Viral resistance and immune responses of the shrimp Litopenaeus vannamei vaccinated by two WSSV structural proteins.

Although adaptive immunity is believed to exist only in higher vertebrates, recent studies showed the ability to vaccinate shrimp and other crayfish against white spot syndrome virus (WSSV). This study attempted to establish parameters of vaccination coordinated with subsequent viral challenge to gain insights into the mechanisms of the protective response of penaeid shrimp. Two WSSV envelope proteins, VP28 and VP36B, were used as subunit vaccines expressed in Escherichia coli followed by histidine-tag affinity chromatographic purification. Shrimp vaccinated with the recombinant WSSV proteins and challenged with diluted WSSV inocula were intramuscularly injected in order to give a precise load. Results of the viral challenge trials showed complete survival in the rVP28 group in contrast to the rVP36B and PBS groups which exhibited 100% mortality. But this effective protection was exclusively induced from a combination of a higher dosage of rVP28 and a lower viral challenge pressure. The innate immune parameters analyzed among the three groups revealed that rVP28-treated shrimp showed the highest activity level (p<0.05) of phenoloxidase and superoxide dismutase during the entire period of 7 days post-vaccination. But there were no significant differences (p>0.05) in mRNA abundances of the Down syndrome cell adhesion molecule (Dscam) among all groups. In addition, total hemocyte counts significantly decreased in shrimp treated with the recombinant viral proteins compared to the PBS group. These results indicated that the existence of structure- and dose-dependent protective responses and the elevated innate immunity in shrimp following a protein-based vaccination might be responsible for conferring resistance against WSSV.

Yang JY ，Chang CI ，Liu KF ，Hseu JR ，Chen LH ，Tsai JM ... -  《-》

Protection of Penaeus monodon against white spot syndrome virus using a WSSV subunit vaccine.

Witteveldt J ，Vlak JM ，van Hulten MC 《FISH &amp; SHELLFISH IMMUNOLOGY》

Localization of VP28 on the baculovirus envelope and its immunogenicity against white spot syndrome virus in Penaeus monodon.

Syed Musthaq S ，Madhan S ，Sahul Hameed AS ，Kwang J ... -  《-》

Injected phage-displayed-VP28 vaccine reduces shrimp Litopenaeus vannamei mortality by white spot syndrome virus infection.

White spot syndrome virus (WSSV) is the most important viral pathogen for the global shrimp industry causing mass mortalities with huge economic losses. Recombinant phages are capable of expressing foreign peptides on viral coat surface and act as antigenic peptide carriers bearing a phage-displayed vaccine. In this study, the full-length VP28 protein of WSSV, widely known as potential vaccine against infection in shrimp, was successfully cloned and expressed on M13 filamentous phage. The functionality and efficacy of this vaccine immunogen was demonstrated through immunoassay and in vivo challenge studies. In ELISA assay phage-displayed VP28 was bind to Litopenaeus vannamei immobilized hemocyte in contrast to wild-type M13 phage. Shrimps were injected with 2 × 10(10) cfu animal(-1) single dose of VP28-M13 and M13 once and 48 h later intramuscularly challenged with WSSV to test the efficacy of the vaccine against the infection. All dead challenged shrimps were PCR WSSV-positive. The accumulative mortality of the vaccinated and challenged shrimp groups was significantly lower (36.67%) than the unvaccinated group (66.67%). Individual phenoloxidase and superoxide dismutase activity was assayed on 8 and 48 h post-vaccination. No significant difference was found in those immunological parameters among groups at any sampled time evaluated. For the first time, phage display technology was used to express a recombinant vaccine for shrimp. The highest percentage of relative survival in vaccinated shrimp (RPS = 44.99%) suggest that the recombinant phage can be used successfully to display and deliver VP28 for farmed marine crustaceans.

Solís-Lucero G ，Manoutcharian K ，Hernández-López J ，Ascencio F ... -  《-》

Comparative proteomic analysis of Litopenaeus vannamei gills after vaccination with two WSSV structural proteins.

White spot syndrome virus (WSSV) is one of the most devastating viral pathogens of cultured shrimp worldwide. Recently published papers show the ability of WSSV structural protein VP28 to vaccinate shrimp and raise protection against the virus. This study attempted to identify the joining proteins of the aforementioned shrimp quasi-immune response by proteomic analysis. The other envelope protein, VP36B, was used as the non-protective subunit vaccine control. Shrimp were intramuscularly injected with rVPs or PBS on day 1 and day 4 and then on day 7 their gill tissues were sampled. The two-dimensional electrophoresis (2-DE) patterns of gill proteins between vaccinated and PBS groups were compared and 20 differentially expressed proteins identified by mass spectrometry, some of which were validated in gill and hemocyte tissues using real-time quantitative RT-PCR. Many of identified proteins and their expression levels also linked with the shrimp response during WSSV infection. The list of up-regulated protein spots found exclusively in rVP28-vaccinated shrimp include calreticulin and heat shock protein 70 with chaperone properties, ubiquitin, and others. The two serine proteases, chymotrypsin and trypsin, were significantly increased in shrimp of both vaccinated groups compared to PBS controls. The information presented here should be useful for gaining insight into invertebrate immunity.

Chen LH ，Lin SW ，Liu KF ，Chang CI ，Hseu JR ，Tsai JM ... -  《-》