The Spectrum of Olive Pollen Allergens

Abstract

Olive pollen is one of the most important causes of seasonal respiratory allergy in Mediterranean countries, where this tree is intensely cultivated. Among the high number of protein allergens detected in this pollen, 8 – Ole e 1 to Ole e 8 – have been isolated and characterized. Ole e 1 is the most frequent sensitizing agent, affecting more than 70% of the patients suffering of olive pollinosis, although others, such as Ole e 4 and Ole e 7, have also been shown to be major allergens. In this context, the prevalence of many olive pollen allergens seems to be dependent on the geographical area where the sensitized patients live. Some of the olive allergens have been revealed as members of known protein families: profilin (Ole e 2), Ca²⁺-binding proteins (Ole e 3 and Ole e 8), superoxide dismutase (Ole e 5) and lipid transfer protein (Ole e 7). No biological function has been demonstrated for Ole e 1, whereas Ole e 4 and Ole e 6 are new proteins without homology to known sequences from databases. cDNAs encoding for Ole e 1, Ole e 3 and Ole e 8 have been overproduced in heterologous systems. The recombinant products were correctly folded and exhibited the functional activities of the natural allergens. In addition to the Oleaceae family, other species, such as Gramineae or Betulaceae, contain pollen allergens structurally or immunologically related to those of the olive tree. This fact allows to detect and evaluate antigenic cross-reactivities involving olive allergens. The aim of this research is the development of new diagnostic tools for olive pollinosis and new approaches to improve the classical immunotherapy.

A Major Allergen from Pollen Defines a Novel Family of Plant Proteins and Shows Intra- and Interspecie Cross-Reactivity

“…Patients exhibiting high radioallergosorbent test values (4 -6) for olive pollen extract are sensitive to a considerable number of its allergens (9). Thus, analysis of the allergogram of olive pollen, at least of their major allergenic components, is essential to design standardized mixtures for effective diagnosis and specific immunotherapy.…”

“…Olive pollen extracts contain a high number of allergenic components, from which up to nine (Ole e 1 to Ole e 9) have been characterized (9,10). Regarding their prevalence, Ole e 1 is the main allergen from olive pollen, affecting Ͼ70% of the hypersensitive population (11,12).…”

“…No linear correlation between the responses was observed. This can be explained because the olive pollen contains at least nine more allergens, and some of them are major allergens (9). As Ole e 10 showed sequence similarity with the C-terminal domain of Ole e 9, IgE binding to this allergen was also analyzed in ELISA with the same 150 allergic sera (Fig.…”

NMR Solution Structure of Ole e 6, a Major Allergen from Olive Tree Pollen

“…Many side chain conformations of residues in rOle e 6 are well defined, with 22 residues (5,8,9,10,11,12,13,15,16,17,18,19,21,24,25,26,27,29,30,31,32, and 33) having 1 circular variances lower than 0.05. These residues with well defined side chain conformations mainly correspond to residues exhibiting high values of surface inaccessibility and to residues located in the secondary structural elements.…”

“…Ole e 6 is a 50-amino acid protein composed of a unique polypeptide chain with unknown function. Its allergenic prevalence varies for different geographical areas and reaches 55% in areas where the olive tree is extensively cultivated (21,25). The amino acid sequence contains two sets of the sequential motif Cys-X 3 -Cys-X 3 -Cys (25) and shows similarity with a polypeptide sequence deduced from tobacco (Nicotiana tabacum) cDNA.…”