title: Interferon-alpha and viral triggers promote functional maturation of human monocyte-derived dendritic cells.
abstract: BACKGROUND
  Type I interferons (IFNs) play an important role in the pathogenesis of many autoimmune disorders including psoriasis. In the presence of IFN-alpha and granulocyte/macrophage colony-stimulating factor (GM-CSF), monocytes differentiate into dendritic cells (DCs) referred to as IFN-DCs. IFN-DCs potentially mimic DC populations involved in psoriasis and express a wide range of Toll-like receptor (TLR) subtypes.
  
  
  OBJECTIVE
  Recently, it was shown that single-stranded RNA (ssRNA) triggers TLR7 and TLR8; therefore we studied ssRNA, as a surrogate for ssRNA viruses and their impact on IFN-DCs.
  
  
  METHODS
  We established culture conditions for IFN-DCs, generated from plastic adherent monocytes using GM-CSF plus IFN-alpha. For DC stimulation ssRNA40, a 20-mer ssRNA oligonucleotide was used. The phenotypic analysis of DC preparations was performed using flow cytometry. The production of various cytokines was analysed by enzyme-linked immunosorbent assay, and real-time quantitative polymerase chain reaction was used to quantify TLR and cytokine gene expression. The ability of IFN-DCs to stimulate allogeneic T-cell proliferation was evaluated in a mixed leucocyte reaction.
  
  
  RESULTS
  We found that IFN-DCs express mRNA for TLR7 and TLR8 and that ssRNA stimulation significantly improves their costimulatory molecule expression, stabilizes their phenotype and enhances their capacity to stimulate naive T-cell proliferation. Unstimulated IFN-DCs did not produce bioactive interleukin (IL)-12 and produced low levels of other proinflammatory cytokines. In contrast, ssRNA stimulation led to a significant production of IL-12p70, IL-1beta, IL-6 and tumour necrosis factor alpha. IFN-DCs contained mRNA for IL-12p35, IL-12p40, IL-23p19, IL-27p28 and IL-27EBI, which was further increased by incubation with ssRNA.
  
  
  CONCLUSIONS
  Our study sheds light on a potential role for IFN-alpha and viral infections in triggering DC populations in psoriasis. These results provide additional data for the better understanding of human autoimmune and antiviral responses and may also have implications for strategies developing cancer immunotherapy.
authors: Department of Dermatology, University Hospital of Zurich, Gloriastrasse 31, 8091 Zurich, Switzerland. farkas_arpad@yahoo.com
authors: A
authors: A
authors: Farkas
authors: G
authors: G
authors: Tonel
authors: F O
authors: FO
authors: Nestle
mesh_terms: D001327:Autoimmune Diseases / Q000276:immunology; D049109:Cell Proliferation; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism*; D003713:Dendritic Cells / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000276:immunology / Q000494:pharmacology*; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology*; D009000:Monocytes; D010641:Phenotype; D012333:RNA, Messenger / Q000378:metabolism*; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D051199:Toll-Like Receptor 7 / Q000378:metabolism; D051200:Toll-Like Receptor 8 / Q000378:metabolism; D014777:Virus Diseases / Q000276:immunology
chemical_list: D016207:Cytokines; D016898:Interferon-alpha; D012333:RNA, Messenger; D051199:Toll-Like Receptor 7; D051200:Toll-Like Receptor 8; D016178:Granulocyte-Macrophage Colony-Stimulating Factor