Food allergens

Abstract

A food allergen may be defined as a substance that reacts with IgE antibodies, induces allergic sensitisation or induces allergic reactions. Some allergens only induce allergic sensitisation but do not provoke symptoms, while others bind IgE but do not induce mast cell degranulation. There is no common structure that can predict whether a given antigen may be a strong food allergen. A complete food allergen, e.g. fish parvalbumin, is capable of stimulating the immune system to produce IgE antibodies, and degranulate mast cells upon subsequent contact. The reason(s) for why some patients with IgE to ovalbumin tolerate eggs, and why some react on one occasion but not on another, are mostly unclear, but may be related to changes in gut permeability induced by other food substances or by gastro-intestinal inflammation prior to the allergen contact. IgE antibodies to fruit or vegetables often show cross-reactivity, due to carbohydrate structures. These cross-reactive glycans have been designated cross-reactive carbohydrate determinants (CCD). Anti-CCD antibodies are highly cross-reactive. The antibodies do not have clinical significant because CCD-containing foods are usually well-tolerated by patients with IgE antibodies to CCD. These IgE antibodies may cause confusion in relation to allergy diagnosis. © 1997 Elsevier Science B.V.

Acid suppression therapy and allergic reactions

“…Moreover, at least for food allergy induction, resistance of food proteins to gastric digestive enzymes seems to be decisive for allergenicity and has for a long time been regarded as predictive for their sensitizing capacity [41]. Digestion experiments with simu lated gastric uid were even considered to distinguish between potentially allergenic and non-allergenic food compounds and digestion labile food proteins were termed non-sensitizing elicitors [87,88]. However, during the past decades it has become evident that major food allergens inducing allergic sensitization via the oral route are readily degraded by gastric enzymes under physiological conditions [89].…”

Molecular Characterization of Arginine Kinase, an Allergen from the Shrimp <i>Litopenaeus vannamei</i>

“…AK is an abundant protein in the L. vannamei crude protein extract and it can also be considered a major shrimp allergen (fig. 1, EC lane) [26,27,28]. The fact that AK protein kept its allergenic activity in denaturing condition (SDS-PAGE) showed that interaction with IgE is probably shared by a lineal rather than a conformational epitope.…”

Criteria for Safe Use of Plant Ingredients in Diets for Aquacultured Fish

“…No common structure can predict whether an antigen may be an allergen but generally allergens resist enzymatic hydrolysis in the gastrointestinal tract (see review by Aalberse, 1997).…”