HIV-1 sequence evolution in vivo after superinfection with three viral strains

Retrovirology. 2007 Aug 23:4:59. doi: 10.1186/1742-4690-4-59.

Abstract

With millions of people infected worldwide, the evolution of HIV-1 in vivo has been the subject of much research. Although recombinant viruses were detected early in the epidemic, evidence that HIV-1 dual infections really occurred came much later. Dual infected patients, consisting of coinfected (second infection before seroconversion) and superinfected (second infection after seroconversion) individuals, opened up a new area of HIV-1 evolution studies. Here, we describe the in-depth analysis of HIV-1 over time in a patient twice superinfected with HIV-1, first with a subtype B (B2) strain and then with CRF01_AE after initial infection with a subtype B (B1) strain. The nucleotide evolution of gag and env-V3 of the three strains followed a similar pattern: a very low substitution rate in the first 2-3 years of infection, with an increase in synonymous substitutions thereafter. Convergent evolution at the protein level was rare: only a single amino acid in a gag p24 epitope showed convergence in the subtype B strains. Reversal of CTL-epitope mutations were also rare, and did not converge. Recombinant viruses were observed between the two subtype B strains. Luciferase-assays suggested that the CRF01_AE long terminal repeat (LTR) constituted the strongest promoter, but this was not reflected in the plasma viral load. Specific real-time PCR assays based upon the env gene showed that strain B2 and CRF01_AE RNA was present in equal amounts, while levels of strain B1 were 100-fold lower. All three strains were detected in seminal plasma, suggesting that simultaneous transmission is possible.

MeSH terms

  • Amino Acid Substitution / genetics
  • Evolution, Molecular*
  • Gene Products, env / genetics
  • Gene Products, env / immunology
  • Gene Products, gag / genetics
  • Gene Products, gag / immunology
  • Genome, Viral / genetics*
  • HIV Infections / virology*
  • HIV-1 / classification
  • HIV-1 / genetics*
  • HIV-1 / isolation & purification*
  • Humans
  • Mutation, Missense
  • RNA, Viral / blood
  • Recombination, Genetic
  • Semen / virology
  • Sequence Analysis, DNA
  • T-Lymphocytes, Cytotoxic / immunology
  • Viral Load
  • Viremia / virology

Substances

  • Gene Products, env
  • Gene Products, gag
  • RNA, Viral