Protective immunity of sevenband grouper, Epinephelus septemfasciatus Thunberg, against experimental viral nervous necrosis |
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| Authors: | S Tanaka K Mori M Arimoto T Iwamoto & T Nakai |
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| Institution: | Owase Branch, Fisheries Research Institute of Mie, Owase, Mie, Japan;Kamiura Station of Japan Sea-Farming Association, Kamiura, Oita, Japan;Faculty of Applied Biological Science, Hiroshima University, Higashihiroshima, Japan |
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| Abstract: | This paper describes the protective immune responses of sevenband grouper, Epinephelus septemfasciatus Thunberg, immunized with live piscine nodavirus, the causative agent of viral nervous necrosis (VNN), or the Escherichia coli – expressed recombinant coat protein. Nodavirus-neutralizing antibodies were detected at titres ranging from 1:158 to 1:1257 in serum of sevenband grouper which survived intramuscular injection with the virus, by a cell culture assay system. The virus-neutralizing ability of immune serum was also confirmed by injecting virus previously treated with serum into fish. This indicates establishment of acquired immunity in survivors and thus explains why survivors from natural infection are resistant to recurrence of the disease. Young sevenband grouper were immunized twice by intramuscular injections with the recombinant coat protein. Immunized fish produced neutralizing antibodies at high titres for at least 110 days and showed significantly lower mortalities in virus challenge tests. These results suggest the potential for vaccination against VNN in sevenband grouper, which is susceptible to piscine nodavirus at all life-stages. |
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| Keywords: | Nodavirus viral nervous necrosis viral encephalopathy and retinopathy neutralizing antibody recombinant protein vaccination |
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