Roasting and lipid binding provide allergenic and proteolytic stability to the peanut allergen Ara h 8.
Abstract Ara h 8 is the peanut allergen homologous to the birch pollen allergen Bet v 1. Because Bet v 1 has been shown to bind lipophilic ligands, the aim of this investigation was to determine the impact of lipid binding and roasting on the Ara h 8 structure and their influences on allergenicity. For the characterization of natural Ara h 8 (nAra h 8) from roasted and unroasted peanuts, circular dichroism spectroscopy, hydrophobic binding assay, immunohistochemistry, and immunoblot with sera of peanut allergic patients were performed and compared with results from recombinant Ara h 8 (rAra h 8) and Bet v 1. rAra h 8 displayed stronger hydrophobicity than rBet v 1. Patients' sera showed IgE reactivity with rAra h 8 and nAra h 8 from roasted peanuts, whereas fewer sera recognized nAra h 8 from unroasted peanuts. Simulated gastric digestion experiments demonstrated low proteolytic stability of rAra h 8, whereas the stability of nAra h 8 was increasingly higher in unroasted and roasted peanuts. The results demonstrate that IgE reactivity and thermal and proteolytic stability are reinforced in nAra h 8 after roasting, most likely due to Maillard reactions, lipid oxidations, and lipophilic associations. These aspects must be considered when estimating the allergenicity of Bet v 1-homologous proteins.
Arnd
A
Petersen
Sandra
S
Rennert
Skadi
S
Kull
Wolf-Meinhard
WM
Becker
Holger
H
Notbohm
Torsten
T
Goldmann
Uta
U
Jappe
D000485:Allergens / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification; D010367:Arachis / Q000737:chemistry / Q000276:immunology*; D006358:Hot Temperature; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008055:Lipids / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification; D059748:Proteolysis
D000485:Allergens; D008055:Lipids; D010936:Plant Extracts