Abstract
Abstract: :
Purpose: Fas ligand(FasL), one of the apoptosis inducing members of the TNF superfamily, is believed to be a major contributor to ocular immune privilege . However, to date, the involvement of FasL on human fetal retinal pigment epithelial cells(HFRPE)-mediated T cell apoptosis is not well defined. Recently, TNF-related apoptosis-inducing ligand(TRAIL) has been identified as a member of the TNF family that induced apoptosis in a variety of cells. TRAIL and FasL cooperate in limiting lymphocyte proliferation in other organ. In this study, we investigate FasL and TRAIL expression in HFRPE and the potential of the FasL and TRAIL to kill lymphocyte. Methods: Pure HFRPE cells were isolated and cultured. Expressions of FasL and TRAIL were examined using RT-PCR, flowcytometry and Western blotting. Sections of fetal ocular tissue were stained for FasL and TRAIL by immunohistochemistry. The role of FasL and TRAIL in HFRPE-mediated apoptosis was assessed by using T cell lines. Results: Analysis by RT-PCR demonstrated mRNAs encoding FasL and TRAIL were expressed constitutively on HFRPE and that their expressions increased when these cells were treated with IFN-γ. Western blotting and immunohistochemical experiments demonstrated that TRAIL protein was expressed in HFRPE. HFRPE induced apoptosis in human T cell line, Peer through TRAIL. Conclusion: FasL and TRAIL were expressed on HFRPE and the expressions were upregulated by cytokine treatment. TRAIL was shown to involve HFPRE mediated apoptosis. We consider that theses results indicate TRAIL molecule expressed on RPE have significant role in maintaining the immune privilege in the subretinal space.
Keywords: 567 retinal pigment epithelium • 323 apoptosis/cell death • 433 immune tolerance/privilege