Abstract
Purpose: :
Ocular immune privileged tissue is well known. Human fRPE cells have been shown to inhibit T cell activation, but little is known about their effect on monocytes and macrophages. We evaluated the contribution of fRPE cells, on monocytes and macrophages, major mediators of inflammation.
Methods: :
CD14+ monocytes were co-cultured with human primary fetal RPE cells in the presence of M-CSF for 3 or 7 days. Phenotyping for surface markers and cytokine profiles were analyzed to assess the differentiation of monocytes into macrophages. As a control, monocyte were also cultured alone or co-cultured with fibroblasts in the presence of M-CSF. To evaluate, the effect of fRPE cells on maturation of macrophages, CD14+ monocytes were differentiated to maturation by treating with M-CSF for 6 days and then co-cultured with fRPE cells with or with out LPS stimulation and was analyzed by macrophage surface markers, cytokine profiles and phagocytosis.
Results: :
Monocytes driven by M-CSF differentiated into macrophages by increasing their cellular size and expressed high levels of CD163, CXCR4, DR and CD25. However, all those markers were down-regulated by the presence of fRPE cells. Fibroblasts from the same donors did not have this effect. This effect was noted at a late stage of differentiation. Macrophages differentiated in the presence of fRPE cells produced more IL-10 than those without. Meanwhile, fRPE cells up-regulated CD163 and CXCR4 expression but down-regulated DR expression as well as phagocytosis during the maturation of macrophages.
Keywords: retinal pigment epithelium • immunomodulation/immunoregulation • phagocytosis and killing