Cross‐reactivity of IgE antibodies to allergens

Abstract

The cross-reactivity of IgE antibodies is of interest for various reasons, three of which are discussed. Firstly, from the clinical view, it is important to know the patterns of cross-reactivity, because they often (but not always) reflect the pattern of clinical sensitivities. We discuss the cross-reactivities associated with sensitization to pollen and vegetable foods: PR-10 (Bet v 1-related), profilin, the cross-reactive carbohydrate determinant (CCD), the recently described isoflavone reductase, and the (still elusive) mugwort allergen that is associated with celery anaphylaxis; cross-reactivities between allergens from invertebrates, particularly tropomyosin, paramyosin, and glutathione S-transferase (GST); and latex-associated cross-reactivities. Clustering cross-reactive allergens may simplify diagnostic procedures and therapeutic regimens. Secondly, IgE crossreactivity is of interest for its immunologic basis, particularly in relation to the regulation of allergic sensitization: are IgE antibodies to allergens more often cross-reactive than IgG antibodies to ''normal'' antigens? If so, why? For this discussion, it is relevant to compare not only the structural relation between the two allergens in question, but also the relatedness to the human equivalent (if any) and how the latter influences the immune repertoire. Thirdly, prediction of IgE cross-reactivity is of interest in relation to allergic reactivity to novel foods. Cross-reactivity is a property defined by individual antibodies to individual allergens. Quantitative information (including relative affinity) is required on cross-reactivity in the allergic population and with specific allergens (rather than with whole extracts). Such information is still scarce, but with the increasing availability of purified (usually recombinant) allergens, such quantitative information will soon start to accumulate. It is expected that similarity in short stretches of the linear amino-acid sequence is unlikely to result in relevant crossreactivity between two proteins unless there is similarity in the protein fold.

Potential, pitfalls, and prospects of food allergy diagnostics with recombinant allergens or synthetic sequential epitopes

“…135 In cross-sensitized patients this process represents an imminent danger regarding a possible switch from a currently existing pollinosis to a future food-pollen allergy syndrome or from a current single food allergy to multiple food hypersensitivity. [136] and [137] Regarding a currently not yet clinically relevant cross-reactivity, component-resolved analyses with recombinant allergens promise improved prediction by means of (1) exact quantification of different sIgE titers and (2) quantitative reciprocal cross-inhibition experiments performing sequential preabsorption of the sera with increasing amounts of homologous allergens.…”

Close-up of the Immunogenic α1,3-Galactose Epitope as Defined by a Monoclonal Chimeric Immunoglobulin E and Human Serum Using Saturation Transfer Difference (STD) NMR

“…Apart from the protein backbone, IgG and IgE may also be directed against xenobiotic and therefore immunogenic and cross-reactive carbohydrate determinants (CCDs) 3 present on a plethora of proteins found in food, pollen, and hymenoptera venom (2). The hallmark of classical CCDs are ␣1,3-linked core fucose residues found on insect venom allergens, and, additionally, ␤1,2-linked xylose on plant-derived CCDs.…”

Computational tools for the study of allergens

“…Patterns of allergic cross-reactivity, are important because they may reflect (a) the pattern of clinical sensitivities, (b) regulation of allergic sensitization via B-and T-cell epitope cross-reactivity and (c) the need for screening of novel foods for allergenicity (89). A large proportion of patients with pollen allergies show hypersensitivity after eating fresh fruit or vegetables.…”