title: Selection and characterization of HIV-1 showing reduced susceptibility to the non-peptidic protease inhibitor tipranavir.
abstract: Tipranavir is a novel, non-peptidic protease inhibitor, which possesses broad antiviral activity against multiple protease inhibitor-resistant HIV-1. Resistance to this inhibitor however has not yet been well described. HIV was passaged for 9 months in culture in the presence of tipranavir to select HIV with a drug-resistant phenotype. Characterization of the selected variants revealed that the first mutations to be selected were L33F and I84V in the viral protease, mutations which together conferred less than two-fold resistance to tipranavir. At the end of the selection experiments, viruses harbouring 10 mutations in the protease (L10F, I13V, V32I, L33F, M36I, K45I, I54V, A71V, V82L, I84V) as well as a mutation in the CA/SP1 gag cleavage site were selected and showed 87-fold decreased susceptibility to tipranavir. In vitro, tipranavir-resistant viruses had a reduced replicative capacity which could not be improved by the introduction of the CA/SP1 cleavage site mutation. Tipranavir resistant viruses showed cross-resistance to other currently approved protease inhibitors with the exception of saquinavir. These results demonstrate that the tipranavir resistance phenotype is associated with complex genotypic changes in the protease. Resistance necessitates the sequential accumulation of multiple mutations.
authors.affiliation: Biological Sciences Department, Boehringer Ingelheim Ltd. Research and Development, 2100 Cunard Street, Laval, Que., Canada H7S 2G5.
authors.forename: Louise
authors.initials: L
authors.lastname: Doyon
authors.forename: Sonia
authors.initials: S
authors.lastname: Tremblay
authors.forename: Lise
authors.initials: L
authors.lastname: Bourgon
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Wardrop
authors.forename: Michael G
authors.initials: MG
authors.lastname: Cordingley
mesh_terms: D015295:Antigens, Tumor-Associated, Carbohydrate / Q000235:genetics; D024882:Drug Resistance, Viral; D015683:Gene Products, gag / Q000235:genetics; D016333:HIV Protease / Q000187:drug effects / Q000235:genetics*; D015497:HIV-1 / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics*; D006801:Humans; D007136:Immunoglobulins / Q000235:genetics; D019169:Jurkat Cells; D009154:Mutation; D011480:Protease Inhibitors / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology*; D011753:Pyrones / Q000494:pharmacology*; D012641:Selection, Genetic; D012692:Serial Passage; D013449:Sulfonamides; D014764:Viral Proteins / Q000235:genetics
chemical_list: D015295:Antigens, Tumor-Associated, Carbohydrate; D015683:Gene Products, gag; D007136:Immunoglobulins; D011480:Protease Inhibitors; D011725:Pyridines; D011753:Pyrones; C090698:SP1 antigen; D013449:Sulfonamides; D014764:Viral Proteins; D016333:HIV Protease; C107201:tipranavir