title: Identification and quantification of tomato allergens: in vitro characterization of six different varieties.
abstract: BACKGROUND
  The prevalence of sensitization to tomato has been estimated in 6.5% in a Mediterranean population.
  
  
  OBJECTIVE
  To characterize the allergenic profile of 6 commonly ingested varieties of tomato and to identify and quantify the most representative allergens.
  
  
  METHODS
  Rama, Rambo, Canario, Kumato, Pera and Raf tomato varieties were carefully peeled and extracts from peel and pulp prepared. The extracts were characterized by SDS-PAGE and immunoblot. Lyc e 3 and osmotin-like protein (OLP) were identified by LC MS/MS and PG2A by immunoblot with a specific polyclonal antibody. Protein content and allergen concentration (Lyc e 3 and PG2A) were measured by scanning densitometry after identification. One hundred and ninety-one patients were enrolled in the study. Specific IgE to all tomato extracts was evaluated by direct ELISA.
  
  
  RESULTS
  Eighty (41.7%) individuals reported symptoms after contact/ingestion with tomato, most of them oral symptoms. Protein profile and allergen quantification of the 6 varieties showed differences in the allergen composition. Lyc e 3 was visualized in all extracts, being the most abundant in all cases. PG2A and OLP were identified in all peel extracts and in some pulp extracts. Higher specific IgE values were obtained for the Kumato variety. Immunoblot showed the existence of several bands with IgE-binding capacity, especially at 12 and 45-50 kDa.
  
  
  CONCLUSIONS
  The study demonstrates differences in the antigenic and allergenic profiles of the analyzed varieties and variations in their allergenic composition, affecting the diagnostic capacity. LTP and PG2A are important tomato allergens in our population but other IgE-binding capacity proteins are also involved.
authors.affiliation: R&D Department, Laboratorios LETI, SL Tres Cantos, Madrid, Spain.
authors.forename: M Ángeles
authors.initials: MÁ
authors.lastname: López-Matas
authors.forename: Carlos H
authors.initials: CH
authors.lastname: Larramendi
authors.forename: Angel
authors.initials: A
authors.lastname: Ferrer
authors.forename: Angel Julio
authors.initials: AJ
authors.lastname: Huertas
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Pagán
authors.forename: José Luis
authors.initials: JL
authors.lastname: García-Abujeta
authors.forename: Joan
authors.initials: J
authors.lastname: Bartra
authors.forename: Carmen
authors.initials: C
authors.lastname: Andreu
authors.forename: José Ramón
authors.initials: JR
authors.lastname: Lavín
authors.forename: Jerónimo
authors.initials: J
authors.lastname: Carnés
mesh_terms: D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification; D002648:Child; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005512:Food Hypersensitivity / Q000276:immunology*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D018551:Solanum lycopersicum / Q000737:chemistry / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010940:Plant Proteins / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification; D012882:Skin Tests; D013030:Spain; D053719:Tandem Mass Spectrometry; D055815:Young Adult
chemical_list: D000485:Allergens; D010940:Plant Proteins; D007073:Immunoglobulin E