| Summary: | 碩士 === 嘉南藥理科技大學 === 生物科技系曁研究所 === 97 === Bacterial genomic DNA with unmethylated cytosine-guanine dinucleotides (CpG) can activate mammalian immune system. Unmethylated CpG motifs act as a danger signal to initiate immune responses in vertebrate. The effects of unmethylated CpG motifs on invertebrate are still not clear.
It has been reported that unmethylated CpG motifs stimulate immune response of the prawns and mussel in present years, which induces antimicrobial proteins and increased antibacterial activity.
Drosophila melanogaster is widely used as a model in the research of invertebrate immune system. Drosophila hemocytes play a key role in defence against microbial aggression by secretion antimicrobial peptides (AMPs）and phagocytosis. The Drosophila cell line malignant blood neoplasm-2 (Mbn-2) was used to investigate the stimulation of CpG DNA on invertebrate animal immune system. The Mbn-2 cell line shows several haemocyte-like characteristics, including the capacity to phagocytose. It also responds to microbial substances by the activation attacin gene, coding for AMPs. It provides a very useful tool for studying the Drosophila immune response to CpG DNA stimulation.
Our results showed E.coli DNA could induce the expression of attacin on Mbn-2 and the stimulatory effect was dose independent . The expression of attacin on Mbn-2 was further enhanced when LPS and E.coli DNA were combined as stimuli. Furthermore, the effect of E.coli DNA on phagocytosis was not observed.
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