CpG motif in synthetic ODN primes respiratory burst of olive flounder Paralichthys olivaceus phagocytes and enhances protection against Edwardsiella tarda

Abstract

Effects of synthetic cytidine-phosphate-guanosine (CpG) oligodeoxynucleotide (ODN) on respiratory burst activity of olive flounder (Paralichthys olivaceus) head-kidney phagocytes and on protection against lethal infection with Edwardsiella tarda were investigated. Phagocytes precultured with a CpG ODN showed significantly higher chemiluminescence (CL) responses than phagocytes precultured with guanosine-phosphate-cytidine (GpC) ODN or culture medium alone (control) at all concentrations. Supernatants produced from leucocytes, which were pulsed with CpG ODN, induced significantly higher respiratory burst activity than supernatants produced by GpC ODN or culture medium alone. In an in vivo experiment, respiratory burst activities of the head kidney phagocytes in the groups injected either 0.25 or 0.5 µg fish -1 of CpG ODN were significantly higher than those in the groups injected with GpC ODN or HBSS (control) at 3, 5 and 7 d after injection. The groups of fish injected with 0.25 or 0.5 µg of CpG ODN showed higher survival rates (83.3%) than groups treated with GpC ODN (33.3%) and a control group (8.3%) after challenge with E. tarda. The present in vitro and in vivo experiments have demonstrated the ability of synthetic CpG ODN to increase phagocyte respiratory burst activity and disease resistance in olive flounder.

Stimulation of type I IFN activity in Atlantic salmon (Salmo salar L.) leukocytes: Synergistic effects of cationic proteins and CpG ODN

“…Works by our group and others have demonstrated potent immunostimulatory activities of CpG ODN in fish and fish leukocytes [5,7,8,12,37] and point to CpG ODN as a promising adjuvant to be tested in fish vaccines. A challenge within this context is to develop appropriate delivery systems for CpG ODN to be combined with a vaccine antigen, to potentiate its immunostimulatory effects.…”

“…Stimulation with CpG ODNs enhances non-specific defence mechanisms, cytokine expression and lymphocyte proliferation in carp (Cyprinus carpio L., Ctenopharyngodon idellus) leukocytes in vitro [4e6] and in vivo [7]. Respiratory burst activities are induced in olive flounder (Paralichthys olivaceus) phagocytes, corresponding with increased protection against the bacterial pathogen Edwardsiella tarda [8] and non-specific cytotoxic cells from channel catfish (Ictalurus punctatus) are activated [9]. Salmonid leukocytes produce type I IFN and interleukin-1 upon stimulation [10,11].…”

The expression profile of TLR9 mRNA and CpG ODNs immunostimulatory actions in the teleost gilthead seabream points to a major role of lymphocytes

“…On the other hand, the ROI production (mediated by macrophages but mainly by acidophilic granulocytes) by seabream HKL was significantly enhanced by most ODNs but to a much lower degree than by bacterial DNA, in contrast to NCC activity. ROI production was also increased in common carp [38 -40], grass carp [41], and olive flounder [42] after in vivo or in vitro treatment with several synthetic ODNs containing CpG motifs or even GpC motifs [42] or with plasmid containing multi-copy CpG motifs (90 in total) in goldfish and Japanese sea bass [43]. Interestingly, the ROI production increase in seabream was lower than the NCC, probably because lymphocytes are not directly involved in this phagocyte-related activity but are the main effectors in tumor-cell killing activity by NCCs.…”

Preventive and therapeutic effects of auxotrophic Edwardsiella tarda mutant harboring CpG 1668 motif-enriched plasmids against scuticociliatosis in olive flounder (Paralichthys olivaceus)

“…Immunostimulation and increased disease resistance by DNA with unmethylated CpG motifs have been reported in various fish species (Jørgensen et al, 2001a(Jørgensen et al, ,b, 2003Lee et al, 2003;Sakai, 2003, 2005;Rhodes et al, 2004;Secombes, 2006, 2007;Strandskog et al, 2007). Preventive potential of DNA with CpG 1668 motif against scuticociliatosis was also demonstrated (Lee and Kim, 2009;Kang and Kim, 2012;Kang et al, 2013a).…”