IgE binding to peanut allergens is inhibited by combined d-aspartic and d-glutamic acids

The objective of this study was to determine if d-amino acids (d-aas) bind and inhibit immunoglobulin E (IgE) binding to peanut allergens. d-aas such as d-Asp (aspartic acid), d-Glu (glutamic acid), combined d-[Asp/Glu] and others were each prepared in a cocktail of 9 other d-aas, along with l-amino acids (l-aas) and controls. Each sample was mixed with a pooled plasma from peanut-allergic donors, and tested by ELISA (enzyme-linked immunosorbent assay) and Western blots for IgE binding to peanut allergens. Results showed that d-[Asp/Glu] (4 mg/ml) inhibited IgE binding (75%) while d-Glu, d-Asp and other d-aas had no inhibitory effect. A higher inhibition was seen with d-[Asp/Glu] than with l-[Asp/Glu]. We concluded that IgE was specific for d-[Asp/Glu], not d-Asp or d-Glu, and that d-[Asp/Glu] was more reactive than was l-[Asp/Glu] in IgE inhibition. The finding indicates that d-[Asp/Glu] may have the potential for removing IgE or reducing IgE binding to peanut allergens in vitro.