Expression of polyhedrin-hEGF fusion protein in cultured cells and larvae of Bombyx mori

For mass production of human epidermal growth factor (hEGF), silkworm baculovirus expression vector system (BEVS) was adopted in this study. hEGF gene was in-frame fused with polyhedrin (Ph) gene under the control of Ph promoter and was used to co-transfect BmN cell with the modified Bombyx mori baculovirus DNA to obtained recombinant virus. The ELISA showed a maximum expression on day 4 in larvae and pupae. Both cellular extracts and haemolymph of silkworm larvae infected with rBacPh-EGF could all support the proliferation of Balb/c 3T3 cell. The corresponding materials from BmN cell and silkworm larvae infected with wild virus also indicated a weak effect of upregulation on 3T3 cells proliferation. The animal study showed that both pupae infected with rBacPhEGF virus and wild virus protected the gastric mucosa against ethanol-induced damage in rats, although the protection from pupae infected with wild virus was slightly weak. The mechanism is under investigating.