Comprehensive Engineering of Ionizable Lipid Nanoparticles and mRNA Elements for Next-Generation Vaccines - PubMed
6 days ago
- #ionizable lipids
- #lipid nanoparticles
- #mRNA vaccines
- Messenger RNA (mRNA) vaccines in lipid nanoparticles (LNPs) are effective but immunity can wane and reactogenicity increases with dose.
- A 96-member biodegradable ionizable lipid library was screened, with stereodefined H9T6 emerging as the lead ionizable lipid.
- An optimized LNP composition (H9T6:DOPG:cholesterol:PEG at 40:16:43.5:0.5 mol %) achieved 3.5-fold higher dendritic-cell transfection than SM-102 and improved endosomal escape.
- Pooled screens of synthetic, barcoded randomized libraries ranked over 630,000 3' UTR variants and 68,000 5' UTR sequences for optimal mRNA performance.
- The 5B-8 UTR scaffold outperformed benchmark UTRs from authorized mRNA vaccines in antigen expression both in vitro and in vivo.
- H9T6 LNPs enhanced lymph node delivery, supported by an albumin-mediated transport mechanism.
- In mice, the formulation elicited strong Th1-biased humoral and cellular responses at low-microgram doses.
- Antibody magnitude depended primarily on UTR architecture, while T-cell responses reflected contributions from both the lipid and the UTR.
- Repeat-dose studies in rats up to 100 μg showed only transient, reversible findings without additional safety signals.
- The study outlines a framework for low-dose, lymph node-targeted mRNA vaccines combining rational lipid design with mechanism-informed UTR selection.