Chimeric antigen receptors: On the road to realising their full potential

Figure 3 Evolution of chimeric antigen receptors. First Gen. CARs contain a source of “signal 1” alone, exemplified by CD3ζ. This is augmented in a second generation CAR by the inclusion of one co-stimulatory module, commonly from either CD28 or 4-1BB. The inclusion of two such co-stimulatory modules defines third generation CARs. CARs: Chimeric antigen receptors; Gen.:Generation.