Identification of oilseed rape (Brassica napus) pollen profilin as a cross-reactive allergen

Int Arch Allergy Immunol. 2003 Oct;132(2):116-23. doi: 10.1159/000073712.

Abstract

Background: Major allergens of oilseed rape (OSR) pollen with molecular weights of 6/8, 14 and between 27 and 69 kD have been described. The aim of the present study was to further characterize the 14-kD allergen.

Methods: The 14-kD protein was purified from OSR pollen extracts by poly-(L-proline) (PLP)-Sepharose affinity chromatography and characterized immunologically by means of allergic patients' IgE antibodies, profilin-specific rabbit antisera, Western blot and ELISA inhibition using recombinant birch profilin (rBet v 2), and skin prick testing.

Results: By PLP affinity chromatography, OSR pollen profilin was purified as a single protein of 14.5 kD and further identified as a profilin by three polyclonal rabbit antisera raised against ragweed and tobacco pollen profilin and the C-terminus of birch profilin. IgE binding of a human serum pool (n = 15) and four profilin-reactive sera to nitrocellulose-blotted OSR profilin was completely inhibited by 1 microg/ml rBet v 2 (birch profilin). Reciprocal ELISA inhibition using increasing concentrations of rBet v 2 and purified OSR profilin, respectively, showed that rBet v 2 strongly inhibits antibody binding to OSR profilin, whereas almost 100 times the amount of OSR profilin was needed to inhibit IgE binding to rBet v 2. Skin prick tests were positive (wheal >/=3 mm) with 5 microg/ml rBet v 2 in all three patients tested, and with OSR profilin in two patients at a concentration of 50 microg/ml.

Conclusions: OSR pollen profilin shares IgE and IgG epitopes with Bet v 2 and other plant profilins and may represent a potentially relevant allergen for profilin-sensitized patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • Brassica napus / immunology*
  • Chromatography, Agarose
  • Contractile Proteins*
  • Cross Reactions / immunology
  • Enzyme-Linked Immunosorbent Assay
  • Humans
  • Immunoglobulin E / immunology
  • Microfilament Proteins / immunology*
  • Microfilament Proteins / isolation & purification
  • Pollen / chemistry
  • Pollen / immunology*
  • Profilins
  • Skin Tests

Substances

  • Contractile Proteins
  • Microfilament Proteins
  • Profilins
  • Immunoglobulin E