Major allergens of date palm (Phoenix dactylifera L.) pollen. Identification of IgE-binding components by ELISA and immunoblot analysis.

The IgE-binding components of date palm (Phoenix dactylifera L.) pollen were determined by ELISA and Western blotting in atopic patients in order to identify its major allergens. From a pool of previously identified allergenic fractions and sera from 15 skin-test-positive, atopic subjects, four components of 12, 14.4, 57, and 65-67 kDa were found to bind IgE in 80-93% of sera. Two other components of molecular masses 28-30 and 37-40 kDa also bound 60-80% of atopic sera. The immunologic specificity of date-pollen allergen that induced antibody response in sera of atopic patients was confirmed with ELISA. Furthermore, most of the reactivity in pooled positive atopic serum and antiserum raised in rabbits was eliminated after the sera were absorbed with the allergen. IgG immunoblot analyses showed varying degrees of cross-reactivity with common local allergens, notably Bermuda grass, but were generally of low intensity. These results indicate that date pollen has six major allergens with the 12, 14.4, 57, and 65-67 kDa bands binding 80-93%, and the 28-30 and 37-40 kDa bands 60-80% of atopic sera. We propose that these major allergens be assigned the notations "Pho d I" to "Pho d VI" in the order listed.