Neurotropin inhibits experimental allergic encephalomyelitis (EAE) in Lewis rats

The effects of Neurotropin, a substance extracted from the inflammatory dermis of rabbits inoculated with Vaccinia virus, for experimental allergic encephalomyelitis (EAE) in Lewis rats, a model for human multiple sclerosis (MS), was studied. The peptide defined by residues 68-84 (MB 68-84) which corresponds to the encephalitogenic portion of the guinea pig myelin basic protein (MBP) in complete adjuvant H37Ra (CFA) was injected into the hind foot pad of each rat. Neurotropin significantly suppressed the clinical and histological expression of actively induced EAE when administered i.p. daily from day 0 to day 6 after immunization. In addition, passive EAE induced by precultured spleen cells from rats immunized with MB 68-84 in CFA was also suppressed by daily administration of Neurotropin after cell transfer. Neurotropin treatment significantly suppressed the delayed-type hypersensitivity (DTH) response to MB 68-84. Furthermore, the ability of spleen cells from Neurotropin-treated rats to transfer EAE was significantly lower than that of saline-treated rats. It seemed that the suppression may be due to the inhibition of the activation by MB 68-84 of sensitized spleen cells, as demonstrated by proliferative response to MB 68-84. However, no difference was observed in Con A-induced proliferative response of the spleen cells between Neurotropin- and saline-treated rats. These findings indicate that Neurotropin inhibits EAE by suppressing the immune responses to encephalitogenic MBP with little non-specific suppression.