Table 4.

GFP transduction into HeLa cells by lentivirus vectors made by linked or split packaging constructs and a pRRL transfer constructa

Packaging constructSeparate rev plasmidbp24 antigen (ng/ml)Endpoint titer (TU/ml)Transduction efficiency (TU/ng of p24)
pCMVΔR8.743641.07 × 107 29,436
pMDLg/pRRE<0.1NDNA
pMDLg/pRRETK-Rev, 5 μg296.9 × 105 23,793
pMDLg/pRRETK-Rev, 12 μg942.02 × 106 21,489
pMDLg/pRRERSV-Rev, 2.5 μg7741.0 × 107 13,495
pMDLg/pRRERSV-Rev, 5 μg7767.6 × 106 9,761
pMDLg/pRRERSV-Rev, 12 μg5654.8 × 106 8,495
  • a Vectors carrying a PGK-eGFP expression cassette were produced by the transfection of a self-inactivating pRRL transfer construct (with a deletion in the 3′ LTR [53]), the indicated packaging and revplasmids, and plasmid pMD.G into 293T cells. Serial dilutions of transfectant conditioned medium were incubated with HeLa cells, and the cultures were scored after 6 days. For calculating endpoint titers, samples were selected from the linear portion of the vector dose-response curve. Data are averages of duplicate determination for a representative experiment of three performed. ND, none detected (the detection limit of the assay was 102 TU/ml); NA, not applicable.

  • b The promoter driving the expression of a synthetic rev cDNA and the amount of plasmid transfected are indicated.