Co-opting signalling molecules enables logic-gated control of CAR T cells

Although chimeric antigen receptor (CAR) T cells have altered the treatment landscape for B cell malignancies, the risk of on-target, off-tumour toxicity has hampered their development for solid tumours because most target antigens are shared with normal cells(1,2). Researchers have attempted to apply Boolean-logic gating to CAR T cells to prevent toxicity(3-5); however, a truly safe and effective logic-gated CAR has remained elusive(6). Here we describe an approach to CAR engineering in which we replace traditional CD3 zeta domains with intracellular proximal T cell signalling molecules. We show that certain proximal signalling CARs, such as a ZAP-70 CAR, can activate T cells and eradicate tumours in vivo while bypassing upstream signalling proteins, including CD3 zeta. The primary role of ZAP-70 is to phosphorylate LAT and SLP-76, which form a scaffold for signal propagation. We exploited the cooperative role of LAT and SLP-76 to engineer logic-gated intracellular network (LINK) CAR, a rapid and reversible Boolean-logic AND-gated CAR T cell platform that outperforms other systems in both efficacy and prevention of on-target, off-tumour toxicity. LINK CAR will expand the range of molecules that can be targeted with CAR T cells, and will enable these powerful therapeutic agents to be used for solid tumours and diverse diseases such as autoimmunity(7) and fibrosis(8). In addition, this work shows that the internal signalling machinery of cells can be repurposed into surface receptors, which could open new avenues for cellular engineering.

Automated summary

Researchers have developed a new CAR T cell platform called LINK CAR, which replaces traditional CD3 zeta domains with intracellular proximal T cell signalling molecules. LINK CAR can activate T cells and eradicate tumors in vivo while bypassing certain upstream signalling proteins, showing superior efficacy and prevention of off-tumor toxicity compared to other systems. This study expands the range of molecules that can be targeted with CAR T cells, enabling their application in solid tumors, autoimmune diseases, and fibrosis, and also highlights the potential of repurposing cellular signaling machinery for cellular engineering.