CHARACTERISTICS OF THE ALLERGENIC POTENTIAL OF CLINICALLY SIGNIFICANT STRAWBERRY ALLERGEN OF CLASS PR-10

Despite its economic importance and health benefits, strawberries (Fragaria × ananassa) can cause IgE-mediated allergic reactions, primarily manifesting as oral allergy syndrome. The primary sensitizing factor is the allergen Fra a 1. This protein is a member of the PR-10 (pathogenesis-related proteins) family and is structurally homologous to the major birch pollen allergen Bet v 1. This study assessed the allergenic potential of the strawberry allergen Fra a 1 and analyze the effect of heat treatment on its structural and functional properties. A recombinant allergen, Fra a 1, was obtained. Fluorescence spectroscopy demonstrated the protein's ability to bind a wide range of fatty acids, confirming the functional activity of the recombinant analogue. Circular dichroism demonstrated that heating to 98°C causes irreversible changes in the protein's secondary structure. Enzyme-linked immunosorbent assay demonstrated that pre-boiling (99°C, 15 min) leads to a statistically significant but partial (up to 30%) reduction in the ability of Fra a 1 to bind cross-reactive polyclonal anti-Bet v 1 IgG, while binding to specific IgE from sera of patients with pollen and food allergy decreased in only half the cases. A study of proteolysis kinetics revealed rapid degradation of the allergen by pepsin in vitro, which was not accelerated by preheating. Furthermore, Fra a 1 exhibited relative resistance to digestion by lysosomal enzymes of human macrophages in vitro compared to birch Bet v 1 and soybean Gly m 4. These data indicate partial thermal stability of the Fra a 1 allergen, its ability to retain IgE-binding activity in some sensitized individuals after heating, and characteristics of proteolytic degradation that may modulate its immunogenicity. The results of the study are important for assessing the risks associated with the consumption of heat-treated strawberries and developing strategies to reduce allergenicity.

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