Figure 1.

RPE Cell Line Generation Yields Cells that Are Either High or Low Phagocytic

(A) Bars graph shows percentage of cells internalizing POS within 5 hr in a standardized POS phagocytosis assay (see Experimental Procedures) of eight RPE lines each from a different donor generated and grown using identical methodology. Error bars show mean ± SEM, n = 3 independent experiments for each line.

(B) Schematic drawing illustrating the experimental strategy for discrimination of bound and internalized POS.

(C and D) Representative images of high-phagocytic line #1 and low-phagocytic line #5 as indicated show POS (green) that are surface-bound in maximal projections of apical x-y sections (C) or that are internalized in maximal projections of x-y sections representing the central part of the same cells (D). Overlay with ZO-1 staining indicates cell-cell junctional complexes (red). Scale bars, 10 μm.

(E) Representative x-z projections of the experiment shown in (D). Cell nuclei are shown in blue.

(F and G) Bar graphs compare the amount of bound POS material (F) or the amount of internalized POS material (G). Error bars show mean ± SEM, n = 4 different high-phagocytic lines (#1–4) and n = 4 different low-phagocytic lines (#5–8). Asterisks indicate significant difference between high- and low-phagocytic lines by Student's t test. ^∗p < 0.001.