Direct modulation of myelin-autoreactive CD4 and CD8 T cells in EAE mice by a tolerogenic nanoparticle co-carrying myelin peptide-loaded major histocompatibility complexes, CD47 and multiple regulatory molecules.

Purpose: Numerous nanomaterials have been reported in the treatment of multiple sclerosis or experimental autoimmune encephalomyelitis (EAE). But most of these nanoscale therapeutics deliver myelin antigens together with toxins or cytokines and underlay the cellular uptake and induction of tolerogenic antigen-presenting cells by which they indirectly induce T cell tolerance. This study focuses on the on-target and direct modulation of myelin-autoreactive T cells and combined use of multiple regulatory molecules by generating a tolerogenic nanoparticle.

Materials And Methods: Poly(lactic-co-glycolic acid) nanoparticles (PLGA-NPs) were fabricated by co-coupling MOG/H-2D-Ig dimer, MOG/I-A multimer, anti-Fas, PD-L1-Fc and CD47-Fc and encapsulating transforming growth factor-β1. The resulting 217 nm tolerogenic nanoparticles (tNPs) were administered intravenously into MOG peptide-induced EAE mice, which was followed by the investigation of therapeutic outcomes and the in vivo mechanism.

Results: Four infusions of the tNPs durably ameliorated EAE with a marked reduction of clinical score, neuroinflammation and demyelination. They were distributed in secondary lymphoid tissues, various organs and brain after intravenous injection, with retention over 36 h, and made contacts with CD4 and CD8 T cells. Two injections of the tNPs markedly decreased the MOG-reactive Th1 and Th17 cells and MOG-reactive Tc1 and Tc17 cells, increased regulatory T cells, inhibited T cell proliferation and elevated T cell apoptosis in spleen. Transforming growth factor-β1 and interleukin-10 were upregulated in the homogenates of central nervous system and supernatant of spleen cells.

Conclusion: Our data suggest a novel therapeutic nanoparticle to directly modulate autoreactive T cells by surface presentation of multiple ligands and paracrine release of cytokine in the antigen-specific combination immunotherapy for T cell-mediated autoimmune diseases.