Purification and characterization of a major allergen from Dactylis glomerata pollen: the Ag Dg1

We have isolated an allergen (Ag Dg1) from Dactylis glomerata pollen which is recognized by the serum of 95% of human patients sensitive to D. glomerata pollen, as has been shown by the nitrocellulose immunoprint technique. After two successive purifications by preparative isoelectric focusing (IEF), Dg1 was characterized as a single band in analytical agarose IEF with a pI of 5.9 and was found to display 3 bands by sodium dodecyl sulfate polyacrylamide gel with the respective molecular weights: 21,000, 31,000 and 33,000 daltons. The high recognition frequency by IgE antibodies of Dg1 in the sera of allergic patients and its ability to trigger histamine release from sensitized human basophils allow to consider that Ag Dg1 is the main major allergen extracted from D. glomerata pollen.