Effects of AIP1/Alix DN mutants on HTLV-1 VLP production. A. 293T cells were cotransfected with pK30-Gag and the expression plasmid for AIP1 (1–628), AIP1 (424–628), or AIP1 WT, or the empty vector as a control. Extracellular VLPs were pelleted from the culture fluids. VLP- or cell-associated Gag was detected by WB using anti-p19 monoclonal antibody. B. Intensities of the bands corresponding to cell- and VLP-associated Gag in A were quantified using the LAS3000 imaging system (Fuji Film). The efficiency of Gag-induced VLP budding in cells cotransfected with pK30-Gag and the control vector (VLP/Cellular) was set to 1.0. The data represent averages and standard deviations (SD) of 3 independent experiments.