Survey of the Expression Pattern and Immuno Stimulatory Effect of DNA Vaccine Using β-Galactosidase Reporter System in Olive Flounder (Paralichthys olivaceus)

The CMV promoter driven lacZ reporter gene (pcDNA-lacZ) was constructed and used for DNA immunization study. The expression of the lacZ gene was confirmed in vitro using RTG-2 cell line before using for in vivo study in olive flounder (Paralichthys olivaceus). In the dose response study, the maximum expression of the lacZ gene was found in the group injected with 5 ${\mu} g$ of the plasmid DNA. Kinetic study showed a significantly increased expression of $\beta-galactosidase$ gene at 7 days after injection. Effects of DNA vaccine on specific and nonspecific immune responses such as antibody and NO production were studied and the significant effect was found in olive flounder injected with 10 and 15 ${\mu} g$ DNA (sub optimal dose for lacZ gene expression). Two pro inflammatory cytokine genes, $IL-l\beta$ and $TNF-\alpha$, were also found to be up regulated in the muscle injected with the plasmid, suggesting an induction of local inflammatory response.