Characterization of the dog lipocalin allergen Can f 6: the role in cross-reactivity with cat and horse

• Published in: Allergy (Copenhagen) Vol. 67; no. 6; pp. 751 - 757
• Main Authors: Nilsson, O. B., Binnmyr, J., Zoltowska, A., Saarne, T., van Hage, M., Grönlund, H.
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Publishing Ltd 01-06-2012; Blackwell
• Subjects: Adolescent; Adult; Aged; allergen; Allergens - immunology; Allergies; Amino Acid Sequence; Animals; Basophil Degranulation Test; Biological and medical sciences; Can f 6; Cats; Child; Child, Preschool; Cross Reactions; cross-reactivity; Dermatology; dog allergy; dog dander; Dogs; Female; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Gene Library; Horses; Humans; Hypersensitivity - immunology; Infant; Lipocalins - immunology; Male; Mammals; Medical sciences; Medicin och hälsovetenskap; Middle Aged; Molecular Sequence Data; Sarcoidosis. Granulomatous diseases of unproved etiology. Connective tissue diseases. Elastic tissue diseases. Vasculitis; Sequence Homology, Amino Acid; Young Adult; Fissipedia; Allergy; Immunopathology; Carnivora; Dermatology; Lipocalin; Can f 6; cross-reactivity; dog dander; Characterization; Vertebrata; Mammalia; Immunology; Animal; Cat; Horse; Cross reaction; dog allergy; Perissodactyla; Dog; Ungulata; Allergen
• ISSN: 0105-4538; 1398-9995; 1398-9995
• DOI: 10.1111/j.1398-9995.2012.02826.x

Background
Allergy to the domestic dog (Canis familiaris) affects 5–10% of the population in affluent countries. Three of four patients are allergic to more than one pet, which can only partially be explained by cross‐reactivity between serum albumins. The lipocalin protein family harbours allergens in mammalian species.
Methods
We set out to clone and characterize a novel dog allergen, and investigate its potential role in cross‐sensitization between dog, cat and horse. The gene encoding Can f 6 was amplified from dog skin and bladder cDNA libraries. The corresponding allergen was produced and purified by recombinant techniques and evaluated by SDS‐PAGE, size exclusion chromatography, circular dichroism spectra, ELISA and basophil activation test.
Results
IgE antibodies to Can f 6 were found in serum from 38% of dog‐sensitized subjects. Sequence similarities between the lipocalin allergens Can f 6, Fel d 4 (cat) and Equ c 1 (horse) suggested a probability for cross‐reactivity, which was demonstrated by competitive ELISA. The biological relevance of Can f 6 was confirmed by basophil activation test in dog‐allergic patients.
Conclusion
Can f 6 is a new lipocalin dog allergen that cross‐reacts with lipocalins from horse and cat. Can f 6 and homologous allergens may contribute to multisensitization and symptoms in individuals allergic to mammals.