title: Mature dendritic cell suppression by IL-1 receptor antagonist on retinal pigment epithelium cells.
abstract: OBJECTIVE
  To determine whether retinal pigment epithelial (RPE) cells can inhibit mature dendritic cells (mDCs).
  
  
  METHODS
  Cultured RPE cells were established from C57BL/6 mice. DCs were established from bone marrow cells of normal mice, and mDCc were induced by culture in medium containing granulocyte macrophage-colony-stimulating factor (GM-CSF) and IL-4 in the presence of lipopolysaccharide and TNF-α. Activation of mDCs was assessed by a proliferation assay and ELISA to measure the production of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-12p40). Expression of major histocompatibility complex (MHC) class II, CD11c, and costimulatory molecules such as CD80, CD86, programmed cell death 1 ligand 1 (PD-L1), and PD-L2 on mDCs or RPE-exposed mDCs was evaluated by immune staining and flow cytometry. Production of IL-1 receptor antagonist (IL-1Ra) by RPE cells was evaluated by oligonucleotide microarray or ELISA. Anti-IL-1Ra neutralizing antibodies or RPE cells from IL-1Ra knockout donors were used for the assay.
  
  
  RESULTS
  Cultured RPE cells greatly suppressed the activation of mDCs, especially the production of pro-inflammatory cytokines, and the expression of cell-surface molecules. Moreover, RPE cells significantly suppressed mixed lymphocyte reactions by mDCs. In an examination of immunoregulatory candidate molecules, RPE cells expressed much higher levels of IL-1Ra as compared with control cells, and RPE cells pretreated with recombinant TNF-α and/or IL-1β produced high levels of IL-1Ra. RPE cells in the presence of anti-IL-1Ra antibodies, but not other candidate factors, failed to suppress activation by mDCs. In addition, RPE cells from IL-1Ra null donors failed to suppress mDC activation.
  
  
  CONCLUSIONS
  Our results suggest that ocular resident cells can produce pro-inflammatory cytokine antagonist that suppresses antigen-presenting cell activation.
authors.affiliation: Department of Ophthalmology and Visual Science, Tokyo Medical and Dental University Graduate School of Medicine and Dental Sciences, Tokyo, Japan. sunaoph@cdb.riken.jp
authors.forename: Sunao
authors.initials: S
authors.lastname: Sugita
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kawazoe
authors.forename: Ayano
authors.initials: A
authors.lastname: Imai
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Usui
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Iwakura
authors.forename: Kikuo
authors.initials: K
authors.lastname: Isoda
authors.forename: Masataka
authors.initials: M
authors.lastname: Ito
authors.forename: Manabu
authors.initials: M
authors.lastname: Mochizuki
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D001854:Bone Marrow Cells / Q000187:drug effects; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D018920:Coculture Techniques; D016207:Cytokines / Q000378:metabolism; D003713:Dendritic Cells / Q000166:cytology*; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D019084:Fluorescent Antibody Technique, Indirect; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D053590:Interleukin 1 Receptor Antagonist Protein / Q000502:physiology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D055213:Retinal Pigment Epithelium / Q000166:cytology / Q000378:metabolism*; D013601:T-Lymphocytes / Q000166:cytology
chemical_list: D016207:Cytokines; C507764:Il1rn protein, mouse; D053590:Interleukin 1 Receptor Antagonist Protein; D008070:Lipopolysaccharides; D016178:Granulocyte-Macrophage Colony-Stimulating Factor
keywords: IL-1 receptor antagonist; cytokine; dendritic cells