Recently, the sensitization of young strain 13 guinea pigs with homologous spinal cord in complete Freund's adjuvant (CFA) containing 10 mg/ml of killed tubercule bacilli (strain H37Ra) has been shown to result in a relapsing and remitting disease in about 65% of the animals injected. The development of a relapsing demyelinating form of experimental allergic encephalomyelitis (EAE), very similar to multiple sclerosis (MS) in humans, will be used as an animal model in order to determine 1. whether immunoglobulins are significantly increased in brain and spinal cord extracts and, 2. whether these antibodies synthesized within central nervous system (CNS) demonstrate oligoclonal bands in electrophoresis in animals sacrificed during the various episodes of the disease. It is anticipated that these studies will contribute to a greater understanding of the role of humoral immune response in relapsing EAE animals and whether a common immunologic mechanism exists between these animals and patients with MS.