Immunohistochemistry for GFP protein expression in flat-mount whole retinas at 1 month following intravitreal delivery. (a) WT AAV2, (b) triple mutant (Y730,500,444F), (c) Comparison of GFP intensity of wild-type AAV2 vector and triple mutant in retinal flatmounts. Values indicate percent GFP intensity relative to treatment with wild-type AAV2 vector. All pictures were taken with the same exposure time to evaluate GFP intensity using ImageJ. AAV2, adeno-associated virus serotype 2; GFP, green fluorescent protein; WT, wild type.