title: Variability of Ole e 9 allergen in olive pollen extracts: relevance of minor allergens in immunotherapy treatments.
abstract: BACKGROUND
  Clustered severe adverse reactions to immunotherapy with olive pollen extracts have been occasionally reported in areas where olive trees are extensively grown. Allergic patients from these areas, in addition to the major olive pollen allergen Ole e 1, frequently recognize a recently described allergen, Ole e 9.
  
  
  OBJECTIVE
  We aimed to develop an immunoassay to measure Ole e 9 concentration and to study the variability of this allergen in olive pollen extracts.
  
  
  METHODS
  Monoclonal antibodies (mAb) to Ole e 9 were produced from mice immunized with the pure allergen. One of these mAbs was used to develop a sandwich ELISA with an anti-olive pollen extract rabbit serum as the tracer. Olive pollen batches from several suppliers were analyzed using this method. These batches were also analyzed for Ole e 1 content and biological activity.
  
  
  RESULTS
  A 10-fold variation between the extreme values was found for the biological activity of the batches analyzed. Ole e 1 concentration showed a 25-fold variation. Variability of Ole e 9 concentration was extremely high, up to 161 times. The ratio Ole e 1/Ole e 9 varied in a range from 0.6 to 390.4.
  
  
  CONCLUSIONS
  The availability of a mAb-based ELISA for Ole e 9 made it possible for us to detect an important source of variability in olive pollen batches. This variability may be the cause of outbreaks of adverse reactions in the course of immunotherapy treatments, which have sometimes been observed among olive-allergic patients living in areas with very high levels of airborne olive pollen.
authors.affiliation: Departamento de Investigación y Desarrollo, ALK-ABELLO, Facultad de Ciencias Químicas, Universidad Complutense, Madrid, España.
authors.forename: Oscar
authors.initials: O
authors.lastname: Duffort
authors.forename: Oscar
authors.initials: O
authors.lastname: Palomares
authors.forename: Manuel
authors.initials: M
authors.lastname: Lombardero
authors.forename: Mayte
authors.initials: M
authors.lastname: Villalba
authors.forename: Domingo
authors.initials: D
authors.lastname: Barber
authors.forename: Rosalía
authors.initials: R
authors.lastname: Rodríguez
authors.forename: Florentino
authors.initials: F
authors.lastname: Polo
mesh_terms: D000485:Allergens / Q000032:analysis* / Q000276:immunology / Q000302:isolation & purification; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000737:chemistry* / Q000276:immunology; D000918:Antibody Specificity; D052179:Antigens, Plant; D002846:Chromatography, Affinity; D003888:Desensitization, Immunologic / Q000009:adverse effects*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D031658:Olea / Q000737:chemistry* / Q000276:immunology; D010936:Plant Extracts / Q000737:chemistry; D010940:Plant Proteins / Q000032:analysis* / Q000276:immunology / Q000302:isolation & purification; D011058:Pollen / Q000009:adverse effects / Q000276:immunology; D001617:beta-Glucosidase / Q000032:analysis* / Q000276:immunology / Q000302:isolation & purification
chemical_list: D000485:Allergens; D000911:Antibodies, Monoclonal; D052179:Antigens, Plant; D010936:Plant Extracts; D010940:Plant Proteins; C433244:OLE9 protein, Olea europaea; D001617:beta-Glucosidase