Inhibition of SIV replication in macrophage-like cells derived from CD34⁺ cells transduced with the 9456 ribozyme. CD34⁺ cells were transduced with a retroviral vector containing either the 9456 ribozyme (•) or, as controls, the LNL6 vector (▪) or the HIV-1–specific ribozyme MJT (♦). After transduction, the macrophage-like cells were derived as described in the legend for Fig 5 and challenged with SIVmac316 using an MOI of 10⁻² TCID₅₀ /cell.