title: In situ action spectra suggest that DNA damage is involved in ultraviolet radiation-induced immunosuppression in humans.
abstract: The mixed epidermal cell lymphocyte reaction (MECLR) is a commonly used method to study the immunomodulatory effects of UV radiation. The in vitro action spectrum for the MECLR showed that the UV-induced suppression of the MECLR responses is associated with UV-induced DNA damage. To investigate whether in vivo DNA damage also leads to the abrogation of the MECLR, in situ action spectra were made for the MECLR and the induction of thymine dimers (T < > T). Human skin, obtained from plastic surgery, was exposed to monochromatic light of 254, 297, 302 and 312 nm. After irradiation, epidermal cells were isolated and used as stimulator cells in the MECLR or processed for flow cytometric detection of T < > T. On the basis of dose-response curves for each wavelength, the action spectra for suppression of the MECLR and the induction of T < > T were calculated. These spectra showed close similarities, suggesting that, also in situ, UV-induced DNA damage is involved in the UV-induced suppression of the MECLR. Both action spectra showed a small decline from 254 nm to 302 nm, followed by a steep decline to 312 nm. These data show that, in situ, UVC can efficiently induce DNA damage and modulate cutaneous immune responses.
authors.affiliation: Department of Dermatology, University Hospital Leiden, The Netherlands.
authors.forename: H M
authors.initials: HM
authors.lastname: Hurks
authors.forename: C
authors.initials: C
authors.lastname: Out-Luiting
authors.forename: B J
authors.initials: BJ
authors.lastname: Vermeer
authors.forename: F H
authors.initials: FH
authors.lastname: Claas
authors.forename: A M
authors.initials: AM
authors.lastname: Mommaas
mesh_terms: D002478:Cells, Cultured; D002588:Cesium Radioisotopes; D004247:DNA / Q000528:radiation effects; D004249:DNA Damage; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D007165:Immunosuppression Therapy; D007959:Lymphocyte Culture Test, Mixed; D008214:Lymphocytes / Q000276:immunology / Q000528:radiation effects*; D011740:Pyrimidine Dimers / Q000032:analysis; D012867:Skin / Q000276:immunology / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D002588:Cesium Radioisotopes; D011740:Pyrimidine Dimers; D004247:DNA