Figure 1.

Chimeric antigen receptor (CAR) design: (a) conventional CARs are composed of an extracellular tumor binding domain followed by a transmembrane and intracellular signaling domains. (b) Adaptor CAR systems are composed of T cells engineered with an adaptor CAR and soluble adaptor molecules (green). Adaptor CAR T cells are per se inactive (OFF). In the presence of tumor-specific adaptor molecules, they are turned ON. (c) Upon cross-linkage via adaptor molecules, adaptor CAR T cells elicit potent anti-tumor responses that finally result in tumor lysis.