Infections by the Ebola virus (EBOV) rapidly cause fatal hemorrhagic fever in humans. Viral entry into host cells is the most critical step in infection and an attractive target for therapeutic intervention. Herein, the invagination behavior and entry dynamics of filamentous Ebola virus-like particles (EBO-VLPs) were investigated using a force tracing technique based on atomic force microscopy and single-particle fluorescence tracking in real time. The filamentous EBOVVLPs might enter cells in both horizontal and vertical modes, and the virus−receptor interactions during endocytic uptake were analyzed. In addition, molecular dynamics simulations and engulfment energy analysis further depicted EBO-VLP entry in the horizontal and vertical directions and suggested that internalization in the vertical direction requires a larger force and more time. This report provides useful information for further revealing the mechanism of viral infection, which is important for understanding viral pathogenesis.
Based on the findings from a single-particle force tracing test, molecular dynamics simulation, and single-particle fluorescence tracking, we proposed a possible model of fibrous EBO-VLP cell entry in parallel/vertical directions. EBO-VLPs under horizontal or vertical enter into cells via a macropinocytosis-like pathway. Subsequently, the EBO-VLPs and cellular macropinosomes are cotransported in the cytoplasm for infections. This work reveals the dynamic mechanism of EBO-VLPs infection at the singleparticle level, which is helpful for better understanding infections by the Filoviridae family.