Experimental myasthenia gravis induced in mice by passive transfer of human myasthenic immunoglobulin. Evidence for an ameliorating effect by alpha-fetoprotein.

The induction of experimental autoimmune myasthenia gravis (EAMG) was studied by the passive transfer of gamma-globulin from myasthenia gravis (MG) patients to C57BL/6 mice. Muscular weakness and electromyographic decrements (EMG) could be consistently induced in all mice injected with gamma-globulin from certain selected MG patients. There was, however, no correlation between the antiacetylcholine receptor antibody titre in the donor gamma-globulin and the ability to induce EAMG. The possible beneficial effects of immunoregulatory alpha-fetoprotein (AFP) treatment were investigated employing the passive EAMG model. Mice were protected against the onset of severe symptoms provided the AFP was administered before and after passive transfer. The exaggerated fatigue characteristics associated with murine EAMG as detected by EMG could be alleviated by AFP treatment. These findings raise the possibility that AFP may be of some therapeutic value in the control of MG.