Development of a neutralization assay using a vesicular stomatitis virus expressing Nipah virus glycoprotein and a fluorescent protein.

Nipah virus (NiV) is a highly pathogenic paramyxovirus with a high case fatality rate. Due to its high pathogenicity, pandemic potential, and lack of therapeutics or approved vaccines, its study requires biosafety level 4 (BSL4) containment. In this report, we developed a novel neutralization assay for use in biosafety level 2 laboratories. The assay uses a recombinant vesicular stomatitis virus expressing NiV glycoprotein and a fluorescent protein. The recombinant virus propagates as a replication-competent virus in a cell line constitutively expressing NiV fusion protein, but it is restricted to a single round of replication in wild-type cells. We used this system to evaluate the neutralization activity of monoclonal and polyclonal antibodies, plasma from NiV-infected hamsters, and serum from human patients. Therefore, this recombinant virus could be used as a surrogate for using pathogenic NiV and may constitute a powerful tool to develop therapeutics in low containment laboratories.