CD5 CAR T cells eliminate malignant T cells in vitro. (A) Cytotoxicity of CD19 CAR- and CD5 CAR-transduced T cells against T-ALL and T-lymphoma cell lines was assessed in a 5-hour Cr release assay. CD19⁺CD5⁻ Raji cells (bottom right panel) were used as a negative control for CD5 CAR and positive control for CD19 CAR T cells. (B) Panel i: production of IFN-γ and TNF-α by CD4⁺ (top) and CD8⁺ (bottom) T cells transduced with CD19 CAR or CD5 CAR was measured by intracellular cytokine staining. Panel ii: bar graphs show mean ± SD from 3 donors. (C) Long-term coculture of CAR T cells with GFP⁺ target cell lines Jurkat, CCRF, and MOLT4 at an initial E:T ratio 1:4. Numbers in dot plots denote percentage of target GFP⁺ cells at indicated time points. (D) Sequential killing of GFP⁺ Jurkat cells by CD5 CAR T cells. Graph indicates number of target Jurkat cells per well at the beginning and the end of each cycle of cell killing. Data from 3 individual donors are shown.