Expression of YAV proteins and vaccination against viral ascites among cultured juvenile yellowtail

• Published in: Bioscience, biotechnology, and biochemistry biotechnology, and biochemistry, 2000-07, Vol.64 (7), p.1494-1499
• Main Authors: Sato, H. (Kyoto Inst. of Technology (Japan)), Nakajima, K, Maeno, Y, Kamaishi, T, Kamata, T, Mori, H, Kamei, K, Takano, R, Kudo, K, Hara, S
• Format: Article
• Language: English
• Subjects: Animal aquaculture; Animal productions; Animals; ASCITES; Ascites - prevention & control; Ascites - veterinary; Ascites - virology; baculovirus; Base Sequence; Biological and medical sciences; BIRNAVIRIDAE; Birnaviridae - genetics; Birnaviridae - immunology; Capsid - genetics; Capsid - immunology; Capsid Proteins; Cell Line; Cells, Cultured; DNA, Viral; FISH CULTURE; FISH DISEASES; Fish Diseases - immunology; Fish Diseases - prevention & control; Fish Diseases - virology; Fundamental and applied biological sciences. Psychology; GENE EXPRESSION; JUVENILES; Marine; Microbiology; Molecular Sequence Data; Pisciculture; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - immunology; Salmon; segment A; Seriola quinqueradiata; Spodoptera - cytology; VACCINATION; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies; Vaccines, Synthetic - genetics; Vaccines, Synthetic - immunology; Vertebrate aquaculture; Viral Vaccines - genetics; Viral Vaccines - immunology; Virology; YAV; Yellowtail ascites virus; YELLOWTAILS
• ISSN: 0916-8451; 1347-6947
• DOI: 10.1271/bbb.64.1494

Yellowtail ascites virus (YAV) is a member of the family Birnaviridae and causes viral ascites among juvenile yellowtail (Seriola quinqueradiata). We have reported the cloning and expression of two viral cDNAs, the first being segment A encoding a polyprotein of viral capsid proteins (VP2 and VP3) and a protease (NS), and the second being VP2-epitope encoding serotype-specific epitope region on VP2, using a baculovirus expression system. Another viral cDNA encoding a polyprotein of NS and VP3 was cloned and expressed in this study. For the expression of NS/VP3 (YAV nt 1626 to 3066) in insect cells a 31-kDa protein, corresponding to VP3 was detected, indicating an appropriate posttranslational processing of NS/VP3 polypeptide by NS protease itself. The analysis of the N-terminal amino acid sequence of this protein showed that NS protease may cleave an Ala-Ser bond. A study of the potential for vaccination of yellowtail fry by injection of insect cell lysates infected with baculovirus, containing either cDNA of segment A, VP2-epitope, or NS/VP3 was undertaken. Only a vaccination with cell lysates infected with a recombinant virus carrying the full length of YAV segment A gene demonstrated approximately the same effect as that of inactivated YAV. This result suggested that all proteins VP2, VP3, and NS are required for an effective vaccination.