title: The major soyabean allergen P34 resists proteolysis in vitro and is transported through intestinal epithelial cells by a caveolae-mediated mechanism.
abstract: Soya is considered to be one of the eight most significant food allergens. Among the allergenic soya proteins determined to date, P34 has been identified as one of the immunodominant soya antigens. Sensitisation to a specific food antigen like P34 generally follows the transit of intact antigens across the intestinal barrier and usually occurs in infants, who are most susceptible to food allergies. In the present study, we used the intestinal epithelial cell line IPEC-J2, which was originally derived from the jejunum of a neonatal piglet, to recapitulate the infant intestinal epithelium and study the binding and uptake of P34 protein. P34 was partially resistant to degradation in an in vitro proteolysis assay. IPEC-J2 cells were able to endocytose intact P34, as shown by immunofluorescence and immunoelectronmicroscopy methods. P34 associated with lipid raft microdomains of IPEC-J2 cells, and disruption of caveolae/lipid raft microdomains using methyl-β-cyclodextrin abolished P34 endocytosis, indicating that the observed endocytosis was mediated by caveolae. Using IPEC-J2 cells grown on Transwell filters, we further demonstrated that P34 is transported through the epithelial monolayer by transcytosis. Piglets frequently show hypersensitivity to soya antigens, and in this study, we show that healthy adult pigs with dietary exposure to soya protein mount an antibody response to soyabean protein P34, suggesting that this protein has entered the body, probably through gastrointestinal uptake. In summary, our data suggest that soya P34 resists proteolysis in the gastrointestinal tract and is transported through the intestinal epithelial barrier, thereby allowing sensitisation of immune cells in the sub-epithelial compartment.
authors.affiliation: Medical Faculty, Institute of Anatomy, Leipziger Strasse 44, Magdeburg, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Sewekow
authors.forename: Diane
authors.initials: D
authors.lastname: Bimczok
authors.forename: Thilo
authors.initials: T
authors.lastname: Kähne
authors.forename: Heidi
authors.initials: H
authors.lastname: Faber-Zuschratter
authors.forename: Lars Christian
authors.initials: LC
authors.lastname: Kessler
authors.forename: Andreas
authors.initials: A
authors.lastname: Seidel-Morgenstern
authors.forename: Hermann-Josef
authors.initials: HJ
authors.lastname: Rothkötter
mesh_terms: D000818:Animals; D017849:Animals, Inbred Strains; D000831:Animals, Newborn; D000906:Antibodies / Q000032:analysis; D052179:Antigens, Plant / Q000009:adverse effects / Q000378:metabolism*; D021941:Caveolae / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D002460:Cell Line; D004063:Digestion / Q000187:drug effects; D004705:Endocytosis / Q000187:drug effects; D020895:Enterocytes / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D005512:Food Hypersensitivity / Q000097:blood / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D007408:Intestinal Absorption / Q000187:drug effects; D021962:Membrane Microdomains / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D049990:Membrane Transport Modulators / Q000494:pharmacology; D016253:Microscopy, Immunoelectron; D021381:Protein Transport / Q000187:drug effects; D059748:Proteolysis; D030262:Soybean Proteins / Q000009:adverse effects / Q000378:metabolism*; D034421:Sus scrofa; D057900:Transcytosis / Q000187:drug effects; D047392:beta-Cyclodextrins / Q000494:pharmacology
chemical_list: D000906:Antibodies; D052179:Antigens, Plant; D049990:Membrane Transport Modulators; D030262:Soybean Proteins; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; C075135:P34 protein, Glycine max