Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Retrovirology art. no. 40 - NIL_1-NIL_11 2006 fdi:010035770 ENG Retrovirology 1742-4690 CC:0002395051-0001 10.1186/1742-4690-3-40 https://www.documentation.ird.fr/hor/fdi:010035770 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2025-01/010035770.pdf 3 Horizon (IRD) 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-I 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/mu L (non-AIDS) or CD4+ T cell counts < 200 cells/mu L (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. Conclusion: 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. 052