We were able to specifically detect and quantify tetherin cell surface expression and its modulation following infection in SupT1-tetherinpos cells, SupT1-tetherinhTMα1 cells, and CEM-SS cells (Fig. 2, Figure S2); cell surface tetherin expression in SupT1-tetherinneg cells was at the limit of specificity of detection (Fig. 2A). Here, BST2 is linked to infection.