Long-term S-antigen (S-Ag) specific T lymphocyte lines can induce experimental autoimmune uveoretinitis (EAU) when transferred into naive rats systemically or intravitreally. The uveitogenic lymphocyte line (ThS) stains positively for the ART 18 (IL-2 receptor) and W3/25 (T helper/inducer); negatively for OX6 (RT1B) and OX8 (T suppressor/cytotoxic cells). The inflammation induced by systemic or intravitreal transfer of the ThS line was studied with respect to the surface markers of the infiltrating cells, as well as the markers expressed by the resident ocular cells, by immunohistopathological techniques. On day 4 to 5 after systemic injection of the ThS line, rare T cells (W3/25+, ART 18+) and macrophages (OX42+, OX6+) surrounded by some resident cells that expressed MHC class II antigens were identified in the ciliary body and choroid. Shortly thereafter (10-20 hr) more macrophages, polymorphonuclear leukocytes, and T lymphocytes (W3/25+, then OX8+) appeared in the inflamed eye. The kinetics was similar to EAU induced by active immunization. The rats with severe disease expressed the MHC class II antigens on large numbers of resident cells in the eye. Intravitreally transferred ThS cells migrated to the retina within 24 hr of transfer. Infiltration of macrophages (OX6+, OX42+) and other T lymphocytes (OX6+, W3/25+ or OX8+), in conjunction with photoreceptor damage, were observed within the next 24-48 hr. The cells with the ThS markers disappeared from the eye on day 4-5 post transfer. These findings suggest that the ThS line can recognize the photoreceptor S-Ag in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)