Chim3-LV confers survival advantage to transduced CEM A3.01 cells under HIV-1 selective pressure. (A) Chim3-transduced CEM A3.01 cells are enriched over mock-transduced cells after HIV-1 infection. Chim3-transduced cells were mixed at a 1:1 ratio with mock-transduced cells and either infected with NL4-3 HIV-1 at an MOI of 0.01 or left uninfected. FACS staining of ΔLNGFR⁺ cells was performed after 49 days of cell cultivation. The results are representative of a sestuplicate culture for infected and of a duplicate culture for uninfected cells. Numbers in the quadrants indicate the percent of ΔLNGFR⁺ cells. (B) Percentage over time of ΔLNGFR⁺ cells in the mock–Chim3-transduced cell mixture of panel A. Results are the means ± SEM of sestuplicate and duplicate cultures for infected and uninfected cells, respectively. (C) CD4 expression. The 12:88 mock-Chim3 cell mixture of panel A was separated by an anti-ΔLNGFR Ab, and CD4 levels in either Chim3 (88% ΔLNGFR⁺ cells) or mock cells (12% ΔLNGFR⁻ cells) were analyzed by FACS. (D) Chim3-cells that survive to HIV-1 infection maintain their resistant phenotype after new viral challenge. The HIV-1–resistant mock-Chim3 (12:88) mixture of panel A was challenged with HIV-1 NL4-3 at an MOI of 0.1. The uninfected mock-Chim3 (59:41) cell mixture, along with the original starting population (mock and original of 95% or more Chim3-expressing cells) were used as control cells. Results are the means ± SEM of a duplicate (□), sestuplicate (▲), and single (■) culture, respectively.