title: Nitration of β-Lactoglobulin but Not of Ovomucoid Enhances Anaphylactic Responses in Food Allergic Mice.
abstract: BACKGROUND
  We revealed in previous studies that nitration of food proteins reduces the risk of de novo sensitization in a murine food allergy model. In contrast, in situations with preformed specific IgE antibodies, in vitro experiments suggested an increased capacity of effector cell activation by nitrated food proteins.
  
  
  OBJECTIVE
  The aim of this study was to investigate the influence of protein nitration on the effector phase of food allergy.
  
  
  METHODS
  BALB/c mice were immunized intraperitoneally (i.p.) with the milk allergen β-lactoglobulin (BLG) or the egg allergen ovomucoid (OVM), followed by intragastric (i.g.) gavages to induce a strong local inflammatory response and allergen-specific antibodies. Subsequently, naïve and allergic mice were intravenously (i.v.) challenged with untreated, sham-nitrated or nitrated BLG or OVM. Anaphylaxis was monitored by measuring core body temperature and determination of mouse mast cell protease-1 (mMCP-1) levels in blood.
  
  
  RESULTS
  A significant drop of body temperature accompanied with significantly elevated concentrations of the anaphylaxis marker mMCP-1 were only observed in BLG allergic animals challenged with nitrated BLG and not in OVM allergic mice challenged with nitrated OVM. SDS-PAGE and circular dichroism analysis of the differentially modified allergens revealed an effect of nitration on the secondary protein structure exclusively for BLG together with enhanced protein aggregation.
  
  
  CONCLUSIONS
  Our data suggest that nitration affects differently the food allergens BLG and OVM. In the case of BLG, structural changes favored dimerization possibly explaining the increased anaphylactic reactivity in BLG allergic animals.
authors.affiliation: Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria; Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria.
authors.forename: Susanne C
authors.initials: SC
authors.lastname: Diesner
authors.affiliation: Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Schultz
authors.affiliation: Department of Molecular Biology, University of Salzburg, Salzburg, Austria.
authors.forename: Chloé
authors.initials: C
authors.lastname: Ackaert
authors.affiliation: Biomedical Sciences, Salzburg University of Applied Sciences, Puch/Salzburg, Austria.
authors.forename: Gertie J
authors.initials: GJ
authors.lastname: Oostingh
authors.affiliation: Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
authors.forename: Anna
authors.initials: A
authors.lastname: Ondracek
authors.affiliation: Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
authors.forename: Caroline
authors.initials: C
authors.lastname: Stremnitzer
authors.affiliation: Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
authors.forename: Josef
authors.initials: J
authors.lastname: Singer
authors.affiliation: Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
authors.forename: Denise
authors.initials: D
authors.lastname: Heiden
authors.affiliation: Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria; Comparative Medicine, Messerli Research Institute of the University of Veterinary Medicine Vienna, Medical University Vienna and University Vienna, Vienna, Austria.
authors.forename: Franziska
authors.initials: F
authors.lastname: Roth-Walter
authors.affiliation: Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
authors.forename: Judit
authors.initials: J
authors.lastname: Fazekas
authors.affiliation: Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
authors.forename: Vera E
authors.initials: VE
authors.lastname: Assmann
authors.affiliation: Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria; Comparative Medicine, Messerli Research Institute of the University of Veterinary Medicine Vienna, Medical University Vienna and University Vienna, Vienna, Austria.
authors.forename: Erika
authors.initials: E
authors.lastname: Jensen-Jarolim
authors.affiliation: Department of Molecular Biology, University of Salzburg, Salzburg, Austria.
authors.forename: Hanno
authors.initials: H
authors.lastname: Stutz
authors.affiliation: Department of Molecular Biology, University of Salzburg, Salzburg, Austria.
authors.forename: Albert
authors.initials: A
authors.lastname: Duschl
authors.affiliation: Department of Pathophysiology and Allergy Research, Center of Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria.
authors.forename: Eva
authors.initials: E
authors.lastname: Untersmayr
mesh_terms: D000485:Allergens / Q000008:administration & dosage* / Q000737:chemistry; D000707:Anaphylaxis; D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D018932:Chemokine CCL2 / Q000097:blood; D002942:Circular Dichroism; D004195:Disease Models, Animal; D021181:Egg Hypersensitivity / Q000097:blood / Q000276:immunology*; D007114:Immunization / Q000379:methods; D007274:Injections, Intraperitoneal; D007782:Lactoglobulins / Q000008:administration & dosage* / Q000737:chemistry; D051379:Mice; D016269:Milk Hypersensitivity / Q000097:blood / Q000276:immunology*; D008958:Models, Molecular; D009584:Nitrogen / Q000737:chemistry*; D010059:Ovomucin / Q000008:administration & dosage* / Q000737:chemistry; D017433:Protein Structure, Secondary
chemical_list: D000485:Allergens; C491768:Ccl2 protein, mouse; D018932:Chemokine CCL2; D007782:Lactoglobulins; D010059:Ovomucin; D009584:Nitrogen