Post-translational covalent assembly of CAR and synNotch receptors for programmable antigen targeting

Chimeric antigen receptors (CARs) and synthetic Notch (synNotch) receptors are engineered cell-surface receptors that sense a target antigen and respond by activating T cell receptor signaling or a customized gene program, respectively. Here, to expand the targeting capabilities of these receptors, we develop universal receptor systems for which receptor specificity can be directed post-translationally via covalent attachment of a co-administered antibody bearing a benzylguanine (BG) motif. A SNAPtag self-labeling enzyme is genetically fused to the receptor and reacts with BG-conjugated antibodies for covalent assembly, programming antigen recognition. We demonstrate that activation of SNAP-CAR and SNAP-synNotch receptors can be successfully targeted by clinically relevant BG-conjugated antibodies, including anti-tumor activity of SNAP-CAR T cells in vivo in a human tumor xenograft mouse model. Finally, we develop a mathematical model to better define the parameters affecting universal receptor signaling. SNAP receptors provide a powerful strategy to post-translationally reprogram the targeting specificity of engineered cells. Chimeric antigen receptors (CARs) and synthetic Notch (synNotch) receptors are promising platforms for cell-based immunotherapies. Here, the authors develop highly programmable versions of these receptors that can be universally targeted to antigens of interest through covalent enzyme chemistry.

Automated summary

This study introduces engineered cell-surface receptors called chimeric antigen receptors (CARs) and synthetic Notch (synNotch) receptors, which can sense target antigens and respond accordingly. The authors develop universal receptor systems that can be post-translationally directed to specific antigens through covalent attachment of BG-conjugated antibodies. They demonstrate successful targeting of SNAP-CAR and SNAP-synNotch receptors using clinically relevant BG-conjugated antibodies, showing anti-tumor activity in a human tumor xenograft mouse model. A mathematical model is also developed to better understand the parameters affecting universal receptor signaling.