Antigenicity and Immunocrossreactivity of Orange Tree Pollen and Orange Fruit Allergenic Extracts

Abstract

Background: It is important to study the crossreactivity between orange tree pollen (OTPE) and orange fruit (OFE) due to the high incidence of pollen/food-related allergies worldwide. The aim of the present study was to determine the antigenic relationship between OTPE and OFE. Methods: OTPE and OFErabbit antisera as well as sera from patients allergic to OTPE and OFE were comparatively applied in IgG- and/or IgE-specific ELISA inhibition, crossover or inhibition immunoblotting assays using OTPE and OFE allergenic extracts as solid phase. Periodate and proteinase K treatments were used for carbohydrate and protein depletion, respectively. Results: The antigenicity of OTPE and the presence of common structures between OTPE and OFE extracts were demonstrated by rabbit IgG-specific ELISA inhibition and crossover immunoblotting assays. A 30-kDa protein, common target of the IgE response on OTPE, OFE and mandarin extract, but absent in lemon extract, was identified by ELISA and immunoblot inhibition assays in patients suffering from primary sensitization to OTPE in the context of occupational exposure. Moreover, biochemical treatments showed that antigenic epitopes on the 30-kDa protein contain polypeptidic but no carbohydrate moieties. Conclusions: The antigenicity of OTPE, the presence of common antigenic determinants between pollen and citrus fruits and an IgE-specific crossreactive protein band of 30 kDa sharing carbohydrate-free epitopes were described. After isolation and purification, this common antigen might be useful for allergen immunotherapy in pollen/fruit-related allergic patients.

Pru p 9, a new allergen eliciting respiratory symptoms in subjects sensitized to peach tree pollen

“…Many plant pollens from fruit trees are entomophilous and therefore considered of low allergenic interest, except for subjects occupationally exposed [3,4]. Cases of allergic reactions to pollen from fruit trees and ornamental plants have been reported, although mainly limited to workers directly exposed or pollen that is transported by airborne particles [5][6][7][8][9]. However, in certain regions of the world fruit tree pollens can be relevant not only in exposed individuals but also in the general population, as occurs with palm tree pollen [10,11].…”

“…In certain cases, pollens from cultivated and non-cultivated plants can be relevant for subjects exposed at different agricultural sites [4,5]. In the case of cultivars of fruit trees, although entomophilous, pollen grains can be transported by the wind for short distances [9,13]. This transport can be facilitated by the presence of pollutants or the disruption of pollen in smaller submicronic particles [2].…”

Immunoglobulin E-Mediated Autoimmunity

“…Other examples of IgE cross-reactivity include pollen–food allergy, such as apple–birch allergy or pollen–fruit allergy ( 249 – 253 ), dog–cat allergy ( 254 , 255 ), poultry–meat allergy ( 256 ), fish–chicken allergy ( 257 ), birch–oak allergy ( 258 ), latex–hymenoptera allergy ( 239 – 241 ). IgE cross reactivity to latex and parasites like Schistosoma has also been described ( 259 , 260 ).…”

Direct evidence for the presence of allergens in Rosaceae fruit tree pollen

“…Pollen from Fagales has been shown to be of high clinical impact due to airborne pollination. In contrast, it was assumed, that inhalation of insect-borne fruit tree pollen is only limited to people having a very close contact to fruit trees in the context of occupational exposure (Iraneta et al, 2005). Monitoring of Rosaceae pollen across Europe during the past 30 years, showed a moderate, but constant exposure.…”

“…First studies in fact revealed similar IgE cross-reactivity among the pollen proteins of birch and apple trees (Berrens, van Dijk, Houben, Hagemans, & Koers, 1990). Recently significant IgE-mediated allergy to papaya and orange tree pollen was demonstrated as a consequence of occupational fruit pollen exposure (Blanco et al, 1998;Iraneta et al, 2005).…”