title: Modulation of IL-10, IL-12, and IFN-gamma in the epidermis of hairless mice by UVA (320-400 nm) and UVB (280-320 nm) radiation.
abstract: We have observed recently that the suppression of contact hypersensitivity (CHS) induced in mice by UVB irradiation may be prevented by suberythemal exposure to UVA radiation. Because the UVB-immunosuppressed state is associated with an upregulation of the Th2-associated cytokines IL-10 and IL-4, and a deficiency in Th1-associated IL-2, IL-12, and IFN-gamma, and because UVA photoimmunoprotection appeared to be IFN-gamma- dependent, we tested the hypothesis that UVA immunoprotection results from an ability to prevent the UVB-induced cytokine disarray. This study describes changes in epidermal IL-10, IL-12 and IFN-gamma for 5 d following irradiation of hairless mice with the CHS-modulating doses of UVB, UVA, or UVA + UVB, using immuno-histochemical detection in paraffin embedded skin sections, followed by image analysis quantitation. We found that UVB, but not UVA exposure, caused an increase in epidermal IL-10 expression, peaking at 3 d. UVA irradiation, but not UVB, resulted in increased epidermal IL-12 expression, peaking at 3 d, and increased epidermal IFN-gamma expression peaking earlier at 1 d. Irradiation with UVA + UVB abrogated the UVB-enhanced expression of IL-10, and caused small but significant increases in IL-12 and IFN-gamma at 3 d and 1 d, respectively. These findings suggest that UVA photoimmunoprotection is mediated via prevention of IL-10 release, and thus the maintenance of the Th1/Th2 balance, probably by upregulation of IL-12 and IFN-gamma, which are known to antagonize IL-10 in numerous models. The time course suggests that IFN-gamma responds initially to UVA radiation, and may stimulate the increased expression of IL-12.
authors.affiliation: Department of Veterinary Anatomy and Pathology, University of Sydney, New South Wales, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Shen
authors.forename: S
authors.initials: S
authors.lastname: Bao
authors.forename: V E
authors.initials: VE
authors.lastname: Reeve
mesh_terms: D000818:Animals; D004817:Epidermis / Q000737:chemistry / Q000528:radiation effects*; D005260:Female; D007150:Immunohistochemistry; D007371:Interferon-gamma / Q000032:analysis*; D016753:Interleukin-10 / Q000032:analysis*; D018664:Interleukin-12 / Q000032:analysis*; D051379:Mice; D008812:Mice, Hairless; D014466:Ultraviolet Rays
chemical_list: D016753:Interleukin-10; D018664:Interleukin-12; D007371:Interferon-gamma