FIG. 5.

Comparison of replication capacity and endogenous RT activity among pM1ex, pNL43 and pNL101 viruses. (A) Jurkat cells (6 × 10⁵ cells) were infected with equivalent amounts (10 ng of p24 content) of viruses. The production of progeny virus was monitored by measuring de novo RT activity in the culture supernatant. (B) HeLa–LTR–β-Gal cells were infected with equivalent amounts (3 ng of p24 content) of viruses. After 48 h, cells were fixed and stained as described in Materials and Methods. The number of blue-stained cells was scored, and the results are expressed as the average ± the standard deviation. Three independent infections were performed for each viral preparation. (C) pM1ex, pNL43, and pNL101 virions were isolated from culture supernatants of transfected Cos-7 cells. Endogenous RT reactions were carried out using pelleted viruses containing 250 ng of p24, as described in Materials and Methods.