An MHC anchor-substituted analog of myelin oligodendrocyte glycoprotein 35-55 induces IFN-gamma and autoantibodies in the absence of experimental autoimmune encephalomyelitis and optic neuritis.

Previous strategies to ameliorate experimental autoimmune encephalitis (EAE) include the treatment of autoreactive T cells with altered peptide ligands, which contain amino acid substitutions at TCR contact residues. We recently showed that a variant of myelin oligodendrocyte glycoprotein (MOG) 35-55 possessing low affinity for MHC (45D) induced anergy in MOG 35-55-specific T cells and reduced their encephalitogenicity upon adoptive transfer. Here we investigate the characteristics of the primary immune response to this MHC anchor-substituted peptide. Overall, we observed that immunization with 45D resulted in the production of IFN-gamma and anti-MOG 35-55 autoantibodies at levels similar to those of MOG 35-55-immunized mice with active EAE. However, no symptoms of clinical or histological EAE or overt histological optic neuritis were observed in 45D-immunized mice. Consistent with this finding, 45D-immunized mice did not exhibit CD4(+) infiltrates into the CNS. Therefore, MOG 35-55-specific precursors stimulated with a weak ligand (45D) mediate some EAE-associated effector functions but are unable to fully initiate the inflammatory process in the central nervous system that leads to clinical manifestation of EAE.