A plant-based cholera toxin B subunit: insulin fusion protein protects against the development of autoimmune diabetes

• Published in: Nature biotechnology 1998-10, Vol.16 (10), p.934-938
• Main Authors: Arakawa, T. (Loma Linda University, CA.), Yu, J, Chong, D.K.X, Hough, J, Engen, P.C, Langridge, W.H.R
• Format: Article
• Language: English
• Subjects: Agriculture; Animals; ANTIGENS; AUTOANTIGENS; BACTERIAL TOXINS; Bioinformatics; Biological and medical sciences; Biomedical and Life Sciences; Biomedical Engineering/Biotechnology; Biomedicine; Biotechnology; Cholera Toxin - chemistry; Cholera Toxin - genetics; Diabetes Mellitus, Type 1 - immunology; Diabetes Mellitus, Type 1 - prevention & control; Fundamental and applied biological sciences. Psychology; Health. Pharmaceutical industry; Humans; Industrial applications and implications. Economical aspects; Insulin - genetics; Insulin - immunology; Life Sciences; Mice; Mice, Inbred NOD; Plants, Genetically Modified; Production of active biomolecules; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - genetics; research-article; SOLANUM TUBEROSUM; Solanum tuberosum - genetics; TRANSGENIC PLANTS; VACCINE DEVELOPMENT; Vaccins; VIBRIO CHOLERAE
• ISSN: 1087-0156; 1546-1696
• DOI: 10.1038/nbt1098-934

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 GM 1 -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.