title: Modulation of regulatory T cell function by monocyte-derived dendritic cells matured through electroporation with mRNA encoding CD40 ligand, constitutively active TLR4, and CD70.
abstract: Regulatory T cells (Tregs) counteract anticancer immune responses through a number of mechanisms, limiting dendritic cell (DC)-based anticancer immunotherapy. In this study, we investigated the influence of various DC activation stimuli on the Treg functionality. We compared DCs activated by electroporation with mRNA encoding constitutively active TLR4 (caTLR4) and CD40 ligand (DiMix-DCs), or these factors together with mRNA encoding the costimulatory molecule CD70 (TriMix-DCs) with DCs maturated in the presence of a mixture of inflammatory cytokines (DCs maturated with a combination of the cytokines IL-1β, IL-6, TNF-α, and PGE2) for their ability to counteract Tregs on different levels. We first demonstrated that there was no difference in the extent of Treg induction starting from CD4(+)CD25(-) T cells under the influence of the different DC maturation stimuli. Second, we showed that both DiMix- and TriMix-DCs could partly alleviate Treg inhibition of CD8(+) T cells. Third, we observed that CD8(+) T cells that had been precultured with DiMix-DCs or TriMix-DCs were partially protected against subsequent Treg suppression. Finally, we showed that Tregs cocultured in the presence of TriMix-DCs, but not DiMix-DCs, partially lost their suppressive capacity. This was accompanied by a decrease in CD27 and CD25 expression on Tregs, as well as an increase in the expression of T-bet and secretion of IFN-γ, TNF-α, and IL-10, suggesting a shift of the Treg phenotype toward a Th1 phenotype. In conclusion, these data suggest that TriMix-DCs are not only able to suppress Treg functions, but moreover could be able to reprogram Tregs to Th1 cells under certain circumstances.
authors.affiliation: Laboratory of Molecular and Cellular Therapy, Department of Physiology-Immunology, Vrije Universiteit Brussel, 1090 Brussels, Belgium.
authors.forename: Joeri J
authors.initials: JJ
authors.lastname: Pen
authors.forename: Brenda
authors.initials: B
authors.lastname: De Keersmaecker
authors.forename: Sarah K
authors.initials: SK
authors.lastname: Maenhout
authors.forename: An M T
authors.initials: AM
authors.lastname: Van Nuffel
authors.forename: Carlo
authors.initials: C
authors.lastname: Heirman
authors.forename: Jurgen
authors.initials: J
authors.lastname: Corthals
authors.forename: David
authors.initials: D
authors.lastname: Escors
authors.forename: Aude
authors.initials: A
authors.lastname: Bonehill
authors.forename: Kris
authors.initials: K
authors.lastname: Thielemans
authors.forename: Karine
authors.initials: K
authors.lastname: Breckpot
authors.forename: Joeri L
authors.initials: JL
authors.lastname: Aerts
mesh_terms: D053282:CD27 Ligand / Q000235:genetics / Q000502:physiology*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology; D023201:CD40 Ligand / Q000235:genetics / Q000502:physiology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division; D002478:Cells, Cultured; D018920:Coculture Techniques; D016207:Cytokines / Q000494:pharmacology; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism; D018274:Electroporation; D006801:Humans; D007108:Immune Tolerance / Q000276:immunology*; D016130:Immunophenotyping; D008213:Lymphocyte Activation; D038041:Lymphopoiesis / Q000502:physiology*; D048369:MAP Kinase Kinase 1 / Q000235:genetics / Q000502:physiology; D009000:Monocytes / Q000166:cytology / Q000187:drug effects; D012333:RNA, Messenger / Q000008:administration & dosage / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000502:physiology*
chemical_list: D053282:CD27 Ligand; D016207:Cytokines; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D051197:Toll-Like Receptor 4; D023201:CD40 Ligand; D048369:MAP Kinase Kinase 1