Figure 3.

Development of Stable Envelope-Expressing Cell Lines

(A and B) HEK293T cell lines were transfected with pMD2-2A-VSVind.G, pMD2-2A-COCV.G, pMD2-2A-VSVnj.G, and pMD2-2A-PIRYV.G. VesG-expressing HEK293T cells were cultured under phleomycin selection starting at 48 hr post-transfection. Throughout a 10-week period, these stable envelope-expressing cells were analyzed for their (A) envelope expression and (B) LV production by transient transfection of gag-pol, rev, and vector expression plasmids. The data shown represent the mean titers ± SD for the titrations performed in triplicate.