The utilization of VP28 gene to protect penaeid shrimps from white spot syndrome virus disease: a review

White spot syndrome (WSS) is a viral disease which affects most of the commercially cultivated marine shrimp species all over the world causing significant losses. Deaths occur within days of symptoms and affect a diverse range of commercial crustacean species. A heavy mortality is usually observed in the entire infected population. Survival rates can be anywhere from 30% to zero. Consequently, tools with the capability to effectively and timely detect the diseases have been developed to prevent and contain these pathogens. White spot syndrome virus (WSSV) envelope protein VP28 gene is widely used because its ability to bind to the surface of shrimp epithelial cells and might promote innate immune recognition of WSSV. Its recombinant protein was expressed in various expression systems and used as recombinant vaccine or immunostimulant to increase shrimp survival against WSSV. An anti-body against VP28 was successfully used in virus neutralization assay. A DNA vaccine encoding VP28 gene also provided long-term and high levels of protection against WSSV. Moreover, RNA interference (RNAi) resulted in endogenous RNA sequence-specific degradation to silence VP28 gene expression as well as induced an immune response against virus using non-specific dsRNA in shrimp. However, in order to use VP28 on a commercial scale in the shrimp industry, there are several concerns that need to be addressed such as storage, delivery methodology, protection efficiency; protection period and ensuring that it can be produced in large scale. All these methods might lead to the new strategies to control WSSV using the VP28 gene in future.