Figure 1

Graphic representations of the various T-cell approaches used to target leukemia antigens. (a) Conventional T-cells target peptides that are presented in the context of an MHC molecule. (b) Modified Ectopic α/β T-cells target the same epitope as a conventional TCR (MHC-peptide) but with an engineered (often higher affinity) TCR from an autologous, allogeneic, or xenogeneic cell. (c) CAR T-cells contain a synthetic polypeptide that contains the single chain variable fragment (scFv) of an antibody as the antigen-binding domain, a hinge, a transmembrane region, a costimulatory (Costim) domain, and a CD3ζ signaling domain. CARs recognize extracellular antigens that are not MHC-bound. (d) A TCR-like CAR utilizes the scFv fragment of a TCR-mimicking Ab, which recognizes a peptide antigen in the context of an MHC molecule, but with a much higher affinity than conventional or most engineered TCRs.