ABSTRACT
This chapter describes the how the silkworm expression system is carried out for recombinant protein production, especially Virus-Like Particles (VLPs), and recombinant Bombyx mori nucleopolyhedrovirus (BmNPV) particles to be used as a vaccine candidate. It introduces the production of VLPs in silkworms, dividing them into two types of VLPs, enveloped and non-enveloped VLPs. In the case of retrovirus VLPs, Gag protein forms enveloped VLPs spontaneously when the gene is solely expressed in mammalian cells and insect cells. Japanese encephalitis virus VLPs composed of prM and E proteins were secreted into the culture supernatant in High Five cells transformed with the expression vector. Most of enveloped VLPs have been produced in insect cells and insects using recombinant BmNPV. Single-capsid VLPs are composed of a single-capsid protein, but multiple- capsid VLPs are composed of several capsid proteins. The expression of single structural protein from viruses sometimes forms its VLPs.
