Impact of Sulfur and Vitamin C on the Allergenicity of Mal d 2 from Apple (Malus domestica)

• Published in: Journal of agricultural and food chemistry 2014-07, Vol.62 (30), p.7622-7630
• Main Authors: Marzban, Gorji, Kinaciyan, Tamar, Maghuly, Fatemeh, Brunner, Richard, Gruber, Clemens, Hahn, Rainer, Jensen-Jarolim, Erika, Laimer, Margit
• Format: Article
• Language: English
• Subjects: allergenicity; allergens; Allergens - immunology; Allergens - isolation & purification; Animals; Antigens, Plant - immunology; Antigens, Plant - isolation & purification; apples; ascorbic acid; Ascorbic Acid - pharmacology; beta-N-Acetylhexosaminidases - metabolism; Cell Line, Tumor; chemical reduction; disulfide bonds; Electrophoresis, Polyacrylamide Gel; Food Handling; Food Hypersensitivity - immunology; Food Hypersensitivity - prevention & control; food preservatives; food processing; Fourier transform infrared spectroscopy; heat treatment; Hot Temperature; Humans; immunoglobulin E; Immunoglobulin E - immunology; immunoglobulin G; Malus - immunology; Malus domestica; Plant Proteins - chemistry; Plant Proteins - immunology; Rats; reducing agents; reflectance; Skin Tests - methods; Spectroscopy, Fourier Transform Infrared; sulfur; Sulfur - pharmacology; Transfection; Western blotting
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf5020878

Mal d 2 is a minor allergen from apple which shows a high conformational stability due to its eight conserved disulfide bridges. Chemical reduction of disulfide bridges and linearization of Mal d 2 lead to enhanced IgE reactivity in vitro and indicate a higher potential for allergenicity. Since food preservatives such as sulfur and vitamin C are reducing and denaturing agents, their influence on Mal d 2 allergenicity was verified by simulated food processing conditions. The immunoreactivity of purified Mal d 2 was investigated after different treatments in vitro and in vivo using IgG/IgE Western blotting, mediator-releasing cell assay, and skin prick and oral smear tests. The conformational changes of Mal d 2 upon addition of 1% and 5% vitamin C were also monitored by attenuated total reflectance Fourier transform infrared spectroscopy. The results show no positive skin and oral smear test reactivity to native, heated, or vitamin C-treated purified Mal d 2. Furthermore, the results confirm that sulfur in combination with heat treatment can influence the structural integrity and thus the allergenicity of Mal d 2, while vitamin C is too weak as a reducing agent to change allergenicity.