Gliadin Nanoparticles Induce Immune Tolerance to Gliadin in Mouse Models of Celiac Disease.

BACKGROUND & AIMS Celiac disease could be treated, and potentially cured, by restoring T-cell tolerance to gliadin. We investigated the safety and efficacy of negatively charged, 500 nm, poly(lactide-co-glycolide) nanoparticles encapsulating gliadin protein (TIMP-GLIA) in 3 mouse models of celiac disease. Uptake of these nanoparticles by antigen-presenting cells was shown to induce immune tolerance in other animal models of autoimmune disease. METHODS We performed studies with C57BL/6, RAG1-/- (C57BL/6), and HLA-DQ8, huCD4 transgenic Ab0 NOD mice. Mice were given 1 or 2 tail-vein injections of TIMP-GLIA or control nanoparticles. Some mice were given intradermal injections of gliadin in complete Freund's adjuvant (immunization), or of soluble gliadin or ovalbumin (ear challenge). RAG-/- mice were given intraperitoneal injections of CD4+CD62L-CD44hi T cells from gliadin-immunized C57BL/6 mice, and were fed with AIN-76A-based diet containing wheat gluten (oral challenge), or without gluten. Spleen or lymph node cells were analyzed in proliferation and cytokine secretion assays, or by flow cytometry, RNA sequencing or real-time quantitative PCR. Serum samples were analyzed by gliadin antibody ELISA, and intestinal tissues were analyzed by histology. Human PBMC, or immature dendritic cells derived from human PBMC, were cultured in medium containing TIMP-GLIA, anti-CD3 antibody, or LPS (controls) and analyzed in proliferation and cytokine secretion assays or by flow cytometry. Whole blood or plasma from healthy volunteers was incubated with TIMP-GLIA, and hemolysis, platelet activation and aggregation, and complement activation or coagulation were analyzed. RESULTS TIMP-GLIA did not increase markers of maturation on cultured human dendritic cells or induce activation of T cells from patients with active or treated celiac disease. In the delayed-type hypersensitivity (model 1), the HLA-DQ8 transgenic (model 2), and the gliadin memory T cell enteropathy (model 3) models of celiac disease, intravenous injections of TIMP-GLIA significantly decreased gliadin-specific T cell proliferation (in models 1 and 2), inflammatory cytokine secretion (in models 1, 2, and 3), circulating gliadin-specific IgG/IgG2c (in models 1 and 2), ear swelling (in model 1), gluten-dependent enteropathy (in model 3), and body weight loss (in model 3). In model 1, the effects were shown to be dose dependent. Splenocytes from HLA-DQ8 transgenic mice given TIMP-GLIA nanoparticles, but not control nanoparticles, had increased levels of FOXP3, and gene expression signatures associated with tolerance induction. CONCLUSIONS In mice with gliadin sensitivity, injection of TIMP-GLIA nanoparticles induced unresponsiveness to gliadin, and reduced markers of inflammation and enteropathy. This strategy might be developed for treatment of celiac disease.