title: Characterisation of Alternaria alternata manganese-dependent superoxide dismutase, a cross-reactive allergen homologue to Asp f 6.
abstract: It is well known that Alternaria alternata presents a significant level of allergenic cross-reactivity with several other phylogenetically related and non-related allergenic moulds. To improve the molecular diagnosis, the identification and characterisation of all clinically relevant allergens, including both species-specific and cross-reacting proteins, is required. In this study we report the molecular and immunological characterisation of the A. alternata manganese-dependent superoxide dismutase (Alt a MnSOD) and its cross-reactivity with Asp f 6, a diagnostic marker allergen in allergic bronchopulmonary aspergillosis (ABPA). The cDNA coding for Alt a MnSOD sequence was isolated by RACE and PCR. Alt a MnSOD is a protein of 191 amino acids that presented significant homology and potential cross-reactive epitopes with Asp f 6. The recombinant protein was produced in Escherichia coli and the immunoreactivity was evaluated in patient sera. Immunoblotting analyses showed that seven of sixty-one A. alternata-sensitised patient sera and two ABPA patient sera reacted with the recombinant Alt a MnSOD. The native counterpart contained in both A. alternata and Aspergillus fumigatus extracts inhibited IgE binding to the recombinant molecule. The allergen was named Alt a 14 by the official Allergen nomenclature subcommittee. Thus, Alt a 14 is a relevant allergen in A. alternata sensitisation that may be used to improve diagnostic procedures. Evidence of cross-reactivity between Asp f 6 and Alt a 14-recognition by ABPA patient sera suggest the existence of an Alt a 14-mediated mechanism that, similar to Asp f 6, may be related to the pathogenesis of ABPA.
authors: Department of Immunology, Microbiology and Parasitology, Faculty of Pharmacy and Laboratory of Parasitology and Allergy, Lascaray Research Centre, University of the Basque Country, Vitoria, Spain; Department of Chemistry and CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal.
authors: Marta F
authors: MF
authors: Gabriel
authors: Department of Immunology, Microbiology and Parasitology, Faculty of Pharmacy and Laboratory of Parasitology and Allergy, Lascaray Research Centre, University of the Basque Country, Vitoria, Spain.
authors: Idoia
authors: I
authors: Postigo
authors: Department of Immunology, Microbiology and Parasitology, Faculty of Pharmacy and Laboratory of Parasitology and Allergy, Lascaray Research Centre, University of the Basque Country, Vitoria, Spain.
authors: Antonio
authors: A
authors: Gutiérrez-Rodríguez
authors: Department of Immunology, Microbiology and Parasitology, Faculty of Pharmacy and Laboratory of Parasitology and Allergy, Lascaray Research Centre, University of the Basque Country, Vitoria, Spain.
authors: Ester
authors: E
authors: Suñén
authors: Department of Immunology, Microbiology and Parasitology, Faculty of Pharmacy and Laboratory of Parasitology and Allergy, Lascaray Research Centre, University of the Basque Country, Vitoria, Spain.
authors: Jorge
authors: J
authors: Guisantes
authors: Department of Chemistry and CICS-UBI - Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal.
authors: Cândida T
authors: CT
authors: Tomaz
authors: Department of Immunology, Microbiology and Parasitology, Faculty of Pharmacy and Laboratory of Parasitology and Allergy, Lascaray Research Centre, University of the Basque Country, Vitoria, Spain. Electronic address: jorge.martinez@ehu.es.
authors: Jorge
authors: J
authors: Martínez
mesh_terms: D000485:Allergens / Q000276:immunology*; D000528:Alternaria / Q000201:enzymology* / Q000276:immunology; D000595:Amino Acid Sequence; D000918:Antibody Specificity / Q000276:immunology; D001229:Aspergillosis, Allergic Bronchopulmonary / Q000175:diagnosis* / Q000276:immunology* / Q000473:pathology; D001232:Aspergillus fumigatus / Q000276:immunology; D001483:Base Sequence; D003429:Cross Reactions / Q000276:immunology; D005656:Fungal Proteins / Q000276:immunology; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology; D007073:Immunoglobulin E / Q000276:immunology; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000276:immunology; D013482:Superoxide Dismutase / Q000235:genetics / Q000276:immunology* / Q000378:metabolism
chemical_list: D000485:Allergens; D005656:Fungal Proteins; D011994:Recombinant Proteins; D007073:Immunoglobulin E; C115317:Asp f 6 allergen; D013482:Superoxide Dismutase
keywords: Allergic bronchopulmonary aspergillosis; Alternaria alternata; Cross-reactivity; Fungal allergy; Recombinant allergen