Immunohistochemical studies of macrophages and MHC class II-positive cells in the iris and ciliary body of Lewis rats.

PURPOSE: To investigate the density, distribution and morphology of macrophages and MHC class II-positive dendritic cells in the iris and ciliary body of lewis rats. METHODS: Immunohistochemistry was performed using monoclonal antibodies specific to monocytes and macrophages (ED1, ED2) and MHC class II-positive cells (OX6) on wholemounts of the iris-ciliary body complex isolated form normal lewis rats. RESULTS: A well developed network of macrophages was present in the iris and ciliary body of normal lewis rats. These cells, morphologically displaying dendritiform or pleiomorphic appearance, were more densely arranged in mid-iris (950 +/- 189 cells/mm2) than in iris base (482 +/- 78 cells/mm2) and pupil margin (595 +/- 92 cells/mm2). A similar network of MHC class II-positive cells with a cell density 452 +/- 78 cells/mm2 was almost uniformly distributed in the iris of normal lewis rats. CONCLUSIONS: A network of macrophages and MHC class II-positive cells was established in the iris and ciliary body of normal lewis rats. These cells may be involved biologically in the generation of anterior chamber associated immune deviation-inducing signal within the anterior chamber and the transferring of this signal from the eye to the spleen, and pathophysiologically in the pathogenesis of uveoretinitis.