title: Isolation of Mal d 1 and Api g 1 - specific recombinant antibodies from mouse IgG Fab fragment libraries - Mal d 1-specific antibody exhibits cross-reactivity against Bet v 1.
abstract: BACKGROUND
  Around 3-5% of the population suffer from IgE-mediated food allergies in Western countries and the number of food-allergenic people is increasing. Individuals with certain pollen allergies may also suffer from a sensitisation to proteins in the food products. As an example a person sensitised to the major birch pollen allergen, Bet v 1, is often sensitised to its homologues, such as the major allergens of apple, Mal d 1, and celery, Api g 1, as well. Development of tools for the reliable, sensitive and quick detection of allergens present in various food products is essential for allergic persons to prevent the consumption of substances causing mild and even life-threatening immune responses. The use of monoclonal antibodies would ensure the specific detection of the harmful food content for a sensitised person.
  
  
  METHODS
  Mouse IgG antibody libraries were constructed from immunised mice and specific recombinant antibodies for Mal d 1 and Api g 1 were isolated from the libraries by phage display. More detailed characterisation of the resulting antibodies was carried out using ELISA, SPR experiments and immunoprecipitation assays.
  
  
  RESULTS
  The allergen-specific Fab fragments exhibited high affinity towards the target recombinant allergens. Furthermore, the Fab fragments also recognised native allergens from natural sources. Interestingly, isolated Mal d 1-specific antibody bound also to Bet v 1, the main allergen eliciting the cross-reactivity syndrome between the birch pollen and apple. Despite the similarities in Api g 1 and Bet v 1 tertiary structures, the isolated Api g 1-specific antibodies showed no cross-reactivity to Bet v 1.
  
  
  CONCLUSIONS
  Here, high-affinity allergen-specific recombinant antibodies were isolated with interesting binding properties. With further development, these antibodies can be utilised as tools for the specific and reliable detection of allergens from different consumable products. This study gives new preliminary insights to elucidate the mechanism behind the pollen-food syndrome and to study the IgG epitope of the allergens.
authors.affiliation: VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, Espoo, FI-02044 VTT, Finland. jaana.haka@vtt.fi.
authors.forename: Jaana
authors.initials: J
authors.lastname: Haka
authors.affiliation: Department of Chemistry, University of Eastern Finland, Joensuu Campus, P.O. Box 111, Joensuu, FI-80101, Finland. merja.niemi@uef.fi.
authors.forename: Merja H
authors.initials: MH
authors.lastname: Niemi
authors.affiliation: VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, Espoo, FI-02044 VTT, Finland. kristiina.iljin@vtt.fi.
authors.forename: Kristiina
authors.initials: K
authors.lastname: Iljin
authors.affiliation: International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067, India. vsreddy@icgeb.res.in.
authors.forename: Vanga Siva
authors.initials: VS
authors.lastname: Reddy
authors.affiliation: VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, Espoo, FI-02044 VTT, Finland. kristiina.takkinen@vtt.fi.
authors.forename: Kristiina
authors.initials: K
authors.lastname: Takkinen
authors.affiliation: VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, Espoo, FI-02044 VTT, Finland. marja-leena.laukkanen@vtt.fi.
authors.forename: Marja-Leena
authors.initials: ML
authors.lastname: Laukkanen
mesh_terms: D000485:Allergens / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D052179:Antigens, Plant / Q000276:immunology; D005512:Food Hypersensitivity / Q000276:immunology*; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology*; D051379:Mice; D010940:Plant Proteins / Q000276:immunology; D011058:Pollen / Q000276:immunology; D011994:Recombinant Proteins / Q000276:immunology*
chemical_list: D000485:Allergens; D052179:Antigens, Plant; C096695:Api g 1 protein, Apium graveolens; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; C095551:MALD1 protein, Malus domestica; D010940:Plant Proteins; D011994:Recombinant Proteins; C061312:Bet v 1 allergen, Betula