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M Van Houtte

Publications and source records attributed to M Van Houtte.

4 recordsLinked to original sources
PubMed2000

Phenotypic and genotypic analysis of clinical HIV-1 isolates reveals extensive protease inhibitor cross-resistance: a survey of over 6000 samples.

OBJECTIVE: To evaluate in HIV-1 the extent of phenotypic and genotypic antiretroviral drug resistance and cross-resistance towards the protease inhibitors (PIs) saquinavir, ritonavir, indinavir and nelfinavir among a set of patient samples originating from European and US routine clinical practice and submitted for phenotypic drug resistance testing and/or genotypic analysis. The mutational pattern(s) underlying both resistance and cross-resistance to PIs was investigated. METHOD: Over 6000 patient isolates with plasma viral load greater than 1000 copies/ml plasma were analysed. Phenotypic resistance was evaluated by a recombinant virus assay. Phenotypic resistance is expressed as the fold-increase of the 50% inhibitory concentration (IC50) value of a compound for a patient-derived recombinant virus isolate compared with that for a wild-type laboratory virus. Genotypic analysis is reported as amino acid changes at positions in the HIV-1 protease compared to a wild-type reference. RESULTS: Phenotypic resistance to any single PI was observed in 17 to 25% of the clinical isolates investigated. Phenotypic cross-resistance among PIs (> 10-fold increase in IC50 value) was detected in 59 to 80% of the samples resistant (> 10-fold increase in IC50 value) to at least one PI. The prevalent mutations in PI-resistant isolates involved substitutions at codons 10, 36, 46, 54, 71, 77, 82 and 90. The most frequent mutational pattern in samples with PI cross-resistance involved combined substitutions at positions 10 and 90, extended with substitutions at positions 54, 71, 77, 82 or 84. CONCLUSIONS: Extensive use of first-generation PIs leads to the emergence of HIV-1 isolates possessing cross-resistance to all members of this class. Identification of particular mutational profiles among these isolates may assist in the design of new generation inhibitors with specific activity against protease-mutant HIV strains.

Amino Acid Substitution↗
PubMed1998

A rapid method for simultaneous detection of phenotypic resistance to inhibitors of protease and reverse transcriptase in recombinant human immunodeficiency virus type 1 isolates from patients treated with antiretroviral drugs.

Combination therapy with protease (PR) and reverse transcriptase (RT) inhibitors can efficiently suppress human immunodeficiency virus (HIV) replication, but the emergence of drug-resistant variants correlates strongly with therapeutic failure. Here we describe a new method for high-throughput analysis of clinical samples that permits the simultaneous detection of HIV type 1 (HIV-1) phenotypic resistance to both RT and PR inhibitors by means of recombinant virus assay technology. HIV-1 RNA is extracted from plasma samples, and a 2.2-kb fragment containing the entire HIV-1 PR- and RT-coding sequence is amplified by nested reverse transcription-PCR. The pool of PR-RT-coding sequences is then cotransfected into CD4+ T lymphocytes (MT4) with the pGEMT3deltaPRT plasmid from which most of the PR (codons 10 to 99) and RT (codons 1 to 482) sequences are deleted. Homologous recombination leads to the generation of chimeric viruses containing PR- and RT-coding sequences derived from HIV-1 RNA in plasma. The susceptibilities of the chimeric viruses to all currently available RT and/or PR inhibitors is determined by an MT4 cell-3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide-based cell viability assay in an automated system that allows high sample throughput. The profile of resistance to all RT and PR inhibitors is displayed graphically in a single PR-RT-Antivirogram. This assay system facilitates the rapid large-scale phenotypic resistance determinations for all RT and PR inhibitors in one standardized assay.

Acquired Immunodeficiency Syndrome↗