Antigen-presenting cells in experimental autoimmune uveoretinitis

The present study attempts to identify the antigen-presenting cells in the retina, utilizing bone marrow-transplanted chimeric rats. Two types of chim eras were used: one produced by transplanting bone marrow cells from F-1 hy brids of Lewis and Brown Norway (BN) into sublethally irradiated Brown Norw ay rats (LBN/F-1 --> BN), followed by adoptive transfer of S-antigen-specif ic T cells obtained from Lewis rats; the second produced by transplanting b one marrow cells from BN rats into sublethally irradiated F-1 hybrids (BN-- >LBN/F-1), followed by adoptive transfer of S-antigen-specific T cells obta ined from F-1 hybrids. As controls, Lewis, F-1 hybrids and BN rats also rec eived adoptive transfer of syngeneic uveitogenic T cen lines. All animals w ere killed on the seventh day after adoptive transfer and their eyes and pi neal glands were analysed immunohistochemically, utilizing antibody directe d against Lewis specific MHC class IT molecules(OX-3). The analyses reveale d the development of uveoretinitis and pinealitis in both types of chimeras and in the Lewis and F-1 hybrid rats. BN rats did not develop uveoretiniti s. OX-3-positive cells were found in the retina and the pineal glands of bo th types of chimeras, and in the Lewis and F-1 hybrid rats but not in the B N rats. These cells in the retina expressed dendritic morphology and periva scular distribution. Retinal pigment epithelia, Muller cells and the vascul ar endothelia of both chimeras, the two strains, and the F-1 hybrid rats di d not demonstrate OX-3-positive staining. These results suggest that the bo ne marrow-derived cells in the retina and pineal grand may present S-antige n to T cells, initiating the cascade of uveoretinitis and pinealitis. (C) 1 998 Academic Press.