Fig. 1. Schematic comparing the structure of T cell receptors (TCRs) and chimeric antigen receptors (CARs).
The TCR complex is composed of TCR-α and -β chains that are assembled together with invariant CD3 molecules. In contrast, a CAR is a modular protein that comprises an extracellular domain (ligand binding region), a hinge region, and an intracellular domain (signaling components). TCR: T cell receptor; CD3: cluster of differentiation 3; scFv: single-chain variable fragment.