Interferon Activated Human Retinal Pigment Epithelial Cells Release a Soluble Factor Which Suppresses the Proliferation of Non-activated Retinal Pigment Epithelial Cells

Abstract

Abstract: : Purpose: To assess the effect of supernatant isolated from interferon gamma (IFN-g) activated human retinal pigment epithelial (RPE) cells on the proliferation of non-activated RPE cells. Methods: Pure cultures of RPE cells were isolated from human fetal eyes. The cells were incubated with IFN-g for 72 hours. The supernatant was discarded and the cells were re-incubated with freshly isolated culture medium for 48 hours. This supernatant was then isolated. Freshly cultured RPE cells were incubated with the supernatant of non-activated or IFN-g activated RPE cells for 72 hours. The rate of RPE proliferation was assessed by flowcytometry. Results: The supernatant isolated from IFN-g activated RPE cells suppressed the proliferation of non-activated RPE cells. This suppression was statistically significant when compared to RPE cells incubated with culture medium alone (without IFN-g). Conclusions: The activation of RPE cells with interferon gamma may induce the production of a soluble factor which can suppress the proliferation of surrounding non-activated RPE cells. These results indicate that cytokines released during inflammation can modulate RPE cells to affect other RPE cells (which have not been in contact with these cytokines). The mechanism of RPE induced inhibition is currently under investigation.

Keywords: retinal pigment epithelium • cytokines/chemokines • proliferation