title: Immunostimulatory properties of phosphorothioate CpG DNA containing both 3'-5'- and 2'-5'-internucleotide linkages.
abstract: Synthetic oligodeoxyribonucleotides containing CpG-dinucleotides (CpG DNA) in specific sequence contexts activate the vertebrate immune system. We have examined the effect of 3'-deoxy-2'-5'-ribonucleoside (3'-deoxynucleoside) incorporation into CpG DNA on the immunostimulatory activity. Incorporation of 3'-deoxynucleosides results in the formation of 2'-5'-internucleotide linkages in an otherwise 3'-5'-linked CpG DNA. In studies, both in vitro and in vivo, CpG DNA containing unnatural 3'-deoxynucleoside either within the CpG-dinucleotide or adjacent to the CpG-dinucleotide failed to induce immunostimulatory activity, suggesting that the modification was not recognized by the receptors. Incorporation of the same modification distal to the CpG-dinucleotide in the 5'-flanking sequence potentiated the immunostimulatory activity of the CpG DNA. The same modification when incorporated in the 3'-flanking sequence had an insignificant effect on immunostimulatory activity of CpG DNA. Interestingly, substitution of a 3'-deoxynucleoside in the 5'-flanking sequence distal to the CpG-dinucleotide resulted in increased IL-6 and IL-10 secretion with similar levels of IL-12 compared with parent CpG DNA. The incorporation of the same modification in the 3'-flanking sequence resulted in lower IL-6 and IL-10 secretion with similar levels of IL-12 compared with parent CpG DNA. These results suggest that site-specific incorporation of 3'-deoxynucleotides in CpG DNA modulates immunostimulatory properties.
authors.affiliation: Hybridon, Inc., 345 Vassar Street, Cambridge, MA 02139, USA.
authors.forename: Dong
authors.initials: D
authors.lastname: Yu
authors.forename: Ekambar R
authors.initials: ER
authors.lastname: Kandimalla
authors.forename: Qiuyan
authors.initials: Q
authors.lastname: Zhao
authors.forename: Yanping
authors.initials: Y
authors.lastname: Cong
authors.forename: Sudhir
authors.initials: S
authors.lastname: Agrawal
mesh_terms: D000818:Animals; D002455:Cell Division / Q000187:drug effects; D018899:CpG Islands / Q000235:genetics*; D016207:Cytokines / Q000187:drug effects / Q000378:metabolism; D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*; D005260:Female; D016753:Interleukin-10 / Q000378:metabolism; D018664:Interleukin-12 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008214:Lymphocytes / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D009841:Oligonucleotides / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology; D013154:Spleen / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D013163:Splenomegaly / Q000139:chemically induced / Q000473:pathology; D013873:Thionucleotides / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology
chemical_list: D016207:Cytokines; D015850:Interleukin-6; D009841:Oligonucleotides; D013873:Thionucleotides; D016753:Interleukin-10; D018664:Interleukin-12; D004247:DNA