Purification, structural and immunological characterization of a timothy grass (Phleum pratense) pollen allergen, Phl p 4, with cross-reactive potential.
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.
Stumvoll
Sabine
S
Department of Pathophysiology, University of Vienna, Austria.
Lidholm
Jonas
J
Thunberg
Roland
R
DeWitt
Asa Marknell
AM
Eibensteiner
Petra
P
Swoboda
Ines
I
Bugajska-Schretter
Agnes
A
Spitzauer
Susanne
S
Vangelista
Luca
L
Kazemi-Shirazi
Lili
L
Sperr
Wolfgang R
WR
Valent
Peter
P
Kraft
Dietrich
D
Valenta
Rudolf
R
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
D000485:Allergens; C100980:Phl p 4 protein, Phleum pratense; D010940:Plant Proteins; D010504:Periodic Acid; D007073:Immunoglobulin E; C009288:metaperiodate