Figure 1. HESC-derived RPE cells internalize fluorescently labeled POS isolated from the porcine eye. A: The pigmented monolayer of HESC-derived RPE binds labeled POS (green). B: A Nomarski image showing pigmented HESC-derived RPE overlaid with Alexa Fluor® 488-labeled porcine POS. Evidence of internalization of outer segments is clear by 4 h. C-D: Alexa Fluor® 488-labeled porcine POS are associated with the apical surface of HESC-derived RPE (delineated by TRITC-labeled Na⁺/K⁺ ATPase immunostaining). D-E: POS are ingested by the cells and are located close to the HESC-derived RPE nuclei (DAPI, stained blue). Photomicrographs in C-E are single (y-axis) confocal optical slices (<0.8 μm) from 3 separate HESC-RPE samples. In A-B, scale bars equal 150 μm; in C-E, scale bars equal 10 μm.