title: Immune modulation by silencing IL-12 production in dendritic cells using small interfering RNA.
abstract: RNA interference is a mechanism of posttranscriptional gene silencing that functions in most eukaryotic cells, including human and mouse. Specific gene silencing is mediated by short strands of duplex RNA of approximately 21 nt in length (termed small interfering RNA or siRNA) that target the cognate mRNA sequence for degradation. We demonstrate here that RNAi can be used for immune modulation by targeting dendritic cell (DC) gene expression. Transfection of DC with siRNA specific for the IL-12 p35 gene resulted in potent suppression of gene expression and blockade of bioactive IL-12 p70 production without affecting unrelated genes or cellular viability. Inhibition of IL-12 was associated with increased IL-10 production, which endowed the DC with the ability to stimulate production of Th2 cytokines from allogenic T cells in vitro. Furthermore, siRNA-silenced DC lacking IL-12 production were poor allostimulators in MLR. IL-12-silenced and KLH-pulsed DC polarized the immune response toward a Th2 cytokine profile in an Ag-specific manner. These data are the first to demonstrate that RNA interference is a potent and specific tool for modulating DC-mediated immune responses.
authors.affiliation: Department of Medicine, Division of Rheumatology, University of Western Ontario, London, Ontario, Canada.
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Hill
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Ichim
authors.forename: Kornel P
authors.initials: KP
authors.lastname: Kusznieruk
authors.forename: Mu
authors.initials: M
authors.lastname: Li
authors.forename: Xuyan
authors.initials: X
authors.lastname: Huang
authors.forename: Xiaotao
authors.initials: X
authors.lastname: Yan
authors.forename: Robert
authors.initials: R
authors.lastname: Zhong
authors.forename: Ewa
authors.initials: E
authors.lastname: Cairns
authors.forename: David A
authors.initials: DA
authors.lastname: Bell
authors.forename: Wei-Ping
authors.initials: WP
authors.lastname: Min
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage / Q000235:genetics / Q000502:physiology*; D019264:Adoptive Transfer; D000818:Animals; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D002470:Cell Survival / Q000235:genetics / Q000276:immunology; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology* / Q000378:metabolism* / Q000637:transplantation; D015536:Down-Regulation / Q000235:genetics / Q000276:immunology; D020868:Gene Silencing / Q000276:immunology*; D006433:Hemocyanins / Q000235:genetics / Q000276:immunology; D016130:Immunophenotyping; D007279:Injections, Subcutaneous; D018664:Interleukin-12 / Q000008:administration & dosage / Q000037:antagonists & inhibitors* / Q000096:biosynthesis* / Q000235:genetics; D053765:Interleukin-12 Subunit p35; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D008810:Mice, Inbred C57BL; D021122:Protein Subunits / Q000008:administration & dosage; D034741:RNA, Small Interfering / Q000008:administration & dosage / Q000235:genetics / Q000502:physiology*; D018418:Th2 Cells / Q000166:cytology / Q000276:immunology; D014162:Transfection
chemical_list: D000276:Adjuvants, Immunologic; C508858:IL12A protein, human; D053765:Interleukin-12 Subunit p35; D021122:Protein Subunits; D034741:RNA, Small Interfering; D018664:Interleukin-12; D006433:Hemocyanins; C032808:keyhole-limpet hemocyanin