Multiple cell types support productive infection and dynamic translocation of infectious Ebola virus to the surface of human skin

Ebola virus (EBOV) within the Filoviridae family causes severe human disease. At late stages of infection, EBOV virions are found on the surface of patients’ skin; however, the permissive cell types within the skin and how infectious virus translocates to the apical skin surfaces is not known. Here, we describe a human transwell skin explant culture model and show that EBOV infection of human skin tissues via the basal media results in a time- and dose-dependent increase in infectious virus in dermal and epidermal tissue. Infectious virus was detected on the apical epidermal surface within 3 days, indicating that the virus propagates within and traffics through the tissue. In the dermis, EBOV-infected cells were of myeloid, endothelial and fibroblast origins, whereas keratinocytes harbored virus in the epidermis. Complementary studies showed that both purified skin fibroblasts and keratinocytes supported EBOV infection ex vivo and that both cell types required the phosphatidylserine receptor, Axl, and the endosomal protein, NPC1, for virus entry. Our experimental platform identified new susceptible cell types and demonstrated dynamic trafficking of EBOV virions that resulted in infectious virus on the skin surface; findings that may explain person-to-person transmission via skin contact.