Identification of Bermuda grass (Cynodon dactylon)--pollen allergens by electroblotting.

Bermuda grass-pollen proteins were electrophoretically separated on polyacrylamide gels and transferred to nitrocellulose where IgE-binding components were detected by reaction with individual patient's serum and 125I-labeled antihuman IgE. Seventeen pollen components (in the molecular weight (MW) range of 8000 to 94,000 daltons), separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, bound IgE antibodies from a panel of 44 sera from allergic patients. The spectrum of Bermuda grass-pollen IgE-binding components detected is greater in number and wider in MW range than has previously been described. A component of MW 34,000 daltons (fraction 9) bound IgE from 100% of atopic sera tested. This component also bound the greatest quantity of IgE. Electrophoresis and transfer under nondissociating conditions revealed a component of MW 100,000 daltons that also bound IgE antibodies in all 44 sera tested. This component may be an aggregated form of fraction 9. A comparison of the electroblotting results obtained under dissociating and nondissociating conditions suggests once again that allergenic proteins in crude extracts may aggregate or associate during in vitro studies. Electrophoretic transfer analysis with sodium dodecyl sulfate-polyacrylamide gel electrophoresis may thus be the method of choice for allergen separation and identification.