title: The predominance of Human Immunodeficiency Virus type 1 (HIV-1) circulating recombinant form 02 (CRF02_AG) in West Central Africa may be related to its replicative fitness.
abstract: BACKGROUND
  CRF02_AG is the predominant HIV strain circulating in West and West Central Africa. The aim of this study was to test whether this predominance is associated with a higher in vitro replicative fitness relative to parental subtype A and G viruses. Primary HIV-1 isolates (10 CRF02_AG, 5 subtype A and 5 subtype G) were obtained from a well-described Cameroonian cohort. Growth competition experiments were carried out at equal multiplicity of infection in activated T cells and monocyte-derived dendritic cells (MO-DC) in parallel.
  
  
  RESULTS
  Dual infection/competition experiments in activated T cells clearly indicated that CRF02_AG isolates had a significant replication advantage over the subtype A and subtype G viruses. The higher fitness of CRF02_AG was evident for isolates from patients with CD4+ T cell counts >200 cells/microL (non-AIDS) or CD4+ T cell counts <200 cells/microL (AIDS), and was independent of the co-receptor tropism. In MO-DC cultures, CRF02_AG isolates showed a slightly but not significantly higher replication advantage compared to subtype A or G isolates.
  
  
  CONCLUSIONS
  We observed a higher ex vivo replicative fitness of CRF02_AG isolates compared to subtype A and G viruses from the same geographic region and showed that this was independent of the co-receptor tropism and irrespective of high or low CD4+ T cell count. This advantage in replicative fitness may contribute to the dominant spread of CRF02_AG over A and G subtypes in West and West Central Africa.
authors.affiliation: HIV and Retrovirology Research Unit, Department of Microbiology, Institute of Tropical Medicine, 155 Nationalestraat, B-2000 Antwerp, Belgium. hnjai@mrc.gm
authors.forename: Harr F
authors.initials: HF
authors.lastname: Njai
authors.forename: Youssef
authors.initials: Y
authors.lastname: Gali
authors.forename: Guido
authors.initials: G
authors.lastname: Vanham
authors.forename: Claude
authors.initials: C
authors.lastname: Clybergh
authors.forename: Wim
authors.initials: W
authors.lastname: Jennes
authors.forename: Nicole
authors.initials: N
authors.lastname: Vidal
authors.forename: Christelle
authors.initials: C
authors.lastname: Butel
authors.forename: Eitel
authors.initials: E
authors.lastname: Mpoudi-Ngolle
authors.forename: Martine
authors.initials: M
authors.lastname: Peeters
authors.forename: Kevin K
authors.initials: KK
authors.lastname: Ariën
mesh_terms: D015496:CD4-Positive T-Lymphocytes / Q000821:virology; D002163:Cameroon / Q000453:epidemiology; D002478:Cells, Cultured; D015331:Cohort Studies; D003713:Dendritic Cells / Q000821:virology; D015658:HIV Infections / Q000453:epidemiology / Q000821:virology*; D015497:HIV-1 / Q000145:classification* / Q000302:isolation & purification / Q000502:physiology; D006801:Humans; D010802:Phylogeny; D017423:Sequence Analysis, RNA; D014779:Virus Replication