IMMUNIZATION WITH THE CROSS-REACTIVE ANTIGENS OV39 FROM ONCHOCERCA-VOLVULUS AND HR44 FROM HUMAN RETINAL TISSUE INDUCES OCULAR PATHOLOGY ANDACTIVATES RETINAL MICROGLIA

Antigen Ov39, derived from Onchocerca volvulus, cross-reacts on both t he T and B cell level with a nonhomologous human retinal antigen, hr44 . Lewis rats were immunized to investigate the potential of these anti gens to induce eye disease. Histologic and immunohistologic examinatio n of ocular tissues revealed pathologic changes as early as day 12, wh ich included induction or up-regulation of class II and CD68-like anti gen on perivascular cells, ramified retinal microglia, dendritiform ce lls of the iris epithelium, and ciliary epithelium and significant bre akdown of anterior and posterior blood-ocular barriers. Extravascular immunoglobulin and staining for CD68-like antigen was detected in the optic nerve after immunization with Ov39, Unrelated structural abnorma lities of retina and lens seen in 8% of eyes examined significantly pr edisposed eyes to the development of Ov39- or hr44-induced pathology. These findings suggest a role for cross-reactive immune responses in t he development of ocular onchocerciasis.