Engineering lipid nanoparticle-stabilized emulsions for spatiotemporal mRNA delivery and enhanced T cell immunity.

Achieving strong T cell responses remains a key challenge in mRNA vaccines and therapeutics. Here, we develop a colloid-engineered, lipid nanoparticle-stabilized emulsion (LSE) to study how spatiotemporal mRNA delivery influences immune dynamics. Multi-omic analyses (single-cell RNA sequencing [scRNA-seq], flow cytometry, and enzyme-linked immunosorbent assay [ELISA]) illustrate that LSE facilitates localizing mRNA to immunocytes, increasing antigen presentation while reducing off-target antigen secretion, and non-immune cell cross-presentation, which are key factors linked to T cell exhaustion in conventional LNP-based systems. This targeted delivery induces durable interferon (IFN)-γ(+) and interleukin (IL)-2(+) T cell responses lasting up to 300 days and expands the T cell repertoire in mice compared to the AS01-adjuvanted Shingrix vaccine. Furthermore, LSE elicits potent protective and therapeutic effects against B16-OVA and LLC-NY-ESO1 inoculation in mice. These results indicate the potential of spatially controlled mRNA delivery for enhanced mRNA vaccinations.