Glycoprotein allergens in pollen of timothy. III. Immunochemical and biological properties of a basic glycoprotein.
Crossed immunoelectrophoresis (CIE) and tandem CIE indicated that a basic glycoprotein allergen isolated from pollen of timothy is immunochemically identical to the allergen formerly denoted as antigen 30. The glycoprotein gave one band in SDS-PAGE and agarose isoelectric focusing. After transfer to nitrocellulose by electroblotting or by capillary blotting, the allergen specifically bound IgE from persons allergic to timothy pollen. The single allergen inhibited about 15% of the IgE binding to radioallergosorbent test discs of whole timothy pollen extract. Sera from patients investigated also contained detectable amounts of IgG towards the allergen. In quantitative skin prick tests, the mean activity of 2 micrograms/ml purified allergen in 7 patients was equivalent to that of a timothy pollen extract containing 10,000 BU/ml (assayed relatively to histamine in skin prick test). The ability of the allergen to form a precipitate in rocket immunoelectrophoresis was lost when it was heated to 80 degrees C or incubated with 4 M guanidine hydrochloride.