Fig. 4

Schematic representation of the evolution of the CAR structure from the first generation to the fifth. First CAR generation contains only a CD3ζ signaling domain and no co-stimulatory molecules (CMs). Second generation CAR adds one CM to CD3ζ, enabling dual signaling. Third generation CAR combines CD3ζ with multiple CMs to enhance signaling. The fourth-generation CAR, like the 2G CAR, features an NFAT-responsive cassette that triggers cytokine expression, delivering triple signaling through CD3ζ, CM, and transgenic proteins. The fifth generation of CAR, rely on 2G CAR and integrates IL-2Rβ receptors, which activates the JAK-STAT signaling domain for synergistic activation of CD3ζ, CMs, and the JAK-STAT3/5 pathway