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Characterization of a human immunodeficiency virus type 1 variant with reduced sensitivity to an aminodiol protease
A K Patick1, R Rose, J Greytok
1Department of Virology, Bristol-Myers Squibb Pharmaceutical Research Institute, Wallingford, Connecticut 06492.
Abstract:
Development of viral resistance to the aminodiol human immunodeficiency virus (HIV) protease inhibitor BMS 186,318 was studied by serial passage of HIV type 1 RF in MT-2 cells in the presence of increasing concentrations of compound. After 11 passages, an HIV variant that showed a 15-fold increase in 50% effective dose emerged. This HIV variant displays low-level cross-resistance to the C2 symmetric inhibitor A-77003 but remains sensitive to the protease inhibitors Ro 31-8959 and SC52151. Genetic analysis of the protease gene from a drug-resistant variant revealed an Ala-to-Thr change at amino acid residue 71 (A71T) and a Val-to-Ala change at residue 82 (V82A). To determine the effects of these mutations on protease and virus drug susceptibility, recombinant protease and proviral HIV type 1 clones containing the single mutations A71T and V82A or double mutation A71T/V82A were constructed. Subsequent drug sensitivity assays on the mutant proteases and viruses indicated that the V82A substitution was responsible for most of the resistance observed. Further genotypic analysis of the protease genes from earlier passages of virus indicated that the A71T mutation emerged prior to the V82A change. Finally, the level of resistance did not increase following continued passage in increasing concentrations of drug, and the resistant virus retained its drug susceptibility phenotype 34 days after drug withdrawal.
Insights
Viral resistance to human immunodeficiency virus (HIV) protease inhibitor BMS 186,318 developed through serial passage. The V82A mutation was the primary driver of this resistance, with A71T emerging earlier.
Area of Science:
- Virology
- Drug Resistance Studies
- Molecular Biology
Background:
- Human immunodeficiency virus (HIV) protease inhibitors are crucial for antiretroviral therapy.
- Viral resistance can emerge during treatment, necessitating the development of new therapeutic strategies.
- Understanding the genetic basis of resistance is key to designing effective drugs.
Purpose of the Study:
- To investigate the development of viral resistance to the aminodiol HIV protease inhibitor BMS 186,318.
- To identify the genetic mutations responsible for drug resistance.
- To assess the cross-resistance profile of the resistant HIV variant.
Main Methods:
- Serial passage of HIV type 1 RF in MT-2 cells with increasing concentrations of BMS 186,318.
- Genetic analysis of the HIV protease gene from drug-resistant variants.
- Construction of recombinant HIV protease and proviral clones with specific mutations (A71T, V82A).
- Drug sensitivity assays on mutant proteases and viruses.
Main Results:
- An HIV variant with a 15-fold increase in the 50% effective dose of BMS 186,318 emerged after 11 passages.
- The resistant variant showed low-level cross-resistance to A-77003 but remained sensitive to Ro 31-8959 and SC52151.
- The V82A substitution in the protease gene was identified as the primary cause of resistance.
- The A71T mutation was observed to emerge prior to the V82A mutation.
- Resistance levels did not increase with further passage, and the resistant phenotype was stable after drug withdrawal.
Conclusions:
- The V82A substitution is a major contributor to BMS 186,318 resistance in HIV.
- The emergence of specific mutations in the HIV protease gene drives drug resistance.
- Understanding resistance mechanisms is vital for the continued development of effective HIV therapies.