title: Expression of hypoallergenic Der f 2 derivatives with altered intramolecular disulphide bonds induces the formation of novel ER-derived protein bodies in transgenic rice seeds.
abstract: House dust mites (HDM) are the most common source of indoor allergens and are associated with allergic diseases worldwide. To benefit allergic patients, safer and non-invasive mucosal routes of oral administration are considered to be the best alternative to conventional allergen-specific immunotherapy. In this study, transgenic rice was developed expressing derivatives of the major HDM allergen Der f 2 with reduced Der f 2-specific IgE reactivity by disrupting intramolecular disulphide bonds in Der f 2. These derivatives were produced specifically as secretory proteins in the endosperm tissue of seeds under the control of the endosperm-specific glutelin GluB-1 promoter. Notably, modified Der f 2 derivatives aggregated in the endoplasmic reticulum (ER) lumen and were deposited in a unique protein body (PB)-like structure tentatively called the Der f 2 body. Der f 2 bodies were characterized by their intracellular localization and physico-chemical properties, and were distinct from ER-derived PBs (PB-Is) and protein storage vacuoles (PB-IIs). Unlike ER-derived organelles such as PB-Is, Der f 2 bodies were rapidly digested in simulated gastric fluid in a manner similar to that of PB-IIs. Oral administration in mice of transgenic rice seeds containing Der f 2 derivatives encapsulated in Der f 2 bodies suppressed Der f 2-specific IgE and IgG production compared with that in mice fed non-transgenic rice seeds, and the effect was dependent on the type of Der f 2 derivative expressed. These results suggest that engineered hypoallergenic Der f 2 derivatives expressed in the rice seed endosperm could serve as a basis for the development of viable strategies for the oral delivery of vaccines against HDM allergy.
authors.affiliation: Functional Crop Research and Development Unit, National Institute of Agrobiological Sciences, Tsukuba 305-8602, Ibaraki, Japan.
authors.forename: Lijun
authors.initials: L
authors.lastname: Yang
authors.forename: Sakiko
authors.initials: S
authors.lastname: Hirose
authors.forename: Kazuya
authors.initials: K
authors.lastname: Suzuki
authors.forename: Takachika
authors.initials: T
authors.lastname: Hiroi
authors.forename: Fumio
authors.initials: F
authors.lastname: Takaiwa
mesh_terms: D000485:Allergens / Q000276:immunology*; D000818:Animals; D039741:Antigens, Dermatophagoides / Q000276:immunology*; D060829:Arthropod Proteins / Q000276:immunology*; D022083:Cytoplasmic Structures / Q000276:immunology*; D004220:Disulfides / Q000276:immunology*; D004721:Endoplasmic Reticulum / Q000378:metabolism* / Q000648:ultrastructure; D059865:Endoplasmic Reticulum Stress; D056625:Endosperm / Q000378:metabolism; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D007108:Immune Tolerance / Q000276:immunology; D007073:Immunoglobulin E / Q000276:immunology; D051379:Mice; D012275:Oryza / Q000235:genetics* / Q000648:ultrastructure; D030821:Plants, Genetically Modified; D021381:Protein Transport; D055314:Seed Storage Proteins / Q000378:metabolism; D012639:Seeds / Q000235:genetics*; D012995:Solubility; D013347:Subcellular Fractions / Q000378:metabolism; D014170:Transformation, Genetic; D014611:Vaccination
chemical_list: D000485:Allergens; D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; C451160:Dermatophagoides farinae antigen f 2; D004220:Disulfides; D055314:Seed Storage Proteins; D007073:Immunoglobulin E