title: Requirement of nucleobase proximal to CpG dinucleotide for immunostimulatory activity of synthetic CpG DNA.
abstract: Synthetic oligodeoxyribonucleotides containing CpG dinucleotides exhibit potent immunostimulatory activity in vertebrates. Although the molecular mechanisms of recognition and interaction of CpG DNA sequences with receptors are not well understood, the current evidence suggests that the receptor shows considerable selectivity for CpG DNA sequences with different preferences in mouse (GACGTT) and human (GTCGTT) species. In our continued effort to understand the chemical and structural characteristics of CpG DNA required for the immunostimulatory activity and thereby for the recognition of receptors in the immunostimulatory pathway, we examined the requirement of nucleobases in the two adjacent nucleotide positions on the 5'- and the 3'-side to the CpG dinucleotide (P(1)P(2)CGP(3)P(4)) for the immunostimulatory activity. These studies, in which a natural nucleoside is substituted with an abasic nucleoside (X), suggest that a nucleobase is absolutely required in C, G, P(3), and P(4) positions for immunostimulatory activity. Surprisingly, an abasic nucleoside is permitted at either P(1) or P(2) depending on the neighboring base. It was found that 'GXCGTT' motif has an intermediate immunostimulatory activity between those of 'GACGTT' and 'GTCGTT' in the mouse cells.
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: Lakshmi
authors.initials: L
authors.lastname: Bhagat
authors.forename: Yanping
authors.initials: Y
authors.lastname: Cong
authors.forename: Sudhir
authors.initials: S
authors.lastname: Agrawal
mesh_terms: D024509:3' Flanking Region; D024506:5' Flanking Region; D000276:Adjuvants, Immunologic / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D000818:Animals; D018899:CpG Islands / Q000276:immunology*; D016207:Cytokines / Q000378:metabolism; D004247:DNA / Q000737:chemistry* / Q000276:immunology; D003853:Deoxyribonucleosides / Q000737:chemistry / Q000276:immunology; D007364:Intercalating Agents / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009841:Oligonucleotides / Q000138:chemical synthesis / Q000737:chemistry* / Q000276:immunology* / Q000494:pharmacology; D009929:Organ Size / Q000187:drug effects; D017384:Sequence Deletion; D013154:Spleen / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D013163:Splenomegaly / Q000139:chemically induced; D013329:Structure-Activity Relationship
chemical_list: D000276:Adjuvants, Immunologic; D016207:Cytokines; D003853:Deoxyribonucleosides; D007364:Intercalating Agents; D009841:Oligonucleotides; D004247:DNA