Proteomic Profiling of Celiac-Toxic Motifs and Allergens in Cereals Containing Gluten

Cereal-based foods
can cause immune-mediated adverse reactions,
including celiac disease and IgE-mediated allergies, but the potency
of different cereal species to cause such reactions appears to vary,
with oats being less celiac-toxic and allergenic than wheat. In order
to define differences in the immunological potential of wheat, barley,
rye, and oats, proteomic profiling of proteins carrying celiac-toxic
motifs and allergens has been undertaken. Total protein extracts were
subjected to chymotryptic digestion and analyzed using data-independent
ion mobility mass spectrometry and a pipeline employing a curated
gluten protein sequence database. Depending on the cereal species,
376–2769 proteins were identified, the majority being grain
storage proteins. Relative quantitation of proteins containing celiac-toxic
motifs showed that they were most abundant and diverse in wheat, with
only a limited number, at much lower abundance, identified in oats.
Allergens belonging to the seed storage prolamins were the most abundant,
while allergens belonging to the α-amylase/trypsin inhibitor
family associated with respiratory allergy were of only moderate abundance
in comparison. Wheat allergen homologues were identified in other
cereal species but at a very low level in oats. These data suggest
that the relative risk of oats in the context of both celiac disease
and IgE-mediated allergy is low.