Detection and Characterization of the Soybean Allergen Gly m 7 in Soybeans and Processed Soybean Foods

Gly m 7, a novel soybean allergen, was recently reported. In this study, we attempted to detect Gly m 7 in various soybeans and processed soybean foods using raised anti-Gly m 7 antibodies and enzyme-linked streptavidin, specifically binding to the biotin moiety of Gly m 7. There was a large difference in Gly m 7 levels in various soybean-processed foods. When Gly m 7 levels were determined, all cultivars contained this allergen almost completely, but the biotin moiety detected by streptavidin varied, suggesting that biotinylated levels of Gly m 7 might differ among cultivars. The thermal stability of Gly m 7 was determined by heating soybean extracts. During detection using anti-peptide antibodies, detectable intact Gly m 7 was gradually reduced by heating. Gly m 7 was not detected by peptide or biotin detection in worm-wounded soybeans. Soybeans were immersed in distilled water as a pretreatment step for germination, and Gly m 7 levels were compared by immersion time (4–96 h). Intact Gly m 7 was rapidly degraded in detection by both peptide and biotin moieties. This suggested that Gly m 7 was degraded by some protease(s) during germination. These results would be useful for understanding the properties or risk assessment of Gly m 7, a newly discovered soybean allergen.

Investigation of Sensitization Potential of the Soybean Allergen Gly m 4 by Using Caco-2/Immune Cells Co-Culture Model

The soybean allergen Gly m 4 is known to cause severe allergic reactions including anaphylaxis, unlike other Bet v 1 homologues, which induce mainly local allergic reactions. In the present study, we aimed to investigate whether the food Bet v 1 homologue Gly m 4 can be a sensitizer of the immune system. Susceptibility to gastrointestinal digestion was assessed in vitro. Transport through intestinal epithelium was estimated using the Caco-2 monolayer. Cytokine response of different immunocompetent cells was evaluated by using Caco-2/Immune cells co-culture model. Absolute levels of 48 cytokines were measured by multiplex xMAP technology. It was shown that Gly m 4 can cross the epithelial barrier with a moderate rate and then induce production of IL-4 by mature dendritic cells in vitro. Although Gly m 4 was shown to be susceptible to gastrointestinal enzymes, some of its proteolytic fragments can selectively cross the epithelial barrier and induce production of Th2-polarizing IL-5, IL-10, and IL-13, which may point at the presence of the T-cell epitope among the crossed fragments. Our current data indicate that Gly m 4 can potentially be a sensitizer of the immune system, and intercommunication between immunocompetent and epithelial cells may play a key role in the sensitization process.

Levels of Airborne Soybean Allergen (Gly m 1) in a Brazilian Soybean Production City: A Pilot Study

Asthma epidemics have been shown to be related to where soybeans are loaded and handled, but data are scarce in the literature. This pilot study evaluated the levels of Gly m 1 in dust samples collected in Maringá, Brazil, a city with high soy production and processing. A dust impactor was used to collect seven isolated samples during 2015 and 2016. Samples were analyzed by an ELISA (enzyme-linked immunosorbent assay) detection method. Gly m 1 was found in all samples, ranging from 0.82–24.38 ng/m3 (median 2.41), regardless of the month or year evaluated. The levels of Gly m 1 were considered low, but the concentrations required to cause sensitization and symptoms are uncertain.

Comparison of Various Soybean Allergen Levels in Genetically and Non-Genetically Modified Soybeans

Several analyses of allergen levels have been reported as part of the safety assessment of genetically modified (GM) soybean; however, few comprehensive analyses have included new allergens. Thus, in this study the levels of eight major soybean allergens, including Gly m 7 (a newly reported soybean allergen), were semi-quantitatively detected in six GM soybeans and six non-GM soybeans using antigen-immobilized ELISA and immunoblotting. We also analyzed the IgE-reactivity to these soybeans through immunoblotting, using sera from three soybean-allergic patients. The results showed that there were no significant differences in the levels of the major soybean allergens in the GM and non-GM soybeans. Moreover, there were no significant differences in the serum IgE-reactive protein profiles of the patients, as analyzed using immunoblotting. These results indicate that, in general, CP4-EPSPS-transfected GM soybeans are not more allergenic than non-GM soybeans.

Fructooligosaccharide Inhibits the Absorption of β-conglycinin (A Major Soybean Allergen) in IPEC-J2

Dissecting the inhibited variation of allergen absorption could contribute to the development of novel therapeutic or preventive treatments for food/feed allergies. This study investigated the effects of fructooligosaccharide (FOS) on the absorption, intracellular accumulation of intact or hydrolysed β-conglycinin in porcine intestinal epithelial cells (IPEC-J2). As demonstrated by ELISA and immunoblotting, β-conglycinin was absorbed in a dose- and time-dependent manner (p < 0.05). Actually, β-conglycinin was easily transported and absorbed after enzymatic hydrolysis. Three peptides (52 kDa, 30 kDa and 25 kDa) were produced during transcellular absorption of intact or hydrolysed β-conglycinin. FOS inhibited the absorption of β-conglycinin, especially the 52 and 30 kDa peptides. The immunoreactive peptides derived from the 52, 35 or 22 kDa peptides were the substrings of the known epitopes determined by mass spectrometry and bioinformatic analyses. These results indicate that FOS can efficiently inhibit the absorption of 52 and 30 kDa peptides derived from β-conglycinin.