Rhodopsin and blindness.

Systemic immunization with purified homologous rhodopsin from retinal outer segments induced blindness in primates (Macaca mulatta). Inflammation and characteristic retinal changes were the earliest clinical signs of the disease. Perivasculitis, subretinal exudations and bullous detachments of the retina were progressive and unrelenting pathological processes leading to rapid and irreversible visual deterioration. Electroretinographic responses (ERG) at this stage of the disorder became abolished. Antibodies and delayed hypersensitivity to rhodopsin were demonstrated only in the experimental diseased animals. Homologous visual purple appears to be organ and immunopathologically specific. Histological confirmation of these findings showed a pathological spectrum of destructive alterations confirmed specifically to the outer segments of the entire retina. The pathologic reaction was supported by a distinct and pronounced granulomatous inflammatory response.