Figure 1.

Diagrams of CAR-T and TCR-T-cell therapy. CAR-T cell, which normally targets only cell surface proteins, has had 4 generations and the latest generation is shown here. All generations of CAR-T cell contain an scFv consisting of an antibody’s variable light (VL) and variable heavy (VH) chain, a transmembrane domain and a CD3ζ chain with ITAM for T-cell activation. The fourth-generation CAR further includes a costimulatory molecule (CM1), such as CD28 and B7, and an interleukin-12 (IL-12) domain for enhanced T-cell effects. T-cell receptor-engineered T cell has 1 TCR consisting of an α chain and a β chain, each containing a variable domain (v) and a constant domain (c), as well as an unlabeled transmembrane domain and 6 CD3 chains for T-cell activation. Class I MHC protein consists of an α chain with 3 domains α1, α2, α3, and a β2-microglobulin, presenting peptides derived from proteolysis of intracellular proteins. CAR indicates chimeric antigen receptor; ITAM, immunoreceptor tyrosine-based activation motif; MHC, major histocompatibility complex; scFv, single-chain fragment variant; TCR, T-cell receptor.