Identification of IgE binding polypeptides cross-reactive with the Parietaria judaica main allergenic polypeptide

The major allergen of the pollen of Parietaria judaica was characterized using an anti-allergen MAb AC/15.1. The antibody was able to immunoadsorb four different polypeptides (10,000, 20,000, 30,000 and 40,000 mol. wt) from the pollen proteins radioiodinated by the Bolton-Hunter's reagent. The four polypeptides have been shown not to be covalently linked, except for the 10,000 mol. wt polypeptide (Pj10), which appeared to form Pj10 dimers under non-reducing conditions. All of them contained the antigenic epitope defined by the monoclonal antibody and demonstrated human IgE binding ability. The structural relationship of these polypeptides in the native allergen is discussed.