title: B cells activated in lymph nodes in response to ultraviolet irradiation or by interleukin-10 inhibit dendritic cell induction of immunity.
abstract: Ultraviolet (UV) radiation suppresses systemic immunity. We explored these cellular mechanisms by exposing mice to systemically immunosuppressive doses of UV radiation and then analyzing cell phenotype and function in the lymphoid organs. Although UV radiation increased total cell number in the draining lymph nodes (DLN), it did not alter the activation state of dendritic cells (DC). Rather, UV radiation selectively activated lymph node B cells, with these cells being larger and expressing higher levels of both anti-major histocompatibility complex II and B220 but not co-stimulatory molecules. This phenotype resembled that of a B cell geared toward immune tolerance. To test whether UV radiation-activated B cells were responsible for immunosuppression, DC and B cells were conjugated to antigen ex vivo and transferred into naive hosts. Although DC by themselves activated T cells, when the B cells from UV radiation-irradiated mice were co-injected with DC, they suppressed DC activation of immunity. Interleukin (IL)-10-activated B cells also suppressed DC induction of immunity, suggesting that IL-10 may be involved in this suppressive effect of UV radiation. These results demonstrate a new mechanism of UV radiation immunosuppression whereby UV radiation activates B cells in the skin-DLN that can suppress DC activation of T cell-mediated immunity.
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, NSW, Australia. scottb@med.usyd.edu.au
authors.forename: Scott N
authors.initials: SN
authors.lastname: Byrne
authors.forename: Gary M
authors.initials: GM
authors.lastname: Halliday
mesh_terms: D000818:Animals; D000938:Antigen-Presenting Cells / Q000166:cytology / Q000187:drug effects / Q000528:radiation effects; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002450:Cell Communication / Q000187:drug effects / Q000276:immunology / Q000528:radiation effects; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology*; D005260:Female; D016130:Immunophenotyping; D016753:Interleukin-10 / Q000494:pharmacology*; D008198:Lymph Nodes / Q000166:cytology*; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology / Q000528:radiation effects; D051379:Mice; D008810:Mice, Inbred C57BL; D010587:Phagocytosis / Q000187:drug effects / Q000276:immunology / Q000528:radiation effects; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology; D013950:Thymus Gland / Q000166:cytology; D014466:Ultraviolet Rays
chemical_list: D016753:Interleukin-10