Heated egg white proteins are more susceptible to gastrointestinal degradation

The majority (80%) of egg-allergic children tolerate extensively heated (baked) egg but the mechanisms underlying the reduced allergenicity of heated egg white are not completely understood. High temperature largely destroys IgE antibody-binding sites that result from protein folding (conformation). However, heated egg white proteins retain the ability to bind IgE antibody and trigger allergic reactions.

In a study published in the March 2011 issue of The Journal of Allergy and Clinical Immunology (JACI), Martos et al reported that heated egg white proteins (ovalbumin and ovomucoid) undergo enhanced digestion in the gastrointestinal tract compared to native proteins. In egg-allergic mice, heated egg white ingestion did not induce symptoms of anaphylaxis, whereas intraperitoneal administration (by-passing gastrointestinal digestion) induced anaphylaxis. Digested egg white proteins were less capable of triggering mediator release and basophil activation. Furthermore, heated egg white was further degraded during the transport across human intestinal epithelial cells to a form incapable of triggering basophil activation.

Martos et al proposed that reduced allergenicity of heated egg white proteins partially results from altered digestion and absorption in the gastrointestinal tract. Enhanced degradation of heated egg white proteins in the gastrointestinal tract is one of the mechanisms that underlie the clinical tolerance of baked egg in the majority of egg-allergic children.

 

The Journal of Allergy and Clinical Immunology (JACI) is the official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.

AAAAI - American Academy of Allergy Asthma & Immunology