Fig. 2

ARMS2 expression by retinal microglia cells. A I, II Co-labeling of ARMS2 (green) and the macrophage/microglia marker CD68 (red) in the human retina shows co-localization (white arrowheads) of ARMS2 and CD68 indicating ARMS2 expression by retinal microglia cells/macrophages in the human retina. Note that blood monocytes in retinal vessels (dotted lines) co-labeled for ARMS2 and CD68. A II, IV Co-labeling of ARMS2 and CD68 shows that retinal microglia are associated with cells of the inner retina that contain high amounts of ARMS2 on their cell surfaces (white squares). A IV–XII Magnifications of squared areas in (II and IV) show close association of microglia with retinal neurons and strong ARMS2 immunoreactivity (white arrowheads). Left panels (V–VIII) show ARMS2 and CD68. Right panels (A IX–XII) show merged pictures of ARMS2 and CD68 and DAPI. INL inner nuclear layer, IPL inner plexiform layer, GCL ganglion cell layer. Scale bar (A I–IV) 50 μm; scale bar (A V–XII) 25 μm. B I, II ARMS2 staining of retinal cross section through the fovea of a human donor with haplotype (I/I). The white squares indicate the area of the macular that is magnified in (B II, IV). B V, VI ARMS2 immunoreactivity in retinal cross section of parafoveal areas obtained from a human donor with haplotype (I/I). The white squares indicate the area of RPE and choroid magnified in (B VII,VIII). ARMS2 staining in the choroid is presumably confined to monocytes and choroidal macrophages, in the retina to microglia cells (arrows) (B IX, X). Retinal cross section from a human donor with haplotype (II/II) that is devoid of ARMS2 immunoreactivity also in the choroid. B XI, XII Control stainings lacking primary antibody. Green autofluorescence lining at the top of the images is derived from RPE (asterisk). Scale bar (B I, II, V, VI, IX, X) 50 μm; scale bar (B III, IV, VII, VII, XI, XII) 25 μm