title: Identification and isolation of a Fel d 1-like molecule as a major rabbit allergen.
abstract: BACKGROUND
  Rabbits are increasingly kept as domestic pets. Several rabbit allergens have been characterized. However, their sequences are still elusive, and none of these molecules are available for diagnosis.
  
  
  OBJECTIVE
  We sought to isolate major allergens from the rabbit Oryctolagus cuniculus and to investigate their importance in sensitized patients.
  
  
  METHODS
  Proteins were extracted from rabbit hair, and IgE-reactive proteins were purified by using sequential chromatography. Allergens were characterized by means of N-terminal sequencing and mass spectrometry. IgE reactivity to a new allergen was analyzed in sera of 35 patients sensitized to rabbits in a domestic setting. A model of the crystal structure of the isolated proteins was constructed.
  
  
  RESULTS
  A new IgE-reactive allergen, Ory c 3, was identified as rabbit lipophilin. The molecule that belongs to the secretoglobin family is a heterodimer of 18 to 19 kDa composed of 2 polypeptide chains, CL2 and AL. CL2 has a predicted N-linked glycosylation site confirmed by using mass spectrometry. Of the 35 patients with rabbit allergy studied, 27 (77%) had IgE to both the glycosylated and deglycosylated Ory c 3 heterodimer. Allergenicity of Ory c 3 was confirmed by using skin prick tests and the basophil activation assay. Modeling of the structure revealed a marked homology to Fel d 1, the major cat allergen. However, no IgE cross-reactivity was detected between Fel d 1 and Ory c 3.
  
  
  CONCLUSIONS
  The rabbit lipophilin heterodimer AL-CL2 has been identified as a major rabbit allergen. After Fel d 1, Ory c 3 is the second mammalian secretoglobin shown to be a major allergen.
authors.affiliation: Laboratory of Immunogenetics and Allergology, CRP-Santé, Luxembourg. Electronic address: christiane.hilger@crp-sante.lu.
authors.forename: Christiane
authors.initials: C
authors.lastname: Hilger
authors.affiliation: Laboratory of Immunogenetics and Allergology, CRP-Santé, Luxembourg.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Kler
authors.affiliation: Laboratory of Retrovirology, CRP-Santé, Luxembourg.
authors.forename: Karthik
authors.initials: K
authors.lastname: Arumugam
authors.affiliation: Department of Immunology, CRP-Santé, Luxembourg.
authors.forename: Dominique
authors.initials: D
authors.lastname: Revets
authors.affiliation: Department of Immunology, CRP-Santé, Luxembourg.
authors.forename: Claude P
authors.initials: CP
authors.lastname: Muller
authors.affiliation: Department of Pneumology, Centre Hospitalier de Luxembourg, Luxembourg.
authors.forename: Catherine
authors.initials: C
authors.lastname: Charpentier
authors.affiliation: National Unit of Immunology-Allergology, Centre Hospitalier de Luxembourg, Luxembourg.
authors.forename: Christiane
authors.initials: C
authors.lastname: Lehners
authors.affiliation: National Unit of Immunology-Allergology, Centre Hospitalier de Luxembourg, Luxembourg.
authors.forename: Martine
authors.initials: M
authors.lastname: Morisset
authors.affiliation: Laboratory of Immunogenetics and Allergology, CRP-Santé, Luxembourg; National Unit of Immunology-Allergology, Centre Hospitalier de Luxembourg, Luxembourg.
authors.forename: François
authors.initials: F
authors.lastname: Hentges
mesh_terms: D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification*; D000595:Amino Acid Sequence; D000818:Animals; D002415:Cats; D002648:Child; D002675:Child, Preschool; D003429:Cross Reactions; D005260:Female; D006023:Glycoproteins / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification*; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D011817:Rabbits / Q000276:immunology*
chemical_list: D000485:Allergens; D006023:Glycoproteins; C586949:Ory c 3 allergen, Oryctolagus cuniculus; D007073:Immunoglobulin E; C059296:Fel d 1 protein, Felis domesticus
keywords: Allergen; Fel d 1; IgE; Ory c 3; cross-reactivity; inhibition; lipophilin; molecular modeling; rabbit; secretoglobin