Rabies virus nucleoprotein expressed in silkworm pupae at high-levels and evaluation of immune responses in mice

Rabies is one of the most fatal zoonotic diseases in developing countries, where a safe, cheap and effective vaccine against the disease remains unaffordable. In this paper, we describe a new silkworm-baculovirus expression system to express the nucleoprotein (N) gene of rabies virus and evaluation of the immune response in BALB/c mice. A recombinant baculovirus -rBmNPV(RV-N) carrying the N gene of rabies virus Evelyn Rokitniki Abelseth (ERA) strain was constructed and the N protein expression was evaluated in Bombyx mori (BmN) cells and silkworm pupae by immunofluorescence staining, Western blots and enzyme-linked immunosorbent assay (ELISA). The immune response to vaccines was evaluated based on serum IgG antibody titers and challenge experiments. The study revealed that N protein of rabies virus can be highly expressed in silkworm baculovirus expression system and the vaccine of N antigen presents a promising approach for the prevention of rabies virus.

► The rabies virus nucleoprotein was expressed in silkworm pupae. ► The yield of purified protein up to 50 mg from 1 L of crude pupae extracts. ► Mice were vaccinated with purified nucleoprotein can induce specific antibodies. ► The survival rates of mice immunized with N antigen showed 90% protection.