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 Njai, H. F. Gali, Y. Vanham, G. Clybergh, C. Jennes, W. /Vidal, Nicole /Butel, Christelle Mpoudi Ngolé, E. /Peeters, Martine Arien, K. K. 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. 2006 text https://www.documentation.ird.fr/hor/fdi:010035770 fdi:010035770 Njai H. F., Gali Y., Vanham G., Clybergh C., Jennes W., Vidal Nicole, Butel Christelle, Mpoudi Ngolé E., Peeters Martine, Arien K. K.. 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. 2006, 3, art. no. 40 - NIL_1-NIL_11 EN