title: Immunostimulatory RNA is a potent inducer of antigen-specific cytotoxic and humoral immune response in vivo.
abstract: Single-stranded RNA stimulates immune cells and induces the secretion of pro-inflammatory cytokines and type I IFN. As adjuvant RNA can induce a T(h)2 type of humoral response, however, its potency in the induction of cytotoxic T cells in vivo has not been analyzed. Here we show that immunization with the antigen ovalbumin (OVA) and the adjuvant phosphodiester RNA complexed to the cationic lipid N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium methylsulfate (DOTAP) induced a Toll-like receptor-7-dependent cytotoxic T cell and humoral response. Staining with SIINFEKL-K(b) tetramers demonstrated the induction of antigen-specific T cells that were functional in in vivo cytotoxic T cell assays against SIINFEKL-loaded target cells. In infection experiments with OVA-secreting Listeria monocytogenes, the cytotoxic T cell response strongly reduced the bacterial load in liver and spleen. The RNA-driven humoral response was characterized by OVA-specific antibodies of the IgG1 isotype whereas CpG-DNA induced antigen-specific antibodies of the IgG2a (BALB/c) or IgG2c (C57BL/6) isotype. Furthermore, stimulation with RNA did not induce splenomegaly, a common feature of CpG-DNA-driven immune activation in mice. Taken together, our data confirm that RNA can be used as a safe adjuvant and induces a strong antibody response of the IgG1 isotype. Additionally, we demonstrate that RNA induces an antigen-specific immunity characterized by a potent cytotoxic T cell response to infection.
authors.affiliation: Institut für Medizinische Mikrobiologie, Immunologie und Hygiene, Technische Universität München, Trogerstrasse 30, 81675 München, Germany.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Hamm
authors.forename: Antje
authors.initials: A
authors.lastname: Heit
authors.forename: Martina
authors.initials: M
authors.lastname: Koffler
authors.forename: Katharina M
authors.initials: KM
authors.lastname: Huster
authors.forename: Shizuo
authors.initials: S
authors.lastname: Akira
authors.forename: Dirk H
authors.initials: DH
authors.lastname: Busch
authors.forename: Herrmann
authors.initials: H
authors.lastname: Wagner
authors.forename: Stefan
authors.initials: S
authors.lastname: Bauer
mesh_terms: D000276:Adjuvants, Immunologic / Q000633:toxicity; D000818:Animals; D000917:Antibody Formation; D000941:Antigens / Q000276:immunology; D001428:Bacterial Vaccines / Q000276:immunology* / Q000633:toxicity; D002478:Cells, Cultured; D004195:Disease Models, Animal; D005229:Fatty Acids, Monounsaturated / Q000276:immunology; D005260:Female; D007114:Immunization; D007074:Immunoglobulin G / Q000097:blood; D008089:Listeria monocytogenes / Q000276:immunology*; D008088:Listeriosis / Q000276:immunology / Q000517:prevention & control; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000172:deficiency / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009838:Oligodeoxyribonucleotides / Q000276:immunology; D009841:Oligonucleotides / Q000276:immunology* / Q000633:toxicity; D010047:Ovalbumin / Q000276:immunology; D000644:Quaternary Ammonium Compounds / Q000276:immunology; D012313:RNA / Q000276:immunology* / Q000633:toxicity; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology; D051199:Toll-Like Receptor 7 / Q000172:deficiency / Q000235:genetics / Q000276:immunology*
chemical_list: D000276:Adjuvants, Immunologic; D000941:Antigens; D001428:Bacterial Vaccines; C408982:CPG-oligonucleotide; D005229:Fatty Acids, Monounsaturated; D007074:Immunoglobulin G; D008562:Membrane Glycoproteins; D009838:Oligodeoxyribonucleotides; D009841:Oligonucleotides; D000644:Quaternary Ammonium Compounds; C477038:Tlr7 protein, mouse; D051199:Toll-Like Receptor 7; D012313:RNA; D010047:Ovalbumin; C070046:1,2-dioleoyloxy-3-(trimethylammonium)propane