Nanoparticles can be used to accomplish antigen-specific immune tolerance in allergic and autoimmune disease.  The available options for custom-designing tolerogenic nanoparticles (NPs) include the use of nanocarriers that introduce antigens into natural tolerogenic environments, such as the liver, where antigen presentation promotes tolerance to self or foreign antigens.  Here, we demonstrate the engineering of a biodegradable polymeric poly (lactic-co-glycolic acid) (PLGA) nanocarrier for the selective delivery of the murine allergen, ovalbumin (OVA), to the liver.  This was accomplished by developing a series of NPs in the 200-300 nm size range as well as decorating particle surfaces with ligands that targets scavenger and mannose receptors on specialized tolerogenic liver sinusoidal endothelial cells (LSECs).  LSECs represent a major antigen presenting cell (APC) type in the liver capable of generating regulatory T-cells (Tregs).  In vitro exposure of LSECs to NPOVA induced abundant TGF-β, IL-4 and IL-10 production, which was further increased by surface ligands. Further animal experiments showed that in the chosen size range, NPOVA was almost exclusively delivered to the liver, where the co-localization of fluorescent-labeled particles with LSECs could be seen to increase by surface ligand decoration. Moreover, prophylactic treatment with NP<sup>OVA</sup> in OVA-sensitized and challenged animals (aerosolized inhalation), could be seen to significantly suppress anti-OVA IgE responses, airway eosinophilia and TH2 cytokine production in the bronchoalveolar lavage fluid. The suppression of allergic airway inflammation was further enhanced by attachment of surface ligands, particularly for particles decorated with the ApoB peptide, which induced high levels of TGF-β production in the lung along with the appearance of Foxp3+ Tregs. The ApoB peptide coated NPs could also interfere in allergic airway inflammation when delivered post-sensitization.  The significance of these findings are that liver and LSEC targeting PLGA NPs could be used for therapy of allergic airway disease, in addition to using their tolerogenic effects for other disease applications.

Use of polymeric nanoparticle platform targeting the liver to induce Treg-mediated antigen-specific immune tolerance in a pulmonary allergen sensitization model

2019 Fall National Meeting

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