Inhibition of SIV replication in CD4⁺ T 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 (♦), which does not recognize SIV. Transduced CD34⁺ cells were then cultured on thymic stroma to support T-cell differentiation, expanded, selected in G418, and then infected with SIVmac239 at an MOI of 0.01 TCID₅₀ (A), 0.1 TCID₅₀ (B), or 1 TCID₅₀ /cell (C).