In order to investigate the effects of tea polyphenols on the conformation and antigenicity of α_s1-casein, epigallocatechin gallate (EGCG) and epigallocatechin (EGC), tea polyphenols with high bioactivity, were used for grafting onto α_s1-casein. The conformational changes of α_s1-casein were studied by fluorescence, synchronous fluorescence and circular dichroism (CD) spectroscopy, and the changes in the antigenicity of α_s1-casein were analyzed by indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and Western blot assay. The results showed that EGC and EGCG both quenched the fluorescence of α_s1-casein, and affected the Tyr and Trp residues of α_s1-casein. The α-helix and β-sheet contents of α_s1-casein increased slightly, and the random coil content decreased slightly. The conformational change of α_s1-casein resulted in a significant decrease in the antigenicity of α_s1-casein. The effect of EGCG on the conformation and antigenicity of α_s1-casein was stronger than that of EGC.

To investigate the effect of thermal processing on the conformation and antigenicity of bovine milk α_s1-casein, the changes in the immunogenicity of α_s1-casein under different heating conditions were analyzed by indirect competitive enzyme immunosorbent assay (icELISA) and Western blotting (WB) methods, and then the secondary structure changes were analyzed by fluorescence spectroscopy using 8-anilino-1-naphthalenesulfonic acid (ANS) as a probe and circular dichroism spectroscopy to preliminarily reveal the regulatory mechanism of heat treatment on the antigenicity of α_s1-casein. The results showed that the α-helix content of α_s1-casein significantly decreased after treatment at 80 ℃ for 60 min, 90 ℃ for 10 min or 90 ℃ for 60 min compared with the untreated control, whereas the random coil content increased significantly after treatment at 70 ℃ for 20 min, 80 ℃ for 20 min or 90 ℃ for 20 min. The surface flourescence intensity was the strongest after heating treatment at 70—100 ℃ for 20 min, while the secondary structure changes were not significant under other heating conditions. The conformational changes of α_s1-casein led to a significant decrease in the antigenicity of α_s1-casein. The icELISA showed that the residual antigenicity of α_s1-casein was the highest after heating treatment at 70—100 ℃for 20 min, while the WB results showed that α_s1-casein still had immunoreactive properties under all heating conditions. It is suggested to further reveal the regulatory mechanism of heat treatment on the antigenicity of α_s1-casein through animal tests.

The aim of this study was to explore a method for screening for proteases specifically hydrolyzing the epitopes of α_s1-casein. First, the epitope aa 83–105 of α_s1-casein was synthesized by solid-phase synthesis method. After purification and identification, the peptide was coupled to bovine serum albumin (BSA) to prepare a complete antigen, and then BALB/c mice were immunized to prepare monoclonal antibodies. In addition, an indirect competitive enzyme linked immunosorbent assay (ELISA) was established. The monoclonal antibody prepared with α_s1-casein and the established method were regarded as controls. The results showed that the purity of the synthetic epitope was over 90%, and the coupling rate with BSA was 6.31. The monoclonal antibody belonged to IgG₁, with a titer of 1:320000, and it could react specifically with α_s1-casein, but did not cross-react with soybean protein. The linear regression equation of the competitive inhibition curve was y = - 9.22x + 100.78 (R² = 0.9891). The indirect competitive ELISA method showed good repeatability and accuracy, and its detection limit was lower than that of the monoclonal antibody method. The amounts of residual antigen in papain and alcalase hydrolysates were relatively small, which needs to be further verified by in vivo test. The successful preparation of G₁ monoclonal antibody against α_S1-casein epitope aa 83–105 provides a specialized tool for ELISA detection of antigen residues and for the development of hypoallergenic formula.

Mango (Mangifera indica L.) is a tropical fruit that is widely consumed as both fresh fruits and processed products around the world. The high incidence of mango allergy, on the other hand, has sparked widespread concern. Therefore, a summary and analysis of the current status and issues in mango allergen research can guide in-depth study on the mechanism of mango allergy and reveal effective desensitization methods. We described the incidence of fruit allergy, as well as the mechanism and clinical symptoms of mango allergy, in this review. We also looked into the structural properties of mango allergens, the effect of processing methods on mango allergens, prediction methods for mango allergen epitopes, and the current state of research on mango cross-reactive allergens and preventive measures. Finally, the research directions and ideas for the future are proposed and discussed.

To investigate the anti-α_s1-casein allergy mechanism of two tea-derived polyphenols, epigallocatechin (EGC) and epigallocatechin gallate (EGCG), BALB/c mice were sensitized and challenged with α_s1-casein and nutritional intervention was given by EGC and EGCG during the sensitization provocation phase. The main evaluation indexes used were levels of mast cell proteases, histamine, and specific antibody immunoglobulin E (IgE), as well as cytokine secretion and pathological observation. The results showed that both EGC and EGCG significantly reduced levels of mast cell protease, histamine, specific IgE antibodies, and Th2 cytokines in allergic mice. The histopathology results showed that both EGC and EGCG markedly reduced the degree of lesions in the intestine, thymus, spleen, and lung. The conclusions from this study can provide a theoretical basis for the mechanism by which tea polyphenols regulate food allergens.

α_s1-Casein is a potential allergen to induce hypersensitivity in cow milk. We had identified α_s1-casein and its epitopes in previous studies. The present study aimed to evaluate the allergic mechanism of α_s1-casein in a BALB/c mouse model. The levels of specific IgE, mast cell proteinase, histamine and cytokines in sensitized mice were determined, and the clinical and pathological observation were evaluated. Results showed that the levels of specific IgE, mast cell proteinase, histamine, IL-4, IL-5, IL-10 increased significantly with a dose-dependent trend. The local alveolar septum collapsed or thickened, and lymphatic foci were produced in the spleen and thymus, and the inflammatory cells infiltrated in small intestinal mucosa mesenchyme. In conclusion, the levels of specific IgE, mast cell proteinase, histamine, IL-4, IL-5, IL-10 and some inflammatory factors could possibly serve as allergic biomarkers of α_s1-casein, however, additional studies on signal transduction and gene expression are necessary in future.