The neonatal Fc receptor is expressed by human retinal pigment epithelial cells and is downregulated by tumor necrosis factor-alpha
Résumé
ABSTRACT Background/aims: The neonatal Fc receptor (FcRn) protects IgG from catabolism, controls its transport between cell layers and extends its serum half-life. In the human vitreous IgG can be found but how vitreous IgG is processed or transported is currently unknown. The FcRn is a candidate molecule to regulate these processes. In this study we examined FcRn expression and regulation in human retinal pigment epithelium (RPE) cells. Methods: In three primary RPE cell cultures (from three donor eyes) and in ARPE-19 cells FcRn and beta-2-microglobulin (β2M) mRNA levels were determined by RQ-PCR. FcRn protein expression was analyzed by Western blot studies. Stimulation experiments were performed with recombinant human TNF-α and IFN-γ. HT-29, THP-1 and HeLa cell lines were used as FcRn positive and negative non-ocular controls, respectively. Results: Expression of FcRn mRNA and protein was demonstrated in all three RPE cultures. After stimulation with TNF-α FcRn expression is downregulated in RPE cells and upregulated in HT-29 and THP-1 cells. IFN-γ has no effect on FcRn expression in RPE cells. Conclusions: Human RPE cells express FcRn. The proinflammatory cytokine TNF-α downregulates FcRn expression. We speculate that the FcRn may play a pivotal role in the immune privilege of the human eye.
Origine : Fichiers produits par l'(les) auteur(s)
Loading...