Immune stimulation in the silkworm, Bombyx mori L., by CpG oligodeoxynucleotides.
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.
Kim
Iksoo
I
Department of Sericulture & Entomology, National Institute of Agricultural Science and Technology, Rural Development Administration, Suwon, South Korea.
Kim
Sang-Hyun
SH
Lee
Young Shin
YS
Yun
Eun Kyung
EK
Lee
Heui-Sam
HS
Kim
Jin-Won
JW
Ryu
Kang-Sun
KS
Kang
Pil-Don
PD
Lee
In Hee
IH
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
D000276:Adjuvants, Immunologic; D000900:Anti-Bacterial Agents; D019476:Insect Proteins; D008070:Lipopolysaccharides; D009838:Oligodeoxyribonucleotides; D010455:Peptides; C039711:attacin antibacterial protein, insect; D004247:DNA