title: Ultraviolet B but not A radiation activates suppressor B cells in draining lymph nodes.
abstract: Immunosuppressive doses of solar-simulated UV radiation activate lymph node B cells that can suppress primary immunity by inhibiting the function of dendritic cells. The aim of this study was to determine the waveband responsible for activation of these suppressor B cells. We exposed C57BL/6 mice to various doses of either UVA or UVB radiation and analyzed the number and activation state of lymph node antigen-presenting cells (APC). Immunosuppressive doses of UVB but not UVA activated B cells as assessed by major histocompatibility complex II (MHC II) expression and doubled their numbers in draining lymph nodes. Higher doses of UVA that were not immunosuppressive actually suppressed B cell activation. Our results show that UVA and UVB suppress systemic immunity via different mechanisms. Lymph node B cells are activated in response to immunosuppressive doses of UVB but not UVA. Thus, the activation state of lymph node APC appears to be important for UV immunomodulation.
authors.affiliation: Department of Medicine, Dermatology Research Laboratories, Melanoma and Skin Cancer Research Institute, Sydney Cancer Centre, Royal Prince Alfred Hospital at the University of Sydney, Sydney, Australia.
authors.forename: Scott N
authors.initials: SN
authors.lastname: Byrne
authors.forename: Jarin
authors.initials: J
authors.lastname: Ahmed
authors.forename: Gary M
authors.initials: GM
authors.lastname: Halliday
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000528:radiation effects*; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology / Q000528:radiation effects; D005260:Female; D007108:Immune Tolerance; D008198:Lymph Nodes / Q000276:immunology*; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D014466:Ultraviolet Rays