Replication kinetics of HIV-1 variants in PBMC. PBMC were isolated using buffy coats from healthy blood donors and stimulated for three days using PHA and IL-2. Subsequently, cells from three individual donors were mixed, and virus harvested from cell culture media of HEK 293 T cells transfected with the respective proviral plasmids was added in triplicates (0.1 ng p24 / 3 × 105cells). Samples of cell culture media were collected at the indicated time points and virus production was measured by p24 ELISA. Results from one infection experiment using six independent virus preparations are shown; data represent mean values and SD. (A) Replication kinetics of HIV-1NL4-3uncwt, FL, FL-N40S, and NL4-3 late(-). (B) Replication kinetics of HIV-1NL4-3uncwt, S40N, and S40F.