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

Summary: Abstract Body: Ebola virus (EBOV) transmission occurs through direct contact with an infected individual or their body fluids. In late infection, EBOV virions and RNA are found on the skin’s surface. However, the permissive skin cell types and the route of virus egress remain undefined. We report a human skin explant model that robustly supports EBOV infection. Virus inoculated into the medium below explants maintained at the air-liquid interface led to time- and dose-dependent increase in viral load in the dermis and epidermis. EBOV antigen-positive cells included dermal myeloid, endothelial, and fibroblast cells and epidermal keratinocytes. Infectious virus spread temporally from the dermis to the epidermis and was detected on the apical epidermal surface by 3 days post-inoculation (pi). These observations were recapitulated using a BSL2 model virus, rVSV/EBOV GP. Focal viral staining was seen in epidermal keratinocytes and infectious virus was detected on the skin surface by day 8 pi. Additionally, several well-established EBOV inhibitors effectively blocked rVSV/EBOV GP infection of the explants. Finally, purified populations of human fibroblasts and keratinocytes were permissive for both EBOV and rVSV/EBOV GP, and viral entry was mediated by the phosphatidylserine receptor AXL and the endosomal receptor NPC-1, which mediate viral entry in other cell types. Using our infection model, we have demonstrated a route of EBOV transmission through the skin, identified the responsible cell subsets, and shown its utility for antiviral testing. This work is significant because it shows that infectious virus can traverse the skin to the epidermal surface, potentially contributing to person-to-person transmission. Kelly N. Messingham¹, Paige Richards³, Anthony Fleck¹, Radhika A. Patel³, Marija Djurkovic², Jonah Elliff³, Samuel J. Connell¹, Tyler P. Crowe¹, Juan M. Gonzalez³, Francoise Gourronc³, Jacob A. Dillard³, Robert A. Davey⁴, Aloysius Klingelhutz³, Olena Shtanko², Wendy Maury³ 1. Dermatology, University of Iowa Health Care, Iowa City, IA, United States. 2. Texas Biomedical Research Institute, San Antonio, TX, United States. 3. Microbiology and Immunology, University of Iowa, IOWA CITY, IA, United States. 4. NEIDL, Boston University, Boston, MA, United States. Innate Immunity, Microbiology, and Microbiome