In vitro effects of ultraviolet B radiation on human Langerhans cell antigen-presenting function.
The effects of ultraviolet B radiation (UBV) on the immune function of human epidermal Langerhans cells (LC) were studied by using the mixed epidermal cell-lymphocyte reaction (MELR). Exposure of both enriched LC suspensions (eLC, 8-20% LC) and purified LC suspensions (pLC, 70-90% LC) to increasing doses of UVB radiation (25 to 200 J/m2) decreased the proliferative T cell response in a very similar dose-dependent way, suggesting that keratinocytes did not play a major role in the UVB-induced inhibition of MELR. Supernatants from irradiated cultured eLC or pLC failed to inhibit T cell proliferation induced by untreated pLC. Furthermore, addition of irradiated eLC to untreated pLC did not affec the allogeneic T cell response. Taken together, these results provide evidence that in vitro UVB-induced immunosuppression was not mediated by inhibitory soluble factors that could affect either LC allostimulatory property or T cell proliferative response. UVB irradiation of human LC inhibited the capacity of these cells to induce CD4+ as well as CD8+ T cell proliferation. UVB-irradiated LC also induced a decreased T cell response to recall antigen or mitogen. Moreover, addition of exogeneous cytokines such as IL-1 beta, IL-1 alpha, or IL-2 did not reverse the defective function of UVB-irradiated LC in MELR. The inhibitory effect of UVB radiation on human LC was not related to a decreased HLA-DR expression. Because cultured LC appeared to be less sensitive than freshly isolated LC to UVB-induced suppressive effects, the deleterious effects of UVB radiation on human LC allostimulatory properties may be associated with an impaired development of LC accessory function.
Rattis
F M
FM
Laboratoire Peau Humaine et Immunité, INSERM U346, Hôpital E. Herriot, Lyon, France.
Péguet-Navarro
J
J
Courtellemont
P
P
Redziniak
G
G
Schmitt
D
D
D017951:Antigen Presentation / Q000528:radiation effects*; D000941:Antigens / Q000528:radiation effects; D002478:Cells, Cultured; D006801:Humans; D007108:Immune Tolerance / Q000187:drug effects; D007375:Interleukin-1 / Q000494:pharmacology; D007376:Interleukin-2 / Q000494:pharmacology; D007801:Langerhans Cells / Q000528:radiation effects*; D007959:Lymphocyte Culture Test, Mixed / Q000592:standards; D008934:Mitogens / Q000528:radiation effects; D014466:Ultraviolet Rays
D000941:Antigens; D007375:Interleukin-1; D007376:Interleukin-2; D008934:Mitogens