FcRn-guided antigen trafficking enhances cancer vaccine efficacy.

The development of tumor vaccines represents a significant focus within cancer therapeutics research. Nonetheless, the efficiency of antigen presentation in tumor vaccine remains suboptimal. We introduce an innovative mRNA-lipid nanoparticle platform designed to express tumor antigenic epitopes fused with the transmembrane domain and cytoplasmic tail of the neonatal Fc receptor (FcRn). This novel design exploits FcRn trafficking signals to direct the epitope-FcRn fusion toward endolysosomal degradation, thereby generating epitopes capable of eliciting targeted T cell responses and establishing immune memory. The FcRn-directed presentation of epitopes enhances MHC class I and II antigen presentation, thereby robustly inducing CD4⁺ and CD8⁺ T cell responses, which translates to the inhibition of tumor growth and extension of survival in preclinical mouse models. In summary, the deliberate incorporation of FcRn trafficking signals into vaccine design markedly boosts T cell responses, underscoring the promise of this novel strategy in advancing the efficacy of tumor vaccines.