title: Purification, structural and immunological characterization of a timothy grass (Phleum pratense) pollen allergen, Phl p 4, with cross-reactive potential.
abstract: Almost 500 million people worldwide suffer from Type I allergy, a genetically determined immunodisorder which is based on the production of IgE antibodies against per se harmless antigens (allergens). Due to their worldwide distribution and heavy pollen production, grasses represent a major allergen source for approximately 40% of allergic patients. We purified Phl p 4, a major timothy grass (Phleum pratense) pollen allergen with a molecular mass of 61.3 kDa and a pl of 9.6 to homogeneity. Circular dichroism spectroscopical analysis indicates that Phl p 4 contains a mixed alpha-helical/beta-pleated secondary structure and, unlike many other allergens, showed no reversible unfolding after thermal denaturation. We show that Phl p 4 is a major allergen which reacts with IgE antibodies of 75% of grass pollen allergic patients (n=150) and induces basophil histamine release as well as immediate type skin reactions in sensitized individuals. Phl p 4-specific IgE from three patients as well as two rabbit-anti Phl p 4 antisera cross-reacted with allergens present in pollen of trees, grasses, weeds as well as plant-derived food. Rabbit antibodies raised against Phl p 4 also inhibited the binding of allergic patients IgE to Phl p 4. Phl p 4 may thus be used for diagnosis and treatment of sensitized allergic patients.
authors.affiliation: Department of Pathophysiology, University of Vienna, Austria.
authors.forename: Sabine
authors.initials: S
authors.lastname: Stumvoll
authors.forename: Jonas
authors.initials: J
authors.lastname: Lidholm
authors.forename: Roland
authors.initials: R
authors.lastname: Thunberg
authors.forename: Asa Marknell
authors.initials: AM
authors.lastname: DeWitt
authors.forename: Petra
authors.initials: P
authors.lastname: Eibensteiner
authors.forename: Ines
authors.initials: I
authors.lastname: Swoboda
authors.forename: Agnes
authors.initials: A
authors.lastname: Bugajska-Schretter
authors.forename: Susanne
authors.initials: S
authors.lastname: Spitzauer
authors.forename: Luca
authors.initials: L
authors.lastname: Vangelista
authors.forename: Lili
authors.initials: L
authors.lastname: Kazemi-Shirazi
authors.forename: Wolfgang R
authors.initials: WR
authors.lastname: Sperr
authors.forename: Peter
authors.initials: P
authors.lastname: Valent
authors.forename: Dietrich
authors.initials: D
authors.lastname: Kraft
authors.forename: Rudolf
authors.initials: R
authors.lastname: Valenta
mesh_terms: D000485:Allergens / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification*; D000818:Animals; D015153:Blotting, Western; D002942:Circular Dichroism; D003429:Cross Reactions / Q000276:immunology; D004591:Electrophoresis, Polyacrylamide Gel; D006636:Histamine Release; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D007525:Isoelectric Focusing; D008970:Molecular Weight; D010504:Periodic Acid / Q000494:pharmacology; D031784:Phleum / Q000737:chemistry / Q000276:immunology*; D010940:Plant Proteins / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification*; D011058:Pollen / Q000737:chemistry / Q000276:immunology*; D011487:Protein Conformation; D017510:Protein Folding; D011817:Rabbits; D012882:Skin Tests
chemical_list: D000485:Allergens; C100980:Phl p 4 protein, Phleum pratense; D010940:Plant Proteins; D010504:Periodic Acid; D007073:Immunoglobulin E; C009288:metaperiodate