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Updated: Aug 21, 2026

Large-Scale Purification of Porcine or Bovine Photoreceptor Outer Segments for Phagocytosis Assays on Retinal Pigment Epithelial Cells
Published on: December 12, 2014
[Receptor mediated endocytosis of retinal pigment epithelial cell]
Ruo-mei Li1, Karen K Sorensen, Bard Smedsrod
1Ophthalmic Research Center, Department of Ophthalmology, Peking Union Medical College, Beijing 100730, China.
Objective:
To evaluate the possibility and mechanism of the turnover of the negatively charged macromolecule by retinal pigment epithelial (RPE) cells.
Methods:
Cultured porcine RPE eye cups were incubated with fluorescence labeled formaldehyde treated serum albumin (F-FSA), a classical ligand for scavenger receptors. The endocytosis of F-FSA by RPE cells under different conditions was evaluated systematically by fluorescent microscopy and electron microscopy.
Results:
The amount of F-FSA ingested by RPE cells depends on the incubation time and the concentration of ligand. Similar ligands compete for the binding site of RPE cells. Small vesicles containing F-FSA are noticed in the cytosol of RPE cells as demonstrated by electron microscopy.
Conclusion:
The RPE cells can effectively ingest negatively charged macromolecules, possibly by scavenger receptor mediated endocytosis.
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