Bioinformatics and Proteomics Evaluations of Potential IgE Cross-Reactive Proteins in Novel Edible Insects and Shrimp for Food Safety

Historically, insects have been consumed in many countries, although rarely in Europe and U.S. The European Food Safety Authority recently recognized mealworm as a potential cross-reactive novel food with risk of allergic cross-reactivity for those with shrimp allergy. Regulators in the United States are asking developers to evaluate products containing cultured insects (crickets) for risks for crustacean allergic subjects, which we evaluated. Transcriptomes of cricket, mealworm, silkworm, and locust and allergenic crustaceans were compiled using de novo and reference based assemblers. Transcripts were compared to allergens in AllergenOnline.org V18B using BLASTX, focusing on sequences of tropomyosin and arginine kinase. Abundance of mRNA of these proteins were estimated using RNA-seq quantification with RSEM software. Protein levels were measured using untargeted proteomics by LC-MS/MS to estimate the abundance of tropomyosin and arginine kinase. Potential IgE epitopes were predicted using five immunoinformatics programs. The predicted epitopes were compared to published epitopes from allergenic arthropod sequences. Specific IgE binding assays were performed to test IgE cross-reactivity using available shrimp and insect allergic sera. High sequence identities were found with high abundance transcripts of tropomyosin and arginine kinase compared to sequences of shrimp allergens. Proteomics confirmed the presence of isoforms. Direct binding and inhibition assays using protein extracts noted positive IgE binding for some allergic subjects. Some crustacean-allergic consumers are likely to experience cross-reactions if they consume foods containing proteins from crickets, mealworm, silkworm, or locust. Allergists should be aware and alert crustacean allergic patients.