Evaluation of the efficacy of a recombinant subunit West Nile vaccine in Syrian golden hamsters

Marina T. Siirin, Amelia P.A. Travassos Da Rosa, Patrick Newman, Carolyn Weeks-Levy, Beth Ann Coller, Shu Yuan Xiao, Michael M. Lieberman, Douglas M. Watts

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


The efficacy of a recombinant subunit West Nile (WN) vaccine candidate was determined in a hamster model of encephalitis. Animals included young, aged, and immunocompromised animals in an effort to simulate key groups at risk of WN virus-induced disease. Groups of aged (12 month old), weanling, and adult hamsters rendered leukopenic after immunization were immunized subcutaneously with a WN virus recombinant envelope protein (WN-80E) with or without WN virus non-structural protein 1 (NS1) mixed with adjuvant or adjuvant alone. A challenge dose of wild-type WN virus was administered to produce 40-100% mortality in the control hamsters. The recombinant antigen preparations containing WN-80E with or without WN NSl gave similar results. Hamsters in both groups had a strong antibody response after immunization, and none of the aged or weanling animals became ill or developed detectable viremia after challenge with WN virus at 2 weeks after booster vaccination. However, mortality among the control animals (administered adjuvant without antigen) at 2 weeks after booster challenge was 40-60%. In hamsters rendered leukopenic after immunization, survival rates up to 80% were observed, and a low-level viremia was detected in the vaccinated and challenged hamsters. The survival rate was significantly (P < 0.05) higher in animals vaccinated with a higher dose of WN-80E than a lower dose. The addition of NSl did not significantly affect survival after challenge. In contrast, all of the control animals that received adjuvant only developed a very high level of viremia, and the mortality rate was 100%. These findings indicate that the recombinant WN vaccines induced antibody in and afforded protection to young and aged hamsters and immunosuppressed hamsters.

Original languageEnglish (US)
Pages (from-to)955-962
Number of pages8
JournalAmerican Journal of Tropical Medicine and Hygiene
Issue number6
StatePublished - Dec 2008

ASJC Scopus subject areas

  • Parasitology
  • Virology
  • Infectious Diseases


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