Outer nuclear layer transduction efficiency in retinal explants from an 84-year-old human donor eye. (A–G′) Immunohistochemical analysis of green fluorescent protein (GFP) expression (green) driven by seven different AAV serotypes. Representative 20 μm z-stacks of retinal explants are shown for each of AAV1 (A–A′), AAV2 (B–B′), AAV4 (C–C′), AAV5 (D–D′), AAV6 (E–E′), AAV8 (F–F′), and AAV9 (G–G′). DAPI was used to visualize retinal nuclei. (H) Bar graph displaying the mean % GFP-positive cells in the outer nuclear layer transduced by each AAV serotype. Error bars represent standard error of the mean (SEM). Scale bars = 50 μm.