Positive selection of gene-modified CD4⁺ T cells following SHIV challenge. (A) The percentage of gene-modified CD4⁺ T cells in peripheral blood was determined by FACS analysis based on GFP expression in the control (squares and diamonds) and mC46 macaques (circles and triangles). (B) The absolute number of CD4⁺CD3⁺ (circles and triangles) and total CD4⁺CD3⁺ GFP⁺ T cells (squares and diamonds) was determined by FACS analysis for control and mC46 macaque set 1. The area between the respective lines of each macaque represents nonmodified CD4⁺ T cells. As indicated, 70% of CD4⁺ T cells at day 140 post-SHIV challenge are nonmodified. (C-D) FACS plots demonstrating the relative percentage of total CD4⁺CD3⁺ T cells and CD4⁺CD3⁺GFP⁺ T cells in mixed cell populations isolated from (C) duodenal biopsies and (D) LN biopsies before and 6 months after SHIV challenge. See supplemental Figure 2 for additional analysis at days 7 and 21 following SHIV challenge and averages of both sets of macaques.