To allow efficient and equivalent delivery of HIV-1 to THP-1 and its derivatives, vesicular stomatitis virus G glycoprotein (VSV-G) pseudotyped full-length HIV-1 and its Vif mutants were produced from 293T cells and titrated with CEM-GXR cells for determination of the multiplicity of infection (MOI) as described (23, 26) (Fig. 1C). The gene discussed is ART4; the disease is infection.