Germin‐like protein Cit s 1 and profilin Cit s 2 are major allergens in orange (Citrus sinensis) fruits

Abstract

Oranges are clinically relevant allergenic foods. To date, orange allergens have not been characterized in detail. The study is aimed at analyzing the sensitization profile in orange-sensitized subjects with and without clinical allergy, and to identify orange allergens. Fifty-six sensitized subjects with selfreported reactions to orange were grouped into reactors (anaphylaxis or multiple episodes of immediate reactions and/or positive challenge tests) and non-reactors (negative open food challenge tests). Allergens were characterized by IgE immunoblotting, N-terminal sequencing, IgE-inhibition assays, and mediator release assays were performed to determine the allergenic potency of orange profilin. Of 56 subjects, 23 were classified as orange allergic showing mainly an oral allergy syndrome. Of 23 subjects classified as orange allergic, 22 were sensitized to profilin, Cit s 2. In patients with monosensitization to profilin in vitro histamine releases up to 75% from basophils were induced using orange extract and purified plant profilins. Of the allergic patients 78% were sensitized to germinlike protein, Cit s 1. Both allergens showed retained IgE reactivity in heat-processed orange juice. Interestingly, subjects with and without clinical allergy showed a comparable sensitization profile. Profilin and germin-like proteins are major orange allergens. The potential clinical relevance of orange profilin was indicated by its strong capacity to release histamine from basophils. However, a predominant sensitization to both allergens in subjects without symptoms also indicates a high frequency of clinically insignificant sensitization.

Reduced allergenicity of tomato fruits harvested from Lyc e 1–silenced transgenic tomato plants

“…In these patients profilins have the capacity to trigger strong mediator release from effector cells. 31 In summary, it is likely that despite the fact that an IgE response to profilins is considered to be of low significance in some patient populations, there is strong evidence that profilins might indeed be responsible for eliciting food allergy in a subgroup of sensitized patients and specific clinical syndromes.…”

Structural, Functional, and Immunological Characterization of Profilin Panallergens Amb a 8, Art v 4, and Bet v 2

“…Currently, it is clear that some profilins may be not only relevant pollen allergens but also important food allergens in some cases. For example, Cit s 2 (profilin from orange) and Cuc m 2 (profilin from melon) are relevant and major food allergens (31,39). In the case of Cit s 2 and Cuc m 2, the fact that oranges and melons most often are consumed in a raw form may be a very important factor because the allergens do not undergo denaturation before contact with a sensitized individual.…”

Maternal diet during pregnancy in relation to eczema and allergic sensitization in the offspring at 2 y of age

“…An association between celery, citrus fruit, or raw sweet pepper intake and allergic sensitization has not yet been described in the literature. Because potential allergens in celery (20), citrus fruit-in particular oranges (21,22)-and bell peppers (23) have been characterized, the observed associations might be linked to the allergenicity of these foods. However, the high antioxidant content of these foods should also be considered, although it seems unlikely that they play a causal role.…”