The lower susceptibility of cells from HICs is apparent during the first cycle of infection and related to blockade of HIV-1 during reverse transcription. (A) Comparison of HIV-1 BaL replication on day 7 after infection (left) and single-cycle infection with HIV-1_VSV-G, measured 48 hours after infection in terms of luciferase activity (right) in CD4⁺ T cells from a representative HIC and a HD. Suboptimal conditions were used for infection. Means ± SDs of 3 independent measurements are shown. (B) HIV replication in MDMs from a HIC and a HD on day 10 after infection with productive HIV-1 BaL (left) and 48 hours after infection with single-cycle VSV-G pseudotyped HIV-1 (right). Two additional experiments were performed with MDMs from 2 other HICs and HDs with similar results. Means ± SDs of 3 independent measurements are shown. (C) Levels of luciferase activity and integrated HIV-1 copies (Alu-LTR) in CD4⁺ T cells from HICs and HDs 48 hours after infection. Means ± SDs of experiments with cells from 7 HICs and 7 HDs are shown. (D) Number of early (R-U5) and late (U5-gag) reverse transcripts determined by qPCR 24 and 48 hours after infection of CD4⁺ T cells from one HIC () and one HD (■) with VSV-G pseudotyped HIV-1 particles. One representative example of experiments with cells from 5 HICs and 5 HDs is shown.