Gas Vesicle-Assisted Ultrasound Imaging for Effective Anti-Tumour CAR-T Cell Immunotherapy Efficacy in Mice Model

Introduction: Real-time tracking of Chimeric Antigen Receptor (CAR) T cell trafficking provides crucial information regarding the targeted migration, infiltration, and persistence of CAR-T cells within the tumour microenvironment (TME). This information is invaluable for the timely adjustment of auxiliary treatment strategies in clinical settings. Methods: We designed a gas vesicles (GVs)-labeled CAR-T (GVs@CAR-T) complex using nanoscale GVs with excellent ultrasound reflectivity to label CAR-T cells for post-labelling ultrasound molecular imaging. Results: GVs@CAR-T complexes achieved stable ultrasound imaging for up to five days. In vitro and vivo experiments demonstrated that GVs labelling did not affect the anti-tumour function of CAR-T cells. In a subcutaneous tumour model, ultrasound molecular imaging was used to monitor the targeted migration of systemically infused GVs@CAR-T cells, which revealed a positive correlation between specific infiltration and therapeutic efficacy. Conclusion: This study presents an efficient method for in vivo tracking of CAR-T cells and offers new insights for predicting the efficacy of CAR-T cell immunotherapy.