Cytokines are communication signals between leukocytes and organ resident cells. Interleukin 1 (IL-1) a pleiotropic cytokine produced by many cell types most notably macrophages can stimulate a general inflammatory reaction by causing the activation of a variety of cells which then, among their other functions, release a cascade of other cytokines. One of these cytokines is interleukin 8 (IL-8), which takes the more direct action of activating neutrophils and T lymphocytes. This research involved the comparison of intravitreal injection of IL-8 with that of IL-1 in both Lewis and Fischer rats. IL-8 induced milder inflammation than IL-1; Lewis rats showed a higher inflammatory response to the injections than did Fischer rats. These data suggest that IL-8 may be active as one component in neutrophil-mediated ocular disease. Further understanding of the role of each cytokine in ocular inflammation will require study of the production of endogenous cytokines in the eye. Cytokines, lymphokines, and adhesion molecules were also observed in ocular inflammatory sites in patients with uveitis and in animals with experimental uveitis. Ocular antigens play an important role in autoimmune diseases. S-antigen (S-Ag), a retinal soluble antigen, can induce experimental autoimmune uveoretinitis. The expression of S-Ag mRNA of non-retinal tissues in the fetus may suggest its involvement in certain ocular diseases. The expression of S-Ag mRNA was found in the iris of some patients with uveitis. The lens crystallin proteins alpha, beta, and gamma were also found in human fetal iris and in retinoblastoma cells. The roles of the expression of these crystallin proteins in non-lenticular tissue require further investigation. Z01 EY 00251-04 LMDB The alphaA-crystallin promoter (-366/+46) has become a very useful tool to target gene expression to the lens of transgenic mice. It is being used to study how foreign gene expression in the lens affects the phenotype of the lens or the rest of the eye. Several fusion genes containing the alphaA-crystallin promoter fused to interferon-gamma, acidic fibroblast growth factor, int-2, or ribozymes are currently being used to study the effect of their expression in the eye.
