The C-terminal domain of F12-Vif possesses antiviral activity. CB-derived CD4⁺ T lymphocytes transduced with empty, F12-Vif-, Chim1-, or Chim2-LV were infected in triplicate cultures with either the X4 HIV-1 NL4-3 (A) or the R5 HIV-1 AD8 (B) molecular clones at an MOI of 0.1. Supernatants of the kinetic of infection were collected every 4 days, stored at −20°C, and then assessed for RT activity.