Densitometry values (D) of the bands were expressed as fold increase above the control (mock). (D) IKK activity was measured in cytosolic cell extracts (100 µg) using HTScan IKK Kinase Assay (Cell Signaling Technology). (E) U937 cells (5 × 107) were infected with HXB2-pseudotyped NL4-3.FLAG-Tat.R−E− virions, or left uninfected.