Cytokine modulation of costimulatory molecules on human fetal retinal pigment epithelial cells

Abstract

Purpose. Experiments were performed to evaluate the effect of various pro- and anti-inflammatory cytokines on the human fetal retinal pigment epithelium's (HFRPE) expression of major histocompatibility complex (MHC) and costimulatory molecules. Methods. Pure cultures of HFRPE cells were isolated. HFRPE cells were incubated in the presence of Interferon-? (IFN-?), IFN-ß, Tumor Necrosis Factor-a (TNF-a), Interleukin-1ß (IL-1ß), Tumor Growth Factor-ß (TGF-ß), and a combination of IFN-? and TGF-ß (pre-incubation and simultaneously incubated). The expression of MHC class I and class II, Intercellular cell adhesion molecule (ICAM-1), B7-1 (CD80), and B7-2 (CD86) molecules was quantitatively analyzed by flow cytometry. Results. The cultured HFRPE cells expressed high levels of MHC class I and low levels of MHC class II and ICAM-1 molecules. After culture with the above mentioned cytokines, IFN-? up-regulated the HFRPE’s expression of MHC class II and ICAM-1. IFN-ß and IL-1ß only up-regulated the expression of ICAM-1. TGF-ß was unable to suppress the up-regulatory effect of IFN-? in HFRPE cells (pre-incubated and simultaneously incubated). The other cytokines did not have any significant effect on HFRPE’s expression of MHC I and II or the selected costimulatory molecules. Conclusions. Our findings indicate that TGF-ß cannot suppress up-regulating effects of IFN-? on HFRPE’s expression of MHC and costimulatory molecules. Overall, the weak or lack of expression of costimulatory molecules after stimulation with various cytokines further confirms that HFRPE cells are weak antigen presenting cells.