The use of an Ebola virus reporter cell line in a semi-automated microtitration assay

•An Ebola reporter cell line TCID50 assay has equivalent sensitivity to standardized methods.•Parts of the new assay can be automated, which improves throughput and reduces subjectivity.•Greater liquid volume in assay wells reduces measured virus titers. A variety of methods have been developed for quantification of infectious Ebola virus in clinical or laboratory samples, but existing methods often require extensive operator involvement, manual assay scoring, or the use of custom reagents. In this study, we utilize a recently developed Ebola-specific reporter cell line that expresses ZsGreen in response to Ebola virus infection, in conjunction with semi-automated processing and quantification techniques, to develop an unbiased, high-throughput microtitration assay for quantification of infectious Ebola virus in vitro. This assay was found to have equivalent sensitivity to a standardized plaque assay for quantifying viral titers. However, the new assay could be implemented with fewer reagents and processing steps, reduced subjectivity, and higher throughput. This assay may be useful for a variety of applications, particularly studies that require the detection or quantification of infectious Ebola virus in large numbers of samples.