T cell receptor peptide therapy for autoimmune encephalomyelitis: stronger immunization is necessary for effective vaccination.

Although T cell receptor (TCR) peptide therapy was initially reported to be a very effective method for prevention of the development of experimental autoimmune encephalomyelitis (EAE), it was recently demonstrated that the same peptide immunization led to enhanced and chronic EAE in some cases. In the present study, we examined the effect of the TCR peptide (V beta 8.2-39-59) vaccination on the development of EAE by employing several immunization protocols. We found that TCR peptide vaccination effectively prevented EAE development only when the peptide was injected with Mycobacterium tuberculosis-enriched CFA in the vicinity of the challenge site. Under such conditions, a sufficient number of peptide-reactive T cells were generated. Flow cytometry and immunohistochemical analyses using anti-peptide antibody and anti-V beta 8.2 mAb revealed that despite the presence of V beta 8.2+ cells, very few peptide-positive T cells appeared in the lymphoid organs throughout the course of EAE. These findings imply that antibodies that are generated after immunization with V beta 8P are hardly accessible to their specific epitopes in the native protein. Insufficient generation of both T cells and antibodies against V beta 8.2-positive T cells may be attributable to the outcome of the therapy. To establish effective TCR peptide immunotherapy, these disadvantages should be overcome by using other TCR sequences and/or by employing a more suitable adjuvant.