Immunization of mice against West Nile virus with recombinant envelope protein

West Nile (WN) virus is a mosquito-borne flavivirus that emerged in the Uni ted States in 1999 and can cause fatal encephalitis. Envelope (E) protein c DNA from a WN virus isolate recovered from Culex pipiens in Connecticut was expressed in Escherichia coli. The recombinant E protein was purified and used as Ag in immunoblot assays and immunization experiments. Patients with WN virus infection had Abs that recognized the recombinant E protein. C3H/ HeN mice immunized with E protein developed E protein Abs and were protecte d from infection with WN virus. Passive administration of E protein antiser a was also sufficient to afford immunity. E protein is a candidate vaccine to prevent WN virus infection.