title: Efficacy and durability of a recombinant subunit West Nile vaccine candidate in protecting hamsters from West Nile encephalitis.
abstract: The efficacy of a new recombinant subunit West Nile virus (WNV) vaccine candidate was determined in a hamster model of meningoencephalitis. Groups of hamsters were immunized subcutaneously with a WNV recombinant envelope protein (80E) with or without WNV non-structural protein 1 (NS1) mixed with adjuvant or adjuvant alone. At 2 weeks, 6 months, and 12 months after two immunizations at 4 week intervals with the respective immunogens, groups of animals were challenged via the intraperitoneal route with a virulent strain of WNV. The two recombinant antigen preparations gave similar results; hamsters in both groups had a strong antibody response following immunization, and none of the animals became ill or developed detectable viremia after challenge with WNV at 2 weeks or 6 months post-booster vaccination. In contrast, mortality among the control animals at 2 weeks post-booster challenge was 73%, and at 6 months post-booster, the mortality was 53% among the control animals. When challenged 12 months after the booster vaccination, a low level viremia was detected in some of the vaccinated hamsters, and one hamster became sick, but recovered. In contrast, all of the control animals that received adjuvant only developed a viremia, and the mortality rate was 77%. These results with the recombinant subunit WNV vaccine are very encouraging and warrant further animal studies to evaluate its potential use to protect humans against WNV disease.
authors.affiliation: University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77551, USA.
authors.forename: Douglas M
authors.initials: DM
authors.lastname: Watts
authors.forename: Robert B
authors.initials: RB
authors.lastname: Tesh
authors.forename: Marina
authors.initials: M
authors.lastname: Siirin
authors.forename: Amelia Travassos da
authors.initials: AT
authors.lastname: Rosa
authors.forename: Patrick C
authors.initials: PC
authors.lastname: Newman
authors.forename: David E
authors.initials: DE
authors.lastname: Clements
authors.forename: Steven
authors.initials: S
authors.lastname: Ogata
authors.forename: Beth-Ann
authors.initials: BA
authors.lastname: Coller
authors.forename: Carolyn
authors.initials: C
authors.lastname: Weeks-Levy
authors.forename: Michael M
authors.initials: MM
authors.lastname: Lieberman
mesh_terms: D000818:Animals; D006224:Cricetinae; D005260:Female; D022223:Vaccines, Subunit / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology / Q000494:pharmacology; D014765:Viral Vaccines / Q000235:genetics / Q000276:immunology / Q000494:pharmacology*; D014901:West Nile Fever / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D014902:West Nile virus / Q000235:genetics / Q000276:immunology*
chemical_list: D022223:Vaccines, Subunit; D014614:Vaccines, Synthetic; D014765:Viral Vaccines