D CD69 up‐regulation on re‐stimulated THEMIS KD CD4+T cells. CD3/CD28 beads were removed on day 1 post‐transduction, and cells were cultured in IL‐2 and IL‐7. After removal of cell debris at day 4, cells were restimulated with CD3/CD28 beads at the indicated bead to cell ratio. CD69 surface expression was assessed by flow cytometry 24 h later. Data shown are representative of two independent experiments. n = 3, means ± SD are shown; two‐tailed unpaired Student's t‐test, *P 0.05, ***P 0.001. 