title: Oral administration of transgenic barley expressing a Culicoides allergen induces specific antibody response.
abstract: BACKGROUND
  Insect bite hypersensitivity is an immunoglobulin (Ig)E-mediated dermatitis of horses initiated by bites of midges of the genus Culicoides. Culicoides spp. are not indigenous to Iceland and the prevalence of insect bite hypersensitivity is much higher in horses born in Iceland and exported as compared to Icelandic horses born in a Culicoides rich environment. Immunotherapy is therefore needed.
  
  
  OBJECTIVE
  The aim of the study was to express an allergen from Culicoides in barley grain and investigate whether an immune response could be obtained in healthy Icelandic horses by oral treatment with transgenic barley expressing the allergen.
  
  
  METHODS
  In vivo experiment.
  
  
  METHODS
  The allergen was expressed in barley grain with the Orfeus technique. A device was developed to treat horses orally with barley flour. Four Icelandic horses were treated with transgenic barley and 3 with control barley, in total 500 g in 7 feedings. Serum and saliva samples were collected for measuring specific antibodies.
  
  
  RESULTS
  The allergen Cul n 2, a hyaluronidase originating from the salivary gland of Culicoides nubeculosus, was expressed in barley. Horses treated with the transgenic barley mounted a Cul n 2 specific IgG1 and IgG4/7 response in serum and saliva. The serum response was significantly different between the transgenic and control barley treated horses for both subclasses and the saliva response for IgG1. The induced serum antibodies bound to the corresponding allergen from Culicoides obsoletus, rCul o 2 and were able to partially block binding of Cul n 2 as well as Cul o 2 specific IgE from insect bite hypersensitivity affected horses.
  
  
  CONCLUSIONS
  Small number of horses.
  
  
  CONCLUSIONS
  This study shows that specific antibody response can be induced in horses not exposed to Culicoides, using oral treatment with transgenic barley expressing an allergen. Further studies will determine whether this approach is a useful alternative for prevention and treatment of equine insect bite hypersensitivity.
authors.affiliation: Institute for Experimental Pathology, Biomedical Center, University of Iceland, Keldur, Iceland.
authors.forename: S
authors.initials: S
authors.lastname: Jonsdottir
authors.affiliation: Institute for Experimental Pathology, Biomedical Center, University of Iceland, Keldur, Iceland.
authors.forename: V
authors.initials: V
authors.lastname: Svansson
authors.affiliation: Institute for Experimental Pathology, Biomedical Center, University of Iceland, Keldur, Iceland.
authors.forename: S B
authors.initials: SB
authors.lastname: Stefansdottir
authors.affiliation: Faculty of Pharmacy, University of Iceland, Reykjavik, Iceland.|ORF Genetics Ltd, Kopavogur, Iceland.
authors.forename: E
authors.initials: E
authors.lastname: Mäntylä
authors.affiliation: Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Berne, Berne, Switzerland.
authors.forename: E
authors.initials: E
authors.lastname: Marti
authors.affiliation: Institute for Experimental Pathology, Biomedical Center, University of Iceland, Keldur, Iceland.
authors.forename: S
authors.initials: S
authors.lastname: Torsteinsdottir
mesh_terms: D000284:Administration, Oral; D000485:Allergens / Q000276:immunology; D000818:Animals; D000917:Antibody Formation; D002519:Ceratopogonidae / Q000276:immunology*; D001467:Hordeum / Q000235:genetics; D006734:Horse Diseases / Q000276:immunology*; D006736:Horses; D006967:Hypersensitivity / Q000662:veterinary; D007055:Iceland; D007299:Insect Bites and Stings / Q000276:immunology / Q000662:veterinary*
chemical_list: D000485:Allergens
keywords: Culicoides allergen; barley grain; horse; insect bite hypersensitivity; oral immunotherapy