Superior In Vivo Efficacy for T Cell Engineering via Citronellol-Tailored mRNA-tLNPs

Area of Science:

• Biotechnology
• Immunotherapy
• Nanomedicine

Background:

• Efficient in vivo generation of Chimeric Antigen Receptor (CAR) T cells using messenger RNA-Lipid Nanoparticle (mRNA-LNP) delivery requires highly effective T cell engineering.
• Current mRNA-LNP systems often show suboptimal T cell transfection, even with high lymphoid tropism, indicating tropism alone is insufficient.

Purpose of the Study:

• To identify novel lipid nanoparticles (LNPs) that enhance both lymphoid tropism and intrinsic T cell transfection potency for improved in vivo CAR T cell engineering.
• To establish intrinsic transfection potency as a key tunable parameter for next-generation CAR T cell platforms.

Main Methods:

• Screening of a tail-varied ionizable lipid library to identify potent LNPs.
• Development and testing of a CD3-targeted H3T4 LNP (αH3T4) for in vivo T cell engineering efficacy.
• Evaluation of αH3T4-generated CAR T cells in murine CD19 solid tumor models.

Main Results:

• Identification of H3T4, a citronellol-tailed LNP, demonstrating enhanced lymphoid tropism and superior intrinsic potency.
• The CD3-targeted αH3T4 LNP achieved approximately 85% in vivo efficacy in T cell engineering, significantly outperforming benchmark LNPs (~50% improvement).
• αH3T4-generated CAR T cells demonstrated 83% tumor clearance in murine CD19 solid tumor models, showcasing potency-driven therapeutic efficacy.

Conclusions:

• Effective in vivo T cell engineering necessitates a balance between LNP potency and lymphoid tropism, not solely maximizing tropism.
• Intrinsic transfection potency is a critical and tunable parameter for developing advanced CAR T cell platforms.
• The novel αH3T4 LNP represents a promising tool for next-generation immunotherapy, enabling efficient CAR T cell generation and potent anti-tumor activity.