title: Poly-guanosine strings improve cellular uptake and stimulatory activity of phosphodiester CpG oligonucleotides in human leukocytes.
abstract: CpG-oligonucleotides (CpG-ODN) have been shown to exert strong immuno-stimulatory effects through activation of Toll-like receptor 9 (TLR-9). However, TLR-9 triggering takes place in endosomal compartments and thus CpG-ODN have to be taken up prior to signal transduction. We here report that 3'-poly-guanosine strings can improve cellular internalisation of phosphodiester but not of phosphorothioate CpG-ODN. Improved cellular uptake correlated with enhanced IL-6 secretion and proliferation of PBMC. Also, TLR-9 transfected HEK293 cells were activated more efficiently by poly-guanosine modified CpG-ODN. The results indicate that the synthesis of stimulatory CpG-ODN based on a phosphodiester backbone is feasible via such poly-guanosine substitutions. In addition we observed that phosphorothioate ODN were able to exert immunostimulatory effects independent of the presence of CpG motifs.
authors.affiliation: Institute of Medical Microbiology and Hygiene, Philipps-University, Pilgrimstein 2, D-35037 Marburg, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Bartz
authors.forename: Yuri
authors.initials: Y
authors.lastname: Mendoza
authors.forename: Miriam
authors.initials: M
authors.lastname: Gebker
authors.forename: Till
authors.initials: T
authors.lastname: Fischborn
authors.forename: Klaus
authors.initials: K
authors.lastname: Heeg
authors.forename: Alexander
authors.initials: A
authors.lastname: Dalpke
mesh_terms: D000276:Adjuvants, Immunologic / Q000235:genetics; D002460:Cell Line; D006151:Guanosine / Q000031:analogs & derivatives / Q000737:chemistry / Q000276:immunology / Q000494:pharmacology*; D006801:Humans; D007962:Leukocytes / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D008213:Lymphocyte Activation / Q000187:drug effects* / Q000276:immunology; D009838:Oligodeoxyribonucleotides / Q000276:immunology / Q000378:metabolism*
chemical_list: D000276:Adjuvants, Immunologic; C408982:CPG-oligonucleotide; D009838:Oligodeoxyribonucleotides; D006151:Guanosine