Fig. 3.

The composition and generation of CAR-T. a Illustrates the structure and mechanism of action of a Chimeric Antigen Receptor (CAR). The CAR is composed of three main domains: the extracellular domain, which includes the antigen recognition domain (scFv) and the hinge region; the transmembrane domain that anchors the receptor in the cell membrane; and the intracellular domain responsible for signaling. The scFv is engineered to recognize specific tumor-associated antigens, such as CD19, CD20, and CD22. The hinge region allows for flexibility in the CAR’s structure, while the transmembrane domain links the extracellular recognition capabilities to the intracellular signaling pathways. The intracellular domain typically contains co-stimulatory motifs that enhance T cell activation upon antigen recognition. b The therapeutic process of CAR-. Genetically engineered CAR-T cells are infused into the patient, where they specifically recognize and bind to tumor antigens via their CARs. This interaction leads to the activation of the CAR-T cells and the release of cytotoxic molecules, such as perforin and granzyme B, which induce apoptosis in the tumor cells. c The evolution of CAR-T. It outlines the five generations of CAR-T cell development. First-generation CAR-T cells had basic signaling domains but lacked co-stimulatory signals, resulting in limited in vivo proliferation and clinical efficacy. Second-generation CAR-T cells included additional co-stimulatory domains, significantly improving their potency and persistence. Third-generation CAR-T cells further enhanced tumor lysis and cytokine secretion by incorporating dual co-stimulatory molecules. Fourth-generation CAR-T cells were designed with controllable suicide genes and pro-inflammatory cytokines for enhanced solid tumor targeting. Fifth-generation CAR-T cells, or “off-the-shelf” universal CAR-T cells, are created by CRISPR/Cas9 gene editing to generate allogeneic T cells, addressing potential GVHD issues. This figure was created with Biorender.com