title: Natural resistance of human immunodeficiency virus type 2 to zidovudine.
abstract: Zidovudine (AZT) is a reverse transcriptase (RT) inhibitor widely used to treat persons infected with HIV-1 and HIV-2. Recent data on treated patients suggest differences in the antiviral activity of AZT between HIV-1 and HIV-2. We evaluated the antiviral activity of AZT on HIV-2 by using multiple approaches including in vitro selection experiments, analysis of growth kinetics with AZT, and phenotypic testing. A total of 5 wild-type (WT) HIV-2 viruses were used in the analysis. For comparison, 4 control WT HIV-1 strains and one HIV-1 mutant carrying the 215S mutation were evaluated in parallel. All 5 HIV-1 isolates acquired AZT resistance mutations after 3-6 passages with AZT or a 4- to 32-fold increase in AZT concentration. Among these viruses, the fastest selection of resistance was seen in HIV-1(S215), which acquired S215Y (1-nucleotide change only) at passage 3 after only 17 days in culture. In contrast, none of the 5 HIV-2 viruses that naturally have S215 acquired S215Y/F or any other RT mutation during 10 passages with AZT (1025-fold increase in AZT concentration). In the presence of AZT + didanosine (ddI), 3 of the 5 HIV-1 isolates acquired AZT or ddI resistance mutations, while only ddI resistance mutations were seen in HIV-2 (4 of 5 isolates). All HIV-2 viruses replicated efficiently in high AZT concentrations and were about 200-fold less sensitive to AZT than HIV-1. In contrast, HIV-2 and HIV-1 were equally susceptible to ddI, a finding consistent with the selection of HIV-2 mutants with AZT + ddI. Our results demonstrate that the activity of AZT on HIV-2 is lower than previously thought, and emphasize the need for novel antiretroviral drugs specific for HIV-2.
authors.affiliation: Laboratory Branch, Division of HIV/AIDS Prevention, National Center for HIV, STD, and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA 30329, USA.
authors.forename: Patrick
authors.initials: P
authors.lastname: Reid
authors.forename: Hamish
authors.initials: H
authors.lastname: MacInnes
authors.forename: Mian-Er
authors.initials: ME
authors.lastname: Cong
authors.forename: Walid
authors.initials: W
authors.lastname: Heneine
authors.forename: J Gerardo
authors.initials: JG
authors.lastname: García-Lerma
mesh_terms: D000595:Amino Acid Sequence; D019380:Anti-HIV Agents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D024882:Drug Resistance, Viral; D015498:HIV-2 / Q000187:drug effects* / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D012194:RNA-Directed DNA Polymerase / Q000235:genetics; D016415:Sequence Alignment; D015215:Zidovudine / Q000494:pharmacology*
chemical_list: D019380:Anti-HIV Agents; D015215:Zidovudine; D012194:RNA-Directed DNA Polymerase