Japanese encephalitis virus fusion protein with protein A expressed in Escherichia coli confers protective immunity in mice.

A complementary DNA (cDNA) that codes C-terminal, one-third of envelope glycoprotein (E) and N-terminal 65 amino acids of NS1 protein of Japanese encephalitis (JE) virus was inserted into Escherichia coli expression vector pRIT2T. The inserted gene was expressed as a fusion protein with protein A, and the expressed protein was intraperitoneally injected into mice. The immunized mice produced anti-JE antibodies measured by the hemagglutination-inhibition and neutralization tests as well as ELISA and were protected from the lethal challenge of JE virus by intraperitoneal inoculation.