title: Baboon model for West Nile virus infection and vaccine evaluation.
abstract: Animal models that closely mimic the human condition are of paramount significance to study pathogenic mechanisms, vaccine and therapy scenarios. This is particularly true for investigations that involve emerging infectious diseases. Nonhuman primate species represent an alternative to the more intensively investigated rodent animal models and in a number of instances have been shown to represent a more reliable predictor of the human response to infection. West Nile virus (WNV) has emerged as a new pathogen in the Americas. It has a 5% fatality rate, predominantly in the elderly and immune compromised. Typically, infections are cleared by neutralizing antibodies, which suggests that a vaccine would be efficacious. Previously, only macaques had been evaluated as a primate model for WNV vaccine design. The macaques did not develop WNV disease nor express the full complement of IgG subclasses that is found in humans. We therefore explored baboons, which exhibit the similar four IgG subclasses observed in humans as a new model for WNV infection and vaccine evaluation. In this present report, we describe the experimental infection of baboons with WNV and test the efficacy of an inactivated WNV vaccination strategy. All experimentally infected animals developed transient viremia and subsequent neutralizing antibodies. Anti-WNV IgM antibodies peaked at 20 days post-infection. Anti-WNV IgG antibodies appeared later and persisted past 60 days. Prior vaccination with chemically inactivated virus induced neutralizing titers and a fast, high titer IgG recall response, which resulted in lower viremia upon challenge. This report is the first to describe the development of the baboon model for WNV experimental infection and the utility of this model to characterize the immunologic response against WNV and a candidate WNV vaccine.
authors.affiliation: Department of Comparative Medicine Science, University of Oklahoma Health Sciences Center, USA.
authors.forename: Roman F
authors.initials: RF
authors.lastname: Wolf
authors.forename: James F
authors.initials: JF
authors.lastname: Papin
authors.forename: Rebecca
authors.initials: R
authors.lastname: Hines-Boykin
authors.forename: Maria
authors.initials: M
authors.lastname: Chavez-Suarez
authors.forename: Gary L
authors.initials: GL
authors.lastname: White
authors.forename: Michael
authors.initials: M
authors.lastname: Sakalian
authors.forename: Dirk P
authors.initials: DP
authors.lastname: Dittmer
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D004195:Disease Models, Animal; D005260:Female; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008297:Male; D009500:Neutralization Tests; D010215:Papio; D014765:Viral Vaccines / Q000276:immunology; D014766:Viremia; D014901:West Nile Fever / Q000276:immunology / Q000517:prevention & control*; D053060:West Nile Virus Vaccines / Q000276:immunology*; D014902:West Nile virus / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D014765:Viral Vaccines; D053060:West Nile Virus Vaccines