Genetic Code Expanded T Cell for Controllable Immunotherapy

ABSTRACT Chimeric antigen receptor (CAR)‐T cell therapy has demonstrated curative potential against hematologic malignancies, but its clinical application remains constrained by the risk of uncontrolled immune activation. To address this, we engineered a translational control system for CAR expression based on Genetic Code Expansion (GCE), enabling tight, dose‐dependent, and function‐preserving regulation through nonsense codon suppression via noncanonical amino acids (ncAAs). By introducing amber stop codons into CAR constructs and engineered aminoacyl‐tRNA synthetase and tRNA pair, we developed a leak‐free regulatory module applicable in both Jurkat and primary human T cells. NcAA‐treated GCE‐CAR‐T cells exhibited antigen‐specific cytotoxicity and cytokine secretion comparable to wild‐type CAR‐T cells. In a xenograft mouse model, tumor‐specific immune responses were observed only upon ncAA administration, with untreated controls showing no therapeutic effect. This work establishes a stringent, fast‐acting translational switch that enables precise modulation of CAR‐T cell function without compromising efficacy, offering a promising platform for next‐generation programmable cell therapies.