title: A new strategy based on recombinant viruses for assessing the replication capacity of HIV-1.
abstract: OBJECTIVE
  In heavily pretreated patients, resistance mutations arise in both protease (PR) and reverse transcriptase (RT) sequences; however, the relative impact of PR and RT mutations on viral fitness cannot be evaluated with the majority of systems. To address this issue we have developed a model based on recombinant viruses (RVs) that allows the analysis of the replication capacity (RC) of viral populations in which PR and RT are cloned either in combination or separately.
  
  
  METHODS
  RVs were generated for full-length polymerase (pol) gene, PR or RT sequences from nine naïve and 14 heavily pretreated HIV-infected patients in therapeutic failure. The relative RC was assessed by comparing luciferase activity between mutant RV and wild-type (wt) isolates.
  
  
  RESULTS
  A strong decrease (>60%) in the RC of the pol RV population was observed in the 14 heavily pretreated patients as compared with the wt RVs. The analysis of PR and RT RVs from these patients showed that the decrease in RC was mainly attributable to PR sequences in three of these 14 patients and to RT sequences in seven of these patients. In the four remaining patients, PR and RT sequences independently reduced the RC of the RVs to similar extents.
  
  
  CONCLUSIONS
  Different patterns of mutations in either PR or RT have a strong impact on RC in highly experienced HIV-infected patients.
authors.affiliation: AIDS Immunopathology Unit, National Centre of Microbiology, Instituto de Salud Carlos III, Madrid, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Garcia-Perez
authors.forename: M
authors.initials: M
authors.lastname: Perez-Olmeda
authors.forename: S
authors.initials: S
authors.lastname: Sanchez-Palomino
authors.forename: P
authors.initials: P
authors.lastname: Perez-Romero
authors.forename: J
authors.initials: J
authors.lastname: Alcami
mesh_terms: D023241:Antiretroviral Therapy, Highly Active; D024921:Drug Resistance, Multiple, Viral; D017930:Genes, Reporter; D005822:Genetic Vectors; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy / Q000235:genetics; D054303:HIV Reverse Transcriptase / Q000235:genetics; D015497:HIV-1 / Q000235:genetics / Q000502:physiology*; D006801:Humans; D049410:Luciferases, Renilla; D009154:Mutation / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D017211:Treatment Failure; D014779:Virus Replication / Q000502:physiology*
chemical_list: D049410:Luciferases, Renilla; D054303:HIV Reverse Transcriptase