Influence of nonthermal extraction technique and allergenicity characteristics of tropomyosin from fish (Larimichthys crocea) in comparison with shrimp (Litopenaeus vannamei) and clam (Ruditapes philippinarum)

Abstract

Recent reports showed that patients could be sensitized to fish tropomyosin (TM), who exhibited clinical symptoms. However, little information is available on differences in TM immune cross-reactivity among fish, shrimp and clam. Moreover, allergenicity might change during the food processing owing to the change of protein structure. In this study, we developed a nonthermal extraction technique to purified TM, IgG/IgE binding, cross-reactivity and structures were compared. Results showed that raw and boiled fish-TM were not cross reactive and had weak recognition of shrimp, while, shrimp-TM and clam-TM were cross reactive. The ELISA further confirmed that fish-TM was not able to trigger allergic immune response in shrimp sensitive subjects, while, surface hydrophobicity of fish-TM was higher. The study demonstrated that fish-TM, being with high sequence similarity, did not have cross-reactivity with shrimp and clam-TM. They could have a variable degree of IgE binding depending on subject sensitivity and allergenicity.

Keywords: Allergenicity; Cross-reactivity; IgG/IgE binding; Nonthermal extraction; Structure; Tropomyosin.