Interferons Inhibit Ebola Virus Infection of Human Keratinocytes

Orthoebolavirus zairense is the species name for Zaire Ebola virus (EBOV) within Filoviridae. This group of viruses can cause severe disease in humans, characterized by hemorrhagic shock, coagulation abnormalities, and severe inflammation. While tissue macrophages are critical targets early during EBOV infection, other cell types support viral replication as disease progresses. At late stages of infection, infectious EBOV is found on the surface of the skin, which may be a critical source of infectious virus transmitted between individuals during outbreaks. Human skin contains a number of cellular targets of EBOV, including keratinocytes. Here, we demonstrate EBOV infection of telomerase-immortalized normal human skin keratinocytes (NHSK-1), as well as EBOVΔVP30 infection of NHSK-1 cells that were stably complemented with EBOV transcription factor VP30. Infection with EBOVΔVP30 did not elicit detectable endogenous interferon responses; however, exogenous pre-treatment of NHSK-1 cells with type I, II, and III interferon (IFN) inhibited EBOVΔVP30 infection and infection of an additional low-containment model of EBOV, rVSV/EBOV GP, in a dose-dependent manner. Analysis of the transcriptome of IFN-treated keratinocytes identified multiple genes unique to each IFN and a subset of ISGs upregulated by all three IFNs. Our results indicate that ISGs induced by IFN pre-treatment of keratinocytes can reduce infection, underlining that ISGs may serve as EBOV-targeting therapeutics.