Fluorogenic Granzyme A Substrates Enable Real‐Time Imaging of Adaptive Immune Cell Activity

Cytotoxic immune cells, including T lymphocytes (CTLs) and natural killer (NK) are essential components of the host response against tumors. CTLs NK cells secrete granzyme A (GzmA) upon recognition cancer cells; however, there very few tools that can detect physiological levels active GzmA with high spatiotemporal resolution. Herein, we report rational design near-infrared fluorogenic substrates for human mouse GzmA. These activity-based probes display catalytic efficiency selectivity over other granzymes, as shown in tissue lysates from wild-type knock-out mice. Furthermore, demonstrate image how adaptive respond to antigen-driven real time.