Abstract
Purpose:
The subretinal transplantation of human embryonic stem cell-derived retinal pigment epithelial cells (hES-RPE) is thought to be one of the most promising therapies for dry AMD and retinitis pigmentosa. Although previous studies indicated that the subretinal space possess immune privilege, the potential immune rejection limits the clinical application of hES-RPE due to the immunological properties of the ES-RPE cells are still unclear. It is necessary to investigate the immunological properties of the ES-RPE cells and develop new strategies to induce immune tolerance of allogeneic transplants. This study was aimed to define the immunological properties of the hES-RPE.
Methods:
Human embryonic stem cells were induced to RPE cells by adding DKK-1, Noggin and IGF to the medium. Then hES-RPE cells were seed onto matrigel and co-cultured with CD 4+ T cells for 72 hours. The expression of MHC class I and II molecules in the hES-RPE cells before and after co-cultured with CD 4+ T cells were detected by flow cytometry. The production of IL-1 beta, IL-6, TGF-beta 1 and TGF-beta 2 was analyzed by ELISA.
Results:
The hES-RPE cells expressed specific RPE marker Mitf and RPE65 after 28 days culture, the matured hES-RPE cells had phagocytic ability and could secret PEDF. hES-RPE cells expressed moderate levels of MHC class I molecules and negative for MHC class II molecules. After co-cultured with CD 4+ T cell, the levels of the MHC class I and II molecules slightly increased. Compared with hRPE cells, the level of IL-1 beta and IL-6 produced by ES-RPE cells was less. Cells pretreated with TGF-beta expressed less MHC-II molecules after co-cultured with T cell.
Conclusions:
ES-RPE cells showed less immunogenicity than hRPE cells; however it still can express MHC class I and II molecules when co-cultured with CD 4+ T cells, indicating it may be rejected after transplantation. TGF-beta might partly suppress the immune rejection.