Immunopathological changes in the eyes were examined in Lewis rats after active and passive induction of experimental autoimmune encephalomyelitis (EAE) with myelin basic proteins (MBP) at various stages of EAE. The onset of anterior uveitis (AU) coincided with hind limb paralysis, but uveitis persisted after clinical signs of EAE had subsided. A mild form of uveitis was characteristic for the majority of rats. The changes within the iris and ciliary body consisted of an accumulation of inflammatory cells lining the anterior surface of iris, the trabecular meshwork, and, in some cases, within the ciliary body and the aqueous humor. A similar histopathological picture was observed when rats were injected with the secondary encephalitogenic determinant for Lewis rats, MBP peptide 87-99. Flow cytometry analysis of T cells from the anterior segment of the inflamed eyes after immunization with MBP revealed the presence of CD4+ cells exclusively expressing V beta 8.2 and OX-40 markers. Our data suggest that MBP are encephalitogenic and uveitogenic in Lewis rats and that the V beta 8.2-positive T cells in the eye represent encephalitogenic T cells. Many of those T cells were distributed in the iris and the anterior chamber. These findings indicate that these MBP-specific T cells may play a critical role in EAE as well as in AU.