The antagonistic 15-peptide EKPKVEAYKAAAAPA competes with MBP (85-99), the immunodominant epitope of myelin basic protein (MBP), a major candidate autoantigen in multiple sclerosis (MS), for binding to human leukocyte antigen (HLA)-DR2. The peptide also inhibits IL-2 secretion by MBP (85-99) specific T-cell clones and induces the production of Th2 cytokines by splenocytes. Furthermore, it could be shown that the peptide is able to suppress experimental autoimmune encephalomyelitis (EAE) in several models in a manner that is equipotent to random amino acid copolymers, such as Copaxone [poly (Y,E,A,K)n]. Therefore, this synthetic peptide might be suitable in the studying of MS.