Rapamycin Liposomes Targeted to Lymph Nodes Inhibit Dendritic Cell Maturation for the Treatment of Transplant Rejection

Abstract The activation of naive T cells by mature dendritic cells (DCs) presenting allograft antigens marks a pivotal stage in triggering transplant rejection. A critical intervention in this process involves the administration of rapamycin, which disrupts the mTOR signaling pathway, thereby impeding DC maturation. Nevertheless, systemic administration of rapamycin faces challenges due to its limited bioavailability, non‐specific targeting, and notable side effects. To address these limitations, LNP@rapa (liposome‐encapsulated rapamycin) is developed, administered via subcutaneous injection. This formulation selectively targets lymph nodes, inhibiting DC maturation within these nodes and mitigating transplant rejection. This study validates the in vivo efficacy of LNP@rapa, demonstrating its ability to hinder DC maturation, reduce inflammatory cytokine secretion, and significantly prolong graft survival in two distinct mouse transplantation models. This study introduces an innovative strategy targeting lymph nodes to impede DC maturation, offering a promising approach to address transplant rejection.