The aim of this research is to study immunoregulatory mechanisms in experimental autoimmune myasthenia gravis (EAMG) and in myasthenia gravis (MG), diseases in which the antigen, nicotinic acetylcholine receptor (AChR), is well-defined. Such information may be applicable to other immunologically-based diseases in which the principle reaction is less well-understood. The idiotypic repertoire of the anti-AChR antibodies active in EAMG will be studied making use of monoclonal anti-AChR antibodies prepared by means of hybridization of antibody-producing cells with myeloma cell lines with subsequent immunization of rats with the monoclonal anti-AChR antibodies produced by this maneuver. The anti-idiotypic antibodies produced by the second immunization will be used to search for idiotypic cross-reactivity between anti-AChR antibodies from different EAMG animals and from patients with MG. In addition, treatment with anti-idiotypic antibody alone and in combination with immunosuppressant drugs will be studied in EAMG.