Deciphering endogenous CD8⁺ T cell interactions using an engineered sortase A system

Addressing the challenge of precisely capturing the transient interactions between CD8⁺ T cells and other components of the tumor microenvironment, this study successfully developed a versatile proximity labeling platform based on engineered sortase A (SrtA). This technology utilizes an αTCR-SrtA fusion protein that specifically targets the TCR on CD8⁺ T cell surface and a smart Förster resonance energy transfer (FRET) probe, enabling the high-precision recording of different interactions between CD8⁺ T cells and targets such as tumor cells or collagen molecules in vivo. Compared with conventional methods, this platform eliminates the need for genetically modified animal models, avoids the use of toxic reagents, and significantly improves detection accuracy. It thus provides a powerful tool for evaluating the efficacy of anti-tumor drugs and advancing the development of immunotherapy.