FIG. 5.

DTT rescue of MLV-luc-HTLV1-C225AEnv vector infectivity. Unpurified vectors with wt or C225A Env in culture medium were bound to suspended 293T cells in tubes at 4°C for 1 h and then incubated at 37°C for 50 min. The medium was exchanged for TN/Ca²⁺ buffer, pH 7.4, and the cultures were incubated for an additional 15 min in the presence of 0 to 8 mM DTT. The reducing agent was then removed, the cultures were plated on dishes, and the infectivity was scored by luciferase activity after a final incubation for 48 h. Two times more C225A Env vectors were used than wt Env vectors. (A) Vectors with C225A Env. (B) Vectors with wt Env. RLU, relative light units.