IMMUNOHISTOCHEMICAL STUDIES ON THE ENDOTOXIN-INDUCED UVEITIS

Objective To investigate the longitudinal changes of macrophages and m ajor histocompatibility complex (MHC) class II-positive cells in the i ris and ciliary body of Lewis rats after lipopolysaccharide (LPS) inje ction. Methods Immunohistochemistry was performed using monoclonal ant ibodies to monocytes and macrophages (ED1) and MHC class II-positive c ells (OX6) on wholemounts of the iris and ciliary body in endotoxin-in duced uveitis (EIU). Results A network of macrophages (ED1(+) cell) an d MHC class II-positive cells, was present in the iris and ciliary bod y of normal Lewis rats. Most cells in the iris and ciliary body displa yed dendritiform appearance. A severe involvement of the iris and cili ary body, as evidenced by a rapid influx of monocytes and macrophages and remarkable increase of MHC class II-positive cells, was observed a fter LPS injection. Conclusions A network of macrophages and MHC class II-positive cells in the iris and ciliary body may play an important role in immune surveillance. LPS injection induces a severe inflammati on in the anterior segment of the eye, which may serve as a model for acute anterior uveitis in human.