title: Role of tumour necrosis factor-alpha in ultraviolet B light-induced dendritic cell migration and suppression of contact hypersensitivity.
abstract: Irradiation with ultraviolet B light (UVB) is known to suppress contact and delayed hypersensitivity response to a variety of antigens encountered within a short period following exposure. Such irradiation results in loss of Langerhans' cells and in synthesis of tumour necrosis factor-alpha (TNF-alpha) in the epidermis. In the present study the effect of broad-band (270-350 nm) and narrow-band (311-312 nm) UVB on the induction of contact hypersensitivity (CH) and on dendritic cell (DC) numbers in draining lymph nodes (DLN) of mice was examined. Broad-band UVB induced the accumulation of DC in DLN and this increase was substantially abrogated by treatment of mice with neutralizing antibody to TNF-alpha before irradiation. In addition, irradiation before sensitization with oxazolone resulted in a suppressed CH response. The suppression was negated to a considerable extent by TNF-alpha antibodies, administered before irradiation. Thus, one of the major effects of broad-band UVB is likely to be the synthesis of epidermal TNF-alpha which, in turn induces the migration of Langerhans' cells to DLN and leads to an impairment of their activity or function. Conversely narrow-band UVB did not result in an accumulation of DC in DLN or in a suppressed CH response. Such irradiation does, however, cause the isomerization from trans to cis-UCA in the epidermis. Cis-UCA has been proposed as a photoreceptor for UV and suppresses immune responses in a variety of experimental systems. Thus cis-UCA does not act through TNF-alpha induction or by influencing DC migration, and other studies indicate that histamine-like receptors in the skin may be involved.
authors.affiliation: Department of Medical Microbiology, University of Edinburgh Medical School, U.K.
authors.forename: A M
authors.initials: AM
authors.lastname: Moodycliffe
authors.forename: I
authors.initials: I
authors.lastname: Kimber
authors.forename: M
authors.initials: M
authors.lastname: Norval
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D002465:Cell Movement / Q000528:radiation effects; D003713:Dendritic Cells / Q000276:immunology / Q000528:radiation effects*; D003877:Dermatitis, Contact / Q000276:immunology* / Q000517:prevention & control; D005260:Female; D007108:Immune Tolerance / Q000528:radiation effects*; D008198:Lymph Nodes / Q000276:immunology; D051379:Mice; D008809:Mice, Inbred C3H; D010081:Oxazolone / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology*; D014466:Ultraviolet Rays
chemical_list: D000906:Antibodies; D014409:Tumor Necrosis Factor-alpha; D010081:Oxazolone