Shellfish Tropomyosin IgE Cross-Reactivity Differs Among Edible Insect Species

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.

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.

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.