title: Evidence for positive selection driving the evolution of HIV-1 env under potent antiviral therapy.
abstract: In HIV-infected individuals treated with potent antiretroviral therapy, viable virus can be isolated from latently infected cells several years into therapy, due to the long life of these cells, ongoing replication replenishing this population, or both. We have analysed the V3 region of the HIV-1 env gene isolated from six patients who have undergone 2 years of potent antiretroviral therapy without frank failure of viral suppression. We show that in two (and possibly three) patients, the sequence changes between baseline virus and virus isolated from infected cells persisting 2 years into infection result from positive selection driving adaptive evolution, occurring either prior to or during therapy. Our analyses suggest low-level replication despite absence of drug resistance due to drug sanctuary sites, or to low-level ongoing replication in the presence of alterations in the selective environment during therapy, perhaps due to a decline in HIV-specific immune responsiveness or changes in target cell pools. In one patient, genetic divergence between baseline plasma and infected cells isolated during therapy may reflect the long half-life of some of these persistent cell populations and the divergence of viral subpopulations that occurred prior to therapy.
authors.affiliation: Centre for HIV Research, University of Edinburgh, Scotland. sdfrost@ucsd.edu
authors.forename: S D
authors.initials: SD
authors.lastname: Frost
authors.forename: H F
authors.initials: HF
authors.lastname: Günthard
authors.forename: J K
authors.initials: JK
authors.lastname: Wong
authors.forename: D
authors.initials: D
authors.lastname: Havlir
authors.forename: D D
authors.initials: DD
authors.lastname: Richman
authors.forename: A J
authors.initials: AJ
authors.lastname: Leigh Brown
mesh_terms: D000595:Amino Acid Sequence; D019380:Anti-HIV Agents / Q000627:therapeutic use; D015699:HIV Envelope Protein gp120 / Q000235:genetics*; D015658:HIV Infections / Q000188:drug therapy / Q000821:virology*; D015497:HIV-1 / Q000737:chemistry / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000235:genetics*; D010802:Phylogeny; D012641:Selection, Genetic
chemical_list: D019380:Anti-HIV Agents; D015699:HIV Envelope Protein gp120; C059762:HIV envelope protein gp120 (305-321); D010446:Peptide Fragments