Effects of CpG Oligodeoxynucleotides on Immune Responses and Expression of Cytokine Genes in Cultured Olive Flounder Paralichthys olivaceus

摘要

The induction of cellular and humoral immunity and cytokine gene expression by synthetic CpGoligodexoynucleotides (CpG-ODNs) has not been investigated systematically in olive flounderParalichthys olivaceus in vivo. We optimized the proper concentration of CpG-ODNs using an invitro assay for the superoxide anion (O_(2~-)). CpG-ODNs induced O_(2~-) and nitric oxide (NO)production, lysozyme activity, and the proinflammatory cytokine gene expression of IL-lbeta andTNF-a in olive flounder significantly in vivo, whereas non-CpG-ODNs did not produce theseeffects or produced them to a lesser extent. This implied that CpG-ODNs could stimulate cellularand humoral immunity and cytokine gene expression in olive flounder. This is the first evidenceof NO production and the first study on the mRNA expression of the proinflammatory cytokinegenes IL-lbeta and TNF-a in olive flounder in response to CpG-ODNs. Comparison of the variationin NO production and lysozyme activity to that of other studies led us to postulate that a groupspecific difference exists in the immune responses of olive flounder against CpG-ODNs.Furthermore, the detailed immunostimulatory spectrum of CpG-ODNs in olive flounder could bea useful index with which to analyze the effect of CpG-ODNs against the challenge test prior tofield applications.