Vaccination trials with Penaeus japonicus to induce resistance to white spot syndrome virus

Crustaceans do not possess an adaptive immune response with immunoglobulins; however, recently, quasi-immune response has been reported by which kuruma shrimp (Penaeus joponicus) surviving from natural or experimental white spot syndrome virus (WSSV) infections possess a resistance against challenge with WSSV In this study, efficacy of vaccines made of inactivated WSSV with or without immunostimulants (beta-1,3-glucan or killed Vibrio penaeicida) and of recombinant proteins of WSSV (rVP26, rVP28) were tested by intramuscular vaccination followed by intramuscular challenge of kuruma shrimp with WSSV The shrimp vaccinated with formalin-inactivated WSSV showed a resistance to the virus on 10th day post-vaccination (dpv) but not on 30th dpv. Heat-inactivated WSSV did not induce a resistance in the shrimp even on 10th dpv. Additional injections with glucan or V. penaeicida enhanced the efficacy of formalin-inactivated WSSV vaccine; however, the relative percent survival (RPS) values did not exceed 60% even when shrimp were vaccinated three times. On the other hand, two injections with rVP26 or rVP28 induced a higher resistance, with RPS values 60% and 95%, respectively, in the shrimp on 30th dpv. These results indicate the possibility of vaccination of kuruma shrimp with recombinant proteins against WSSV. (C) 2004 Elsevier Science B.V. All rights reserved.