HIV-2 replication in activated and in unstimulated CD4+ T cells. (a) Replication of different HIV-2 isolates in activated CD4+ T cells. Primary activated CD4+ T cells were infected with the laboratory-adapted HIV-2 strain ROD or with TOE and ROK, two HIV-2 isolated from infected patients (viral inoculum was 30 ng p27 mL−1). The HIV-1 NL strain (30 ng p24 mL−1) was used as a control. Viral replication was followed by intracellular Gag staining and quantification of Gag release in the supernatants. NI: Non infected. Results are Mean ± SEM of 6 independent donors. (b) SAMHD1 down-regulation. At day 5 post-infection (p.i.), Gag and SAMHD1 levels were analyzed by flow cytometry. One representative donor, out of 6, is shown. (c) Infection of resting, unstimulated CD4+ T cells with different HIV-2 strains. Unstimulated CD4+ T cells were exposed to HIV-2 ROD, ROK (30 ng p27 mL−1) or TOE (15 ng p27 mL−1) for 4 h. One day post-infection, cells were activated or not with PHA/IL-2. Gag and SAMHD1 levels were measured over time by flow-cytometry. Data are Mean ± SEM of 5 independent donors.