APPLICATION OF DNA MICROARRAY TECHNOLOGY FOR THE EVALUATION OF DNA VACCINES IN JAPANESE FLOUNDER (Paralichthys olivaceus )

¹ Laboratory of Genome Science, Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Konan 4-5-7, Minato-ku, Tokyo 108-8477, Japan

DNA vaccine is a new and revolutionary technology that can induce both cellular and humoral immune response and protect various animals from infectious diseases. We assessed DNA vaccines made from HIRRV (Rhabdovirus olivaceus) G protein and N protein in Japanese flounder (Paralichthys olivaceus). High protective ability against HIRRV infection was observed following vaccination with the G protein vaccine construct but no protection was observed following vaccination with the N protein vaccine construct. To examine the molecular mechanisms of the protective response during DNA vaccination in Japanese flounder, we used DNA microarrays containing 796 unique genes; 213 of which are immune related and 583 are unknowns. Japanese flounders weighing about 10g were intramuscularly injected with 10ƒÊg of either HIRRV G or N protein DNA vaccine constructs, and an empty vector for control. mRNA was isolated from the kidney of treated fishes at 1, 3, 7, 14 and 28 days after injection. Microarray analyses showed that a total of 30 genes (2.5%) of the 796 genes tested were up-regulated in the presence of G protein while N protein induced 31 genes (2.6%). Of these up-regulated genes, 30% were found to be commonly induced by both G protein and N protein, and the remaining 70% were differentially regulated. Five (5) genes, (Mx1, Ubiquitin-like protein, Interferon-inducible 56 kD protein and 2 unknowns), were strongly induced after injection by the G protein DNA vaccine. These results suggest that DNA microarray technology can be utilized to evaluate potential vaccine agents in fish.