A synthetic HIV-1 subtype C backbone generates comparable PR and RT resistance profiles to a subtype B backbone in a recombinant virus assay

PLoS One. 2011;6(5):e19643. doi: 10.1371/journal.pone.0019643. Epub 2011 May 24.

Abstract

In order to determine phenotypic protease and reverse transcriptase inhibitor-associated resistance in HIV subtype C virus, we have synthetically constructed an HIV-1 subtype C (HIV-1-C) viral backbone for use in a recombinant virus assay. The in silico designed viral genome was divided into 4 fragments, which were chemically synthesized and joined together by conventional subcloning. Subsequently, gag-protease-reverse-transcriptase (GPRT) fragments from 8 HIV-1 subtype C-infected patient samples were RT-PCR-amplified and cloned into the HIV-1-C backbone (deleted for GPRT) using In-Fusion reagents. Recombinant viruses (1 to 5 per patient sample) were produced in MT4-eGFP cells where cyto-pathogenic effect (CPE), p24 and Viral Load (VL) were monitored. The resulting HIV-1-C recombinant virus stocks (RVS) were added to MT4-eGFP cells in the presence of serial dilutions of antiretroviral drugs (PI, NNRTI, NRTI) to determine the fold-change in IC50 compared to the IC50 of wild-type HIV-1 virus. Additionally, viral RNA was extracted from the HIV-1-C RVS and the amplified GPRT products were used to generate recombinant virus in a subtype B backbone. Phenotypic resistance profiles in a subtype B and subtype C backbone were compared. The following observations were made: i) functional, infectious HIV-1 subtype C viruses were generated, confirmed by VL and p24 measurements; ii) their rate of infection was slower than viruses generated in the subtype B backbone; iii) they did not produce clear CPE in MT4 cells; and iv) drug resistance profiles generated in both backbones were very similar, including re-sensitizing effects like M184V on AZT.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Drug Resistance, Viral / genetics*
  • Genotype
  • HIV Reverse Transcriptase / genetics
  • HIV-1 / drug effects
  • HIV-1 / genetics*
  • HIV-1 / metabolism
  • Mutation
  • RNA, Viral / genetics
  • Reverse Transcriptase Inhibitors / therapeutic use
  • Reverse Transcriptase Polymerase Chain Reaction

Substances

  • RNA, Viral
  • Reverse Transcriptase Inhibitors
  • HIV Reverse Transcriptase