title: Higher order structure of short immunostimulatory oligonucleotides studied by atomic force microscopy.
abstract: Immunostimulatory CpG-DNA activates the innate immune system by binding to Toll-like receptor 9. Structurally different CpG-containing oligonucleotides trigger a different type of immune response while activating the same receptor. We therefore investigated the higher order structure of two different classes of immunostimulatory CpG-DNA. Class A, which contains a partly self-complementary sequence and poly-G ends, forms duplexes and nanoparticles in salt solution, while class B, which does not contain these features and is purely linear, does not form a duplex or nanoparticles. Results obtained here by high-resolution atomic force microscopy of classes A and B CpG-DNA, reflect these differences in secondary structure. Detailed structural analysis of the atomic force microscopy topographs is presented for two different sample preparation methods.
authors.affiliation: Department of Physics, Norwegian University of Science and Technology, Trondheim, Norway. dionne.c.g.klein@ntnu.no
authors.forename: Dionne C G
authors.initials: DC
authors.lastname: Klein
authors.forename: Eicke
authors.initials: E
authors.lastname: Latz
authors.forename: Terje
authors.initials: T
authors.lastname: Espevik
authors.forename: Bjørn T
authors.initials: BT
authors.lastname: Stokke
mesh_terms: D000276:Adjuvants, Immunologic / Q000737:chemistry*; D018899:CpG Islands; D004247:DNA / Q000737:chemistry; D018625:Microscopy, Atomic Force / Q000379:methods*; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*
chemical_list: D000276:Adjuvants, Immunologic; C408982:CPG-oligonucleotide; D009838:Oligodeoxyribonucleotides; D004247:DNA