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.
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.
Njai
Harr F
HF
HIV and Retrovirology Research Unit, Department of Microbiology, Institute of Tropical Medicine, 155 Nationalestraat, B-2000 Antwerp, Belgium. hnjai@mrc.gm
Gali
Youssef
Y
Vanham
Guido
G
Clybergh
Claude
C
Jennes
Wim
W
Vidal
Nicole
N
Butel
Christelle
C
Mpoudi-Ngolle
Eitel
E
Peeters
Martine
M
Ariën
Kevin K
KK
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