Experimental immunogenic proliferative retinopathy in monkeys

When a small amount of bovine serum albumin (BSA) was injected into the posterior vitreous body of a sensitized monkey, an immunogenic response occurred in the major blood vessels of the optic disk. In nonsensitized monkeys, the same phenomenon appeared after repeated intravitreal injections of small amounts of BSA. Focal leaks of fluorescein from the optic disk vessels were demonstrated by fluorescein angiography. Correlative light and electron microscopy revealed infiltration of acute and chronic inflammatory cells from the vessels of the optic disk into the vitreous body. When larger amounts of BSA were injected in sensitized monkeys, in addition to optic nerve involvement, there were scattered retinal vascular hemorrhagic and exudative lesions throughout the posterior pole. Immunologic mechanisms can result in preferential optic disk involvement with formation of proliferative lesions during the healing phase of the immunogenic inflammation.