Although it is important to note that the subcellular compartment in which HIV-1 fuses and enter cells leading to productive infection remains controversial, and may depend on the cell type used [38, 39], one likely interpretation of our results is that in THP1 cells, HIV-1 fuses predominantly at the plasma membrane, rather than in endosomal vesicles where IFITM3 and other ISGs may act. The gene discussed is IFITM3; the disease is infection.