Amino acid PRO (1 to 99) and CS (449, 452, and 453) sequences of clones derived from HIV-1HXB2 passaged under high-pressure selection of GW640385. HIV-1HXB2 was passaged in the presence of GW640385 at the following concentrations: passage 2 (P2), 0.5 nM; P4, 2 nM; P5, 4 nM; P6, 5 nM; P9, 40 nM; P10, 40 nM; P11, 60 nM; P12, 80 nM; P14, 100 nM; and P15, 120 nM.