FIG. 3.

Infection of PBL by R5X4 HIV-1 primary isolates. (A) PBL were treated for 1 h with or without the CXCR4 antagonist T22 (2.5 uM), then infected with primary R5X4 strains 93BR020, 92HT594, and 96USHIPS9, X4 prototype NL43, and R5 prototype Bal. Following overnight incubation the cells were washed and refed with or without T22, and supernatant p24 antigen was determined at day 7 postinfection. (B) PBL were incubated for 1 h with T22 (2.5 uM), M657 (1 uM), both in combination, or CD4-blocking MAb 19 (5 μg/ml) prior to infection. Quantitative real-time PCR amplification was carried out on cellular DNA 2 days later by using primer and probe sets specific for the HIV-1 LTR and cellular GAPDH gene. Data are representative of three experiments with cells from different donors.