Figure 3. RGR opsin in human cone photoreceptors. A: RGR opsin in cone photoreceptors of a 50-year-old human donor. Retinal sections were prepared from tissue fixed in 4% paraformaldehyde and embedded in frozen optimum cutting temperature (OCT) compound. The sections were probed with the DE15 antibody. The tissue section contained an intact retina still attached to the choroid. A few retinal ganglion cells (arrowheads) showed positive immunostaining for RGR. B: The negative control slide was treated in parallel as in panel A, except that the DE15 primary antibody was omitted from the incubation buffer. C: Immunohistochemical staining of RGR-d in cone photoreceptor outer segments of an 87-year-old donor. The sections were probed with affinity-purified DE21 antibody, which is directed against human RGR-d. The section contained the intact retina attached to the RPE layer and choroid. RGR-d was seen in Bruch’s membrane, intercapillary regions, subcapillary regions, drusen and basal deposits, Müller cell bodies, and cone photoreceptor outer segments (arrowheads). No counterstains were used. Scale bars, 50 μm.