CD5 CAR T cells produce limited fratricide and spare VSTs. (A) Autologous GFP⁺ T cells were mixed with T cells transduced with Ctrl CAR, truncated CD5 CAR (ΔCD5 CAR, without intracellular signaling domains), or full length CD5 CAR at 1:2 E:T ratio and cocultured for 7 days. Numbers in dot plots denote cell counts of gated GFP⁺ autologous T cells per well at indicated time points (left). Graph (right) summarizes data from 4 donors ± SD. (B) Phenotype of activated T cells 10 days after transduction with Ctrl CAR or CD5 CAR. Naïve T cells (T_NAIVE, CD45RA⁺ CCR7⁺), central memory (T_CM, CD45RA⁻ CCR7⁺), effector and effector-memory (T_EFF/T_EM, CD45RA⁻ CCR7⁻), and T_EMRA (CD45RA⁺ CCR7⁻) subsets are shown on representative dot plots with gating strategy (left) and as mean data from 3 donors (right). (C) Phenotype of autologous GFP⁺ T cells after coculture with Ctrl CAR- or CD5 CAR-transduced T cells for 24 hours. Data shown as mean average from 3 donors. (D) Autologous GFP⁺ T cells were cocultured with Ctrl CAR T or CD5 CAR T cells for 72 hours and purified by cell sorting. Frequency of T cells specific for cytomegalovirus, Epstein-Barr virus, and adenovirus among sorted cells was measured by IFN-γ ELISPOT.