Development of an in situ CAR-T cell protocol through optical and PSMA-targeted PET imaging

Area of Science:

• Immunotherapy
• Nanotechnology
• Medical Imaging

Background:

• Conventional chimeric antigen receptor (CAR)-T therapy is complex and costly.
• In situ CAR-T cell generation requires advanced imaging for monitoring due to the lack of ex vivo quality control.

Purpose of the Study:

• To develop and validate an in situ T cell engineering method for cancer therapy.
• To enable tracking and functional assessment of in situ-generated CAR-T cells using positron emission tomography (PET).

Main Methods:

• Utilized anti-CD5-conjugated lipid nanoparticles to deliver CD19 CAR mRNA (mCAR19) and a prostate-specific membrane antigen mRNA (mPSMA) tag for in situ T cell engineering.
• Employed interleukin-7 (IL-7) preconditioning and repeated administration of nanoparticles.
• Tracked engineered T cells using PET imaging with ⁶⁸Ga-PSMA-617.

Main Results:

• Achieved tumor-free survival in 75% of B cell lymphoma-bearing mice, comparable to ex vivo CAR-T therapy.
• Validated the generation and tumor infiltration of in situ-engineered, PSMA-tagged CD19 CAR-T cells via PET imaging.

Conclusions:

• The developed in situ CAR-T cell generation and tracking approach offers a promising alternative to conventional ex vivo methods.
• This technique allows for effective monitoring of CAR-T cell therapy in vivo, addressing a key challenge in current approaches.