Experimental retinal autoimmunity (ERA) in strain 13 guinea pigs: induction of ERA-retinopathy with rhodopsin

Strain 13 guinea pigs injected with either homologous or bovine rhodopsin, the visual pigment of the retinal outer segments, in complete Freund's adjuvant (CFA) developed experimental retinal autoimmunity (ERA). Initial clinical signs of disease were seen within 21 days after immunization. Pathologic examination of the eyes revealed the presence of inflammatory cells in the choroid and the destruction of the retinal rod outer segments. The unique feature of this disease is that despite the destruction of the inner and outer segments of the retina, at no time is there a substantial inflammatory cell infiltrate. Even as late as 45 days after immunization, when destruction of the retinal ganglion cell layer was noted, no inflammatory cells were detected in the retina. These findings suggest that the retinal inner and outer segments are the target of the autoimmune reaction subsequent to sensitization with purified rhodopsin-CFA.