Cloning, sequencing and immunological characterization of Dac g 3, a major allergen from Dactylis glomerata pollen.
Preliminary work showed that a 14-kDa allergen with a pI of 9 was recognized by more than 60% of sera from Dactylis glomerata (Dac g) pollen-allergic individuals. The N-terminal amino acid sequence of this Dac g allergen was determined by Edman degradation and compared with that of Lol p 3, a major allergen of Lolium perenne. A sequence identity of 65% was found, suggesting that the Dac g allergen could be the homologue of Lol p 3 and therefore named Dac g 3. We report the cloning and sequence analysis of a cDNA encoding the Dac g 3 pollen allergen. The recombinant allergen (rDac g 3) expressed in plasmid vector pGEX-2T contained IgE-reactive epitopes found in its natural counterpart, and induced histamine release from basophils of Dac g-allergic individuals, confirming that the recombinant protein has biological properties similar to the pollen extracted allergen. Computer analyses showed that, in spite of a high degree of sequence homology, even closely related allergens such as Dac g 3 and Lol p 3 have dissimilar predictive secondary structures and potential different antigenicity. Because it possesses the properties of the native counterpart, rDac g 3 could be a relevant tool for molecular studies in allergy.
Guérin-Marchand
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C
Unité d'Immuno-Allergie, Institut Pasteur, Paris, France. clobert@pasteur.fr
Sénéchal
H
H
Bouin
A P
AP
Leduc-Brodard
V
V
Taudou
G
G
Weyer
A
A
Peltre
G
G
David
B
B
D000485:Allergens / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification*; D000595:Amino Acid Sequence; D052179:Antigens, Plant; D001483:Base Sequence; D003001:Cloning, Molecular; D003429:Cross Reactions; D018076:DNA, Complementary / Q000302:isolation & purification; D015180:Electrophoresis, Gel, Two-Dimensional; D006636:Histamine Release; D006801:Humans; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification*; D006109:Poaceae / Q000276:immunology*; D011058:Pollen / Q000276:immunology*; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D000485:Allergens; D052179:Antigens, Plant; D018076:DNA, Complementary; C102060:Dac g 3 allergen; D010940:Plant Proteins