Fas/Fas ligand-mediated apoptosis of murine Langerhans cells

Epidermal Langerhans cells (LC) are potent antigen-presenting cells (APC), that play a crucial role in initiating cutaneous immune responses. The Fas/ Fas ligand pathway has been implicated as an important cellular pathway in the regulation of peripheral immunity. The morphologic, functional and phen otypic characteristics of LC are becoming well-characterized. However, the mechanisms involved in eliminating LC are pearly understood. In this report , we demonstrated that murine epidermal LC constitutively express the Fas a ntigen (CD95) and the expression was lip-regulated by the addition of IFN-g amma in cultures. Interestingly, epidermal LC underwent apoptosis by the ad dition of both recombinant soluble Fas ligand (FasL) and IFN-gamma, but not by Fast alone. These results suggest that LC may acquire the susceptibilit y to Fas-mediated apoptosis through up-regulation of the Fas expression by IFN-gamma derived from activated T cells and that the elimination of LC map be important for preventing excess cutaneous inflammatory diseases. (C) 20 00 Elsevier Science Ireland Ltd. All rights reserved.