FAS LIGAND-INDUCED APOPTOSIS AS A MECHANISM OF IMMUNE PRIVILEGE

The eye is a privileged site that cannot tolerate destructive inflamma tory responses. inflammatory cells entering the anterior chamber of th e eye in response to viral infection underwent apoptosis that was depe ndent on Fas (CD95)-Fas ligand (FasL) and produced no tissue damage. I n contrast, viral infection in gld mice, which lack functional Fast, r esulted in an inflammation and invasion of ocular tissue without apopt osis. Fas-positive but not Fas-negative tumor cells were killed by apo ptosis when placed within isolated anterior segments of the eyes of no rmal but not Fast-negative mice. Fast messenger RNA and protein were d etectable in the eye. Thus, Fas-FasL interactions appear to be:an impo rtant mechanism for the maintenance of immune privilege.