T-cell receptor peptide immunization leads to enhanced and chronic experimental allergic encephalomyelitis

It has previously been reported that synthetic peptides corresponding to sequences derived from T-cell receptor variable regions identified as dominant in the T-cell-mediated autoimmune disease experimental allergic encephalomyelitis in both the mouse and the rat can down-regulate disease in Lewis rats. In contrast to these results, we have found that immunization of Lewis rats with such peptides in complete Freund's adjuvant prior to induction of experimental allergic encephalomyelitis with myelin basic protein leads to responses ranging from profound disease enhancement to lack of disease. In some cases, enhanced disease was followed by a prolonged neurologic deficit that resembles multiple sclerosis more closely than does acute experimental allergic encephalomyelitis. These findings, on the one hand, support previous results showing T-cell receptor peptide-induced modulation of the disease experimental allergic encephalomyelitis and, on the other, indicate that such immunization is not a reliable method for inducing suppression of encephalitogenic effector cells.