Efficacy and durability of a recombinant subunit West Nile vaccine candidate in protecting hamsters from West Nile encephalitis.
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.
Watts
Douglas M
DM
University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77551, USA.
Tesh
Robert B
RB
Siirin
Marina
M
Rosa
Amelia Travassos da
AT
Newman
Patrick C
PC
Clements
David E
DE
Ogata
Steven
S
Coller
Beth-Ann
BA
Weeks-Levy
Carolyn
C
Lieberman
Michael M
MM
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*
D022223:Vaccines, Subunit; D014614:Vaccines, Synthetic; D014765:Viral Vaccines