Characterization of suppressive oligodeoxynucleotides that inhibit Toll-like receptor-9-mediated activation of innate immunity.
Synthetic oligodeoxynucleotides containing unmethylated CpG sequences (CpG-ODNs) stimulate Toll-like receptor-9 (TLR-9), thereby activating innate immunity. Stimulatory CpG-ODNs have been shown to be valuable in modifying immune responses in allergy, infection and cancer. Recently, it has been reported that the stimulation of TLR-9 by endogenous DNA might contribute to the pathogenesis of autoimmune diseases. We here report the identification of a suppressive, guanosine-rich ODN (G-ODN) that inhibited the activation of TLR-9 by stimulatory CpG-ODNs. The G-ODN was suppressive in murine macrophages and dendritic cells as well as in human plasmacytoid dendritic cells in vitro. G-ODN blocked the secretion of tumour necrosis factor-alpha (TNF-alpha) and interleukin-12p40 and interfered with the up-regulation of major histocompatibility complex (MHC) class II and costimulatory molecules. G-ODN was inhibitory even at a molar ratio of 1:10 (G-ODN:CpG-ODN) and when administered up to 7 hr after stimulation with CpG. G-ODN specifically inhibited TLR-9 but not other TLRs. Inhibition was dependent on a string of five guanosines. G-ODN was also inhibitory in an in vivo model of CpG/galactosamin (GalN) lethal shock. G-ODN interfered with upstream TLR-9 signalling. However, by extensive analysis we can exclude that G-ODN acts at the stage of cellular uptake. G-ODN therefore represents a class of suppressive ODNs that could be of therapeutic use in situations with pathologic TLR-9 activation, as has been proposed for certain autoimmune diseases.
Peter
Mirjam
M
Department of Medical Microbiology and Hygiene, University Heidelberg, Heidelberg, Germany.
Bode
Konrad
K
Lipford
Grayson B
GB
Eberle
Florian
F
Heeg
Klaus
K
Dalpke
Alexander H
AH
D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology; D005260:Female; D006801:Humans; D007108:Immune Tolerance / Q000276:immunology; D007113:Immunity, Innate; D007166:Immunosuppressive Agents / Q000276:immunology*; D008262:Macrophage Activation / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D009838:Oligodeoxyribonucleotides / Q000276:immunology*; D012772:Shock, Septic / Q000276:immunology / Q000517:prevention & control; D015398:Signal Transduction / Q000276:immunology; D013329:Structure-Activity Relationship; D051217:Toll-Like Receptor 9 / Q000276:immunology*
C408982:CPG-oligonucleotide; D007166:Immunosuppressive Agents; D009838:Oligodeoxyribonucleotides; D051217:Toll-Like Receptor 9