Nano-Zoledronate synergizing with TLR agonists potentiates adaptive immunity via improved lymphatic drainage and subcapsular sinus penetration.

In the post-pandemic era, the growing demands for vaccines in the prevention of infectious diseases and the treatment of tumors have accelerated the research and development of immune adjuvants. Recent efforts have focused on multi-component adjuvant systems that achieve immune potentiation through synergistic activation of distinct pathways. However, the role of multi-component adjuvants in the lymphatic delivery of vaccines to lymph nodes is often overlooked. Here, we developed a dual-component nano-adjuvant system with enhanced lymphatic delivery functionality. Based on the regulatory role of the mevalonate metabolism in innate immunity, we selected zoledronate (ZOL), an inhibitor of mevalonate pathway, and combined it with various canonical Toll-like receptor agonists (TLR-A) to construct a series of nano-vaccine systems containing dual adjuvant components (ZOL/TLR-A@Ag). Compared with treatment with TLR agonists alone, the addition of ZOL significantly enhanced the maturation of dendritic cells (DCs) and the secretion of pro-inflammatory cytokines. Nanoparticulated ZOL/TLR-A@Ag exhibited greater innate immune activation effects both in vitro and in vivo. More importantly, we demonstrated that nanoparticulated ZOL/TLR-A@Ag expanded lymphatic vessels and promoted lymphatic drainage. Furthermore, ZOL facilitated the penetration of ZOL/TLR-A@Ag into the deep regions of lymph nodes and amplified adaptive immune responses through dual effects on the subcapsular sinus macrophage (SSM) barrier in lymph nodes via cytotoxicity and immune activation. These effects ultimately resulted in robust antigen-specific IgG and T cell responses, as well as significant tumor suppression. Collectively, the dual-component nano-adjuvant system based on nanoparticulated zoledronate establishes a synergistic adjuvant paradigm that remodels lymphatic transport and amplifies immune responses through dual activation of metabolic and innate immune signaling pathways.