RevM10-modified primary myeloid cells showed resistance to HIV-1 replication. (A) Transduced CD34⁺ cells were enriched by FACS sorting to greater than 90% lyt2⁺. Fifty thousand sorted cells per well were differentiated in the presence of GM-CSF and IL-3 and infected with a macrophage-tropic HIV-1 isolate (JR-FL, 2,000 TCID50/well). p24 levels in the supernatant of JR-FL–infected primary cells were assayed for 30 days. Data were from triplicate wells and standard errors are shown. (B1) As in (A), 10,000 sorted Lyt2⁺CD34⁺ cells from a different UBC donor were challenged with HIV-1 JR-FL at 2,000 TCID50/well. (B2) was the same as (B1), except that the challenge was with JR-FL at 20,000 TCID50/well. Similar data were obtained with two other donor tissues (data not shown).