title: Cis-urocanic-acid-induced suppression of contact hypersensitivity in Monodelphis domestica is prevented by ultraviolet A radiation/photoreactivating light.
abstract: The suppression of contact hypersensitivity by UVB (280-320 nm) radiation can be prevented by photoreactivating light (PRL; 320-400 nm) in the opossum Monodelphis domestica, implicating epidermal DNA lesions as the immunosuppressive impairment. However, contact hypersensitivity can also be suppressed in the opossum with exogenous cis-urocanic acid, a molecule which is produced in UVB-irradiated epidermis and is a second potential mediator of photo-immunosuppression apparently independent of UVB-induced DNA damage. Here we demonstrate that irradiation of opossums with PRL either before or following treatment with exogenous cis-urocanic acid, significantly reduced the degree of immunosuppression. This suggests that, in addition to its capacity to initiate post-UVB-exposure epidermal DNA repair, the PRL waveband can induce an immunoprotective product, as yet unidentified, in opossum epidermis.
authors.affiliation: Department of Veterinary Pathology, University of Sydney, Australia.
authors.forename: V E
authors.initials: VE
authors.lastname: Reeve
authors.forename: R D
authors.initials: RD
authors.lastname: Ley
mesh_terms: D000287:Administration, Topical; D000818:Animals; D003877:Dermatitis, Contact / Q000209:etiology / Q000276:immunology* / Q000517:prevention & control*; D004139:Dinitrofluorobenzene; D007108:Immune Tolerance / Q000187:drug effects / Q000528:radiation effects*; D009893:Opossums / Q000276:immunology*; D010081:Oxazolone; D012867:Skin / Q000528:radiation effects; D014466:Ultraviolet Rays; D014560:Urocanic Acid / Q000494:pharmacology*
chemical_list: D010081:Oxazolone; D004139:Dinitrofluorobenzene; D014560:Urocanic Acid