CD80 Antibody and MTX Co-Engineered Extracellular Vesicles Targets CD80+ Macrophages to Suppress Inflammation and Alleviate Chronic Inflammatory Diseases.

Introduction: Aberrant interaction between innate immune and adaptive immune cells can disrupt tissue homeostasis, consequently triggering chronic inflammatory diseases such as rheumatoid arthritis (RA) and periodontitis (PD). Pro-inflammatory macrophages serve as critical mediators in the early immune response, constituting a major population of CD80⁺ cells, while anti-inflammatory macrophages modulating inflammatory processes through the secretion of transforming growth factor-beta (TGF-β). This cytokine facilitates the differentiation of peripheral regulatory T cells (Tregs) and contributes to the establishment of immune tolerance. However, there are no definitive therapies to reshape the tissue homeostasis between innate immune and adaptive immune cells.

Methods: (1) anti-CD80-MTX-EVs was obtained by gradient centrifugation, which were characterized by TEM and DLS, and the associated membrane proteins were identified by Western Blot. (2) The mouse bone marrow-derived macrophages were co-cultured separately with EVs, anti-CD80-EVs, and anti-CD80-MTX-EVs in vitro, and the expression of CD80 on the macrophages surface as well as the proportion of Treg cell generation were detected. (3) EVs, anti-CD80-EVs and anti-CD80-MTX-EVs were injected into mice models of arthritis and periodontitis for treatment, the therapeutic effect was evaluated by the expressions of related cytokines, staining of HE, the proportion of CD80⁺ macrophages and the phenotypic differentiation of T cells in the tissues.

Results: We successfully constructed engineered EVs (anti-CD80-MTX-EVs) targeting inflammatory macrophages for intracellular MTX delivering, which inducing the anti-inflammatory transformation while upregulating the expression of TGF-β of macrophages. Furthermore, our findings demonstrate that anti-CD80-MTX-EVs effectively reduce CD80⁺ macrophage levels, promote Treg cell generation, and inhibit Th1 cell production in vivo.

Conclusion: In this study, the anti-CD80-MTX-Evs demonstrated significant therapeutic effects in both rheumatoid arthritis and periodontitis models through a triple mechanism: reducing CD80⁺ macrophage population, enhancing Treg cell differentiation, and suppressing Th1 cell development. Overall, this study presents an innovative strategy for resolving inflammation within chronic inflammatory diseases.