Engineering an in vivo charging station for CAR-redirected invariant natural killer T cells to enhance cancer therapy.

Invariant natural killer T (iNKT) cells are a distinct subset of T lymphocytes that possess unique properties making them highly suitable for addressing the challenges of solid tumor immunotherapy. Unlike conventional T cells, which are restricted by polymorphic major histocompatibility complex (MHC) molecules and recognize peptide antigens, iNKT cells are restricted by the non-polymorphic CD1d molecule and respond to lipid antigens. Chimeric antigen receptor (CAR)-redirected iNKT (CAR-iNKT) cells represent a significant advancement in cancer immunotherapy. However, optimizing sustained activation and long-term persistence of CAR-iNKT cells remains a critical need for effective solid tumor treatment. To address these limitations, we develop the iNKT cell-targeted microparticle recruitment and activation system (iMRAS), a biomimetic platform designed to enhance iNKT cell functionality through localized immunostimulation in vivo. This biomimetic platform is designed to function as an in vivo "charging station" containing chemotactic and activation signals for the recruitment, activation, and expansion of CAR-iNKT cells, leading to more effective tumor killing and longer persistence of CAR-iNKT cells, as demonstrated in the therapy of lymphoma and melanoma. Through its biomimetic design and localized immunostimulatory effects, iMRAS helps overcome the limitations of current therapies for solid tumors, establishing a robust platform for enhancing systemic CAR-iNKT cell-mediated immunotherapy.