Development of gamma-irradiated vaccine against Nocardia seriolae in Seriola species

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K19139
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 40:Forestry and forest products science, applied aquatic science, and related fields
• Research Institution: Tokyo University of Marine Science and Technology
• Principal Investigator: Kato Goshi 東京海洋大学, 学術研究院, 准教授 (50624219)
• Project Period (FY): 2021-07-09 – 2024-03-31
• Keywords: 水産用ワクチン

Outline of Final Research Achievements

Nocardiosis caused by Nocardia seriolae is one of the most important infectious diseases in aquaculture of seriola species in Japan. In this study, we investigated protective efficacy of a gamma-irradiated vaccine against the disease using a model fish species, Ginbuna crucian carp Carassius auratus langsdorfii. Ginbuna injected with gamma-irradiated N. seriolae showed no symptoms of nocardioasis at 4 weeks after the adminidtaration, suggesting that the vaccine is not virulento to fish. Furthermore, the vaccinated fish were challenged with live N. seriolae and showed statistically higher survival rate compared with phosphate-buffered saline asa negative control. These results suggest that gamma-irradiaet N. seriolae is effective as a vaccine against fish nocardiosis.

Free Research Field

魚病学

Academic Significance and Societal Importance of the Research Achievements

水産用ワクチンとして一般的に使用されているホルマリン不活化菌体は、ノカルジア症に対して有効性を示さないことから、本症に対する実用化可能なワクチンの開発は難航してきた。本研究の成果により、γ線照射不活化ワクチンは本症に有効性を示し、現段階では最も実用化に近いワクチン候補であると考えられる。今後、本ワクチンの安全性および有効性についてブリ属魚類を用いて試験を行えば、実用化に大きく近づくと考えられる。