Interferon-alpha treatment inhibits the production of Ebola virus proteins. 200 IU/ml of IFN-alpha reduces the amount of NP, VP35 and VP40 both in the highly susceptible Vero E6 cells and in the less virus sensitive MCF7 cells. The Y axis shows the relative fluorescence intensity. The columns represent the mean fluorescence intensity per cell. Standard deviation was calculated from three independently captured random fields of immunostained cells. All the steps of IFN-alpha treatment, virus infection, fixation, immunofluorescence staining and image capturing were carried out in parallel for the two cell lines allowing the direct comparison of expression levels of the individual viral proteins between treated and non-treated as well as between Vero E6 and MCF7 cell lines. This is represented by the identical scale of the Y axis for the given proteins. Due to the unknown binding affinity of the antibodies the staining intensities for NP, VP35 and VP40 are not comparable with each other. To avoid confusion due to the presence of an expanding non-infected cell population in the MCF7 cultures we show not only the fluorescence intensity of staining per cell (columns of the upper right chart) but also the average fluorescence intensity for the entire field (lines – with a corresponding Y axis on the right).