A Novel Isoallergen Dau c 1.0401 in Carrot: Stability, Allergenicity, and Comparison with Other Isoallergens

Mol Nutr Food Res. 2021 Apr;65(7):e2001110. doi: 10.1002/mnfr.202001110. Epub 2021 Mar 3.


Scope: Around 25% of food allergic persons in Central Europe suffer from carrot allergy caused by the major carrot allergen Dau c 1. Three different isoallergens, Dau c 1.01, Dau c 1.02 and Dau c 1.03 are identified. However, information about the qualitative and quantitative composition of natural (n)Dau c 1 is scarce.

Methods and results: The new carrot allergen Dau c 1.0401 is identified on the mRNA and protein level by RT-PCR and mass spectrometry. It displays only around 60% sequence identity to the other known Dau c 1 isoallergens. NMR and CD-spectra are typical for a well-folded protein containing both α-helices and β-strands. It showed a poor refolding capacity after incubation at 95 °C. IgE-binding is impaired in immunoblots, whereas in inhibition assays IgE binding to soluble Dau c 1.0401 is detected and it clearly provoked a response in mediator release assays.

Conclusion: Dau c 1.0401 is a new isoallergen which contributes to the allergenicity of carrots. The absence of immunoreactivity in immobilized assays indicates that IgE binding is impaired when the protein is blotted on a solid phase. Altogether, the results point out that its allergenicity can be reduced upon carrot processing.

Keywords: Dau c 1 isoallergen; RT-PCR; allergenicity; mass spectrometry; protein stability.

MeSH terms

  • Allergens / chemistry*
  • Allergens / genetics
  • Allergens / immunology*
  • Allergens / metabolism*
  • Antigens, Plant / chemistry
  • Antigens, Plant / genetics
  • Antigens, Plant / immunology*
  • Antigens, Plant / metabolism
  • Cloning, Molecular
  • Daucus carota / immunology*
  • Food Hypersensitivity / immunology*
  • Humans
  • Immune Sera
  • Immunoglobulin E / metabolism
  • Plant Proteins / chemistry
  • Plant Proteins / genetics
  • Plant Proteins / immunology*


  • Allergens
  • Antigens, Plant
  • Dau c 1 protein, Daucus carota
  • Immune Sera
  • Plant Proteins
  • Immunoglobulin E