Fish immunization using a synthetic double-stranded RNA Poly(I:C), an interferon inducer, offers protection against RGNNV, a fish nodavirus

• Nishizawa, Toyohiko

• Takami, Ikuo

• Kokawa, Yuki

• Yoshimizu, Mamoru

Abstract

Viral nervous necrosis (VNN), caused by a fish nodavirus, is one of the most serious fish diseases worldwide. Here we report a unique vaccination method in sevenband grouper Epinephelus septemfasciatus using a synthetic double-stranded RNA polyinosinic polycytidylic acid (Poly(I:C)), an interferon inducer, followed by challenge with a live fish nodavirus. Fish injected with Poly(I:C) at 200 µg fish(-1) were highly protected from artificial challenge with red-spotted grouper nervous necrosis virus (RGNNV) (relative percentage survival, RPS: 100%), and specific antibodies against RGNNV were detected in sera from survivors. Moreover, the surviving fish were protected from rechallenge with RGNNV (relative percent survival RPS: 100%). Thus, it was confirmed that specific immunity against RGNNV was established in sevenband grouper by injection with live RGNNV following Poly(I:C) administration. Antiviral state was induced in fish by injection with Poly(I:C) at ≥50 µg fish(-1), but no toxic response was observed in the fish even if Poly(I:C) was injected at a dose of 200 µg fish(-1). In fish injected with Poly(I:C) at 200 µg fish(-1), a high level of antiviral state of > 90% RPS against RGNNV challenge lasted for at least 4 d after Poly(I:C) injection. However, no curative effect by Poly(I:C) injection was observed in fish already infected with RGNNV. It is considered that the present immunization method using Poly(I:C) followed by a live virus injection could offer protection against various viral infections in a broader range of fish species.

Journal

• Diseases of aquatic organisms

  Diseases of aquatic organisms 83 (2), 115-122, 2009-02-12

  Inter-Research

Keywords

• Poly(I:C)
• Immunization
• Fish nodavirus
• Viral nervous necrosis
• VNN
• Sevenband grouper
• Vaccine
• Antiviral state

Details

• CRID: 1050845763944577408
• NII Article ID: 120005323614
• NII Book ID: AA10443976
• ISSN: 16161580
• ISSN: 01775103
• HANDLE: 2115/53184
• Text Lang: en
• Article Type: journal article
• Data Source:
  • IRDB
  • CiNii Articles