Study of Andes virus entry and neutralization using a pseudovirion system

Andes virus (ANDV), a member of the Hantavirus genus in the family Bunyaviridae, causes an acute disease characteristic of New-World hantaviruses called hantavirus pulmonary syndrome (HPS). HPS is a highly pathogenic disease with a case-fatality rate of 40%. ANDV is the only hantavirus reported to spread directly from human-to-human. The aim of the present study was to develop a quantitative and high-throughput pseudovirion assay to study ANDV infection and neutralization in biosafety level 2 facilities (BSL-2). This pseudovirion assay is based on incorporation of ANDV glycoproteins onto replication-defective vesicular stomatitis virus (VSV) cores in which the gene for the surface G protein has been replaced by that encoding Renilla luciferase. Infection by the pseudovirions can be quantified by luciferase activity of infected cell lysates. ANDV pseudovirions were neutralized by ANDV-specific antisera, and there was good concordance between specificity and neutralization titers of ANDV hamster sera as determined by our pseudovirion assay and a commonly used plaque reduction neutralization titer (PRNT) assay. In addition, the pseudovirions were used to evaluate the requirements for ANDV entry, like pH dependency and the role of beta 3 integrin, the reported receptor for other pathogenic hantaviruses, on entry. (C) 2009 Elsevier B.V. All rights reserved.