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Designer protein circuits enable safe cancer immunotherapy
Synthetic receptor proteins can enable customized and flexible control of immune cells called T lymphocytes. A defined framework for the proteins’ design now improves their potential for use in cancer immunotherapy.
A promising tool in the fight against cancer is CAR T therapy, in which immune cells called T cells are engineered to express a synthetic receptor protein, the chimeric antigen receptor (CAR), on their surface. CAR proteins recognize an extracellular target — an antigen molecule from a nearby tumour cell — and stimulate the T cell to trigger an immune cascade in response. However, the widespread application of this emerging therapy in tumours is limited by the lack of truly tumour-specific antigens, which often leads to unwanted side effects in healthy tissues. The design of synthetic-protein circuits that prevent CAR T cells from being activated outside tumours could reconcile potency with safety. Writing in Cell, Zhu et al.1 describe one such system of proteins.