1. Live vaccine of viral hemorrhagic septicemia virus (VHSV) for Japanese flounder at fish rearing temperature of 21°C instead of Poly(I:C) administration
- Author
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Nishizawa, Toyohiko, Takami, Ikuo, Yang, Minji, and Oh, Myung-Joo
- Subjects
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HEMORRHAGIC septicemia , *VIRUS diseases in fishes , *VIRAL vaccines , *FLATFISHES , *IMMUNE response , *PARALICHTHYS , *FISH farming - Abstract
Abstract: The process of “Poly(I:C) immunization” involves immunization of fish with a pathogenic live virus, followed by administration of Poly(I:C), which induces a transient, non-specific antiviral state. As a result, fish in an antiviral state survive the initial immunization with live virus. Moreover, these fish are able to mount a specific protective immune response against the injected pathogenic virus. In the present study, we investigated the optimum temperature for Poly(I:C) immunization of Japanese flounder Paralichthys olivaceus with live viral hemorrhagic septicemia virus (VHSV). It was revealed that the optimum temperature was around at 17°C for Poly(I:C) immunization in Japanese flounder. Furthermore, the protection efficacy of Poly(I:C) immunization was significantly decreased by elevation of fish rearing temperature, and no efficacy was observed at a fish rearing temperature of 25°C. Interestingly, no mortality by VHSV infection was observed in fish reared at 21°C and 25°C even when those fish were not administered Poly(I:C). All of the survivors from the first VHSV-challenge at 21°C were strongly protected from re-challenge with VHSV. However, almost all of the survivors (≥82.6%) from the first challenge at 25°C were lost by the second challenge with VHSV. It was thus concluded that by rearing fish at 21°C and challenging with live VHSV, it is possible to induce strong specific immunity in Japanese flounder without Poly(I:C) administration. [Copyright &y& Elsevier]
- Published
- 2011
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