Ole e 3, An Olive‐Tree Allergen, Belongs to a Widespread Family of Pollen Proteins

Abstract

An allergen has been isolated from a saline extract of olive tree (Olea europaea) pollen. The protein consists of a single polypeptide chain of 9.2-kDa, as determined by mass spectrometry. It contains neither tryptophan nor tyrosine residues, and displays an acidic isoelectric point. The secondary structure of the protein, estimated from the analysis of the circular-dichroism spectrum in the peptide-bond region, is composed of 52% a-helix, 10% a-strand, 29% Sturn and 9% non-regular conformation. The N-terminal end of the protein is blocked. Amino-acid-sequence data have been obtained from peptides produced by CNBr treatment of the native allergen. A partial sequence of 36 amino acids has thus been elucidated. The protein exhibits sequence similarity with pollen allergens from Brassica species and contains a Caz'-binding motif. The isolated protein displays IgE-binding activity against sera of patients allergic to olivetree pollen. It has been named Ole e 3, according to the recommendations of the IUIS Nomenclature Committee. IgG ELISA inhibition assays with polyclonal antibodies specific for Ole e 3 reveal the presence of proteins similar to Ole e 3 in the pollen from non-related plant species, which may explain allergic cross-reactivity processes.Keywords: allergen ; olive pollen ; Olea europaea ; Ole e 3 ; protein characterization.Type-I allergy is a clinical disorder that affects more than 15 % of the human population in developed countries. Olive pollinosis is one of the most important causes of type-I allergy in Mediterranean countries, where the olive tree is widely cultivated [l]. Ole e 1 has been shown to be a major allergen from olive pollen, since the IgE of more than 70% of olive-allergic patients recognize this protein [2-41. In addition to Ole e 1, other allergenic proteins have been detected in saline extracts of the olive pollen 15-71, some of which exhibit low molecular masses. Preliminary studies on these molecules were performed with pools of sera from patients hypersensitive to olive pollen. Lauzurica et al. 121 showed the existence of an IgE-reacting protein of 8 kDa upon SDS/PAGE of the pollen extract. Proteins of 7, 9, 14, 15 and 16 kDa, present in olive pollen, have been immunostained with individual sera from olive allergic patients [8]. However, isolation or molecular characterization was not performed for these allergens.Allergic cross-reactivities have been described among Oleaceae members. such as olive, ash and privet [9-131 as well as between olive-pollen and grass-pollen proteins [8]. In addition to profilin, which is an important and well defined panallergen involved in cross-reactions [ 141, other proteins contained in pollen from different species that have conserved sequences could be responsible for allergic processes in individuals not previously sensitized to a given biological source.In spite of the knowledge of a high number of allergenic structures, little is known about their B-cell and T-cell epitopes and the mechanism of induction of allergy. The protein allergens fre...

Characterization and Immunolocalization of a Cytosolic Calcium-Binding Protein from Brassica napus and Arabidopsis Pollen1

“…This linkage is highly conserved among diverse species. In addition to the Brassica proteins, highly related pollen allergens have been identified in Betula verrucosa (Engel et al, 1997;Twardosz et al, 1997), Olea europaea (Batanero et al, 1997), Artemisia vulgaris (Engel et al, 1997), and the monocots Cynodon dactylon (Suphioglu et al, 1997), Phleum pratens, and Lilium longiflorum (Engel et al, 1997;Twardosz et al, 1997). The present study also describes cloning of APC1, a homolog from Arabidopsis, and demonstrates the presence of related sequences in Antirrhinum but not in tobacco (Nicotiana tabacum).…”

“…In addition to the demonstration of homologous sequences in Antirrhinum described here, related proteins have been identified in Betula verrucosa (Engel et al, 1997;Twardosz et al, 1997), Olea europaea (Batanero et al, 1997), Artemisia vulgaris (Engel et al, 1997), Cynodon dactylon (Knox et al, 1992), Phleum pratense, and Lilium longiflorum (Engel et al, 1997;Twardosz et al, 1997), and multiple types were identified in Brassica rapa and B. napus (Toriyama et al, 1995;Lim et al, 1996) during the course of this study. The partial amino acid sequence from the second pollen protein purified in this study, PP-A, indicates that it, too, is a member of this protein family.…”

Solution Structure, Dynamics, and Hydrodynamics of the Calcium-bound Cross-reactive Birch Pollen Allergen Bet v 4 Reveal a Canonical Monomeric Two EF-Hand Assembly with a Regulatory Function

“…91 Polcalcin accumulation at the tip of growing pollen tubes 18,24,25 suggests a correlation with the tipfocused Ca 2þ gradient which determines the direction of pollen tube growth. 10,18,19,21,23 -26 The polcalcins are rapidly washed out of the cytosol upon pollen hydration, 10,13,18,19,24,25,27 which explains the allergenicity of the intracellular polcalcins. Although the polcalcins are minor allergens in terms of IgE binding prevalence, human basophil histamine release assays and skin prick tests revealed remarkable allergenic potency in affected patients.…”

“…9 Between 5% and 20% of birch pollinotics mount IgE antibodies against the 9.4 kDa minor birch pollen allergen Bet v 4, an acidic two EF-hand Ca 2þ -binding polcalcin. 10,11 A series of allergenic polcalcins have been reported in the literature, namely Aln g 4 from alder (Alnus glutinosa), 12 Ole e 3 from olive (Olea europaea), 13,14 Syr v 3 from lilac (Syringa vulgaris; Ledesma et al, unpublished), Bra n 1 or BPC1 and Bra n 2 from oilseed rape (Brassica napus) as well as Bra r 1 and Bra r 2 from turnip rape (Brassica rapa), 15 -18 Phl p 7 from timothy grass (Phleum pratense), 19 and Cyn d 7 from Bermuda grass (Cynodon dactylon). 20,21 Aln g 4, Syr v 3, Bra n 1 or BPC1, Bra n 2, Bra r 1, Bra r 2 and Phl p 7 as well as the polcalcin APC1 from mouse-ear cress (Arabidopsis thaliana), 18 however, have not been included in the official allergen list of the International Union of Immunological Societies (IUIS) yet and the allergen designations Bra n 1 and Bra r 2 even conflict with two unrelated allergens.…”

Detection and Quantitation of Olive Pollen Allergen Isoforms Using 2-D Western Blotting

“…The allergenic activity of polcalcins is primarily associated with the Ca 2+ -bound isoforms (Engel et al 1997, Hayek et al 1998& Twardosz et al 1997. The prevalence of Ole e 3 is higher than 50% of the olive pollen sensitized population (Batanero et al 1996a). This allergen shows polymorphism at positions 43 (L  P) and 80 (V  I) of its amino acid sequence (Ledesma et al 1998b).…”