FIG. 2.
Viral protein production from recombinant proviral clones. (A) p19 Gag expression in transiently transfected 293T cells. 293T cells (2× 105) were transfected with 2 μg of proviral DNA by using Lipofectamine PLUS reagent. At 72 h posttransfection, p19 Gag expression in the culture medium was measured by ELISA. The values, which represent p19 Gag levels for three independent experiments, are normalized for transfection efficiency. Error bars indicate standard deviations. (B) 729 stable transfectants containing wtHTLV-1, wtHTLV-2, HTLV-2/LTR1, HTLV-1/LTR2, HTLV-1/Env2, or HTLV-2/Env1 were isolated as described in Materials and Methods. A representative of each cell clone used in syncytium and transformation assays is shown. Culture supernatants were harvested after 48 h of growth and tested for p19 Gag production by ELISA. In general, p19 Gag production from these stable producer cell lines showed a level similar to that from transiently transfected 293T cells.