FIG 4.

Block of HIV-1 release in human cells with ectopic expression of chBST-2. (A) Human 293T cells (2 × 10⁴ per well) were seeded on 96-well plates. After 24 h, the cells were transfected using 0.3 μl X-tremeGENE reagent with 100 ng of psPAX2 HIV-1 gag-pol vector and various doses (5 ng, 15 ng, or 50 ng) of pIRES-hBST2, pIRES-chBST2, or pIRES plasmids. Two days later, samples of cell culture media were collected and analyzed for RT activity by the PERT assay. Addition of up to 50 ng of control plasmid DNA (in place of BST-2 constructs) in transfection did not influence the PERT results (data not shown). The means and standard deviations from six independent replicates are shown, and statistical significance (Welch’s t test) is indicated above the graphs. (B) Human 293T cells (6 × 10⁵) were seeded on 6-well plates and, after 24 h, transfected with 2 μg of psPAX2 HIV-1 gag-pol vector and 0.8 μg of pIRES-chBST2 plasmid or with the psPAX2 vector only. Two days later, the cells were processed for transmission electron microscopy as described in Materials and Methods.