T-lymphocyte recognition of a portion of myelin basic protein encoded by an exon expressed during myelination

Abstract

The major isoform of myelin basic protein (MBP) in the healthy adult central nervous system is the 18.5-kDa protein which is produced by mRNA derived from exons 1, 3, 4, 5, 6 and 7 of the MBP gene. Since isoforms containing exon 2-encoded protein (X2MBP) are expressed during myelin formation, we examined T cell reactivity specific for X2MBP in a disease characterized by remyelination subsequent to demyelination, multiple sclerosis (MS). T cell lines specific for X2MBP were derived from three MS patients as well as one healthy control. This suggests that candidate autoantigens in demyelinating/remyelinating diseases should include not only the major isoforms of myelin proteins, but also isoforms expressed aberrantly during a disease process since they too may be the target of a T cell-mediated autoimmune process.