Myelin basic protein in experimental allergic encephalomyelitis is not affected at the posttranslational level: implications for demyelinating disease.

The microheterogeneity of myelin basic protein, expressed as the ratio between the least cationic (C-8) charge isomer and the most cationic (C-1), was examined in experimental allergic encephalomyelitis (EAE) cases. These included acute EAE of 2 months' duration induced with bovine proteolipid protein in complete Freund's adjuvant (CFA), chronic EAE induced with mouse spinal cord homogenate in varying doses from 0.5 to 2.0 mg in CFA, and chronic relapsing EAE of 12 months' duration induced with synthetic peptide 139-151 of the proteolipid protein sequence. The C-8/C-1 ratio was within the normal range for all groups of animals. However, the C-8/C-1 ratio was six- to sevenfold increased in a spontaneously demyelinating transgenic model, ND4, which contains 70 copies of the cDNA for DM20 (Mastronardi et al.: 1996). Since an increase in the C-8/C-1 ratio was also observed in victims of multiple sclerosis but not other neurological diseases, the ND4 model may address primary changes prior to demyelination, while the EAE model addresses the autoimmune aspects of the disease.