Figure 1.

Immunolocalization of complement factor H (CFH) and the membrane attack complex (MAC)/C5b-9 in the retinal pigment epithelium (RPE)/choroid (Chor) complex. A and B, Confocal immunofluorescence images from an 84-year-old man with atrophic age-related macular degeneration (AMD). Anti-CFH antibody labels substructural elements (arrows) in drusen (Dr) and the sub-RPE space (green; Cy2 channel). C and D, Localization of CFH in drusen and the sub-RPE space in an 83-year-old man with AMD (green). Drusen immunoreactivity (IR) is homogeneous; CFH IR is associated with the choriocapillaris and the sub-RPE space (arrowheads). E–L, The brown pigment in the RPE cytoplasm and Chor is melanin. E, Localization of CFH in drusen of a 79-year-old donor eye. Anti-CFH labeling (purple reaction product) is apparent in Dr, along the Bruch membrane (BM), and on the choroidal capillary walls (arrows). F, Control section of the same eye with no primary antibody; labeling is absent. G, Extensive labeling is present along the BM, the choroidal capillary walls, and intercapillary pillars (arrows) in a 78-year-old individual with AMD. H, Control section from the macula of a donor without AMD; much less labeling is apparent. Localization of C5b-9 in the RPE-Chor underlying the macula (I) and extramacula (J) in the same eye of an 81-year-old AMD donor. I, Intense anti-C5b-9 IR is associated with Dr, BM, and the choroidal capillary endothelium. J, Outside the macula, there is only sporadic labeling in the vicinity of the BM. Localization of C5b-9 in the macula from a donor with AMD (K) and from a second donor without AMD (L). K, Anti-C5b-9 labeling is associated primarily with the choroidal capillary walls (black arrowheads) and intercapillary pillars (white arrowheads). Labeling is much more intense in the AMD eye. Note the strong similarity to the anti-CFH labeling pattern in the macula from the same donor (G). Ret indicates retina. Reproduced with permission from Hageman et al.¹³