Homologous tropomyosins from vertebrate and invertebrate: Recombinant calibrator proteins in functional biological assays for tropomyosin allergenicity assessment of novel animal foods

• DOI: 10.1111/cea.13503
• Publication Date: 2019-09-21T14:59:10Z
• Authors: Julia Klueber; Joana Costa; Stefanie Randow; Françoise Codrean...; Kitty Verhoeckx; Carsten Bindslev‐...; Markus Ollert; Karin Hoffmann‐So...; Martine Morisset; Thomas Holzhauser; Annette Kuehn
• Keywords: Basophil activation; Penaeus monodon; Tropomyosin

Abstract Background Novel foods may provide new protein sources for a growing world population but entail risks of unexpected food‐allergic reactions. No guidance on allergenicity assessment novel exists, while genetically modified (GM) crops it includes comparison sequence identity with known allergens, digestibility tests and IgE serum screening. Objective As proof concept, to evaluate non‐/allergenic tropomyosins (TMs) regarding their potential as calibrator proteins in functional biological vitro assays the semi‐quantitative allergy risk TM‐containing animal mealworm TM an example. Methods Purified TMs (shrimp, Penaeus monodon ; chicken Gallus gallus E coli overexpression) were compared by sequencing, circular dichroism analysis digestion. binding was quantified using shrimp‐allergic patients' sera (ELISA). Biological activities investigated (skin testing; titrated basophil activation tests, BAT), mediator release humanized rat leukaemia (RBL) cells. Results Shrimp showed high homology, both alpha‐helical structures thermal stability. stable during gastric digestion, degraded quickly. Both bound specific from patients (significantly higher shrimp TM), whereas skin reactivity mostly positive only TM. BAT RBL cell TM, although at up 100‐ 1000‐times lower allergen concentrations than In calibrators, effector cells similar that confirmed already reported allergenic potency source. Conclusions & clinical relevance According current GM crops' assessment, non‐allergenic could falsely be considered weight‐of‐evidence approach. However, calibrating clinically validated allowed discrimination food protein's allergenicity. With calibration systems homologous might developed scale axis