Reprint of “Evolution of specific immunity in shrimp – A vaccination perspective against white spot syndrome virus”

Abstract

Invertebrates lack true adaptive immunity and it solely depends on the primitive immunity called innate immunity. However, various innate immune molecules and mechanisms are identified in shrimp that plays potential role against invading bacterial, fungal and viral pathogens. Perceiving the shrimp innate immune mechanisms will contribute in developing effective vaccine strategies against major shrimp pathogens. Hence this review intends to explore the innate immune molecules of shrimp with suitable experimental evidences together with the evolution of "specific immune priming" of invertebrates. In addition, we have emphasized on the development of an effective vaccine strategy against major shrimp pathogen, white spot syndrome virus (WSSV). The baculovirus displayed rVP28 (Bac-VP28), a major envelope protein of WSSV was utilized to study its vaccine efficacy by oral route. A significant advantage of this baculovirus expression cassette is the use of WSSV-immediate early 1 (ie1) promoter that derived the abundant expression of rVP28 protein at the early stage of the infection in insect cell. The orally vaccinated shrimp with Bac-VP28 transduced successfully in the shrimp cells as well as provided highest survival rate. In support to our vaccine efficacy we analysed Pattern Recognition Proteins (PRPs) β-1,3 glucan lipopolysaccharides (LGBP) and STAT gene profiles in the experimental shrimp. Indeed, the vaccination of shrimp with Bac-VP28 demonstrated some degree of specificity with enhanced survival rate when compared to control vaccination with Bac-wt. Hence it is presumed that the concept of "specific immune priming" in relevant to shrimp immunity is possible but may not be common to all shrimp pathogens.

Molecular Mechanisms of White Spot Syndrome Virus Infection and Perspectives on Treatments

“…As a consequence, it is not possible to develop vaccines in the traditional way as is done in mammals and other vertebrates. However, recent developments have provided evidence that certain forms of pathogen-specific “immune priming” are possible in some invertebrates [ 210 ]. For example, short-term protection against WSSV can be achieved through exposing shrimp to inactivated viral particles [ 211 ].…”

“…For example, short-term protection against WSSV can be achieved through exposing shrimp to inactivated viral particles [ 211 ]. Musthaq and Kwang reviewed the possibilities of such vaccinations for WSD and the types of treatments (vaccines) that can provide temporal protection against WSD [ 210 ]. These include inactivated virus, recombinant viral proteins, viral DNA, and double-stranded RNA, and often involve WSSV envelope proteins like VP28 because of their importance to the infection process.…”

The Enhanced Immune Protection in Small Abalone Haliotis diversicolor Against a Secondary Infection With Vibrio harveyi

“…Invertebrates include a wide variety of species, accounting for more than 95% of the animal kingdom ( 14 ). Invertebrate immunology has attracted more and more attention, and with the further study of invertebrate immune priming, some mechanisms have been identified.…”

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“…No medicines yet to prove effective against WSSV; hence, finding ways to combat this shrimp pathogen now become to be indispensable. Oral vaccination with two structural proteins: VP19 and VP466, were unsuccessful in term of reducing mortality and envelope protein VP28 experimentally elicited the immune response by only some degrees (Ha et al, 2008;Syed Musthaq & Kwang, 2015). Another study with recombinant VP292 protein vaccine also showed unsatisfactory results in-vivo (mortality >50%) (Zhu, Du, Miao, Quan, & Xu, 2009).…”