Development of a DNA Aptamer-Based Approach to Noninvasively Image CAR-T Cells In Vivo and Traceless Enrichment In...

Area of Science:

• Biotechnology
• Immunotherapy
• Molecular Biology

Background:

• Chimeric antigen receptor (CAR) T-cell therapy shows promise for malignancies but requires better methods for monitoring in vivo distribution and tumor homing.
• Understanding CAR T-cell dynamics is critical for assessing treatment success, predicting failure, and identifying off-target toxicities.

Purpose of the Study:

• To develop a novel aptamer (A3) for sensitive and specific in vivo imaging and enrichment of CAR T-cells.
• To evaluate the utility of aptamer A3 in tracking CAR T-cells within a tumor model.

Main Methods:

• Systematic evolution of ligands by exponential enrichment (Cell-SELEX) was used to generate aptamer A3, which binds CAR T-cells with nanomolar affinity.
• Fluorescence imaging using Cy5-labeled A3 was performed in a Nalm6 xenograft tumor model after intravenous CAR T-cell injection.
• A3's ability to enrich CAR T-cells from mixed cell populations was assessed.

Main Results:

• Aptamer A3 demonstrated high affinity binding to CAR T-cells.
• Fluorescence signals from Cy5-labeled A3 accumulated in tumor areas, peaking at day 14 post-injection.
• A3 successfully enriched CAR T-cells from mixed cell populations without leaving a trace.

Conclusions:

• Aptamer A3 provides a sensitive, specific, and repeatable method for in vivo assessment of CAR T-cells.
• This aptamer has significant potential for tracking CAR T-cells in clinical settings, informing treatment efficacy, and managing toxicities.