title: A role for inflammatory mediators in the induction of immunoregulatory B cells.
abstract: UV exposure suppresses the immune response to a variety of microbial, fungal, and viral Ags. In addition, UV radiation is a complete carcinogen and the immune suppression induced by UV radiation is a major risk factor for skin cancer induction. In this study, we examined the mechanisms underlying the induction of immune suppression and tolerance induction by UV radiation. Transferring lymph nodes cells from UV-irradiated, FITC-sensitized mice into normal recipients transferred immune tolerance. Contrary to expectations, the cell responsible was an FITC(+), IL-10-secreting, CD19(+), B220(+) B cell. Because the lipid mediator of inflammation, platelet-activating factor (PAF) is released by UV-irradiated keratinocytes and is essential for the induction of immune suppression, we determined its role in tolerance induction. When UV-irradiated mice were injected with PCA 4248, a selective PAF receptor (PAFR) antagonist, transfer of tolerance was suppressed. However, immune suppression was not transferred when FITC(+) cells from the draining lymph nodes of UV-irradiated, PAFR-deficient donor mice were injected into the recipients. Because PCA 4248 also blocks serotonin receptor binding, we measured the effect that blocking both serotonin and PAFR binding has on the transfer of immune suppression. Only when both PAF and serotonin binding were blocked could we inhibit tolerance induction. These data identify a novel function for PAF and serotonin in modulating immune function, the activation of immunoregulatory B cells.
authors.affiliation: Department of Immunology and Center for Cancer Immunology Research, University of Texas, M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Matsumura
authors.forename: Scott N
authors.initials: SN
authors.lastname: Byrne
authors.forename: Dat X
authors.initials: DX
authors.lastname: Nghiem
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Miyahara
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Ullrich
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D018941:Antigens, CD19 / Q000378:metabolism; D001402:B-Lymphocytes / Q000276:immunology* / Q000528:radiation effects*; D003877:Dermatitis, Contact / Q000276:immunology*; D004095:Dihydropyridines / Q000494:pharmacology; D005434:Flow Cytometry; D016650:Fluorescein-5-isothiocyanate; D007108:Immune Tolerance; D007249:Inflammation / Q000276:immunology; D016753:Interleukin-10 / Q000378:metabolism; D017493:Leukocyte Common Antigens / Q000378:metabolism; D008213:Lymphocyte Activation / Q000276:immunology / Q000528:radiation effects; D051379:Mice; D008817:Mice, Mutant Strains; D010972:Platelet Activating Factor / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism*; D012702:Serotonin Antagonists / Q000494:pharmacology; D014466:Ultraviolet Rays
chemical_list: D018941:Antigens, CD19; D004095:Dihydropyridines; D010972:Platelet Activating Factor; D012702:Serotonin Antagonists; C066024:PCA 4248; D016753:Interleukin-10; D012701:Serotonin; D017493:Leukocyte Common Antigens; D016650:Fluorescein-5-isothiocyanate