FIG. 1.
Spread of HIV-1 infection from HIV-infected PHA blasts to indicator cells. PHA blasts were infected with HIV-1 isolates: molecularly cloned laboratory strains: Ba-L (R5) and NL4-3 (X4), and clinical isolates: 208K8 (R5) and 208K10 (X4). Three days postinfection, blasts were added to uninfected indicator cells: 104 cells from cell lines or 4 × 105 PHA blasts. The number of cells from the infected culture is indicated on the horizontal axis. Infected and uninfected cells were incubated for 3 days (A and B) or 5 days (C) and then supernatant p24 was measured (optical density is shown on the vertical axis).