Antibody titers against a viral pathogen are typically measured using an antigen binding assay, such as an enzyme-linked immunosorbent assay (ELISA), which only measures the ability of antibodies to identify a viral antigen of interest. Neutralization assays measure the presence of virus-neutralizing antibodies in a sample. Traditional neutralization assays, such as the plaque reduction neutralization test (PRNT), are often difficult to use on a large scale due to being both labor and resource intensive. Here we describe an Ebola virus fluorescence reduction neutralization assay (FRNA), which tests for neutralizing antibodies, that requires only a small volume of sample in a 96-well format and is easy to automate. The readout of the FRNA is the percentage of Ebola virus-infected cells measured with an optical reader or overall chemiluminescence that can be generated by multiple reading platforms. Using blinded human clinical samples (EVD survivors or contacts) obtained in Liberia during the 2013–2016 Ebola virus disease outbreak, we demonstrate there was a high degree of agreement between the FRNA-measured antibody titers and the Filovirus Animal Non-clinical Group (FANG) ELISA titers with the FRNA providing information on the neutralizing capabilities of the antibodies.
Bibliographical noteFunding Information:
This work was supported by US National Institute of Allergy and Infectious Diseases (NIAID) Divisions of Intramural Research and Clinical Research. This work was funded in part through Battelle Memorial Institute?s prime contract with NIAID under Contract No. HHSN272200700016I (E.N.P., M.R.H., L.B., S.Y., Y.C., J.L., J.H.K., R.S. B.). The authors acknowledge funding by the National Institutes of Allergy and Infectious Diseases; ClinicalTrials.gov number, NCT02431923. The content of this publication does not necessarily reflect the views or policies of the US Department of Health and Human Services or of the institutions and companies affiliated with the authors.
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