymph IgG from patients with myasthenia gravis was shown to inhibit the binding of radio-labelled Naja naja siamensisα-neurotoxin to membrane fragments from the electric organ of Torpedo marmorata. This effect could be related to IgG subclass 3 and to the F(ab)2 fragment. These findings confirm the involvement of antibodies to postsynaptic structures in myasthenia gravis.