Tolerogenic Nanovaccine Synergizing Citrullinated Peptide and TSP‐1 Plasmid for Antigen‐Specific Immunotherapy of Rheumatoid Arthritis

ABSTRACT Rheumatoid arthritis (RA) is a chronic autoimmune disorder driven by systemic inflammation and progressive joint damage. While antigen‐specific immune tolerance holds promise as a therapeutic strategy, its clinical translation is hampered by the rapid clearance and unintended immunogenicity associated with conventional antigen delivery. To address these limitations, we developed a tolerogenic nanovaccine (CMLT) that co delivers a multi epitope citrullinated peptide (CitC) and an immunosuppressive thrombospondin‐1 (TSP‐1) plasmid via a lipid nanoparticle (LNP) platform. By rationally tuning LNP components, we achieved efficient plasmid encapsulation and stable conjugation of CitC, resulting in homogeneous nanoparticles with favorable stability. In a collagen induced arthritis (CIA) mouse model, prophylactic administration of CMLT potently suppressed disease development, significantly mitigating clinical symptoms, reducing histopathological joint damage, and preserving bone architecture. Mechanistically, CMLT fostered an immunosuppressive microenvironment marked by elevated expression of TGF‐β1 and TSP‐1, expansion of antigen specific regulatory T cells (Tregs), and suppression of autoreactive antibodies and pro inflammatory cytokines. Therapeutic intervention during active arthritis similarly alleviated inflammation and attenuated joint pathology. This synergistic nanovaccine platform provides a targeted and effective approach for re establishing immune homeostasis in RA.