Dynamic changes in HIV‐1 quasispecies from azidothymidine (AZT)‐treated patients

Abstract

The emergence of azidothymidine (AZT)-resistant human immunodeficiency virus (HIV) variants in clinical samples was studied by a direct genomic sequencing method. Sequential lymphocyte samples from four patients, who had been treated with AZT for up to 27 months, were shown to gradually accumulate multiple nucleotide changes, some of which are known to be associated with AZT resistance. Several samples were shown to contain mixtures of wild-type and mutated genomes, indicating gradual rather than sudden changes in the HIV-1 quasispecies. These results demonstrate for the first time that automated solid-phase DNA sequencing is a rapid and useful tool for investigation of antiviral drug resistance and suggest that DNA sequencing may be important in routine clinical diagnostics in the future.

Cross-Resistance between AZT, ddl and other Antiretroviral Drugs in Primary Isolates of HIV-1

“…1989; Land et al, 1990), which is accompanied by specific mutations in the reverse transcriptase gene (Larder and Kemp 1989;Larder et al, 1991;Wahlberg et al, 1992). Although the pathogenicity of AZT-resistant virus is not fully understood, these virus variants appear to revert relatively slowly if treatment is discontinued (Albert et sl., 1992).…”

Human immunodeficiency virus type 2 (HIV-2) env gene analysis: prediction of glycoprotein epitopes important for heterotypic neutralization and evidence for three genotype clusters within the HIV-2a subtype

“…Taq mutations have been reported to occur at a frequency as high as 1 in 400 bases (Saiki et al, 1988) but the probability of detecting such mutations can be reduced to 1 in 5000 bases by direct sequencing of PCR products (Innis et al, 1988). The latter approach has been used successfully to screen for azidothymidine-resistance mutations in clinical samples (Wahlberg et al, 1992). In our study, direct sequencing of PCR products encompassing the env gene was achieved for six HIV-2 isolates, four HIV-2c~ L and two HIV-2cAM, whilst the remaining four HIV-2cA M isolates (1, 2, 3, 5; Fig.…”

Characterization of HIV Reverse Transcriptases with Tyr181→Cys and Leu100→lle Mutations

“…Polymerase chain reaction (PCR) was performed with Taq DNA polymerase and reaction components from Perkin Elmer Cetus, The cloning vector bluescript KS+ and the VCS-M 13 helper phage were from Stratagene and the expression vector pET11 a from Novagene. The DNA sequencing was performed according to Wahlberg et al (1992a), with some modification since the starting material was purified plasmid DNA. The plasmid (10ng) was amplified with primers RIT134-137(Wahlberget al, 1992a)in a nested approach and immobilized to paramagnetic beads (Wahlberg et al, 1992b) (DynalAs, Oslo, Norway).…”