Active immunization with complementary peptide PBM 9-1: preliminary evidence that it modulates experimental allergic encephalomyelitis in PL/J mice and Lewis rats.

The idiotype (Id) of T cells and possibly antibodies are involved in an Id network that may immunoregulate experimental allergic encephalomyelitis (EAE). Thus, the adoptive EAE in PL/J mice responding to myelin basic protein (MBP) peptide acetyl 1-9 can be modulated by monoclonal antibody (mAb) anti-Id generated by immunization with a peptide of inverted hydropathy to MBP peptide 1-9, designated as PBM 9-1. A cross-reactive Id between species can be recognized on the T cell receptor (TCR) of Vb8.2 restricted T cells in either PL/J mice or Lewis rats. The present study was undertaken to examine the vaccine effect of PBM 9-1 presented in the form of a multiple antigen peptide (MAP) to induce active immunity against active EAE in Lewis rats and active or adoptive EAE in PL/J mice. MAP-PBM 9-1 induced an antibody response in both Lewis rats and PL/J mice, but more in the former. A low level of anti-Id antibody, including a low level of reactivity with specific but not control T cells, was also detected in the sera collected before induction of or after recovery from EAE. Active immunization with MAP-PBM 9-1 had a protective effect on relapses of adoptive EAE in PL/J mice and could prevent active EAE in Lewis rats. A relationship was noted between the titer of serum anti-PBM 9-1 Ab and the protective effect of active immunization in Lewis rats. Although the mechanism of effect remains to be clarified, these results suggest that MAP-PBM 9-1 is a nonencephalitogenic candidate for protection against inflammatory demyelination.