Minor influence of the immunosuppressive cytokines IL-10 and TGF-β on the proliferation and apoptosis of human retinal pigment epithelial (RPE) cells in vitro

Undesirable immune reactions such as uveitis or graft rejection after corneal and subretinal transplantations are serious inflammations in the eye. Minimizing this process by means of physiological suppressors, either through systemic or intraocular administration with or without gene therapy, is a future therapeutic possibility. In our study, we used different concentrations of transforming growth factor-beta (TGF-beta; 5, 10, and 50 ng/ml) and interleukin-10 (IL-10; 100, 200, and 500 U/ml), both known as modulators of the suppression process, to treat human retinal pigment epithelium (RPE) cells in vitro. The influence of both cytokines on the viability and proliferation of the RPE cells was measured. Furthermore, the secretion of typical markers of the apoptosis process, such as Fas, soluble Fas ligand, and bcl-2, was investigated. Our results show that the concentrations of TGF-beta and IL-10 used have only a slight influence on RPE cells. Cell proliferation under the influence of TGF-beta was significantly reduced, whereas more Fas protein could be found in the cell lysate of the IL-10 samples. In general, IL-10 seemed to have less effect on the physiology of RPE cells. The discussion of the therapeutic use of an immunosuppressive factor in the eye should therefore be focused more on this cytokine.