Comparative mass spectrometry analysis of N-glycans from the glycoproteins of eight allergy-inducing plants

Extensive cross-allergic reactivity exists among food-borne plants. As most allergens are glycoproteins, protein sensitization has been extensively studied. However, little attention has been given to the glycan component of glycoproteins. Here, we qualitatively and quantitatively compared the N-glycans of eight cross-reactive plant glycoproteins derived from peach pollen, soy, pine nut, cashew nut, pistachio, walnut, almond, and hazelnut. Cross-reactive carbohydrate determinants (CCDs) were widely present in the allergic glycoproteins according to the following order: pollen > soybean > pistachios > pine nuts > walnuts > cashews > hazelnuts > almonds. The N-glycan structure presented clear differences between the germplasm and vegetative tissue. Importantly, fucosylation and xylosylation levels correlated positively with extensive cross-reactivity between plants, which suggests that CCDs may be one of the causes of cross-allergy. This result provides the foundation for mechanistic studies on plant-derived CCDs as a source of food cross-allergies.