title: Immune stimulation in the silkworm, Bombyx mori L., by CpG oligodeoxynucleotides.
abstract: Synthetic ODNs containing unmethylated CpG dinucleotides are known to stimulate immune responses in vertebrates, but so far the effect has not been studied in insects. In this report, we describe an induction of immune response following injection of oligodeoxynucleotides (ODNs) into the insect hemocoel. The fifth instar silkworm (Bombyx mori L.) larvae were injected with several synthetic ODNs containing variable number of unmethylated CpG motifs, heat-denatured genomic DNA of B. mori itself, or intact genomic DNA to observe a new induction pattern in the insect immune mechanism. When the induction of immune response was examined based on the expression rates of genes for antibacterial peptides such as attacin and cecropin, we could confirm that it was triggered upon injection of ODNs. The expression was, however, neither dependent on numbers of CpG motifs nor methylation of CpGs in ODNs. Furthermore, it was confirmed that the presence of CpG in ODN was not involved in the induction pattern of insect immunity caused by ODNs, although it has been reported that vertebrates respond in a specific manner against invading ODNs containing CpG dinucleotides. In addition, insect immunity was not stimulated by injection of intact DNA from host. In contrast, the injection of denatured genomic DNA provoked the host immune reaction. Taken together, our data suggest that foreignness of ODNs or DNA might be a key factor in the induction of insect immunity.
authors.affiliation: Department of Sericulture & Entomology, National Institute of Agricultural Science and Technology, Rural Development Administration, Suwon, South Korea.
authors.forename: Iksoo
authors.initials: I
authors.lastname: Kim
authors.forename: Sang-Hyun
authors.initials: SH
authors.lastname: Kim
authors.forename: Young Shin
authors.initials: YS
authors.lastname: Lee
authors.forename: Eun Kyung
authors.initials: EK
authors.lastname: Yun
authors.forename: Heui-Sam
authors.initials: HS
authors.lastname: Lee
authors.forename: Jin-Won
authors.initials: JW
authors.lastname: Kim
authors.forename: Kang-Sun
authors.initials: KS
authors.lastname: Ryu
authors.forename: Pil-Don
authors.initials: PD
authors.lastname: Kang
authors.forename: In Hee
authors.initials: IH
authors.lastname: Lee
mesh_terms: D000276:Adjuvants, Immunologic / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000096:biosynthesis; D001483:Base Sequence; D015152:Blotting, Northern; D012831:Bombyx / Q000235:genetics / Q000276:immunology* / Q000821:virology; D018899:CpG Islands; D004247:DNA / Q000737:chemistry / Q000276:immunology / Q000494:pharmacology; D005216:Fat Body / Q000276:immunology; D006790:Host-Parasite Interactions; D006358:Hot Temperature; D019476:Insect Proteins / Q000096:biosynthesis / Q000235:genetics; D007814:Larva / Q000276:immunology; D008070:Lipopolysaccharides / Q000494:pharmacology; D009691:Nucleic Acid Denaturation; D017924:Nucleopolyhedroviruses / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity; D009838:Oligodeoxyribonucleotides / Q000737:chemistry / Q000494:pharmacology*; D010455:Peptides
chemical_list: D000276:Adjuvants, Immunologic; D000900:Anti-Bacterial Agents; D019476:Insect Proteins; D008070:Lipopolysaccharides; D009838:Oligodeoxyribonucleotides; D010455:Peptides; C039711:attacin antibacterial protein, insect; D004247:DNA