Comparison of Allergenicity at Gly m 4 and Gly m Bd 30K of Soybean after Genetic Modification

Abstract

Despite rapid growth of genetically modified (GM) crops, effective evaluations of genetic modification on allergenicity are still lacking. Gly m Bd 30K is cross-reactive with cow's milk protein casein, Gly m 4, and with birch pollen allergen Bet v 1. Here we compared the allergenicity between GM and non-GM soybeans with respect to the foci Gly m 4 and Gly m Bd 30K. Recombinant allergens of Gly m Bd 30K and Gly m 4 were generated and polyclonal antibodies raised to identify these two allergenic components in soybeans. GM soybean was first PCR-confirmed using 35S promoter. A total of 20 soybeans (half GM, half non-GM) obtained from a food market were used to assess their allergenicity based on IgE-binding and histamine release. The concentrations of Gly m Bd 30K and Gly m 4 in soybeans were then determined. Most soybean-allergic patients (9 of 10) showed IgE-positive reactions to the allergen of 30 kDa in molecular weight. That allergen turned out to be Glycine max Gly m Bd 30K based on LC-MS/MS analyses. Gly m Bd 30K is therefore the major allergen in the soybean. An increase in the transcription of both the Gly m 4 (stress-induced protein SAM22) and Gly m Bd 28K (soybean allergen precursor) was found after genetic modification. The protein concentrations of Gly m 4 and Gly m Bd 30K were not statistically significant different between non-GM and GM soybeans. There were also no statistical significances between them in the tests of IgE binding and histamine release. In conclusion, soybeans showed similar concentrations of Gly m Bd 30K and Gly m 4 regardless of genetic modification or absence thereof. The allergenicity of both Gly m Bd 30K and Gly m 4 was therefore not altered after genetic modification. Patients showing hypersensitivity to soybeans and who had pre-existing allergy to birch pollen and cow's milk casein might not further increase their allergic reactions following exposures to the GM soybeans.

From proteomics to ionomics: Soybean genetic improvement for better food safety

“…The expression of the P34 allergen protein has also been monitored in the widely grown genetically modified soybeans: No difference between conventional (non-GM) and genetically modified (glyphosate tolerant) soybean was found in gene expression of the P34 allergen in a recent study which also confirmed the immunodominant character of the P34 allergen (TSAI et al, 2017).…”

Food Safety Assessment of Commercial Genetically Modified Soybeans in Rats

“…Non-GM soybeans (imported from DG Global Inc., Toronto, ON, Canada) and two GM soybeans (GM-1 and GM-2 samples, imported from the United States) were purchased from retailers in Taiwan. The soybeans were fully matured at the R8 stage before harvest and then export to Taiwan [ 17 ]. Soybean samples were steamed for 20 min at 121 °C by autoclave and then dried for 24–72 h in a dryer.…”

“…The allergenicity is compared between transgenic and conventional soybeans with respect to the foci Gly m 4 and Gly m Bd 30K in human serum. Patients allergic to soy and those with a history of hypersensitivity to birch pollen and bovine casein might not experience further increased allergic reactions after exposure to GM soybeans [ 17 ].…”

Soybean (Glycine max) allergens─A Review on an Outstanding Plant Food with Allergenic Potential

“…According to several studies, − Gly m Bd 30K/P34, Gly m Bd 28K/P28, and Gly m 5 are classified as major soybean allergens. In contrast, Lu et al and Holzhauser et al only recognized Gly m 5 and Gly m 6 as clinically relevant soybean allergens and classified Gly m Bd 30K/P34, Gly m Bd 28K/P28, lectin, and the lipoxygenase as putative allergens only.…”