Allergenicity of tropomyosin variants identified in the edible insect Hermetia illucens (black soldier fly)

Insect consumption could address the increasing protein demand in compliance with environmental sustainability. Hermetia illucens (black soldier fly, BSF) is a promising insect for human diet and it is essential to assess the related allergenic risk, meant as primary sensitization or cross-reactivity with known allergens. In this work, we investigate the allergenicity of two tropomyosin variants identified in the BSF genome and produced as recombinant proteins. Immunoblot experiments showed that both proteins were recognized by sera of patients allergic to shrimp or mites highlighting the cross-reactivity risk. CD spectroscopy, cross-linking assays and size-exclusion chromatography showed a structure composed of alpha-helices oligomers for both variants. These proteins were quite stable to pH but sensitive to increasing temperatures. In vitro simulated digestion associated to mass-spectrometry allowed the identification of peptides resistant to gastrointestinal conditions which were compared with epitopes of Arthropoda and Mollusca allergens to predict the persistence of allergenicity upon digestion.