Reduced Allergenicity of Shrimp (Penaeus vannamei) by Altering the Protein Fold, Digestion Susceptibility, and Allergen Epitopes

Abstract

The mechanism by which thermal/pressure processing influences the allergenicity of shrimp (Penaeus vannamei) was explored by anaphylaxis in mice, the protein structure, gastrointestinal digestion, and linear epitopes. Roasting induced the unfolding of the structure, which may reduce the allergenicity, but it made more linear epitopes to be exposed, causing mice to exhibit similar systemic anaphylaxis as mice fed with the raw shrimp protein (p > 0.05). However, the roasted + reverse-pressure-sterilized shrimp can significantly reduce specific antibodies, mast cell degranulation, vascular permeability, and histopathological morphology in mice compared with the raw and roasted shrimp (p < 0.05) because reverse-pressure sterilization causes protein to aggregate, hiding the heat/digested stable epitopes of arginine kinase (Glu59-Ser63, Asn112-Lys118, Leu131-Phe136, and Ser158-Glu162) and sarcoplasmic calcium-binding protein (Asn57-Phe67, Ser159-Cys165, and Glu126-Ala130) inside a 3D structure, while gastrointestinal digestion can destroy immunodominant, minor epitopes and the epitopes exposed by roasting. Meanwhile, the low binding frequency of IgE to troponin C was also responsible for maintaining the hypoallergenicity of shrimp.

Digestion-Resistant Linear Epitopes as Dominant Contributors to Strong Allergenicity of Tropomyosin in Antarctic Krill (Euphausia superba)

“…The anaphylactic degree of mice in the TM-I group was the most serious, which indicated that TM has strong sensitizing potential. It may cause the occurrence of Th2-type immune response when it entered the mice body, disrupting the immune balance and then inducing B cells to produce a large number of specific antibodies . However, the levels of specific antibodies in the serum of mice were significantly reduced by gavage, suggesting that the allergenicity of TM may be impaired by gastrointestinal digestion.…”

“…The morphology of mast cells during anaphylaxis was observed by staining paraffin sections of mice spleen with toluidine blue, and morphometric analysis of degranulation was performed . Six toluidine blue-stained sections of the same mouse spleen were taken, and degranulated mast cells were counted in six different fields of each section, calculated as follows degranulated mast cells false( % false) = D 1 / D 0 × 100 % where D 1 refers to the number of degranulated mast cells in each section, and D 0 refers to the number of all mast cells in each section.…”

“…Based on the method of Liu et al., the TM samples before and after digestion were successively diluted into five concentration gradients of 0.1, 0.2, 0.3, 0.4, and 0.5 mg/mL, respectively. ANS was mixed into the samples as a fluorescence probe and reacted in the dark for 15 min.…”

Characterization and Hydrolysis Mechanism Analysis of a Cold-Adapted Trypsin-Like Protease from Antarctic Krill

“…Arginine kinase is recognized as an allergenic protein found in multiple crustacean sources, including different species of shrimp 46 and crab. 47 Bioinformatics tools predicted linear allergen epitopes of arginine kinase in P. vannamei 48,49 The predictions of the disruption of the linear epitopes of arginine kinase by OUC-Pp-20 are annotated in Figure 8B. Therefore, OUC-Pp-20 holds broad prospective applications in reducing the allergenicity of arginine kinase in shrimp and crab.…”

Dual Action of Reduced Allergenicity and Improved Memory of Instant Soybean Powder Hydrolysates

“…The protocol for animal sensitization experiments was derived from the methods of Li et al and Liu et al, with little modification. , BALB/c mice were randomly divided into 4 groups ( n = 10), named blank control group (BC), ISP group, ISPH group, and commercially available soy peptide group (CASP). The mice were treated by gavage administration on days 0, 7, 14, 21, and 28 of the experiment, in which mice in the BC group were treated with only 500 μL of saline solution, and the remaining three groups received 5 mg protein equivalents of the tested samples, respectively.…”