Insect Immune Activation by Recombinant Apolipophorin-III and Its Application to Pest Control in Hyphantria cunea

다국어 초록 (Multilingual Abstract)

Apolipophorin­III is a hemolymph protein whose function is to facilitate lipid transport in an aqueous medium. Recently, apolipophorin­III in Galleria mellonella larvae showed to play an unexpected role in insect immune activation. We identified the cDNA sequence of Hyphantria cunea apolipophorin­III by oligonucleotide­primed amplification, and 5'­and 3'­RACE PCR. Since H. cunea has an unusually low level of apolipophorin­III in the hemolymph, a recombinant apolipophorin­III was overexpressed using a baculovirus expression system to investigate its biological activity. Recombinant apolipophorin­III and E. coli were injected into the hemocoel of last instar larvae, and the changes in apolipophorin­III in hemolymph was determined by Western blot. Injection of apolipophorin­III induced a slight increase of apolipophorin­III in the recipients' hemolymph. While E. coli injection led to remarkably increased concentration of apolipophorin­III in hemolymph. To investigate the induction of antimicrobial peptide by the injection of recombinant apoLp­III and E. coli, Northern blot was performed. Apolipophorin­III injection as well as bacterial injection into the larvae showed the induction on the expression of lysozyme gene. Apolipophorin­III is apparently related to the immune response through an unknown mechanism. The role of apolipophorin­III in insect immunity should be related to the activation of transcription factor of antimicrobial peptide.