INTEGRATED AQUATIC ANIMAL HEALTH STRATEGIES
Location: Aquatic Animal Health Research
Title: Efficacy of QCDCR formulated CpG ODN 2007 in Nile tilapia against Streptococcus iniae and identification of upregulated genes
Submitted to: Veterinary Immunology and Immunopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 10, 2011
Publication Date: December 1, 2011
Citation: Wei Pridgeon, Y., Klesius, P.H., Mu, X., Yancey, R.J., Kievit, M.S., Dominowski, P.J. 2011. Efficacy of QCDCR formulated CpG ODN 2007 in Nile tilapia against Streptococcus iniae and identification of upregulated genes. Veterinary Immunology and Immunopathology. 145:179-190.
Interpretive Summary: The potential of using a formulated oligonucleotide to protect Nile tilapia against bacterial infection was evaluated in this study. The formulated oligonucleotide offered significant protection to Nile tilapia at two days after treatment, with relative percent survival of 63% compared to fish treated by the formulation alone. To understand how the oligonucleotide was able to protect fish at molecular level, a subtraction method was used to identify genes induced by the oligonucleotide. A total of 44 genes were found to be significantly induced by the oligonucleotide, including 29 were induced for more than 10 fold and 15 were induced for less than 10 fold. Of all genes, peroxisomal sarcosine oxidase was induced the most. Of all genes identified, six had putative functions related to immunity, of which two were confirmed to be significantly induced by the oligonucleotide. Our results suggest that the protection provided by the oligonucleotide is mainly through innate immune responses directly or indirectly related to immunity.
The potential of using a QCDCR (quilA:cholesterol:dimethyl dioctadecyl ammonium bromide:carbopol:R1005 glycolipid) formulated CpG oligodeoxynucleotide (ODN), ODN 2007, to confer protection in Nile tilapia against Streptococcus iniae infection was evaluated in this study. At two days post treatment, QCDCR formulated ODN 2007 elicited significant (P<0.05) protection to Nile tilapia, with relative percent survival of 63% compared to fish treated by QCDCR alone. To understand the molecular mechanisms involved in the protective immunity elicited by ODN 2007, suppression subtractive cDNA hybridization technique was used to identify upregulated genes induced by ODN 2007. A total of 69 expressed sequence tags (ESTs) were identified from the subtractive cDNA library. Quantitative PCR revealed that 44 ESTs were significantly (P<0.05) upregulated by ODN 2007, including 29 highly (>10 fold) and 15 moderately (<10 fold) upregulated ESTs. Of all ESTs, putative peroxisomal sarcosine oxidase was upregulated the highest. The 69 ESTs only included six genes that had putative functions related to immunity, of which only two (putative glutaredoxin-1 and carboxypeptidase N catalytic chain) were confirmed to be significantly upregulated. Our results suggest that the protection elicited by ODN 2007 is mainly through innate immune responses directly or indirectly related to immunity.