Cypress (Cupressus sempervirens) Pollen Allergens: Identification by Protein Blotting and Improved Detection of Specific IgE Antibodies

Abstract

On the basis of results of an investigation of the effects of different treatments employed, a dialysed and reduced extract of Cupressus sempervirens was separated electrophoretically on sodium dodecylsulphate-polyacrylamide gels before being transferred and then fixed with glutaraldehyde to nitrocellulose membrane. Probing with sera from 91 subjects allergic to C. sempervirens pollen followed by detection of bound IgE antibodies with [¹²⁵I]-labelled anti-human IgE revealed 17 IgE-binding proteins in the molecular weight range 14–96 kilodaltons (kDa). One component, of molecular weight ∼42 kDa, reacted with IgE antibodies in the sera of 81.3% of the allergic subjects and, for each of the subjects, this component bound the greatest quantity of IgE. Almost 50% of the sera recognized only the ∼42 kDa component, reinforcing the conclusion that this component is the major allergen of C. sempervirens pollen. A comparative study employing C. sempervirens pollen allergen discs prepared commercially or in the laboratory showed that values of the uptakes of [¹²⁵I]-anti-IgE indicating the presence of pollen-reactive IgE antibodies obtained with the latter discs were consistently higher (means 4.5 vs. 0.88), and that false-negative results were obtained when many sera were used with the commercial discs. The results of this study provide an essential basis for the production of standardized, safe and effective C. sempervirens pollen extract applicable to diagnosis and therapy of cypress pollen allergy.