Complementary DNA cloning of the major allergen Phl p I from timothy grass (Phleum pratense); recombinant Phl p I inhibits IgE binding to group I allergens from eight different grass species.
BACKGROUND
Grass pollens, such as pollen from timothy grass (Phleum pratense), represent a major cause of type I allergy.


OBJECTIVE
In this report we attempted to determine how cross-reactive allergenic components of grass pollens from different species can be represented by a minimum number of recombinant allergens.


METHODS
We isolated and sequenced a timothy grass pollen cDNA coding for the major allergen Phl p I. A recombinant Phl p I-beta-galactosidase fusion protein, which bound to IgE in 87% of patients with grass pollen allergy, was produced in Escherichia coli. Using recombinant Phl p V and Phl p I, we defined representative patients' sera that bound to group I but not to group V allergens, as well as sera with reactivity against group I and group V allergens. IgE immunoblot inhibition studies were done with nitrocellulose-blotted pollen extracts from eight grass species with different geographic distribution.


RESULTS
Preadsorption of patients' sera with recombinant nonfusion Phl p I strongly reduced IgE binding to group I allergens from the eight grasses, showing extensive cross-reactivity between species.


CONCLUSIONS
A single recombinant group I allergen contains many of the IgE epitopes of group I isoallergens from a number of different grass species.
Laffer
S
S
Institute of General and Experimental Pathology, Vienna, Austria.
Valenta
R
R
Vrtala
S
S
Susani
M
M
van Ree
R
R
Kraft
D
D
Scheiner
O
O
Duchêne
M
M
D000485:Allergens / Q000235:genetics* / Q000494:pharmacology*; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics*; D006801:Humans; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000276:immunology*; D008969:Molecular Sequence Data; D010936:Plant Extracts / Q000494:pharmacology; D006109:Poaceae / Q000276:immunology*; D011058:Pollen / Q000276:immunology*; D011994:Recombinant Proteins
D000485:Allergens; D018076:DNA, Complementary; D010936:Plant Extracts; D011994:Recombinant Proteins; D007073:Immunoglobulin E