title: Sal k 5, a member of the widespread Ole e 1-like protein family, is a new allergen of Russian thistle (Salsola kali) pollen.
abstract: BACKGROUND
  Salsola kali is an Amaranthaceae weed with important repercussions for pollinosis in temperate areas. Ole e 1-like members are relevant allergens in pollen from different species. We aimed to characterize and produce as recombinant allergen S. kali Ole e 1-like protein.
  
  
  METHODS
  The natural allergen was purified at homogeneity after three chromatographic steps. Specific cDNA was sequenced and expressed in Pichia pastoris yeast. Structural relationships of natural and recombinant forms were carried out by 2D electrophoresis and spectroscopic analyses. Its immunological relevance was analyzed by ELISA and immunoblotting using an IgG antiserum and monoclonal antibodies specific to Ole e 1, as well as sera from 57 allergic patients recruited from two Spanish regions where this pollinosis is frequent.
  
  
  RESULTS
  The purified allergen, Sal k 5, is an acidic glycoprotein of 151 amino acid residues and 17,628 Da of molecular mass. Its amino acid sequence exhibits 68 and 32% identity with the allergens of Che a 1 and Ole e 1, respectively. The recombinant protein was correctly processed and its structural and immunologic equivalence to the natural form was proven. A sensitization frequency between 30 and 40% was observed in pollinic patients from the center and east coast of Spain.
  
  
  CONCLUSIONS
  Sal k 5 is a member of the Ole e 1-like protein family which can be considered an important allergen from S. kali. Its inclusion in diagnosis protocols would allow the accurate defining of patients allergic to this pollen.
authors.affiliation: Universidad Complutense de Madrid, Madrid, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Castro
authors.forename: S
authors.initials: S
authors.lastname: Mas
authors.forename: R
authors.initials: R
authors.lastname: Barderas
authors.forename: C
authors.initials: C
authors.lastname: Colás
authors.forename: J
authors.initials: J
authors.lastname: García-Sellés
authors.forename: D
authors.initials: D
authors.lastname: Barber
authors.forename: R
authors.initials: R
authors.lastname: Rodríguez
authors.forename: M
authors.initials: M
authors.lastname: Villalba
mesh_terms: D000485:Allergens / Q000276:immunology / Q000302:isolation & purification; D052179:Antigens, Plant / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D018076:DNA, Complementary / Q000032:analysis*; D005260:Female; D006801:Humans; D008297:Male; D031658:Olea / Q000276:immunology; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D010843:Pichia / Q000235:genetics; D010940:Plant Proteins / Q000276:immunology*; D015995:Prevalence; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D006255:Rhinitis, Allergic, Seasonal / Q000175:diagnosis / Q000453:epidemiology / Q000276:immunology*; D031248:Salsola / Q000276:immunology*; D012698:Serologic Tests; D013030:Spain
chemical_list: D000485:Allergens; D052179:Antigens, Plant; D018076:DNA, Complementary; C081946:Ole e I protein, Olea europaea; D010446:Peptide Fragments; D010940:Plant Proteins; D011994:Recombinant Proteins; C587928:Sal k 5 allergen, Salsola kali