HeLa mutants are resistant to infection. (A) Resistance to infection is independent of the reporter. Clones 30-2 and 42-7 were infected (moi ~ 0.5) with HIV-1 viral vector transducing the gene for secreated alkaline phosphatase (SEAP). The amount of SEAP released by infected cells was measured 72 hours latter and is expressed as the Vmax of SEAP activity. (B) Resistance to infection is not due to a defect in reporter gene expression. HeLa, Parental (Round 6 mutagenesis), 30-2 and 42-7 cell lines were transfected with an HIV vector plasmid where EGFP expression is dictated by the human EF1α promoter and with the MLV viral vector where EGFP expression is controlled by the CMV promoter. Although the cells differ in their transfection efficiencies they show comparable levels of GFP expression. The x-geo mean intensity of EGFP expression is indicated above each bar. (C) Resistance to infection is independent of receptor use and HIV-1 accessory proteins. Parental, 30-2 and 42-7 were infected with a fully accessorized HIV-1 viral vector psuedotyped with a 10A1 envelope, which uses a pH independent pathway of entry. The line graph depicts that x-geo mean intensity of each sample.