Myelin oligodendrocyte glycoprotein peptide-induced experimental allergic encephalomyelitis and T cell responses are unaffected by immunoproteasome deficiency

The inoculation of MOG peptides into C57BL/6 mice induces CD4+ and CD8+ T cells, and recent work has shown that adoptive transfer of the latter population, after extensive in vitro stimulation, can cause EAE in naïve recipient mice. Herein, we have evaluated the incidence and severity of EAE, and the induction of CD4+ and CD8+ T cells, following MOG peptide inoculation of wt mice and of LMP-2KO mice that lack an intact immunoproteasome, a cytoplasmic organelle that is induced by chronic inflammation and that may be important for the presentation of MHC class I epitopes to CD8+ T cells. We report that EAE, evaluated by both clinical and histological criteria, is similar in LMP-2KO mice and wildtype C57B/6 mice (wt) in response to immunization with MOG peptides MOG35–55 and MOG40–54, suggesting that the immunoproteasome does not play a key role in the development of demyelinating disease. Furthermore, and consistent with previous reports, peptide-specific CD8+ T cells were barely detectable in the CNS of peptide-immunized mice, although peptide-specific CD4+ T cells were abundant. Therefore, we used a new technique to look for autoreactive CD8+ T cells in MOG peptide-immunized mice, and we report the identification of CD4+ and CD8+ T cells that, as late as 19 days after peptide injection, are actively producing IFNγ in vivo, in response to in vivo antigen contact.