title: A plant-based cholera toxin B subunit-insulin fusion protein protects against the development of autoimmune diabetes.
abstract: Oral administration of disease-specific autoantigens can prevent or delay the onset of autoimmune disease symptoms. We have generated transgenic potato plants that synthesize human insulin, a major insulin-dependent diabetes mellitus autoantigen, at levels up to 0.05% of total soluble protein. To direct delivery of plant-synthesized insulin to the gut-associated lymphoid tissues, insulin was linked to the C-terminus of the cholera toxin B subunit (CTB). Transgenic potato tubers produced 0.1% of total soluble protein as the pentameric CTB-insulin fusion, which retained GM1-ganglioside binding affinity and native antigenicity of both CTB and insulin. Nonobese diabetic mice fed transformed potato tuber tissues containing microgram amounts of the CTB-insulin fusion protein showed a substantial reduction in pancreatic islet inflammation (insulitis), and a delay in the progression of clinical diabetes. Feeding transgenic potato tissues producing insulin or CTB protein alone did not provide a significant reduction in insulitis or diabetic symptoms. The experimental results indicate that food plants are feasible production and delivery systems for immunotolerization against this T cell-mediated autoimmune disease.
authors.affiliation: Center for Molecular Biology and Gene Therapy, Department of Microbiology and Molecular Genetics, School of Medicine, Loma Linda University, CA 92350, USA.
authors.forename: T
authors.initials: T
authors.lastname: Arakawa
authors.forename: J
authors.initials: J
authors.lastname: Yu
authors.forename: D K
authors.initials: DK
authors.lastname: Chong
authors.forename: J
authors.initials: J
authors.lastname: Hough
authors.forename: P C
authors.initials: PC
authors.lastname: Engen
authors.forename: W H
authors.initials: WH
authors.lastname: Langridge
mesh_terms: D000818:Animals; D002772:Cholera Toxin / Q000737:chemistry / Q000235:genetics*; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology / Q000517:prevention & control*; D006801:Humans; D007328:Insulin / Q000235:genetics* / Q000276:immunology; D051379:Mice; D016688:Mice, Inbred NOD; D030821:Plants, Genetically Modified; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics*; D011198:Solanum tuberosum / Q000235:genetics
chemical_list: D007328:Insulin; D011993:Recombinant Fusion Proteins; D002772:Cholera Toxin