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 and
the readout is compatible with lytic and non-lytic viruses. Using blinded
human clinical samples (EVD survivors or contacts) obtained in Liberia
during the 2013–2016 Ebola virus disease outbreak, we demonstrate that
FRNA-measured antibody titers are highly correlated with those measured by
the Filovirus Animal Non-clinical Group (FANG) ELISA - the current
standard for anti-EBOV antibody measurement with the important distinction
of providing information on the neutralizing capabilities of the
antibodies. FDA-FRNA50-07MAR17_plosOperetta and chemiluminescent raw data