Natural Shrimp (Litopenaeus vannamei) Tropomyosin Shows Higher Allergic Properties than Recombinant Ones as Compared through SWATH-MS-Based Proteomics and Immunological Response

Abstract

Tropomyosin (TM) is the major shrimp allergen that could trigger anaphylactic reactions. Recently, recombinant TM (rTM) has been accepted widely in the field of allergen-specific immunotherapy, but the allergenicity of rTM has not been compared with natural TM (nTM) based on an in vitro digestion profile. In this work, IgG-/IgE binding, allergen peptides, and degranulation ability of the digested samples in simulated gastric fluid/simulated intestinal fluid/gastrointestinal models from nTM and rTM were evaluated by immunoassays, proteomics, and basophil degranulation assay. Results showed that pepsin-digested and trypsin-digested samples of rTM exhibited lower IgG-/IgE binding and degranulation than those of nTM. More peptides of the digested samples from rTM (57.8%) matched shrimp allergic epitopes than those from nTM (33.3%). However, the peptide SITDELDQTF (269− 278) appeared most frequently. These findings would supply foundation data for epitope-based immunotherapy to shrimp allergic individuals.

Identification of the Dominant T-Cell Epitopes of Lit v 1 Shrimp Major Allergen and Their Functional Overlap with Known B-Cell Epitopes

“…Lit v 1 was purified from raw shrimp muscles as described . The anti-Lit v 1 IgG was obtained from Lit v 1-immunized mouse sera and purified by a Protein A Sepharose Column . Goat anti-mouse IgG, goat anti-mouse IgE, and goat anti-human IgE antibodies were purchased from Zhongshan Jinqiao Co. (Beijing, China).…”

“…ELISA assay was carried out as described . In brief, plate wells were coated with either 30 μg of synthetic peptides, 3 μg Lit v 1 (positive control), or 3 μg bovine serum albumin (BSA, negative control) in PBS (pH 7.4) by an overnight incubation at 4 °C followed by several washes with PBST.…”

“…The RBL-2H3 cells were cultured in DMEM medium with 10% FBS and 1% penicillin–streptomycin at 37 °C in a humidified incubator with 5% CO 2 as described. , The cells were seeded in a 96-well plate (1 × 10 6 cells/mL) and passively primed with Lit v 1-sensitized mouse sera IgE (1:15 dilution in culture medium). After 24 h, the medium was replaced by Tyrode’s buffer containing each of the synthetic peptides (200 μg/mL), Lit v 1 (20 μg/mL, positive control), Compound 48/80 (20 μg/mL, positive control), or none (negative control).…”

Identification of linear epitopes and their major role in the immunoglobulin E-binding capacity of tropomyosin from Alectryonella plicatula

“…1-2), twelve oyster-sensitive patients (no. [3][4][5][6][7][8][9][10][11][12][13][14], and five scallop-sensitive patients with positive ATM specific-IgE (no. [15][16][17][18][19] were stored at −80 °C until further use.…”

“…6 Among them, allergens in crustacean aquatic products have been widely identified, including the gene sequence information, physicochemical characteristics, structural characteristics, and antigenic epitopes. [7][8][9] However, there are relatively few studies on allergens in molluscan aquatic products.…”