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

Abstract

White spot syndrome virus (WSSV) is a large dsDNA virus responsible for white spot disease in shrimp and other crustaceans. VP28 is one of the major envelope proteins of WSSV and plays a crucial role in viral infection. In an effort to develop a vaccine against WSSV, we have constructed a recombinant baculovirus with an immediate early promoter 1 which expresses VP28 at an early stage of infection in insect cells. Baculovirus expressed rVP28 was able to maintain its structural and antigenic conformity as indicated by immunofluorescence assay and western blot analysis. Interestingly, our results with confocal microscopy revealed that rVP28 was able to localize on the plasma membrane of insect cells infected with recombinant baculovirus. In addition, we demonstrated with transmission electron microscopy that baculovirus successfully acquired rVP28 from the insect cell membrane via the budding process. Using this baculovirus displaying VP28 as a vaccine against WSSV, we observed a significantly higher survival rate of 86.3% and 73.5% of WSSV-infected shrimp at 3 and 15 days post vaccination respectively. Quantitative real-time PCR also indicated that the WSSV viral load in vaccinated shrimp was significantly reduced at 7 days post challenge. Furthermore, our RT-PCR and immunohistochemistry results demonstrated that the recombinant baculovirus was able to express VP28 in vivo in shrimp tissues. This study will be of considerable significance in elucidating the morphogenesis of WSSV and will pave the way for new generation vaccines against WSSV.

Transgene expression in Penaeus monodon cells: evaluation of recombinant baculoviral vectors with shrimp specific hybrid promoters

“…Immediately early (IE) gene Ie1 of WSSV along with ie2, and ie3 were identified in infected shrimps (Liu et al 2005), wherein Ie1 gene promoter has been considered as an efficient viral promoter to construct expression vectors. Moreover, WSSV Ie1 promoter was found active and controls transcription in insect, shrimp, avian and mammalian cells Syed Musthaq et al 2009;He et al 2008;Gao et al 2007). Syed Musthaq et al (2009) constructed a recombinant baculovirus encoding VP28 envelop protein under the control of WSSV Ie1 protein and expressed this vector in shrimp tissue.…”

“…Moreover, WSSV Ie1 promoter was found active and controls transcription in insect, shrimp, avian and mammalian cells Syed Musthaq et al 2009;He et al 2008;Gao et al 2007). Syed Musthaq et al (2009) constructed a recombinant baculovirus encoding VP28 envelop protein under the control of WSSV Ie1 protein and expressed this vector in shrimp tissue. He et al (2008) suggested that recombinant baculovirus with WSSV Ie1 promoter was more active than with cytomegalovirus (CMV) promoter for displaying expression of haemagglutination activity of H5N1 virus.…”

“…Additionally, Condreay et al (1999) described the use of a recombinant baculovirus vector carrying a mammalian expression cassette comprising the CMV immediate early (CMV-IE) promoter and the gene for GFP to direct gene expression in a wide variety of mammalian cell lines as well as primary human cells derived from different tissues. Likewise, studies suggested that recombinant baculovirus vectors carrying GFP reporter gene under the control of WSSV Ie1 promoter were capable of transducing shrimp cells in vivo (Syed Musthaq et al 2009;Syed Musthaq and Kwang 2011) and in vitro (Lu et al 2005).…”

“…After a long history, in 1985, first successful in vitro gene transfer by a recombinant baculovirus was accomplished by Carbonell et al (1985) that made baculovirus a tool in gene transfer technology, especially in the over expression of cloned genes (O'Reilly et al 1992). Since then, the recombinant baculoviruses have been successfully used for gene transfer in various eukaryotic cells including those of fishes (Smith and Summers 1989;Leisy et al 2003;Wagle and Jesuthasan 2003;Wagle et al 2004), chicken and duck (Ping et al 2006;Song et al 2006), fruit fly (Oppenheimer et al 1999; Lee et al 2000), honey bees (Ando et al 2007), shrimp (Lu et al 2005;Syed Musthaq et al 2009; Syed Musthaq and Kwang 2011) rabbit (Airenne et al 2000), monkey (Tani et al 2001) and human (Hofmann et al 1995;Kost and Condreay 2002). Besides, recombinant baculovirus has been used for gene therapy (Luo et al 2011;Zhao et al 2012), and vaccine production (van Oers 2006;Treanor et al 2007;Hu et al 2008;Cox 2012).…”

Antiviral immunity and protection in penaeid shrimp

“…While the mechanisms of immune priming in invertebrates remain unknown, it is important that the distinction between this protective response and adaptive immunity is maintained [125]. A summary of the major immune priming assays is provided in Table 1 [65,[120][121][122][123][124][126][127][128][129][130][131][132][133][134][135]. A schematic representation of the WSSV virion is shown in Figure 1, which also outlines the virion location of the proteins and components used in immune priming assays [136].…”