Fig 2.

In vitro selection of TPV-resistant variants using multidrug-resistant clinical HIV-1 isolates. A mixture of 11 multi-PI-resistant HIV-1 isolates (HIV_11MIX), four multidrug-resistant clinical HIV-1 isolates (HIV_B, HIV_C, HIV_G, and HIV_TM), and an infectious molecular HIV-1 clone (cHIV_NL4-3) were propagated in the presence of increasing concentrations of TPV in MT-4 cells. The selection was carried out in a cell-free manner for a total of 10 to 15 passages with drug concentrations escalating from the IC₅₀ for each virus up to 15 μM. The nucleotide sequences of proviral DNA were determined using the cell lysates of HIV-1-infected MT-4 cells at the termination of each indicated passage.