title: Isolation and characterization of major banana allergens: identification as fruit class I chitinases.
abstract: BACKGROUND
  Banana allergy has been associated with the latex-fruit syndrome. Several IgE-binding components, the relevant ones being proteins of 30-37-kDa, have been detected in banana fruit, but none of them have been isolated and characterized yet. Objective To purify and characterize the 30-37 kDa banana allergens.
  
  
  METHODS
  Fifteen patients allergic to banana were selected on the grounds of a latex-allergic population. Prick by prick tests to this fruit were performed. Total and specific IgE to banana were determined. Banana allergens were isolated by affinity chromatography, followed by cation-exchange chromatography. Their characterization includes N-terminal sequencing, enzymatic activity assays, immunodetection with sera from allergic patients and with antichitinase antibodies, and CAP and immunoblot inhibition tests. Skin prick tests with banana extracts and with the purified allergens were also carried out.
  
  
  RESULTS
  Two major IgE-binding proteins of 34 and 32 kDa, also recognized by polyclonal antibodies against chestnut chitinases, were immunodetected in crude banana extracts. Purification and characterization of both proteins have allowed their identification as class I chitinases with an hevein-like domain. Each isolated allergen reached inhibition values higher than 90% in CAP inhibition assays, and fully inhibited the IgE-binding by the crude banana extract when tested by an immunoblot inhibition method. The two purified allergens provoked positive skin prick test responses in more than 50% of the banana-allergic patients.
  
  
  CONCLUSIONS
  Class I chitinases with an hevein-like domain are major allergens in banana fruit. Their presence in other fruits and nuts, such as avocado and chestnut, could explain the cross-sensitization among these foods.
authors.affiliation: Unidad de Bioquímica, Departamento de Biotecnología, E.T.S. Ingenieros Agrónomos, Madrid, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Sanchez-Monge
authors.forename: C
authors.initials: C
authors.lastname: Blanco
authors.forename: A
authors.initials: A
authors.lastname: Díaz-Perales
authors.forename: C
authors.initials: C
authors.lastname: Collada
authors.forename: T
authors.initials: T
authors.lastname: Carrillo
authors.forename: C
authors.initials: C
authors.lastname: Aragoncillo
authors.forename: G
authors.initials: G
authors.lastname: Salcedo
mesh_terms: D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000032:analysis* / Q000276:immunology / Q000302:isolation & purification; D000595:Amino Acid Sequence; D023181:Antimicrobial Cationic Peptides; D002688:Chitinases / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D003429:Cross Reactions; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005512:Food Hypersensitivity; D006801:Humans; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000097:blood; D037102:Lectins / Q000737:chemistry; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D037121:Plant Lectins; D010940:Plant Proteins / Q000737:chemistry; D011446:Prospective Studies; D012882:Skin Tests; D019862:Zingiberales / Q000009:adverse effects* / Q000201:enzymology
chemical_list: D000485:Allergens; D023181:Antimicrobial Cationic Peptides; D037102:Lectins; D037121:Plant Lectins; D010940:Plant Proteins; C045875:hevein; D007073:Immunoglobulin E; D002688:Chitinases