C5a receptor-mediated production of IL-8 by the human retinal pigment epithelial cell line, ARPE-19

Purpose. C5a anaphylatoxin is a potent inflammatory mediator that acts on polymorphonuclear cells (PMN) and monocytes via C5a receptors (C5aR). It mediates chemotaxis of both cell types and stimulates cytokine release from the latter. To investigate whether C5a can act on retinal pigment epithelial (RPE) cells, we examined ARPE-19 cells for the presence of C5aR and the effect of C5a stimulation. Methods. C5aR expression was measured by flow cytometry using specific anti-C5aR antibody and by RT-PCR analyses. Cells were stimulated with 50 nM C5a and the induction of IL-8 mRNA expression was measured by semi-quantitative RT-PCR. Results. Surface levels of C5aR on ARPE-19 cells were found to be comparable to those on human PMN. Stimulation with C5a induced a dose- and time-dependent increase of IL-8 mRNA expression. Conclusion. The findings of C5aR on ARPE-19 cells and induction of IL-8 mRNA upon C5a stimulation suggests that C5a may participate in the defense of choroidal and retinal tissue during inflammation.