Shrimp protected from WSSV disease by treatment with egg yolk antibodies (IgY) against a truncated fusion protein derived from WSSV

White spot syndrome virus (WSSV) is a virulent pathogen known to affect penaeid shrimp. It has a bacilliform morphology and a tail-like appendage at one end. The virus particle consists of at least four major proteins. VP28 and VP19 reside in the envelope, while VP26 and VP24 are present in the nucleocapsid. Truncated VP28 (TrVP28) gene was fused to a truncated VP19 (TrVP19) to form TrVP28:19. This together with TrVP28, TrVP24, and TrVP26 were expressed in Escherichia coli. The panel of resulting recombinant proteins was immunoblotted with serum from rabbit anti-glutathione S-transferase (GST), rabbit anti-WSSV, and normal rabbit serum. TrVP28:19 immunoreacted strongly with rabbit anti-WSSV. When TrVP28:19 was used as an antigen, dramatically increased titres against it were obtained when compared to other antigens for the production of egg yolk antibodies (IgY). The fusion protein was used as an immunogen with chickens. Shrimp used in WSSV neutralization assays was P. chinensis. Shrimp treated with 0.01 mg/10 mul of IgY exhibited a survival rate of 50% at day 15 post-challenge with WSSV while those treated with 0.1 and 0.5 mg/mul exhibited survival rates of 85% and 83%, respectively. The results showed that WSSV can be neutralized by the IgY against TrVP28:19 and that it has potential for immunotherapeutic application to prevent WSSV infection in P. chinensis. (C) 2004 Elsevier B.V. All rights reserved.