Linker-directed lipid-antigen conjugates co-enhance lymph node targeting and antigen presentation for potent T cell immunity.

Abstract

The clinical efficacy of peptide-based cancer vaccines is limited by inefficient lymphatic delivery and suboptimal antigen presentation. Here, we report a rationally engineered class of lipid-antigen conjugates that co-enhance lymph node (LN) targeting and antigen-presenting cell (APC) uptake through molecular-level structural optimization. By systematically varying lipid tail composition and linker chemistry, we identify a lead construct (dOA-K-O) incorporating a dioleic acid (dOA) lipid tail and an L-lysine (K) linker, which outperforms the clinically used DSPE-PEG₂₀₀₀ conjugate (DSPE-O). Mechanistically, the positively charged L-lysine linker promotes albumin binding while reducing excessive self-assembly, enhancing lymphatic trafficking and facilitating APC internalization. In vivo, dOA-K-O elicits robust antigen cross-presentation and induces an 8-fold increase in antigen-specific CD8⁺ T cell responses compared to unmodified antigenic peptide and 3-fold higher than DSPE-O. This enhanced cellular immunity translates into marked tumor suppression in both prophylactic and therapeutic B16-OVA melanoma models. Our results establish a design paradigm in which linker chemistry and lipid tail composition are synergistically optimized to boost the immunogenicity of peptide vaccines for cancer immunotherapy, which may provide a chemical and structural basis for the optimization of peptide-based vaccine delivery systems.