Defining the targets of Dengue virus infection in human skin (VIR8P.1069)

Abstract

Abstract Dengue is the most important arboviral infection of humans. Dengue virus (DENV) is introduced into human skin by the bite of infected mosquitoes. While Langerhans cells (LCs) have been implicated as the main targets of DENV infection the dynamics of infection of human skin remain ill-defined. Here, we exposed skin explants from healthy human donors to DENV to determine the targets of infection. Skin explants were inoculated with DENV and analyzed by immunofluorescence after intervals of incubation using antibodies to cell-specific markers and viral protein NS3. Time course experiments showed that the first targets of DENV infection were basal keratinocytes, with infection detected within 8 h. From 12-48 h of infection abundant virus replication was detected in epidermal LCs and dermal macrophages (MØs) as well as tubular structures consistent with lymphatic endothelium. Quantitative analysis indicated that exposure to DENV resulted in significant infiltration of MØs into dermis. These preliminary data suggest that DENV initially infects basal keratinocytes which may release factors promoting the mobilization of infected LCs out of the epidermis, and the influx of MØs into the dermis, which subsequently replicate DENV to high levels. Ongoing experiments are designed to determine the mechanism for MØ recruitment. These studies are revealing that DENV infection of human skin is a dynamic process involving sequential infection and recruitment of distinct cellular targets.