Dengue Virus Infection Mediated by DC-SIGN

Abstract

DC-SIGN (dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin) is a pattern recognition receptor which binds to the mannose or fucose structures present on a variety of pathogens and stimulates diverse immune responses. DC-SIGN forms nanodomains on cell surfaces which are entry portals for viruses including HIV, Ebola, dengue and hepatitis C. In particular, dengue is a mosquito-borne viral infection and has become a rapidly growing global health threat. Many reports have shown that ectopically expressed DC-SIGN enhances productive dengue infection in different human cell types; however, detailed molecular-level studies on interactions between DC-SIGN membrane assemblies and dengue virus (DENV) at the initial binding and internalization stages are lacking. By employing immunostaining, confocal imaging, super-resolution direct stochastical optical reconstruction microscopy (dSTORM) and flow cytometry assays, we show that cell surface DC-SIGN nanodomains are sufficient to capture the small sized DENV ( 50 nm), leading to efficient virus internalization and productive infection of the host cells. At the initial binding stage, DENV is highly colocalized with cell surface DC-SIGN domains. Internalization of DENV was observed within a few minutes after incubating DENV with cells expressing DC-SIGN, and massive viral particle synthesis was observed at 24h after infection. In contrast, no virus replication was observed on control cells even after 72h of incubating with DENV. The results indicate that DC-SIGN capturing of DENV leads to rapid internalization of the viruses and productive infection thereafter. Furthermore, superresolution dSTORM shows that a single DC-SIGN nanodomain is sufficient to capture single DENV particles. Supported by NIH GM 41402 and NIAID RO1-AI107731.