Allergenic characteristics of a modified peanut allergen

Attempts to treat peanut allergy using traditional methods of allergen desensitization are accompanied by a high risk of anaphylaxis. The aim of this study was to determine if modifications to the IgE‐binding epitopes of a major peanut allergen would result in a safer immunotherapeutic agent for the treatment of peanut‐allergic patients. IgE‐binding epitopes on the Ara h 2 allergen were modified, and modified Ara h 2 (mAra h 2) protein was produced. Wild‐type (wAra h 2) and mAra h 2 proteins were analyzed for their ability to interact with T‐cells, their ability to bind IgE, and their ability to release mediators from a passively sensitized RBL‐2H3 cell line. Multiple T‐cell epitopes were identified on the major peanut allergen, Ara h 2. Ara h 2 amino acid regions 11–35, 86–125, and 121–155 contained the majority of peptides that interact with T‐cells from most patients. The wAra h 2 and mAra h 2 proteins stimulated proliferation of T‐cells from peanut‐allergic patients to similar levels. In contrast, the mAra h 2 protein exhibited greatly reduced IgE‐binding capacity compared to the wild‐type allergen. In addition, the modified allergen released significantly lower amounts of β‐hexosaminidase, a marker for IgE‐mediated RBL‐2H3 degranulation, compared to the wild‐type allergen.