Self-Dissociating Albumin Nanoclusters for Passive Lymph Node-Targeted Inverse Vaccination in a Rheumatoid Arthritis Model

Engineering lymph node-targeted tolerogenic nanomaterials requires simultaneous antigen–drug coloading and efficient lymphatic transport. However, conventional biocompatible nanoparticles with static architectures often face a size-dependent trade-off: larger particles enable cargo coloading but drain inefficiently to lymph nodes, whereas smaller particles favor lymphatic transport but have limited cargo versatility. Here, a size-transformable, self-dissociating albumin nanocluster inverse vaccine is introduced to address this materials design trade-off. Citrullinated peptide antigens are conjugated to human serum albumin, and rapamycin (RAPA) is coloaded using ball-milling technology to generate 200–300 nm nanoclusters. After subcutaneous injection, the nanoclusters dissociate into sub-10 nm albumin-based units, enabling passive lymphatic transport and accumulation in draining lymph nodes while maintaining coordinated antigen–RAPA codelivery. In vitro mechanistic studies show that the nanoclusters induce a tolerogenic dendritic cell phenotype and promote antigen-specific immune regulation. In a collagen-induced arthritis mouse model, weekly administration attenuates synovial inflammation, humoral autoimmune responses, bone erosion, and cartilage degradation while expanding Foxp3+ regulatory T cells. These findings establish self-dissociation-mediated size transformation as a functional materials strategy for lymph node-targeted antigen-specific immune tolerance and tolerogenic nanomedicine.