The effect of two CpG oligodeoxynucleotides with different sequences on haemocytic immune responses of giant freshwater prawn, Macrobrachium rosenbergii.
A previous study has demonstrated that the intrahaemocytic phenoloxidase (PO) activity of the prawn Macrobrachium rosenbergii was enhanced by CpG oligodeoxynucleotide (ODN) 2006, but not by os-ODN13. The study described herein determined the binding characteristics of the two ODNs to haemocytes. Treating haemocytes with FAM-ODN or FAM-ODN plus different concentrations of the same ODN revealed that both ODNs specifically bound to haemocytes. Results from haemocytes treated with FAM-ODN2006 plus ROX-os-ODN13 in a competitive assay indicated that about 91% of haemocytes were simultaneously bound by the two ODNs and that the remaining haemocytes were only bound by ODN2006; moreover, ODN2006 binding to haemocytes was stronger than that of os-ODN13. To clarify the interactive effect of the two ODNs on haemocytic function, mRNA levels of haemocytic genes from single or double ODN-injected prawns were determined by semi-quantitative RT-PCR. The expression of either the prophenoloxidase (proPO) or peroxinectin (pon) genes was elevated by ODN2006 but reduced by os-ODN13; furthermore, ODN2006-increased proPO expression was abated following treatment with os-ODN13. In comparison with ODN-injected prawns alone, the NF-kappaB inhibitor PDTC reduced the proPO mRNA levels induced by ODN2006, but it elevated proPO expression inhibited by os-ODN13. These results support the notion that os-ODN13 may be able to neutralise or negate the enhancing effect of ODN2006 on proPO expression via the NF-kappaB signalling pathway as well as an unknown signalling pathway.
Sung
Hung-Hung
HH
Department of Microbiology, Soochow University, Taipei, Taiwan, ROC. hhsung@scu.edu.tw
Yang
Chu-Wen
CW
Lin
Yi-Hsiu
YH
Chang
Po-Tzung
PT
D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D018899:CpG Islands; D005786:Gene Expression Regulation / Q000187:drug effects; D006434:Hemocytes / Q000187:drug effects / Q000276:immunology; D009838:Oligodeoxyribonucleotides / Q000494:pharmacology*; D033541:Palaemonidae / Q000187:drug effects* / Q000276:immunology*; D011759:Pyrrolidines / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D013859:Thiocarbamates / Q000494:pharmacology
D000276:Adjuvants, Immunologic; D000975:Antioxidants; D009838:Oligodeoxyribonucleotides; D011759:Pyrrolidines; D012333:RNA, Messenger; D013859:Thiocarbamates; C020972:pyrrolidine dithiocarbamic acid