CD1a CARTs retain the ability to control progression of CD1a⁺ cell lines and coT-ALL primary samples in a rechallenge PDX setting. (A) IVIS imaging of Jurkat cells burden in the rechallenged mice. (B) Total radiance quantification over time in the mice rechallenged with Jurkat cells. (C) Circulating Jurkat cells in PB 16 days after rechallenge. (D) Robust effector T-cell persistence in PB, BM, and spleen at euthanization of the rechallenged animals. (E) Scheme of the rechallenge PDX experiments using coT-ALL primary samples. CART-bearing PDX mice were rechallenged with 1 × 10⁶ primary CD1a⁺ T-ALL 7 weeks after initial CART infusion. (F) Secondary coT-ALL burden in engrafted PB (left panel) and BM (right panel) 6 weeks after leukemia rechallenge. (G) Effector T-cell persistence over time in PB (weeks 2, 4, and 6) from PDXs rechallenged with coT-ALL primary samples. Each dot represents an independent mouse. *P < .05, **P < .01, ****P < .0001.