FIG. 6.
Sensitivity of site-directed mutants of group O CMO2.41 virus to nonnucleoside RT inhibitors. Group O CMO2.41 virus and its derivative mutants as well as the group M subtype B Yu2 were tested for sensitivity to lamivudine (3TC) as an NRTI control and four NNRTIs. U87-CD4/CCR5 cells were incubated with 10-fold dilutions of (A) lamivudin (3TC), (B) nevirapine (NVP), (C) efavirenz (EFV), (D) etravirine (ETV), and (E) delaviride (DLV) and exposed to virus for 24 h before washing. The supernatants were collected at 4, 6, and 9 days postinfection. Drug susceptibility curves (data not shown) were plotted to determine IC50s using the Probit program. The two group O clusters (C181 and Y181 backbones) are shaded. The bars in all panels are shown in different shades of red based on the number of NNRTI resistance-associated codons harbored in each. The Yu2 control is in green and does not harbor NNRTI-resistant codons. Each virus is identified by amino acid sequence at positions 181, 98, 103, and 179 but contains CMO.2.41 sequence for the remainder of the genome. Amino acids in red text represent an NNRTI-resistant codon, and black text represents an NNRTI-sensitive codon. The amino acids boxed by a green line represent the change introduced by site-directed mutagenesis.