The Partial Purification and Biological Activity of FGF-2-encapsulating Cypovirus 1 Polyhedra Formed in the Silkworm Middle Silk Gland

Abstract

　　We have previously produced a transgenic silkworm with posterior silk glands that expresses cypovirus 1 polyhedra-encapsulated cytokines, for which the activity remains stable in the individual organ and processed silk guts. In the present study, we describe a method that utilizes a specific lysis solution to isolate human-FGF-2-encapsulating polyhedra produced in the middle silk glands of fifth instar silkworm larvae. These polyhedra exhibited the biological activity of FGF-2, inducing the signaling events of MAP kinase phosphorylation in proliferating NIH-3T3 cells. This study demonstrates the potential use of polyhedra prepared from silkworm organs as effective biomaterials in tissue engineering.