Molecular characterization of major cat allergen Fel d 1: Expression of heterodimer by use of a baculovirus expression system

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  • Ulla Seppälä
  • Hägglund, Per Mårten
  • Peter A. Wurtzen
  • Henrik Ipsen
  • Peter Thorsted
  • Thomas Lenhard
  • Peter Roepstorff
  • Michael D. Spangfort

Fel d 1 is a major cat allergen inducing allergic rhinitis and asthma in sensitized individuals. It has a more complex structure when compared with other allergens and therefore expression of recombinant Fel d 1 has been considered a challenge. The present study shows for the first time that a Baculovirus expression system is able to produce an intact rFel d 1 molecule that is glycosylated and structurally equivalent to the natural cat allergen, nFel d 1. Enzymatic digestion of rFel d 1 and further analysis by use of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) resulted in a complete coverage of the amino acid sequence of rFel d 1. In addition, the three disulfide bridges at the positions α70-β7, α44-β48, and α3-β373 were verified. The N-glycan structure of rFel d 1 was investigated by a combination of MALDI-TOF MS and monosaccharide analysis by high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAC). The N-glycosylation analyses of rFel d 1 refer to a pattern, of glycoforms including core α1.3-fucosylation that is different from nFel d 1. Further characterization by use of human serum IgE, histanaine release, and lymphocyte proliferation assays demonstrated that the immunological characteristics of rFel d 1 are similar to those of nFel d 1. Detailed characterization of both natural and recombinant allergens provides tools to explore immunological mechanisms associated with allergen sensitization and desensitization.

Original languageEnglish
JournalJournal of Biological Chemistry
Issue number5
Pages (from-to)3208-3216
Number of pages9
Publication statusPublished - 4 Feb 2005

ID: 240161696