title: Sexually-transmitted/founder HIV-1 cannot be directly predicted from plasma or PBMC-derived viral quasispecies in the transmitting partner.
abstract: OBJECTIVE
  Characterization of HIV-1 sequences in newly infected individuals is important for elucidating the mechanisms of viral sexual transmission. We report the identification of transmitted/founder viruses in eight pairs of HIV-1 sexually-infected patients enrolled at the time of primary infection ("recipients") and their transmitting partners ("donors").
  
  
  METHODS
  Using a single genome-amplification approach, we compared quasispecies in donors and recipients on the basis of 316 and 376 C2V5 env sequences amplified from plasma viral RNA and PBMC-associated DNA, respectively.
  
  
  RESULTS
  Both DNA and RNA sequences indicated very homogeneous viral populations in all recipients, suggesting transmission of a single variant, even in cases of recent sexually transmitted infections (STIs) in donors (n = 2) or recipients (n = 3). In all pairs, the transmitted/founder virus was derived from an infrequent variant population within the blood of the donor. The donor variant sequences most closely related to the recipient sequences were found in plasma samples in 3/8 cases and/or in PBMC samples in 6/8 cases. Although donors were exclusively (n = 4) or predominantly (n = 4) infected by CCR5-tropic (R5) strains, two recipients were infected with highly homogeneous CXCR4/dual-mixed-tropic (X4/DM) viral populations, identified in both DNA and RNA. The proportion of X4/DM quasispecies in donors was higher in cases of X4/DM than R5 HIV transmission (16.7-22.0% versus 0-2.6%), suggesting that X4/DM transmission may be associated with a threshold population of X4/DM circulating quasispecies in donors.
  
  
  CONCLUSIONS
  These suggest that a severe genetic bottleneck occurs during subtype B HIV-1 heterosexual and homosexual transmission. Sexually-transmitted/founder virus cannot be directly predicted by analysis of the donor's quasispecies in plasma and/or PBMC. Additional studies are required to fully understand the traits that confer the capacity to transmit and establish infection, and determine the role of concomitant STIs in mitigating the genetic bottleneck in mucosal HIV transmission.
authors.affiliation: Equipe d'accueil 3620, Université Paris-Descartes, Sorbonne Paris Cité, Paris, France. pierre.frange@nck.aphp.fr
authors.forename: Pierre
authors.initials: P
authors.lastname: Frange
authors.forename: Laurence
authors.initials: L
authors.lastname: Meyer
authors.forename: Matthieu
authors.initials: M
authors.lastname: Jung
authors.forename: Cecile
authors.initials: C
authors.lastname: Goujard
authors.forename: David
authors.initials: D
authors.lastname: Zucman
authors.forename: Sylvie
authors.initials: S
authors.lastname: Abel
authors.forename: Patrick
authors.initials: P
authors.lastname: Hochedez
authors.forename: Marine
authors.initials: M
authors.lastname: Gousset
authors.forename: Olivier
authors.initials: O
authors.lastname: Gascuel
authors.forename: Christine
authors.initials: C
authors.lastname: Rouzioux
authors.forename: Marie-Laure
authors.initials: ML
authors.lastname: Chaix
mesh_terms: D000328:Adult; D019143:Evolution, Molecular; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D015699:HIV Envelope Protein gp120 / Q000235:genetics; D015658:HIV Infections / Q000635:transmission* / Q000821:virology*; D015497:HIV-1 / Q000145:classification / Q000502:physiology*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000821:virology*; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D012367:RNA, Viral / Q000235:genetics; D012747:Sexual Partners; D019562:Viral Load; D056189:Viral Tropism; D055815:Young Adult
chemical_list: D015699:HIV Envelope Protein gp120; D012367:RNA, Viral