Background: The inhalation of olive (Olea europaea) pollen is an important cause of allergic respiratory diseases in southern Europe and California.

Objective: The aims of this study were to characterize the allergenic composition of O. europaea pollen collected in California and to purify two important allergens.

Methods: One hundred grams of O. europaea pollen was extracted dialyzed in 10 kd cut-off membranes and lyophilized. Allergen characterization was done by sodium dodecylsulfate–polyacrylamide gel electrophoresis and immunoblotting. Two allergens were isolated by gel filtration, ion exchange, and hydrophobic interaction chromatography and sequenced.

Results: Ole e 4 has an apparent molecular weight, under reducing conditions, of 32 kd and pIs between 4.65 and 5.1. The N-terminal was blocked and the analysis of the amino acid sequence of two internal regions revealed no homology with other known proteins. Ole e 5 has a molecular weight of 16 kd and pIs between 5.1 and 6.5. The amino acid sequence of the N-terminal showed a high degree of homology with superoxide dismutase of several plant species. Ole e 4 and Ole e 5 had an IgE binding frequency by immunoblot of 80% and 35%, respectively.

Conclusions: Olive pollen extracts have a heterogeneous composition, with several important allergens. One of these allergens showed a high degree of homology with a superoxide dismutase. (J Allergy Clin Immunol 1998;101:210-6.)