MOG (92–106), mouse, rat, is a biologically active peptide corresponding to the fragment of amino acids 92 to 106 in myelin oligodendrocyte glycoprotein (MOG) from mice and rats. Mice subjected to MOG (92–106)-induced experimental autoimmune encephalomyelitis show substantial B cell reactivity to secondary myelin antigens. Although this MOG fragment elicits only modest T cell responses, the resultant autoimmunity is profoundly severe. The peptide demonstrates encephalitogenic properties in various species, including SJL mice, DA rats, and rhesus monkeys.