Shellfish Tropomyosin IgE Cross‐Reactivity Differs Among Edible Insect Species

Abstract

Scope: Insects are a potentially environmentally friendly alternative dietary protein source to supplement mammalian and fish sources, but potential allergenic risks are a concern. Consumption of insects may result in anaphylaxis and has been implicated in cross-reactivity with shellfish. Many allergenic proteins may be involved in cross-reactivity, including tropomyosin (TM). The uniformity of TM cross-reactivity among edible insects is unknown. Candidate edible insects for variability in shellfish IgE cross-reactivity are investigated. Methods and results: Selected insects and known related sources of allergens are extracted and probed by immunoblot with sera/plasma from patients sensitized to insects or shellfish. Quantification of TM in these extracts is performed using mass spectrometry. A comparison of the quantity of TM and the IgE reactivity of TM from these insects is performed. Distinct patterns of IgE cross-reactivity are observed with three insect species showing diminished reactivity. This pattern is not consistent with the amount of TM present in these insects, or with overall sequence homology. Conclusion: Insects display a diversity of TM-associated IgE reactivity. It is likely that minor sequence features and/or structural effects are primarily responsible. Additionally, it is demonstrated that some insect species may present significantly less IgE cross-reactivity to shrimp than do others.

A Proteomic- and Bioinformatic-Based Identification of Specific Allergens from Edible Insects: Probes for Future Detection as Food Ingredients

“…More recently, an anaphylactic reaction was reported after consumption of yellow mealworm [34], and silkworm pupae [35]. Most of the insect allergens identified as IgE-binding allergens, cross-react with shellfish, mollusk and nematod allergens and thus correspond to IgEbinding cross-reacting pan-allergens, widely distributed in various animal phyla [36][37][38][39][40][41][42][43][44]. Among these cross-reacting allergens, alpha-actin, arginine-kinase (AK), enolase, fructose-1,6-biphosphate aldolase (FPA), glyceraldehyde-3-phopho-deshydrogenase (GAPDH), and tropomyosin, consist of the frequently identified IgE-binding cross-reacting allergens [33].…”

Allergens from Edible Insects: Cross-reactivity and Effects of Processing

“…In contrast, crustacean allergic patients clearly showed sensitization to tropomyosin in the same extracts. The identity degree between Der p 10 and YMW TM and between Lit v 1 and YMW TM are very similar, i.e., 66 and 70% respectively ( https://blast.ncbi.nlm.nih.gov ), but differences in crucial sequences of epitopes regions might explain the differences observed in terms of cross-reactivity, as suggested Palmer and co-workers [ 51 ••].…”

“…Francis et al [ 50 ••] investigated the cross-reactivity of AK from A. domesticus and T. molitor in subjects exposed to edible insects, and no cross-reaction phenomena were observed, although AK from different insects are acknowledged to share high sequence identity (70% on average) and homology (90% on average) [ 37 ]. Small differences in the sequences could likely cause a differential IgE binding, as Palmer and collaborators also stated [ 51 ••]. This could be the reason for the absence of cross-reactivity observed by Francis and co-workers [ 50 ••].…”

“…It has to be taken into consideration that, although the amino acid identity between two compared structures correlates with the probability of cross-reactivity, the mere amino acid identity and the structural homology are weak predictors and should be used prudently [ 48 •, 51 ••]. Thus, EFSA guidelines suggest additional clinical tests, like SPT or basophils activation test (BAT), and the golden standard to determine the absence/presence of allergenicity, i.e., the double-blind placebo-controlled food challenge (DBPCFC) [ 47 , 52 ].…”

“…An important aspect that has to be considered is the fact that most of the studies based on immunoblotting, BAT, and/or ELISA techniques described the sensitization of patients allergic to shellfish/inhalant allergens (e.g., cockroach or mites) to protein extracts derived from edible insects [ 11 , 13 ••, 15 , 45 ••, 51 ••], and in some cases also to purified proteins [ 50 ••]. As claimed by Broekman et al [ 55 ], particular attention should be paid to the extract preparation because this could modify the representative set of proteins.…”