Expression of domain III of the envelope protein from GP-78: a Japanese encephalitis virus.

Acute encephalitis caused by the Japanese encephalitis virus (JEV) represents a growing epidemic and is a cause for concern in Southeast Asia. JEV is transmitted to humans through the bite of the mosquito species. The virus genome comprising of an RNA strand also encodes the envelope protein (E) which surrounds the virus. The E protein aids in fusion of virus with the cellular membrane of the host cell with the help of three structurally distinct domains (DI, DII, DIII) that are connected by flexible hinge regions. Of these domains, DIII (JEV-DIII) has been reported to interact with the cellular membrane, aid viral entry and viral replication. Hence JEV-DIII has the potential to be an antigen that can provide immune protection to a JEV infection. In this study, we describe the cloning and expression of DIII of GP-78, a virulent strain of JEV prevalent in India. Our data clearly shows that JEV-DIII expressed from pVAC1 in HEK293T cells is membrane targeted. To our knowledge, this is the first demonstration of a recombinant construct that may block JEV entry into the cells and/or evoke specific antibodies against JEV. Future studies will reveal if our construct will elicit significant immune responses which will alleviate or ameliorate the pro-inflammatory responses induced by JEV.