Experimental autoimmune encephalomyelitis, an experimental murine model for multiple sclerosis, is induced by stimulation of myelin-specific T lymphocytes. Myelin oligodendrocyte glycoprotein (MOG), a minor component of myelin proteins, is a potent autoantigen which contributes extensively to the anti-myelin response. In the present work, immunoscope analyses and sequencing of the oligoclonal expansions revealed anti-MOG Valpha and Vbeta public repertoires in lymphocytes infiltrating the CNS of wild-type (WT) mice. Moreover, a subset of CNS-infiltrating CD4+ T lymphocytes bearing the public Vbeta8.2 segment have an inflammatory phenotype strongly suggesting that it is encephalitogenic. We then observed that, in lymph node cells of MOG-deficient and WT animals, the Valpha and Vbeta public repertoires expressed by MOG-specific T cells are identical in both strains of mice and correspond to those found in the CNS of WT animals. These findings indicate that the MOG immunodominant determinant is unable to induce tolerance by deletion, and public anti-MOG T cell repertoires are selected for, regardless of the presence of MOG in the thymus and peripheral organs.