To determine whether the CD8+ T cell-mediated suppressive activity is affecting pre- or post-entry viral replication, we next used two separate models of single cycle of infection in our dual color CD4/CD8 assay: (i) by blocking the production of mature viral particles from the replication-competent NL4-3_eGFP virus with the protease inhibitor Darunavir; and (ii) by infecting CD4+ T cells with a replication-incompetent, Envelope (Env)-defective NL4-3_eGFP complemented in trans with a dual-tropic Env. This evidence concerns the gene CD4 and infection.