title: Early exposure of interferon-γ inhibits signal transducer and activator of transcription-6 signalling and nuclear factor κB activation in a short-term monocyte-derived dendritic cell culture promoting 'FAST' regulatory dendritic cells.
abstract: Interferon (IFN)-γ is a cytokine with immunomodulatory properties, which has been shown previously to enhance the generation of tolerogenic dendritic cells (DC) when administered early ex vivo in 7-day monocyte-derived DC culture. To generate tolerogenic DC rapidly within 48 h, human monocytes were cultured for 24 h with interleukin (IL)-4 and granulocyte-macrophage colony-stimulating factor (GM-CSF) in the presence (IFN-γ-DC) or absence of IFN-γ (500 U/ml) (UT-DC). DC were matured for 24 h with TNF-α and prostaglandin E(2) (PGE(2) ). DC phenotype, signal transducer and activator of transcription-6 (STAT-6) phosphorylation and promotion of CD4(+) CD25(+) CD127(neg/low) forkhead box P3 (FoxP3)(hi) T cells were analysed by flow cytometry. DC nuclear factor (NF)-κB transcription factor reticuloendotheliosis viral oncogene homologue B (RELB) and IL-12p70 protein expression were also determined. Phenotypically, IFN-γ-DC displayed reduced DC maturation marker CD83 by 62% and co-stimulation molecules CD80 (26%) and CD86 (8%). IFN-γ treatment of monocytes inhibited intracellular STAT6, RELB nuclear translocation and IL-12p70 production. IFN-γ-DC increased the proportion of CD4(+) CD25(+) CD127(neg/low) foxp3(hi) T cells compared to UT-DC from 12 to 23%. IFN-γ-DC primed T cells inhibited antigen-specific, autologous naive T cell proliferation by 70% at a 1:1 naive T cells to IFN-γ-DC primed T cell ratio in suppression assays. In addition, we examined the reported paradoxical proinflammatory effects of IFN-γ and confirmed in this system that late IFN-γ exposure does not inhibit DC maturation marker expression. Early IFN-γ exposure is critical in promoting the generation of regulatory DC. Early IFN-γ modulated DC generated in 48 h are maturation arrested and promote the generation of antigen-specific regulatory T cells, which may be clinically applicable as a novel cellular therapy for allograft rejection.
authors.affiliation: Renal and Transplantation Immunobiology Laboratory, Hanson Institute, Royal Adelaide Hospital, Adelaide, SA, Australia.
authors.forename: D
authors.initials: D
authors.lastname: Rojas-Canales
authors.forename: R
authors.initials: R
authors.lastname: Krishnan
authors.forename: C F
authors.initials: CF
authors.lastname: Jessup
authors.forename: P T
authors.initials: PT
authors.lastname: Coates
mesh_terms: D002454:Cell Differentiation / Q000187:drug effects / Q000276:immunology; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000166:cytology / Q000187:drug effects* / Q000276:immunology* / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000008:administration & dosage; D006801:Humans; D007108:Immune Tolerance / Q000187:drug effects; D007371:Interferon-gamma / Q000008:administration & dosage* / Q000378:metabolism; D018664:Interleukin-12 / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D015847:Interleukin-4 / Q000008:administration & dosage; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000378:metabolism; D050800:STAT6 Transcription Factor / Q000037:antagonists & inhibitors* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D050378:T-Lymphocytes, Regulatory / Q000276:immunology; D051841:Transcription Factor RelB / Q000235:genetics / Q000378:metabolism; D023001:Transplantation Tolerance / Q000187:drug effects
chemical_list: C508594:IL2 protein, human; C508598:IL4 protein, human; D007376:Interleukin-2; D016328:NF-kappa B; C497593:RELB protein, human; D050800:STAT6 Transcription Factor; C494101:STAT6 protein, human; D051841:Transcription Factor RelB; D018664:Interleukin-12; D015847:Interleukin-4; D007371:Interferon-gamma; D016178:Granulocyte-Macrophage Colony-Stimulating Factor