FIG 2.

Gag 126del and 127del mutations occurring with T122A and G123E confer resistance to the protease inhibitor lopinavir in the absence of any major protease mutations. (A) Sequences of the viral clones showing the amino acid changes (in red) introduced using standard site-directed mutagenesis techniques. (B and C) Full-length Gag-protease with the indicated mutations was amplified from plasma samples and cloned into p8.9NSX+. VSV-G-pseudotyped viruses encoding luciferase were produced by cotransfection in 293T cells. PI susceptibility of pseudovirions derived from each patient was measured by luciferase activity, as determined using a single-replication-cycle drug susceptibility assay. Data are fold differences in IC₅₀s of LPV in comparison to that for the assay reference strain, p8.9NSX. Error bars represent standard errors of the means from at least three independent experiments performed in duplicate.