Scallop (Chlamys nobilis) cause IgE mediated food allergy, however, studies on allergens in its musculus are not comprehensive enough. In this connection, the target protein was purified from scallop and...

Tropomyosin (TM) was reported to be a supercoil allergen of shellfish. However, little information is available about its link between structure and allergenicity. In this study, the subunit of TM (α-TM) and supercoil of TM (α 2 -TM) were identified from Haliotis discus hannai. α 2 -TM showed higher immunoreactivity than α-TM. Meanwhile, seven linear epitopes in α-TM and α 2 -TM were verified, and two conformational epitopes in α 2 -TM were predicted. The physicochemical properties and chemical bond assays confirmed the existence of the disulfide bond in α 2 -TM. According to spectroscopy and hydrophobicity analysis, α-TM showed higher α-helix features and blueshift of the fluorescence intensity peak compared with those of α 2 -TM. The structure analysis revealed the possibility of conformational epitopes in α 2 -TM, which could explain the immunoreactivity differences between α-TM and α 2 -TM further. These results improved the understanding of Haliotis discus hannai TM, which lay the foundation for the food processing of abalone.

The allergen TM was purified from Alectryonella plicatula; the sequence was cloned. Linear epitopes played a major role in IgE-binding capacity of ATM. Nine linear epitopes were verified. L-ATM-2 was the key epitope to bind with IgE; L-ATM-5 and L-ATM-7 were most conservative in shellfish.

Tropomyosin (TM) is an important crustacean (Scylla paramamosain) allergen. This study aimed to assess Maillard-reacted TM (TM-G) induction of allergenic responses with cell and mouse models. We analyzed the difference of sensitization and the ability to induce immune tolerance between TM and TM-G by in vitro and in vivo models, then we compared the relationship between glycation sites of TM-G and epitopes of TM. In the in vitro assay, we discovered that the sensitization of TM-G was lower than TM, and the ability to stimulate mast cell degranulation decreased from 55.07 ± 4.23% to 27.86 ± 3.21%. In the serum of sensitized Balb/c mice, the level of specific IgE produced by TM-G sensitized mice was significantly lower than TM, and the levels of interleukins 4 and interleukins 13 produced by Th2 cells in spleen lymphocytes decreased by 82.35 ± 5.88% and 83.64 ± 9.09%, respectively. In the oral tolerance model, the ratio of Th2/Th1 decreased from 4.05 ± 0.38 to 1.69 ± 0.19. Maillard reaction masked the B cell epitopes of TM and retained some T cell epitopes. Potentially, Maillard reaction products (MRPs) can be used as tolerance inducers for allergen-specific immunotherapy.

No abstract