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

Area of Science:

• Immunology
• Biochemistry
• Molecular Biology

Background:

• Cytotoxic lymphocytes (CTLs) and natural killer (NK) cells are crucial for anti-tumor immunity.
• These cells release granzyme A (GzmA) upon encountering cancer cells.
• Existing tools lack the resolution to detect active GzmA at physiological levels.

Purpose of the Study:

• To design and synthesize novel near-infrared fluorogenic substrates for human and mouse GzmA.
• To develop activity-based probes for detecting active GzmA with high spatiotemporal resolution.
• To visualize adaptive immune cell responses during cancer cell recognition in real time.

Main Methods:

• Rational design of near-infrared fluorogenic substrates.
• Synthesis of probes targeting GzmA.
• Validation using tissue lysates from wild-type and GzmA knock-out mice.
• In vivo imaging of immune cell-cancer interactions.

Main Results:

• Developed highly efficient and selective near-infrared fluorogenic probes for GzmA.
• Demonstrated probe selectivity over other granzymes.
• Successfully imaged adaptive immune cell responses to antigen-driven cancer cell recognition in real time.

Conclusions:

• The novel GzmA probes provide a powerful tool for studying anti-tumor immunity.
• These probes facilitate real-time visualization of immune cell activity against cancer.
• This technology has potential applications in cancer immunotherapy research and diagnostics.