Epidermal antigen-presenting cells in activation of suppression: identification of a new functional type of ultraviolet radiation-resistant epidermal cell.

Abstract

Exposure of mice to low doses of ultraviolet radiation (UVR) in vivo leads to an inability to sensitize them to contact sensitizing reagents at the site of irradiation, and this depressed sensitization is accompanied by the formation of antigen-specific T suppressor (Ts) cells. It has also been demonstrated that hapten-coupled epidermal cells (EC) from UVR-treated mice are unable to immunize mice efficiently when administered subcutaneously, and such immunization results in the appearance of suppressor cells. The authors report that the murine epidermis contains a previously unrecognized antigen-presenting cell (APC) that is required for the activation of suppression, and that this APC is resistant to UVR. The dose of UVR employed is, however, sufficient to prevent substantial positive immunization of mice with syngeneic UV-irradiated hapten-coupled EC. These data explain in part the changes induced in epidermal antigen-presenting function of UVR, and has consequences for the understanding of UVR-induced cutaneous carcinogenesis.