Association of end-product adducts with increased IgE binding of roasted peanuts

Recently, we have shown that roasted peanuts have a higher level of IgE bin ding (i.e., potentially more allergenic) than raw peanuts. We hypothesized that this increase in IgE binding of roasted peanuts is due to an increased levels of protein-bound end products or adducts such as advanced glycation end products (AGE), N-(carboxymethyl)lysine (CML), malondialdehyde (MDA), and 4-hydroxynonenal (HNE). To support our hypothesis, we produced polyclon al antibodies (IgG) to each of these adducts, determined their levels in ra w and roasted peanuts, and examined their ability to bind to IgE from a poo led serum of patients with clinically important peanut allergy. Results sho wed that AGE, CML, MDA, and HNE adducts were all present in raw and roasted peanuts. Roasted peanuts exhibited a higher level of AGE and MDA adducts t han raw peanuts. IgE was partially inhibited in a competitive ELISA by anti bodies to AGE but not by antibodies to CML, MDA, or HNE. This indicates tha t IgE has an affinity for peanut AGE adducts. Roasted peanuts exhibited a h igher level of IgE binding, which was correlated with a higher level of AGE adducts. We concluded that there is an association between AGE adducts and increased IgE binding (i.e., allergenicity) of roasted peanuts.