USE OF THE MEMBRANE GLYCOPROTEINS OF NIPAH VIRUS TO DEVELOP NEW DIAGNOSTIC TESTS

Nipah virus (NiV) and Hendra virus (HeV) are zoonotic paramyxoviruses capable of causing severe disease in humans and animals. These viruses require BSL-4 containment. Like other paramyxoviruses, the serum neutralization test (SNT) can be used to detect antibodies to the surface glycoproteins, fusion (F) and attachment (G), where SNT titers give an indication of protective immunity. However for NiV and HeV, SNT must be performed in BSL-4 containment and it takes 5-7 days to complete. We have developed alternative diagnostic tests that are rapid, and can be performed at BSL-2. These assays include a plasmid based quantitative fusion inhibition assay (QFIA) and a neutralization assay using VSV pseudotype particles containing both the F and G proteins of NiV (VSV-FG) as target antigens. The assays were tested using serum samples from outbreak investigations and more than 300 serum samples from an experimental vaccine study in swine.  In the QFIA, antibodies to G protein inhibited fusion more efficiently than antibody to the F protein, while antibody to the N protein did not inhibit fusion. Overall, the results from QFIA and VSV-FG showed a good correlation with the results of SNT. The antigenic differences between NiV and HeV that were detected by SNY were also detected with QFIA. These methods have the potential to be rapid diagnostic methods and will provide valuable tools for basic research and/or vaccine development.