Doses of ultraviolet radiation that modulate accessory cell activity and ICAM-1 expression are ultimately cytotoxic for murine epidermal Langerhans cells.
Mechanisms that underlie immunomodulatory properties of ultraviolet (UV) radiation remain incompletely characterized. Recently, we have studied effects of UV on the functional activity of epidermal Langerhans cells (LC) and have attempted to relate inhibitory effects of UV on LC function to modulatory effects of UV on adhesion molecule expression by LC. Exposure of LC in vitro to amounts of UVB, UVC, or psoralen+UVA (PUVA) radiation that inhibited LC function also prevented increased expression of intercellular adhesion molecule-1 by LC in vitro. Subsequent studies revealed that amounts of UV radiation that inhibited LC function and modulated ICAM-1 expression also decreased LC survival in vitro, although UV-induced LC cytotoxicity did not become apparent until 48-72 h after UV exposure. Our results are consistent with those of previous studies that suggested that low doses of UV radiation were cytotoxic for LC in situ. The potential cytotoxicity of UV radiation for LC should be considered when studies of effects of UV radiation on immune responses in skin are interpreted.
Tang
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Dermatology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.
Udey
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MC
D000818:Animals; D000938:Antigen-Presenting Cells / Q000166:cytology* / Q000187:drug effects / Q000528:radiation effects; D015815:Cell Adhesion Molecules / Q000502:physiology* / Q000528:radiation effects; D002478:Cells, Cultured; D003602:Cytotoxicity, Immunologic / Q000528:radiation effects; D018799:Intercellular Adhesion Molecule-1; D007801:Langerhans Cells / Q000276:immunology* / Q000528:radiation effects*; D051379:Mice; D008807:Mice, Inbred BALB C; D014466:Ultraviolet Rays
D015815:Cell Adhesion Molecules; D018799:Intercellular Adhesion Molecule-1