10.1021/acsnano.7b00275.s009 Qin Li Qin Li Wei Li Wei Li Wen Yin Wen Yin Jia Guo Jia Guo Zhi-Ping Zhang Zhi-Ping Zhang Dejun Zeng Dejun Zeng Xiaowei Zhang Xiaowei Zhang Yuntao Wu Yuntao Wu Xian-En Zhang Xian-En Zhang Zongqiang Cui Zongqiang Cui Single-Particle Tracking of Human Immunodeficiency Virus Type 1 Productive Entry into Human Primary Macrophages American Chemical Society 2017 accessory protein Vpr-conjugated QDs drug inhibition assays particles encapsulating QDs Rab 5A endosomes infection envelope-mediated endosomal fusion entry pathway virus Human Immunodeficiency Virus Type 1 Productive Entry macrophage HIV 2017-04-03 00:00:00 Media https://acs.figshare.com/articles/media/Single-Particle_Tracking_of_Human_Immunodeficiency_Virus_Type_1_Productive_Entry_into_Human_Primary_Macrophages/4823398 Macrophages are one of the major targets of human immunodeficiency virus (HIV-1), but the viral entry pathway remains poorly understood in these cells. Noninvasive virus labeling and single-virus tracking are effective tools for studying virus entry. Here, we constructed a quantum dot (QD)-encapsulated infectious HIV-1 particle to track viral entry at a single-particle level in live human primary macrophages. QDs were encapsulated in HIV-1 virions by incorporating viral accessory protein Vpr-conjugated QDs during virus assembly. With the HIV-1 particles encapsulating QDs, we monitored the early phase of viral infection in real time and observed that, during infection, HIV-1 was endocytosed in a clathrin-mediated manner; the particles were translocated into Rab5A-positive endosomes, and the core was released into the cytoplasm by viral envelope-mediated endosomal fusion. Drug inhibition assays verified that endosome fusion contributes to HIV-1 productive infection in primary macrophages. Additionally, we observed that a dynamic actin cytoskeleton is critical for HIV-1 entry and intracellular migration in primary macrophages. HIV-1 dynamics and infection could be blocked by multiple different actin inhibitors. Our study revealed a productive entry pathway in macrophages that requires both endosomal function and actin dynamics, which may assist in the development of inhibitors to block the HIV entry in macrophages.