Isolation and characterization of relevant allergens from boiled lentils

J Allergy Clin Immunol. 2000 Nov;106(5):955-61. doi: 10.1067/mai.2000.109912.


Background: Lentils seem to be the most common legume implicated in pediatric allergic patients in the Mediterranean area. However, no lentil allergen has been isolated and characterized.

Objective: We sought to purify and characterize relevant IgE-binding proteins from boiled lentil extracts.

Methods: IgE-binding proteins from crude and boiled lentil extracts were detected with a pool of sera from patients with lentil allergy. Allergens were isolated by gel-filtration chromatography followed by cation- and anion-exchange chromatography or by reverse-phase HPLC. Their characterization included N-terminal amino acid sequencing, complex asparagine-linked glycan detection, specific IgE immunodetection with 22 individual sera from allergic patients, and immunoblot and CAP inhibition assays.

Results: Heat treatment of lentils produced substantial changes in the SDS-PAGE patterns of whole extracts, mainly a strong increase of 12- to 16-kd bands and a decrease of 25- to 45-kd components. Major IgE-binding proteins from the boiled lentil extract were located in the 12- to 16-kd and 45- to 70-kd ranges. Two allergens of 16 kd, proteins L1 and L2, and another one of 12 kd, protein L3, were purified. N-terminal sequencing indicated that all 3 were related and allowed their identification as gamma-vicilin subunits. Protein L1 was recognized by 68% of the individual sera tested and inhibited 64% of the IgE binding by commercial lentil CAPs. A second type of allergen of 66 kd, named protein H, was also isolated and identified as a seed-specific biotinylated protein. Protein H reacted with 41% of the individual sera and produced 45% inhibition in CAP inhibition assays.

Conclusions: Two different types of allergens have been identified in boiled lentils. Those of 12 to 16 kd, called Len c 1, correspond to gamma-vicilin subunits, and those of 66 kd, designated Len c 2, correspond to seed-specific biotinylated protein. Homology with proteins from other legume species can explain potential cross-reactions among these foods.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Allergens / chemistry
  • Allergens / immunology*
  • Allergens / isolation & purification
  • Amino Acid Sequence
  • Child
  • Electrophoresis, Polyacrylamide Gel / methods
  • Fabaceae / immunology*
  • Heating
  • Humans
  • Immunoglobulin E / immunology
  • Molecular Sequence Data
  • Plant Extracts / analysis
  • Plant Extracts / chemistry
  • Plant Extracts / immunology
  • Plant Proteins / analysis
  • Plant Proteins / immunology*
  • Plants, Medicinal*
  • Seed Storage Proteins
  • Sequence Analysis, Protein / methods


  • Allergens
  • Plant Extracts
  • Plant Proteins
  • Seed Storage Proteins
  • Immunoglobulin E
  • vicilin protein, plant