Conjugation of Transforming Growth Factor Beta to Antigen-Loaded Poly(lactide- co-glycolide) Nanoparticles Enhances Efficiency of Antigen-Specific Tolerance.

Current strategies for treating autoimmunity involve the administration of broad-acting immunosuppressive agents that impair healthy immunity. Intravenous (i.v.) administration of poly(lactide- co-glycolide) nanoparticles (NPs) containing disease-relevant antigens (Ag-NPs) have demonstrated antigen (Ag)-specific immune tolerance in models of autoimmunity. However, subcutaneous (s.c.) delivery of Ag-NPs has not been effective. This investigation tested the hypothesis that codelivery of the immunomodulatory cytokine, transforming growth factor beta 1 (TGF-β), on Ag-NPs would modulate the immune response to Ag-NPs and improve the efficiency of tolerance induction. TGF-β was coupled to the surface of Ag-NPs such that the loadings of Ag and TGF-β were independently tunable. The particles demonstrated bioactive delivery of Ag and TGF-β in vitro by reducing the inflammatory phenotype of bone marrow-derived dendritic cells and inducing regulatory T cells in a coculture system. Using an in vivo mouse model for multiple sclerosis, experimental autoimmune encephalomyelitis, TGF-β codelivery on Ag-NPs resulted in improved efficacy at lower doses by i.v. administration and significantly reduced disease severity by s.c. administration. This study demonstrates that the codelivery of immunomodulatory cytokines on Ag-NPs may enhance the efficacy of Ag-specific tolerance therapies by programming Ag presenting cells for more efficient tolerance induction.