Immunologic characterization of purified recombinant timothy grass pollen (Phleum pratense) allergens (Phl p 1, Phl p2, Phl p 5).
BACKGROUND
Grass pollen allergens belong to the potent elicitors of type I allergy. Approximately 40% of allergic individuals display IgE reactivity with grass pollen allergens. In previous studies we have reported the complementary DNA cloning and expression in Escherichia coli of three of the most relevant timothy grass pollen allergens: Phl p 1, Phl p 2, and Phl p 5.


OBJECTIVE
To achieve high level expression of immunologically active timothy grass pollen allergens in E. coli, the cDNAs were inserted into expression plasmids.


METHODS
The three recombinant grass pollen allergens were expressed at high levels in E. coli as recombinant nonfusion proteins, purified by conventional protein chemical methods and tested for their IgE-binding capacity by immunoblot and ELISA, as well as in histamine release assays.


RESULTS
Milligram amounts of pure recombinant allergens were obtained from cultured E. coli. IgE binding to purified recombinant Phl p 1, Phl p 2, and Phl p 5 could be demonstrated by immunoblot and ELISA. With ELISAs the percentage of grass pollen-specific IgE directed against the individual recombinant allergens could be estimated. In addition, the purified recombinant timothy grass pollen allergens induced dose-dependent and specific histamine release from patients' blood basophils.


CONCLUSIONS
Purified recombinant timothy grass pollen allergens represent useful tools for diagnosis and therapy of grass pollen allergy.
Vrtala
S
S
Institute of General and Experimental Pathology, University of Vienna, Austria.
Susani
M
M
Sperr
W R
WR
Valent
P
P
Laffer
S
S
Dolecek
C
C
Kraft
D
D
Valenta
R
R
D000485:Allergens / Q000737:chemistry / Q000276:immunology* / Q000302:isolation & purification; D004306:Dose-Response Relationship, Immunologic; D000939:Epitopes / Q000494:pharmacology; D004926:Escherichia coli / Q000235:genetics / Q000276:immunology; D005822:Genetic Vectors / Q000276:immunology; D006636:Histamine Release; D006801:Humans; D007073:Immunoglobulin E / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification; D006109:Poaceae / Q000276:immunology; D011058:Pollen / Q000737:chemistry* / Q000276:immunology*; D011994:Recombinant Proteins / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology / Q000378:metabolism
D000485:Allergens; D000939:Epitopes; C084984:PHLPII protein, Phleum pratense; C076049:Phl p V protein, Phleum pratense; D010940:Plant Proteins; D011994:Recombinant Proteins; C090396:PHLPI protein, Phleum pratense; D007073:Immunoglobulin E