Expression profile of key immune-related genes in Penaeus monodon juveniles after oral administration of recombinant envelope protein VP28 of white spot syndrome virus.

White spot syndrome virus (WSSV) is the most catastrophic pathogen the shrimp industry has ever encountered. VP28, the abundant envelope protein of WSSV was expressed in bacteria, the purified protein administered orally to Penaeus monodon juveniles and its immune modulatory effects examined. The results indicated significant up-regulation of caspase, penaeidin, crustin, astakine, syntenin, PmRACK, Rab7, STAT and C-type lectin in animals orally administered with this antigen. This revealed the immune modulations in shrimps followed by oral administration of rVP28P which resulted in the reduced transcription of viral gene vp28 and delay in mortality after WSSV challenge. The study suggests the potential of rVP28P to elicit a non-specific immune stimulation in shrimps.

Immunogenicity and protective efficacy of a major White Spot Syndrome Virus (WSSV) envelope protein VP24 expressed in Escherichia coli against WSSV.

The study reports cloning, expression and characterization of immunogenic activity of VP24, a major envelope protein of White Spot Syndrome Virus (WSSV). His-tagged VP24 was expressed as truncated protein and purified from inclusion bodies by metal affinity chromatography under denaturing conditions. The ability to confer protection from WSSV by oral administration of recombinant viral protein (rVP24) was examined in black tiger shrimp Penaeus monodon (P. monodon) juveniles (advanced post larvae). Animals were fed with rVP24 for 10 days, orally challenged with WSSV and assayed for expression of viral genes and shrimp immune genes on the 2nd, 5th and 8th days of challenge. The survival of juvenile shrimps in the vaccinated and challenged group was significantly higher compared to the unvaccinated and challenged group with lesser viral gene expression (DNA polymerase, latency 1 and vp28). Analysis of immune gene expression showed upregulation of syntenin and down regulation of STAT, Rab 7 and caspase during the experimental period. This study points to the feasibility of using rVP24 as candidate vaccine in P. monodon against WSSV.