title: Induction of alloantigen-specific CD4+ T regulatory Type 1 cells by alloantigen immunization and ultraviolet-B irradiation: a pilot study in murine transplantation models with skin and cardiac allografts.
abstract: BACKGROUND
  The use of ultraviolet (UV)-B irradiation after alloantigen immunization is unknown because previous studies focused on UV-B irradiation before immunization. Here, we investigated immunosuppressive effects induced by UV-B irradiation after immunization, and examined the phenotype of induced regulatory T cells and the possible mechanism of induction.
  
  
  METHODS
  B6 mice (H-2(b)) were intravenously immunized by splenocytes from CBF1 mice (H-2(b/d)). One week after alloantigen immunization, B6 mice received high-dose UV-B irradiation (40 kJ/m(2)). Four weeks after UV-B irradiation, proliferation assays (n=4, in each), transplantations with skin or cardiac allografts (n=5, in each), cytokines in mixed lymphocyte culture (n=6, in each), and adoptive transfer of CD4(+) T cells to naïve B6 mice (n=5, in each) were performed. Mice were divided into 4 groups: untreated control, immunized control, UV-irradiated control, and an immunized and UV-irradiated group. B6C3F1 mice (H-2(b/k)) were used as irrelevant alloantigen with immunization controls. Anti-IL-10 monoclonal antibody was used to block IL-10 before and after UV-B irradiation.
  
  
  RESULTS
  Immune responses against the immunizing antigen were markedly suppressed in immunized and UV-irradiated mice in an alloantigen-specific manner. Surprisingly, CD4(+) T cells from immunized and UV-irradiated mice produced significantly larger amounts of IL-10, in an alloantigen-specific manner. Moreover, alloantigen-specific immunosuppression via CD4(+) regulatory T cells was transferable to naïve B6 mice. IL-10 blocking clearly abrogated alloantigen-specific immunosuppression, indicating that UV-B irradiation evoked T regulatory type 1 cells.
  
  
  CONCLUSIONS
  This study demonstrates for the first time that immunization and UV irradiation induces alloantigen-specific CD4(+) T regulatory type 1 cells, and that IL-10 plays an important role for this induction.
authors.affiliation: Department of Transplant Surgery, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Tomohide
authors.initials: T
authors.lastname: Hori
authors.affiliation: Department of Cellular and Molecular Immunology, Mie University Graduate School of Medicine, Tsu, Japan.
authors.forename: Kagemasa
authors.initials: K
authors.lastname: Kuribayashi
authors.affiliation: Department of Hematology and Oncology, Mie University Hospital, Tsu, Japan.
authors.forename: Kanako
authors.initials: K
authors.lastname: Saito
authors.affiliation: Department of Cellular and Molecular Immunology, Mie University Graduate School of Medicine, Tsu, Japan.
authors.forename: Linan
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Cellular and Molecular Immunology, Mie University Graduate School of Medicine, Tsu, Japan.
authors.forename: Mie
authors.initials: M
authors.lastname: Torii
authors.affiliation: Department of Transplant Surgery, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Uemoto
authors.affiliation: Department of Cellular and Molecular Immunology, Mie University Graduate School of Medicine, Tsu, Japan.
authors.forename: Takuma
authors.initials: T
authors.lastname: Kato
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D019138:Antibodies, Blocking / Q000008:administration & dosage; D016207:Cytokines / Q000378:metabolism; D003713:Dendritic Cells / Q000276:immunology; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006085:Graft Survival / Q000276:immunology; D016027:Heart Transplantation; D007114:Immunization; D007165:Immunosuppression Therapy / Q000379:methods; D016753:Interleukin-10 / Q000037:antagonists & inhibitors / Q000378:metabolism; D007519:Isoantigens / Q000008:administration & dosage*; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D018448:Models, Immunological; D010865:Pilot Projects; D016038:Skin Transplantation; D050378:T-Lymphocytes, Regulatory / Q000145:classification / Q000276:immunology* / Q000528:radiation effects*; D014184:Transplantation, Homologous; D014466:Ultraviolet Rays
chemical_list: D019138:Antibodies, Blocking; D016207:Cytokines; C556062:IL10 protein, mouse; D007519:Isoantigens; D016753:Interleukin-10