Determination of Ole e 1 by enzyme immunoassay and scanning densitometry. Validation by skin-prick testing

Ole e 1 is an important allergen in Olea europaea pollen extracts. This stu dy describes the development of two new methods that can be used to estimat e the Ole e 1 content in olive tree pollen extracts. They are based on (1) an enzyme immunoassay that uses rabbit polyclonal, monospecific antibodies and purified Ole e 1, and (2) scanning densitometry of SDS-PAGE gels. Twelv e extracts were evaluated by in vivo and in vitro methods. The in vivo biol ogical potency was estimated by prick skin testing 17 allergic individuals; the in vitro allergenic potency by direct IgE and IgE inhibition assays. T he enzyme immunoassay showed an operative range of 0.03-100 mu g/ml and dem onstrated to be specific for Ole e 1. The Ole e 1 content ranged from 1% to 5% of the total protein in the 12 extracts. The amount of Ole e 1, assesse d by gel scanning densitometry significantly correlated with the Ole e 1 co ntent obtained by the immunoassay (r = 0.92; p < 0.001). The Ole e 1 conten t showed a significant correlation with the total allergenic potency of the extracts, evaluated by direct IgE, specific IgE inhibition and skin-prick testing. These two methods can be used to determine the Ole e 1 content in olive pollen extracts. The content of Ole e 1 can vary from 1% to 5% of the total protein in the extracts. (C) 1999 Elsevier Science B.V. All rights r eserved.